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Part V - Airworthiness Manual Chapter 523 - Normal, Utility, Aerobatic And Commuter Category Aeroplanes

Content last revised: 2009/12/01

Preamble

SUBCHAPTERS 

  • A (523.1-523.3), 
  • B (523.21-523.253), 
  • C (523.301-523.575), 
  • D (523.601-523.871), 
  • E (523.901-523.1203), 
  • F (523.1301-523.1461), 
  • G (523.1501-523.1589)

APPENDICES 

ABCDEFGHIJ

(2002/03/01;no previous version)

SUBCHAPTER A GENERAL

523.1 Applicability

(a) This chapter sets out airworthiness standards for the issue of type certificates, and changes to those type certificates, for aeroplanes in the normal, utility, aerobatic, and commuter categories.

(b) Reserved.
(amended 2009/12/01; previous version)

(Change 523-1 (88-01-01))
(Change 523-3 (92-01-02))
(Change 523-4 (96-09-01))
(Change 523-5)

523.2   Special Retroactive Requirements

(a) Subject to the requirements of CAR 605.24 and irrespective of the type certification basis, each normal, utility, and aerobatic category aeroplane having a passenger seating configuration, excluding pilot seats, of nine or less, manufactured after December 12, 1986, or any such foreign aeroplane for entry into Canada must provide a safety belt and shoulder harness for each forward or aft-facing seat which will protect the occupant from serious head injury when subjected to the inertia loads resulting from the ultimate static load factors prescribed in 523.561 (b) (2) of this chapter, or which will provide the occupant protection specified in 523.562 of this chapter when that section is applicable to the aeroplane. For other seat orientation, the seat/restraint system must be designed to provide a level of occupant protection equivalent to that provided for forward of aft-facing seats with a safety belt and shoulder harness installed.

(b) Each shoulder harness installed at a flight crew member station, as required by this section, must allow the crew member, when seated with the safety belt and shoulder harness fastened, to perform all functions necessary for flight operations.

(c) For the purpose of this section, the date of manufacture is:

(1) The date the statement of conformity or equivalent inspection acceptance records, reflects that the aeroplane is complete and meets the type design data approved by the Minister; or

(2) In the case of a foreign manufactured aeroplane, the date the foreign civil airworthiness authority certifies the aeroplane is complete and issues an original standard airworthiness certificate, or the equivalent in that country.

(Change 523-1 (88-01-01))
(Change 523-2 (89-01-01))
(Change 523-3 (92-01-02))
(Change 523-5)

523.3   Aeroplane Categories

(a) The normal category is limited to aeroplanes that have a seating configuration, excluding pilot seats, of nine or less, a maximum certificated takeoff weight of 5700 kg (12,566 lbs.) or less, and intended for non-aerobatic operation. Non-aerobatic operation includes:

FAR:

(a) The normal category is limited to airplanes that have a seating configuration, excluding pilot seats of nine or less, a maximum certificated takeoff weight of 12,500 lbs (5670 kg) or less, and intended for non-acrobatic operation. Non- acrobatic operation includes:

(1) Any manoeuvre incident to normal flying;

(2) Stalls (except whip stalls); and

(3) Lazy eights, chandelles, and steep turns, in which the angle of bank is not more than 60°.

(b) The utility category is limited to aeroplanes that have a seating configuration, excluding pilot seats, of nine or less, a maximum certificated takeoff weight of 5700 kg (12,566 lbs.) or less, and intended for limited aerobatic operation.  Aeroplanes certificated in the utility category may be used in any of the operations covered under paragraph (a) of this section and in limited aerobatic operations. Limited aerobatic operation includes:

FAR:

(b) The utility category is limited to airplanes that have a seating configuration, excluding pilot seats, of nine or less, a maximum certificated takeoff weight of 12,500 lbs (5670 kg) or less, and intended for limited acrobatic operation.  Airplanes certificated in the utility category may be used in any of the operations covered under paragraph (a) of this section and in limited acrobatic operations.  Limited acrobatic operation includes:

(1) Spins (if approved for the particular type of aeroplane); and

(2) Lazy eights, chandelles, and steep turns, or similar manoeuvres, in which the angle of bank is more than 60 degrees but not more than 90 degrees.

(c) The aerobatic category is limited to aeroplanes that have a seating configuration, excluding pilot seats, of nine or less, a maximum certificated takeoff weight of 5700 kg (12,566 lbs.) or less, and intended for use without restrictions, other than those shown to be necessary as a result of required flight tests.

FAR:

(c) The acrobatic category is limited to airplanes that have a seating configuration, excluding pilot seats, of nine or less, a maximum certificated takeoff weight of 12,500 lbs (5670 kg) or less, and intended for use without restrictions, other than those shown to be necessary as a result of required flight tests.

(d) The commuter category is limited to propeller-driven, multi-engine aeroplanes that have a seating configuration, excluding pilot seats, of 19 or less, and a maximum certificated takeoff weight of 8618 kg (19,000 lbs.) or less. The commuter category operation is limited to any manoeuvre incident to normal flying, stalls (except whip stalls), and steep turns, in which the angle of bank is not more than 60 degrees.

(e) Except for commuter category, aeroplanes may be type certificated in more than one category if the requirements of each requested category are met.

(Change 523-1 (88-01-01))
(Change 523-5)

SUBCHAPTER B FLIGHT - GENERAL

523.21   Proof of Compliance

(a) Each requirement of this subchapter must be met at each appropriate combination of weight and centre of gravity within the range of loading conditions for which certification is requested.  This must be shown:

(1) By tests upon an aeroplane of the type for which certification is requested, or by calculations based on, and equal in accuracy to, the results of testing; and

(2) By systematic investigation of each probable combination of weight and centre of gravity, if compliance cannot be reasonably inferred from combinations investigated.

(b) The following general tolerances are allowed during flight testing. However, greater tolerances may be allowed in particular tests (see Table below).  

Item

Tolerance

Weight.
Critical items affected by weight.
C.G.  

+ 5%, -10%
 + 5%, -1%
 + 7% total travel  

523.23   Load Distribution Limits

(a) Ranges of weights and centres of gravity within which the aeroplane may be safely operated must be established.  If a weight and centre of gravity combination is allowable only within certain lateral load distribution limits that could be inadvertently exceeded, these limits must be established for the corresponding weight and centre of gravity combinations.

(b) The load distribution limits may not exceed any of the following:

(1) The selected limits;

(2) The limits at which the structure is proven; or

(3) The limits at which compliance with each applicable flight requirement of this subchapter is shown.

(Change 523-4 (96-09-01))

523.25   Weight Limits

(a) Maximum weight. The maximum weight is the highest weight at which compliance with each applicable requirement of this chapter (other than those complied with at the design landing weight) is shown. The maximum weight must be established so that it is:

(1) Not more than the least of:

(i) The highest weight selected by the applicant; or

(ii) The design maximum weight, which is the highest weight at which compliance with each applicable structural loading condition of this Chapter (other than those complied with at the design landing weight) is shown; or

(iii) The highest weight at which compliance with each applicable flight requirement is shown, and

(2) Not less than the weight with:

(i) Each seat occupied, assuming a weight of 170 pounds for each occupant for normal and commuter category aeroplanes, and 190 pounds for utility and aerobatic category aeroplanes, except that seats other than pilot seats may be placarded for a lesser weight; and

(A) Oil at full capacity, and

(B) At least enough fuel for maximum continuous power operation of at least 30 minutes for day-VFR approved aeroplanes and at least 45 minutes for night-VFR and IFR approved aeroplanes; or

(ii) The required minimum crew, and fuel and oil to full tank capacity.

(b) Minimum weight.  The minimum weight (the lowest weight at which compliance with each applicable requirement of this Chapter is shown) must be established so that it is not more than the sum of:

(1) The empty weight determined under 523.29;

(2) The weight of the required minimum crew (assuming a weight of 170 pounds for each crew member); and

(3) The weight of:

(i) For turbojet powered aeroplanes, 5 percent of the total fuel capacity of that particular fuel tank arrangement under investigation; and

(ii) For other aeroplanes, the fuel necessary for one-half hour of operation at maximum continuous power.

(Change 523-1 (88-01-01))
(Change 523-4 (96-09-01))
(Change 523-5)

523.29   Empty Weight and Corresponding Centre of Gravity

(a) The empty weight and corresponding centre of gravity must be determined by weighing the aeroplane with:

(1) Fixed ballast;

(2) Unusable fuel determined under 523.959; and

(3) Full operating fluids, including:

(i) Oil;

(ii) Hydraulic fluid; and

(iii) Other fluids required for normal operation of aeroplane systems, except potable water, lavatory precharge water, and water intended for injection in the engines.

(b) The condition of the aeroplane at the time of determining empty weight must be one that is well defined and can be easily repeated.

523.31   Removable Ballast

Removable ballast may be used in showing compliance with the flight requirement of this subchapter, if:

(a) The place for carrying ballast is properly designed and installed, and is marked under 523.1557; and

(b) Instructions are included in the Aeroplane Flight Manual, approved manual material, or markings and placards, for the proper placement of the removable ballast under each loading condition for which removable ballast is necessary.

523.33   Propeller Speed and Pitch Limits

(a) General.  The propeller speed and pitch must be limited to values that will assure safe operation under normal operating conditions.

(b) Propellers not controllable in flight.  For each propeller whose pitch cannot be controlled in flight:

(1) [During takeoff and initial climb at the all engine(s) operating climb speed specified in 523.65, the propeller must limit the engine r.p.m., at full throttle or at maximum allowable takeoff manifold pressure, to a speed not greater than the maximum allowable takeoff r.p.m.; and

(2) [During a closed throttle glide, at VNE, the propeller may not cause an engine speed above 110 percent of maximum continuous speed.

(c) Controllable pitch propellers without constant speed controls.  Each propeller that can be controlled in flight, but that does not have constant speed controls, must have a means to limit the pitch range so that:

(1) The lowest possible pitch allows compliance with paragraph (b) (1) of this section; and

(2) The highest possible pitch allows compliance with paragraph (b) (2) of this section.

(d) Controllable pitch propellers with constant speed controls.  Each controllable pitch propeller with constant speed controls must have:

(1) With the governor in operation, a means at the governor to limit the maximum engine speed to the maximum allowable takeoff r.p.m.; and

(2) With the governor inoperative, the propeller blades at the lowest possible pitch, with takeoff power, the aeroplane stationary, and no wind, either:

(i) A means to limit the maximum engine speed to 103 percent of the maximum allowable takeoff r.p.m., or

(ii) For an engine with an approved overspeed, a means to limit the maximum engine and propeller speed to not more than the maximum approved overspeed.

(Change 523-4 (96-09-01))
(Change 523-5)

Performance

523.45   General

(a) Unless otherwise prescribed, the performance requirements of this chapter must be met for:

(1) Still air and standard atmosphere; and

(2) Ambient atmospheric conditions, for commuter category aeroplanes, for reciprocating engine-powered aeroplanes of more than 6,000 pounds maximum weight, and for turbine engine-powered aeroplanes.

(b) Performance data must be determined over not less than the following ranges of conditions:

(1) Airport altitudes from sea level to 10,000 feet; and

(2) For reciprocating engine-powered aeroplanes of 6,000 pounds, or less, maximum weight, temperature from standard to 30ºC above standard; or

(3) For reciprocating engine-powered aeroplanes of more than 6,000 pounds maximum weight and turbine engine-powered aeroplanes, temperature from standard to 30ºC above standard, or the maximum ambient atmospheric temperature at which compliance with the cooling provisions of 523.1041 to 523.1047 is shown, if lower.

(c) Performance data must be determined with the cowl flaps or other means for controlling the engine cooling air supply in the position used in the cooling tests required by 523.1041 to 523.1047.

(d) The available propulsive thrust must correspond to engine power, not exceeding the approved power, less:

(1) Installation losses; and

(2) The power absorbed by the accessories and services appropriate to the particular ambient atmospheric conditions and the particular flight condition.

(e) The performance, as affected by engine power or thrust, must be based on a relative humidity:

(1) Of 80 percent at and below standard temperature; and

(2) From 80 percent, at the standard temperature, varying linearly down to 34 percent at the standard temperature plus 50ºF.

(f) Unless otherwise prescribed, in determining the takeoff and landing distances, changes in the aeroplane's configuration, speed, and power must be made in accordance with procedures established by the applicant for operation in service. These procedures must be able to be executed consistently by pilots of average skill in atmospheric conditions reasonably expected to be encountered in service.

(g) The following, as applicable, must be determined on a smooth, dry, hard-surfaced runway:

(1) Takeoff distance of 523.53(b);

(2) Accelerate-stop distance of 523.55;

(3) Takeoff distance and takeoff run of 523.59; and

(4) Landing distance of 523.75.

Information Note:

The effect on these distances of operation on other types of surfaces (for example, grass, gravel) when dry, may be determined or derived and these surfaces listed in the Aeroplane Flight Manual in accordance with 523.1583(p).

(h) For commuter category aeroplanes, the following also apply:

(1) Unless otherwise prescribed, the applicant must select the takeoff, en route, approach, and landing configurations for the aeroplane.

(2) The aeroplane configuration may vary with weight, altitude, and temperature, to the extent that they are compatible with the operating procedures required by paragraph (h)(3) of this section.

(3) Unless otherwise prescribed, in determining the critical-engine-inoperative take-off performance, takeoff flight path, and accelerate-stop distance, changes in the aeroplane's configuration, speed, and power must be made in accordance with procedures established by the applicant for operation in service.

(4) Procedures for the execution of discontinued approaches and balked landings associated with the conditions prescribed in 523.67(c)(4) and 523.77(c) must be established.

(5) The procedures established under paragraphs (h)(3) and (h)(4) of this section must:

(i) Be able to be consistently executed by a crew of average skill in atmospheric conditions reasonably expected to be encountered in service;

(ii) Use methods or devices that are safe and reliable; and

(iii) Include allowance for any reasonably expected time delays in the execution of the procedures.

(Change 523-1 (88-01-01))
(Change 523-4 (96-09-01))
(Change 523-5)

523.49   Stalling Speed
(amended 2005/06/03; previous version)

(a) VSO and VS1 are the stalling speeds, or the minimum steady speed flight speeds, in knots (CAS), at which the aeroplane is controllable, with:

(1) For reciprocating engine-powered aeroplanes, the engine(s) idling, the throttle(s) closed or at not more than the power necessary for zero thrust at a speed not more than 110 percent of the stalling speed;

(2) For turbine engine-powered aeroplanes, the propulsive thrust not greater than zero at the stalling speed, or, if the resultant thrust has no appreciable effect on the stalling speed, with engine(s) idling and throttle(s) closed;

(3) The propeller(s) in the takeoff position;

(4) The aeroplane in the condition existing in the test, in which VSO and VS1 are being used;

(5) The centre of gravity in the position that results in the highest value of VSO and VS1; and

(6) The weight used when VSO and VS1 are being used as a factor to determine compliance with a required performance standard.

(b) VSO and VS1 must be determined by flight tests, using the procedure and meeting the flight characteristics specified in 523.201.

(c) Except as provided in paragraph (d) of this section, VSO and VS1 at maximum weight must not exceed 61 knots for:

(1) Single-engine aeroplanes; and

(2) Multi-engine aeroplanes of 6,000 pounds or less maximum weight that cannot meet the minimum rate of climb specified in 523.67(a)(1) with the critical engine inoperative.

(d) All single-engine aeroplanes, and those multi-engine aeroplanes of 6,000 pounds or less maximum weight with a VSO of more than 61 knots that do not meet the requirements of 523.67(a)(1), must comply with 523.562(d).

(Change 523-1 (88-01-01))
(Change 523-4 (96-09-01))
(Change 523-5)

523.51   [Takeoff Speeds

(a) For normal, utility, and aerobatic category aeroplanes, rotation speed, VR, is the speed at which the pilot makes a control input, with the intention of lifting the aeroplane out of contact with the runway or water surface.

(1) For multi-engine landplanes, VR, must not be less than the greater of 1.05 VMC; or 1.10 VS1;

(2) For single-engine landplanes, VR, must not be less than VS1; and

(3) For seaplanes and amphibians taking off from water, VR, may be any speed that is shown to be safe under all reasonably expected conditions, including turbulence and complete failure of the critical engine.

(b) For normal, utility, and aerobatic category aeroplanes, the speed at 50 feet above the takeoff surface level must not be less than:

(1) For multi-engine aeroplanes, the highest of:

(i) A speed that is shown to be safe for continued flight (or emergency landing, if applicable) under all reasonably expected conditions, including turbulence and complete failure of the critical engine;

(ii) 1.10 VMC; or

(iii) 1.20 VS1;

(2) For single-engine aeroplanes, the higher of:

(i) A speed that is shown to be safe under all reasonably expected conditions, including turbulence and complete engine failure; or

(ii) 1.20 VS1.

(c) For commuter category aeroplanes, the following apply:

(1) V1 must be established in relation to VEF as follows:

(i) VEF is the calibrated airspeed at which the critical engine is assumed to fail. VEF must be selected by the applicant but must not be less than 1.05 VMC determined under 523.149(b) or, at the option of the applicant, not less than VMCG determined under 523.149(f).

(ii) The takeoff decision speed, V1, is the calibrated airspeed on the ground at which, as a result of engine failure or other reasons, the pilot is assumed to have made a decision to continue or discontinue the takeoff. The takeoff decision speed, V1, must be selected by the applicant but must not be less than VEF plus the speed gained with the critical engine inoperative during the time interval between the instant at which the critical engine is failed and the instant at which the pilot recognizes and reacts to the engine failure, as indicated by the pilot's application of the first retarding means during the accelerate-stop determination of 523.55.

(2) The rotation speed, VR, in terms of calibrated airspeed, must be selected by the applicant and must not be less than the greatest of the following:

(i) V1;

(ii) 1.05 VMC determined under 523.149(b);

(iii) 1.10 VS1; or

(iv) The speed that allows attaining the initial climb-out speed, V2, before reaching a height of 35 feet above the takeoff surface in accordance with 523.57(c)(2).

(3) For any given set of conditions, such as weight, altitude, temperature, and configuration, a single value of VR must be used to show compliance with both the one-engine-inoperative takeoff and all-engines-operating takeoff requirements.

(4) The takeoff safety speed, V2, in terms of calibrated airspeed, must be selected by the applicant so as to allow the gradient of climb required in 523.67(c)(1) and (c)(2) but must not be less than 1.10 VMC or less than 1.20 VS1.

(5) The one-engine-inoperative takeoff distance, using a normal rotation rate at a speed 5 knots less than VR, established in accordance with paragraph (c)(2) of this section, must be shown not to exceed the corresponding one-engine-inoperative takeoff distance, determined in accordance with 523.57 and 523.59(a)(1), using the established VR. The takeoff, otherwise performed in accordance with 523.57, must be continued safely from the point at which the aeroplane is 35 feet above the takeoff surface and at a speed not less than the established V2 minus 5 knots.

(6) The applicant must show, with all engines operating, that marked increases in the scheduled takeoff distances, determined in accordance with 523.59(a)(2), do not result from over-rotation of the aeroplane or out-of-trim conditions.

(Change 523-1 (88-01-01))
(Change 523-5)

523.53   [Takeoff Performance

(a) For normal, utility, and aerobatic category aeroplanes, the takeoff distance must be determined in accordance with paragraph (b) of this section, using speeds determined in accordance with 523.51(a) and (b).

(b) For normal, utility, and aerobatic category aeroplanes, the distance required to take-off and climb to a height of 50 feet above the takeoff surface must be determined for each weight, altitude, and temperature within the operational limits established for take-off with:

(1) Takeoff power on each engine;

(2) Wing flaps in the takeoff position(s); and

(3) Landing gear extended.

(c) For commuter category aeroplanes, takeoff performance, as required by 523.55 through 523.59, must be determined with the operating engine(s) within approved operating limitations.

(Change 523-1 (88-01-01))
(Change 523-4 (96-09-01))
(Change 523-5)

523.55   Accelerate-Stop Distance

For each commuter category aeroplane, the accelerate-stop distance must be determined as follows:

(a) The accelerate-stop distance is the sum of the distances necessary to:

(1) Accelerate the aeroplane from a standing start to VEF with all engines operating;

(2) Accelerate the aeroplane from VEF to V1, assuming the critical engine fails at VEF; and

(3) Come to a full stop from the point at which V1 is reached.

(b) Means other than wheel brakes may be used to determine the accelerate-stop distances if that means:

(1) Is safe and reliable;

(2) Is used so that consistent results can be expected under normal operating conditions; and

(3) Is such that exceptional skill is not required to control the aeroplane.

(Change 523-1 (88-01-01))
(Change 523-5)

523.57   Takeoff Path

For each commuter category aeroplane, the takeoff path is as follows:

(a) The takeoff path extends from a standing start to a point in the takeoff at which the aeroplane is 1,500 feet above the takeoff surface at or below which height the transition from the takeoff to the enroute configuration must be completed; and

(1) The takeoff path must be based on the procedures prescribed in 523.45;

(2) The aeroplane must be accelerated on the ground to VEF at which point the critical engine must be made inoperative and remain inoperative for the rest of the takeoff; and

(3) After reaching VEF, the aeroplane must be accelerated to V2.

(b) During the acceleration to speed V2, the nose gear may be raised off the ground at a speed not less than VR. However, landing gear retraction must not be initiated until the aeroplane is airborne.

(c) During the takeoff path determination, in accordance with paragraphs (a) and (b) of this section:

(1) The slope of the airborne part of the takeoff path must not be negative at any point;

(2) The aeroplane must reach V2 before it is 35 feet above the takeoff surface, and must continue at a speed as close as practical to, but not less than V2, until it is 400 feet above the takeoff surface;

(3) At each point along the takeoff path, starting at the point at which the aeroplane reaches 400 feet above the takeoff surface, the available gradient of climb must not be less than:

(i) 1.2 percent for two-engine aeroplanes;

(ii) 1.5 percent for three-engine aeroplanes;

(iii) 1.7 percent for four-engine aeroplanes; and

(4) Except for gear retraction and automatic propeller feathering, the aeroplane configuration must not be changed, and no change in power that requires action by the pilot may be made, until the aeroplane is 400 feet above the takeoff surface.

(d) The takeoff path to 35 feet above the takeoff surface must be determined by a continuous demonstrated takeoff.

(e) The takeoff path to 35 feet above the takeoff surface must be determined by synthesis from segments; and

(1) The segments must be clearly defined and must be related to distinct changes in the configuration, power, and speed;

(2) The weight of the aeroplane, the configuration, and the power must be assumed constant throughout each segment and must correspond to the most critical condition prevailing in the segment; and

(3) The takeoff flight path must be based on the aeroplane's performance without utilizing ground effect.

(Change 523-1 (88-01-01))
(Change 523-5)

523.59   Takeoff Distance and Takeoff Run

For each commuter category aeroplane, the takeoff distance and, at the option of the applicant, the takeoff run, must be determined.

(a) Takeoff distance is the greater of:

(1) The horizontal distance along the takeoff path from the start of the takeoff to the point at which the aeroplane is 35 feet above the takeoff surface as determined under 523.57; or

(2) With all engines operating, 115 percent of the horizontal distance from the start of the takeoff to the point at which the aeroplane is 35 feet above the takeoff surface, determined by a procedure consistent with 523.57.

(b) If the takeoff distance includes a clearway, the takeoff run is the greater of:

(1) The horizontal distance along the takeoff path from the start of the takeoff to a point equidistant between the lift-off point and the point at which the aeroplane is 35 feet above the takeoff surface as determined under 523.57; or

(2) With all engines operating, 115 percent of the horizontal distance from the start of the takeoff to a point equidistant between the lift off point and the point at which the aeroplane is 35 feet above the takeoff surface, determined by a procedure consistent with 523.57.

(Change 523-1 (88-01-01))
(Change 523-5)

523.61   Takeoff Flight Path

For each commuter category aeroplane, the takeoff flight path must be determined as follows:

(a) The takeoff flight path begins at 35 feet above the takeoff surface at the end of the takeoff distance determined in accordance with 523.59.

(b) The net takeoff flight path data must be determined so that they represent the actual takeoff flight paths, as determined in accordance with 523.57 and with paragraph (a) of this section, reduced at each point by a gradient of climb equal to:

(1) 0.8 percent for two-engine aeroplanes;

(2) 0.9 percent for three-engine aeroplanes; and

(3) 1.0 percent for four-engine aeroplanes;

(c) The prescribed reduction in climb gradient may be applied as an equivalent reduction in acceleration along that part of the takeoff flight path at which the aeroplane is accelerated in level flight.

(Change 523-1 (88-01-01))

[523.63   Climb:  General

(a) Compliance with the requirements of 523.65, 523.66, 523.67, 523.69, and 523.77 must be shown:

(1) Out of ground effect; and

(2) At speeds that are not less than those at which compliance with the powerplant cooling requirements of 523.1041 to 523.1047 has been demonstrated; and

(3) Unless otherwise specified, with one-engine-inoperative, at a bank angle not exceeding 5 degrees.

(b) For normal, utility, and aerobatic category reciprocating engine-powered aeroplanes of 6,000 pounds or less maximum weight, compliance must be shown with 523.65(a), 523.67(a), where appropriate, and 523.77(a) at maximum takeoff or landing weight, as appropriate, in a standard atmosphere.

(c) For normal, utility, and aerobatic category reciprocating engine-powered aeroplanes of more than 6,000 pounds maximum weight, and turbine engine-powered aeroplanes in the normal, utility, and aerobatic category, compliance must be shown at weights as a function of airport altitude and ambient temperature, within the operational limits established for takeoff and landing, respectively, with:

(1) Sections 523.65(b) and 523.67(b) (1) and (2), where appropriate, for takeoff, and

(2) Section 523.67(b)(2), where appropriate, and 523.77(b), for landing.

(d) For commuter category aeroplanes, compliance must be shown at weights as a function of airport altitude and ambient temperature within the operational limits established for takeoff and landing, respectively, with:

(1) Sections 523.67(c)(1), 523.67(c) (2), and 523.67(c)(3) for takeoff; and

(2) Sections 523.67(c)(3), 523.67(c) (4), and 523.77(c) for landing.

(Change 523-5)

523.65   Climb:  All Engines Operating

(a) Each normal, utility, and aerobatic category reciprocating engine-powered aeroplane of 6,000 pounds or less maximum weight must have a steady climb gradient at sea level of at least 8.3 percent for landplanes or 6.7 percent for seaplanes and amphibians with:

(1) Not more than maximum continuous power on each engine;

(2) The landing gear retracted;

(3) The wing flaps in the takeoff position(s); and

(4) A climb speed not less than the greater of 1.1 VMC and 1.2 VS1 for multi-engine aeroplanes and not less than 1.2 VS1 for single-engine aeroplanes.

(b) Each normal, utility, and aerobatic category reciprocating engine-powered aeroplane of more than 6,000 pounds maximum weight and turbine engine-powered aeroplanes in the normal, utility, and aerobatic category must have a steady gradient of climb after take-off of at least 4 percent with:

(1) Takeoff power on each engine;

(2) The landing gear extended, except that if the landing gear can be retracted in not more than seven seconds, the test may be conducted with the gear retracted;

(3) The wing flaps in the takeoff position(s); and

(4) A climb speed as specified in 523.65(a)(4).

(Change 523-1 (88-01-01))
(Change 523-4 (96-09-01))
(Change 523-5)

523.66   Takeoff Climb:  One-Engine Inoperative

For normal, utility, and aerobatic category reciprocating engine-powered aeroplanes of more than 6,000 pounds maximum weight, and turbine engine-powered aeroplanes in the normal, utility, and aerobatic category, the steady gradient of climb or descent must be determined at each weight, altitude, and ambient temperature within the operational limits established by the applicant with:

(a) The critical engine inoperative and its propeller in the position it rapidly and automatically assumes;

(b) The remaining engine(s) at takeoff power;

(c) The landing gear extended, except that if the landing gear can be retracted in not more than seven seconds, the test may be conducted with the gear retracted;

(d) The wing flaps in the takeoff position(s);

(e) The wings level; and

(f) A climb speed equal to that achieved at 50 feet in the demonstration of 523.53.

(Change 523-5)

523.67   Climb:  One-Engine Inoperative

(a) For normal, utility, and aerobatic category reciprocating engine-powered aeroplanes of 6,000 pounds or less maximum weight, the following apply:

(1) Except for those aeroplanes that meet the requirements prescribed in 523.562(d), each aeroplane with a VSO of more than 61 knots must be able to maintain a steady climb gradient of at least 1.5 percent at a pressure altitude of 5,000 feet with the:

(i) Critical engine inoperative and its propeller in the minimum drag position;

(ii) Remaining engine(s) at not more than maximum continuous power;

(iii) Landing gear retracted;

(iv) Wing flaps retracted; and

(v) Climb speed not less than 1.2 VS1.

(2) For each aeroplane that meets the requirements prescribed in 523.562(d), or that has a VS0 of 61 knots or less, the steady gradient of climb or descent at a pressure altitude of 5,000 feet must be determined with the:

(i) Critical engine inoperative and its propeller in the minimum drag position;

(ii) Remaining engine(s) at not more than maximum continuous power;

(iii) Landing gear retracted;

(iv) Wing flaps retracted; and

(v) Climb speed not less than 1.2 VS1.

(b) For normal, utility, and aerobatic category reciprocating engine-powered aeroplanes of more than 6,000 pounds maximum weight, and turbine engine-powered aeroplanes in the normal, utility, and aerobatic category:

(1) The steady gradient of climb at an altitude of 400 feet above the takeoff must be measurably positive with the:

(i) Critical engine inoperative and its propeller in the minimum drag position;

(ii) Remaining engine(s) at takeoff power;

(iii) Landing gear retracted;

(iv) Wing flaps in the takeoff position(s); and

(v) Climb speed equal to that achieved at 50 feet in the demonstration of 523.53.

(2) The steady gradient of climb must not be less than 0.75 percent at an altitude of 1,500 feet above the takeoff surface, or landing surface, as appropriate, with the:

(i) Critical engine inoperative and its propeller in the minimum drag position;

(ii) Remaining engine(s) at not more than maximum continuous power;

(iii) Landing gear retracted;

(iv) Wing flaps retracted; and

(v) Climb speed not less than 1.2 VS1.

(c) For commuter category aeroplanes, the following apply:

(1) Takeoff; landing gear extended. The steady gradient of climb at the altitude of the takeoff surface must be measurably positive for two-engine aeroplanes, not less than 0.3 percent for three-engine aeroplanes, or 0.5 percent for four-engine aeroplanes with:

(i) The critical engine inoperative and its propeller in the position it rapidly and automatically assumes;

(ii) The remaining engine(s) at takeoff power;

(iii) The landing gear extended, and all landing gear doors open;

(iv) The wing flaps in the takeoff position(s);

(v) The wings level; and

(vi) A climb speed equal to V2.

(2) Takeoff; landing gear retracted. The steady gradient of climb at an altitude of 400 feet above the takeoff surface must be not less than 2.0 percent for two-engine aeroplanes, 2.3 percent for three-engine aeroplanes, and 2.6 percent for four-engine aeroplanes with:

(i) The critical engine inoperative and its propeller in the position it rapidly and automatically assumes;

(ii) The remaining engine(s) at takeoff power;

(iii) The landing gear retracted;

(iv) The wing flaps in the takeoff position(s);

(v) A climb speed equal to V2.

(3) Enroute. The steady gradient of climb at an altitude of 1,500 feet above the take-off or landing surface, as appropriate, must be not less than 1.2 percent for two-engine aeroplanes, 1.5 percent for three-engine aeroplanes, and 1.7 percent for four-engine aeroplanes with:

(i) The critical engine inoperative and its propeller in the minimum drag position;

(ii) The remaining engine(s) at not more than maximum continuous power;

(iii) The landing gear retracted;

(iv) The wing flaps retracted; and

(v) A climb speed not less than 1.2 VS1.

(4) Discontinued approach. The steady gradient of climb at an altitude of 400 feet above the landing surface must be not less than 2.1 percent for two-engine aeroplanes, 2.4 percent for three-engine aeroplanes, and 2.7 percent for four-engine aeroplanes, with:

(i) The critical engine inoperative and its propeller in the minimum drag position;

(ii) The remaining engine(s) at takeoff power;

(iii) Landing gear retracted;

(iv) Wing flaps in the approach position(s) in which VS1 for these position(s) does not exceed 110 percent of the VS1 for the related all-engines-operated landing position(s); and

(v) A climb speed established in connection with normal landing procedures but not exceeding 1.5 VS1.

(Change 523-1 (88-01-01))
(Change 523-3 (92-01-02))
(Change 523-4 (96-09-30))
(Change 523-5)

[523.69   Enroute Climb/Descent

(a) All engines operating. The steady gradient and rate of climb must be determined at each weight, altitude, and ambient temperature within the operational limits established by the applicant with:

(1) Not more than maximum continuous power on each engine;

(2) The landing gear retracted;

(3) The wing flaps retracted; and

(4) A climb speed not less than 1.3 VS1.

(b) One engine inoperative. The steady gradient and rate of climb/descent must be determined at each weight, altitude, and ambient temperature within the operational limits established by the applicant with:

(1) The critical engine inoperative and its propeller in the minimum drag position;

(2) The remaining engine(s) at not more than maximum continuous power;

(3) The landing gear retracted;

(4) The wing flaps retracted; and

(5) A climb speed not less than 1.2 VS1.

(Change 523-5)

[523.71   Glide:  Single-Engine Aeroplanes

The maximum horizontal distance travelled in still air, in nautical miles, per 1,000 feet of altitude lost in a glide, and the speed necessary to achieve this must be determined with the engine inoperative, its propeller in the minimum drag position, and landing gear and wing flaps in the most favourable available position.

(Change 523-5)

[523.73   Reference Landing Approach Speed

(a) For normal, utility, and aerobatic category reciprocating engine-powered aeroplanes of 6,000 pounds or less maximum weight, the reference landing approach speed, VREF, must not be less than the greater of VMC, determined in 523.149(b) with the wing flaps in the most extended takeoff position, and 1.3 VSO.

(b) For normal, utility, and aerobatic category reciprocating engine-powered aeroplanes of more than 6,000 pounds maximum weight, and turbine engine-powered aeroplanes in the normal, utility, and aerobatic category, the reference landing approach speed, VREF, must not be less than the greater of VMC, determined in 523.149(c), and 1.3 VSO.

(c) For commuter category aeroplanes, the reference landing approach speed, VREF, must not be less than the greater of 1.05 VMC, determined in 523.149(c), and 1.3 VSO.

(Change 523-5)

523.75   [Landing Distance

The horizontal distance necessary to land and come to a complete stop from a point 50 feet above the landing surface must be determined, for standard temperatures at each weight and altitude within the operational limits established for landing, as follows:

(a) A steady approach at not less than VREF, determined in accordance with 523.73(a), (b), or (c), as appropriate, must be maintained down to the 50 foot height and:

(1)  The steady approach must be at a gradient of descent not greater than 5.2 percent (3 degrees) down to the 50 foot height.

(2)  In addition, an applicant may demonstrate by tests that a maximum steady approach gradient steeper than 5.2 percent, down to the 50 foot height, is safe. The gradient must be established as an operating limitation and the information necessary to display the gradient must be available to the pilot by an appropriate instrument.

(b) A constant configuration must be maintained throughout the manoeuvre.

(c)  The landing must be made without excessive vertical acceleration or tendency to bounce, nose over, ground loop, porpoise, or water loop.

(d) It must be shown that a safe transition to the balked landing conditions of 523.77 can be made from the conditions that exist at the 50 foot height, at maximum landing weight, or at the maximum landing weight for altitude and temperature of 523.63 (c)(2) or (d)(2), as appropriate.

(e) The brakes must be used so as to not cause excessive wear of brakes or tires.

(f) Retardation means other than wheel brakes may be used if that means:

(1) Is safe and reliable; and

(2) Is used so that consistent results can be expected in service.

(g)  If any device is used that depends on the operation of any engine, and the landing distance would be increased when a landing is made with that engine inoperative, the landing distance must be determined with that engine inoperative unless the use of other compensating means will result in a landing distance not more than that with each engine operating.

(Change 523-1 (88-01-01))
(Change 523-3 (92-01-02))
(Change 523-5)

523.77   Balked Landing

(a) Each normal, utility, and aerobatic category reciprocating engine-powered aeroplane of 6,000 pounds or less maximum weight must be able to maintain a steady gradient of climb at sea level of at least 3.3 percent with:

(1) Takeoff power on each engine;

(2) The landing gear extended;

(3) The wing flaps in the landing position, except that if the flaps may safely be retracted in two seconds or less without loss of altitude and without sudden changes of angle of attack, they may be retracted; and

(4) A climb speed equal to VREF, as defined in 523.73(a).

(b) Each normal, utility, and aerobatic category reciprocating engine-powered aeroplane of more than 6,000 pounds maximum weight and each normal, utility, and aerobatic category turbine engine-powered aeroplane must be able to maintain a steady gradient of climb of at least 2.5 percent with:

(1) Not more than the power that is available on each engine eight seconds after initiation of movement of the power controls from minimum flight-idle position;

(2) The landing gear extended;

(3) The wing flaps in the landing position; and

(4) A climb speed equal to VREF, as defined in 523.73(b).

(c) Each commuter category aeroplane must be able to maintain a steady gradient of climb of at least 3.2 percent with:

(1) Not more than the power that is available on each engine eight seconds after initiation of movement of the power controls from the minimum flight idle position;

(2) Landing gear extended;

(3) Wing flaps in the landing position; and

(4) A climb speed equal to VREF, as defined in 523.73(c).

(Change 523-1 (88-01-01))
(Change 523-3 (92-01-02))
(Change 523-5)

Flight Characteristics

523.141   General

The aeroplane must meet the requirements of 523.143 through 523.253 at all practical loading conditions and operating altitudes for which certification has been requested, not exceeding the maximum operating altitude established under 523.1527, and without requiring exceptional piloting skill, alertness, or strength.

(Change 523-4 (96-09-01))

Controllability and Manoeuvrability

523.143    General

(a) The aeroplane must be safely controllable and manoeuvrable during all flight phases including:

(1) Takeoff;

(2) Climb;

(3) Level flight;

(4) Descent;

(5) Go-around; and

(6) Landing (power on and power off) with the wing flaps extended and retracted.

(b) It must be possible to make a smooth transition from one flight condition to another (including turns and slips) without danger of exceeding the limit load factor, under any probable operating condition, (including, for multi-engine aeroplanes, those conditions normally encountered in the sudden failure of any engine).

(c) If marginal conditions exist with regard to required pilot strength, the control forces necessary must be determined by quantitative tests. In no case may the control forces under the conditions specified in paragraphs (a) and (b) of this section exceed those prescribed in Table below:

[Values In Pounds Force
Applied To The Relevant Control]



Pitch



Roll



Yaw


(a) For temporary application:
Stick   
Wheel (two hands on rim)        
Wheel (one hand on rim)          
Rudder pedal   

(b) For prolonged application:           
 

60
75
50
....

10


30
[50]
[25]
....

5


....
....
....
150

20

(Change 523-4 (96-09-01))
(Change 523-5)

523.145   Longitudinal Control

(a) With the aeroplane as nearly as possible in trim at 1.3 VSl, it must be possible, at speeds below the trim speed, to pitch the nose downward so that the rate of increase in airspeed allows prompt acceleration to the trim speed with:

(1) Maximum continuous power on each engine;

(2) Power off; and

(3) Wing flap and landing gear:

(i) retracted, and

(ii) extended.

(b) Unless otherwise required, it must be possible to carry out the following manoeuvres without requiring the application of single-handed control forces exceeding those specified in 523.143(c). The trimming controls must not be adjusted during the manoeuvres:

(1) With the landing gear extended, the flaps retracted, and the aeroplane as nearly as possible in trim at 1.4 VS1, extend the flaps as rapidly as possible and allow the airspeed to transition from 1.4 VS1 to 1.4 VSO:

(i) With power off; and

(ii) With the power necessary to maintain level flight in the initial condition.

(2) With landing gear and flaps extended, power off, and the aeroplane as nearly as possible in trim at 1.3 VSO, quickly apply takeoff power and retract the flaps as rapidly as possible to the recommended go around setting and allow the airspeed to transition from 1.3 VSO to 1.3 VS1. Retract the gear when a positive rate of climb is established.

(3) With landing gear and flaps extended, in level flight, power necessary to attain level flight at 1.1 VSO, and the aeroplane as nearly as possible in trim, it must be possible to maintain approximately level flight while retracting the flaps as rapidly as possible with simultaneous application of not more than maximum continuous power. If gated flap positions are provided, the flap retraction may be demonstrated in stages with power and trim reset for level flight at 1.1 VS1, in the initial configuration for each stage:

(i) From the fully extended position to the most extended gated position;

(ii) Between intermediate gated positions, if applicable; and

(iii) From the least extended gated position to the fully retracted position.

(4) With power off, flaps and landing gear retracted and the aeroplane as nearly as possible in trim at 1.4 VS1,  apply takeoff power rapidly while maintaining the same airspeed.

(5) With power off, landing gear and flaps extended, and the aeroplane as nearly as possible in trim at VREF, obtain and maintain airspeeds between 1.1 VSO and either 1.7 VSO or VFE, whichever is lower without requiring the application of two-handed control forces exceeding those specified in 523.143(c).

(6) With maximum takeoff power, landing gear retracted, flaps in the takeoff position, and the aeroplane as nearly as possible in trim at VFE appropriate to the take-off flap position, retract the flaps as rapidly as possible while maintaining constant speed.

(c) At speeds above VMO/MMO, and up to the maximum speed shown under 523.251, a manoeuvring capability of 1.5g must be demonstrated to provide a margin to recover from upset or inadvertent speed increase.

(d) It must be possible, with a pilot control force of not more than 10 pounds, to maintain a speed of not more than VREF during a power-off glide with landing gear and wing flaps extended, for any weight of the aeroplane, up to and including the maximum weight.

(e) By using normal flight and power controls, except as otherwise noted in paragraphs (e)(1) and (e)(2) of this section, it must be possible to establish a zero rate of descent at an attitude suitable for a controlled landing without exceeding the operational and structural limitations of the aeroplane, as follows:

(1) For single-engine and multi-engine aeroplanes, without the use of the primary longitudinal control system.

(2) For multi-engine aeroplanes:

(i) Without the use of the primary directional control; and

(ii) If a single failure of any one connecting or transmitting link would affect both the longitudinal and directional primary control system, without the primary longitudinal and directional control system.

(Change 523-1 (88-01-02))
(Change 523-4 (96-09-01))
(Change 523-5)

523.147   Directional and Lateral Control

(a) For each multi-engine aeroplane, it must be possible, while holding the wings level within 5 degrees, to make sudden changes in heading safely in both directions. This ability must be shown at 1.4 VS1 with heading changes up to 15 degrees, except that the heading change at which the rudder force corresponds to the limits specified in 523.143 need not be exceeded, with the:

(1) Critical engine inoperative and its propeller in the minimum drag position;

(2) Remaining engines at maximum continuous power;

(3) Landing gear:

(i) Retracted, and

(ii) Extended; and

(4) Flaps retracted.

(b) For each multi-engine aeroplane, it must be possible to regain full control of the aeroplane without exceeding a bank angle of 45 degrees, reaching a dangerous attitude or encountering dangerous characteristics, in the event of a sudden and complete failure of the critical engine, making allowance for a delay of two seconds in the initiation of recovery action appropriate to the situation, with the aeroplane initially in trim, in the following condition:

(1) Maximum continuous power on each engine;

(2) The wing flaps retracted;

(3) The landing gear retracted;

(4) A speed equal to that at which compliance with 523.69(a) has been shown; and

(5) All propeller controls in the position at which compliance with 523.69(a) has been shown.

[(c) For all aeroplanes, it must be shown that the aeroplane is safely controllable without the use of the primary lateral control system in any all-engine configuration(s) and at any speed or altitude within the approved operating envelope. It must also be shown that the aeroplane's flight characteristics are not impaired below a level needed to permit continued safe flight and the ability to maintain attitudes suitable for a controlled landing without exceeding the operational and structural limitations of the aeroplane. If a single failure of any one connecting or transmitting link in the lateral control system would also cause the loss of additional control system(s), compliance with the above requirement must be shown with those additional systems also assumed to be inoperative.

(Change 523-4 (96-09-30))
(Change 523-5)

523.149   Minimum Control Speed

(a) VMC is the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the aeroplane with that engine still inoperative, and thereafter maintain straight flight at the same speed with an angle of bank of not more than 5 degrees. The method used to simulate critical engine failure must represent the most critical mode of powerplant failure expected in service with respect to controllability.

(b) VMC for takeoff must not exceed 1.2 VS1, where VS1 is determined at the maximum takeoff weight. VMC must be determined with the most unfavourable weight and centre of gravity position and with the aeroplane airborne and the ground effect negligible, for the takeoff configuration(s) with:

(1) Maximum available takeoff power initially on each engine;

(2) The aeroplane trimmed for takeoff;

(3) Flaps in the takeoff position(s);

(4) Landing gear retracted; and

(5) All propeller controls in the recommended takeoff position throughout.

(c)  [For all aeroplanes except reciprocating engine-powered aeroplanes of 6,000 pounds or less maximum weight, the conditions of paragraph (a) of this section must also be met for the landing configuration with:

(1) Maximum available takeoff power initially on each engine;

(2) The aeroplane trimmed for an approach, with all engines operating, at VREF, at an approach gradient equal to the steepest used in the landing distance demonstration of 523.75;

(3) Flaps in the landing position;

(4) Landing gear extended; and

(5) All propeller controls in the position recommended for approach with all engines operating.

(d) A minimum speed to intentionally render the critical engine inoperative must be established and designated as the safe, intentional, one-engine-inoperative speed, VSSE.

(e) At VMC, the rudder pedal force required to maintain control must not exceed 150 pounds and it must not be necessary to reduce power of the operative engine(s). During the manoeuvre, the aeroplane must not assume any dangerous attitude and it must be possible to prevent a heading change of more than 20 degrees.

(f) At the option of the applicant, to comply with the requirements of 523.51(c)(1), VMCG may be determined. VMCG is the minimum control speed on the ground, and is the calibrated airspeed during the takeoff run at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the aeroplane using the rudder control alone (without the use of nosewheel steering), as limited by 150 pounds of force, and using the lateral control to the extent of keeping the wings level to enable the takeoff to be safely continued. In the determination of VMCG, assuming that the path of the aeroplane accelerating with all engines operating is along the centreline of the runway, its path from the point at which the critical engine is made inoperative to the point at which recovery to a direction parallel to the centreline is completed may not deviate more than 30 feet laterally from the centreline at any point.  VMCG must be established with:

(1) The aeroplane in each takeoff configuration or, at the option of the applicant, in the most critical takeoff configuration;

(2) Maximum available takeoff power on the operating engines;

(3) The most unfavourable centre of gravity;

(4) The aeroplane trimmed for takeoff; and

(5) The most unfavourable weight in the range of takeoff weights.

(Change 523-4 (96-09-01))
(Change 523-5)

523.151   Aerobatic Manoeuvres

Each aerobatic and utility category aeroplane must be able to perform safely the aerobatic manoeuvres for which certification is requested. Safe entry speeds for these manoeuvres must be determined.

523.153   Control During Landings

It must be possible, while in the landing configuration, to safely complete a landing without exceeding the one-hand control force limits specified in 523.143(c) following an approach to land:

(a) At a speed of VREF minus 5 knots;

(b) With the aeroplane in trim, or as nearly as possible in trim and without the trimming control being moved throughout the manoeuvre;

(c) At an approach gradient equal to the steepest used in the landing distance demonstration of 523.75; and

(d) With only those power changes, if any, that would be made when landing normally from an approach at VREF.

(Change 523-4 (96-09-01))
(Change 523-5)

523.155   Elevator Control Force in Manoeuvres

(a)  The elevator control force needed to achieve the positive manoeuvring load factor may not be less than:

(1)  For wheel controls, W/100 (where W is the maximum weight) or 20 pounds, whichever is greater, except that it need not be greater than 50 pounds; or

(2)  For stick controls, W/l40 (where W is the maximum weight) or 15 pounds, whichever is greater, except that it need not be greater than 35 pounds.

(b) The requirement of paragraph (a) of this section must be met at 75 percent of maximum continuous power for reciprocating engines, or the maximum continuous power for turbine engines, and with the wing flaps and landing gear retracted:

(1) In a turn, with the trim setting used for wings level flight at VO; and

(2)  In a turn with the trim setting used for the maximum wings level flight speed, except that the speed may not exceed VNE or VMO/MMO, whichever is appropriate.

(c) There must be no excessive decrease in the gradient of the curve of stick force versus manoeuvring load factor with increasing load factor.

(Change 523-4 (96-09-01))
(Change 523-5)

523.157   Rate of Roll

(a)  Takeoff. It must be possible, using a favourable combination of controls, to roll the aeroplane from a steady 30-degree banked turn through an angle of 60 degrees, so as to reverse the direction of the turn within:

(1)  For an aeroplane of 6,000 pounds or less maximum weight, 5 seconds from initiation of roll; and

(2)  For an aeroplane of over 6,000 pounds maximum weight, (W + 500)/1,300 seconds but not more than l0 seconds where W is the weight in pounds.

(b)  The requirement of paragraph (a) of this section must be met when rolling the aeroplane in each direction with:

(1)  Flaps in the takeoff position;

(2)  Landing gear retracted;

(3)  For a single-engine aeroplane, at maximum takeoff power; and for a multi-engine aeroplane with the critical engine inoperative and the propeller in the minimum drag position, and the other engines at maximum takeoff power; and

(4)  The aeroplane trimmed at a speed equal to the greater of l.2 VS1 or 1.1 VMC, or as nearly as possible in trim for straight flight.

(c)  Approach. It must be possible, using a favourable combination of controls, to roll the aeroplane from a steady 30-degree banked turn through an angle of 60 degrees, so as to reverse the direction of the turn within:

(1)  For an aeroplane of 6,000 pounds or less maximum weight, 4 seconds from initiation of roll; and

(2)  For an aeroplane of over 6,000 pounds maximum weight, (W + 2,800)/2,200 seconds but not more than 7 seconds where W is the weight in pounds.

(d) The requirement of paragraph (c) of this section must be met when rolling the aeroplane in each direction in the following conditions:

(1) Flaps in the landing position(s);

(2) Landing gear extended;

(3) All engines operating at the power for a 3 degree approach; and

(4) The aeroplane trimmed at VREF.

(Change 523-4 (96-09-01))
(Change 523-5)

Trim

523.161   Trim

(a) General. Each aeroplane must meet the trim requirements of this section after being trimmed and without further pressure upon, or movement of, the primary controls or their corresponding trim controls by the pilot or the automatic pilot. In addition, it must be possible, in other conditions of loading, configuration, speed and power to ensure that the pilot will not be unduly fatigued or distracted by the need to apply residual control forces exceeding those for prolonged application of 523.143(c). This applies in normal operation of the aeroplane and, if applicable, to those conditions associated with the failure of one engine for which performance characteristics are established.

(b)  Lateral and directional trim. The aeroplane must maintain lateral and directional trim in level flight with the landing gear and wing flaps retracted as follows:

(1) For normal, utility, and aerobatic category aeroplanes, at a speed of 0.9 VH, VC, or VMO/MMO, whichever is lowest; and

(2) For commuter category aeroplanes, at all speeds from 1.4 VS1 to the lesser of VH or VMO/MMO.

(c) Longitudinal trim. The aeroplane must maintain longitudinal trim under each of the following conditions:

(1) A climb with:

(i) Takeoff power, landing gear retracted, wing flaps in the takeoff position(s), at the speeds used in determining the climb performance required by 523.65; and

(ii) Maximum continuous power at the speeds and in the configuration used in determining the climb performance required by 523.69(a).

(2) Level flight at all speeds from the lesser of VH and either VNO or VMO/MMO (as appropriate), to 1.4 VS1, with the landing gear and flaps retracted.

(3) A descent at VNO or VMO/MMO, whichever is applicable, with power off and with the landing gear and flaps retracted.

(4) Approach with landing gear extended and with:

(i) A 3 degree angle of descent, with flaps retracted and at a speed of 1.4 VS1;

(ii) A 3 degree angle of descent, flaps in the landing position(s) at VREF; and

(iii) An approach gradient equal to the steepest used in the landing distance demonstrations of 523.75, flaps in the landing position(s) at VREF.

(d) In addition, each multiple aeroplane must maintain longitudinal and directional trim, and the lateral control force must not exceed 5 pounds at the speed used in complying with 523.67(a), (b)(2), or (c)(3), as appropriate, with:

(1)  The critical engine inoperative and if applicable, its propeller in the minimum drag position.

(2)  The remaining engines at maximum continuous power;

(3)  The landing gear retracted;

(4) Wing flaps retracted; and

(5)An angle of bank of not more than 5°.

(e) In addition, each commuter category aeroplane for which, in the determination of the takeoff path in accordance with 523.57, the climb in the takeoff configuration at V2 extends beyond 400 feet above the takeoff surface, it must be possible to reduce the longitudinal and lateral control forces to 10 pounds and 5 pounds, respectively, and the directional control force must not exceed 50 pounds at V2 with:

(1) The critical engine inoperative and its propeller in the minimum drag position;

(2) The remaining engine(s) at takeoff power;

(3) Landing gear retracted;

(4) Wing flaps in the takeoff position(s); and

(5) An angle of bank not exceeding 5 degrees.

(Change 523-3 (92-01-02))
(Change 523-5)

Stability

523.171   General

The aeroplane must be longitudinally, directionally, and laterally stable under 523.173 through 523.181. In addition the aeroplane must show suitable stability and control "feel" (static stability) in any condition normally encountered in service, if flight tests show it is necessary for safe operation.

523.173   Static Longitudinal Stability

Under the conditions specified in 523.175 and with the aeroplane trimmed as indicated, the characteristics of the elevator control forces and the friction within the control system must be as follows:

(a)  A pull must be required to obtain and maintain speeds below the specified trim speed and a push required to obtain and maintain speeds above the specified trim speed. This must be shown at any speed that can be obtained, except that speeds requiring a control force in excess of 40 pounds or speeds above the maximum allowable speed or below the minimum speed for steady unstalled flight, need not be considered.

(b)  The airspeed must return to within the tolerances specified for applicable categories of aeroplanes when the control force is slowly released at any speed within the speed range specified in paragraph (a) of this section. The applicable tolerances are:

(1)  The airspeed must return to within plus or minus l0 percent of the original trim airspeed; and

(2)  For commuter category aeroplanes, the airspeed must return to within plus or minus 7.5 percent of the original trim airspeed for the cruising condition specified in 523.175(b).

(c)  The stick force must vary with speed so that any substantial speed change results in a stick force clearly perceptible to the pilot.

(Change 523-1 (88-01-01))

523.175   Demonstration of Static Longitudinal Stability

Static longitudinal stability must be shown as follows:

(a)  Climb. The stick force curve must have a stable slope at speeds between 85 and 115 percent of the trim speed, with:

(1) Flaps retracted;

(2) Landing gear retracted;

(3) Maximum continuous power; and

(4) The aeroplane trimmed at the speed used in determining the climb performance required by 523.69(a).

(b) Cruise. With flaps and landing gear retracted and the aeroplane in trim with power for level flight at representative cruising speeds at high and low altitudes, including speeds up to VNO or VMO/MMO, as appropriate, except that the speed need not exceed VH:

(1) For normal, utility, and aerobatic category aeroplanes, the stick force curve must have a stable slope at all speeds within a range that is the greater of 15 percent of the trim speed plus the resulting free return speed range, or 40 knots plus the resulting free return speed range, above and below the trim speed, except that the slope need not be stable:

(i) At speeds less than 1.3 VS1; or

(ii) For aeroplanes with VNE established under 523.1505(a), at speeds greater than VNE>NE; or

(iii) For aeroplanes with VMO/MMO established under 523.1505(c), at speeds greater than VFC>FC/MFC; or

(2) For commuter category aeroplanes, the stick force curve must have a stable slope at all speeds within a range of 50 knots plus the resulting free return speed range, above and below the trim speed, except that the slope need not be stable:

(i) At speeds less than 1.4 VS1 or

(ii) At speeds greater than VFC/MFC; or

(iii) At speeds that require a stick force greater than 50 pounds.

(c) Landing. The stick force curve must have a stable slope at speeds between 1.1 VS1 and 1.8 VS1 with:

(1) Flaps in the landing position;

(2) Landing gear extended; and

(3) The aeroplane trimmed at:

(i) VREF, or the minimum trim speed if higher, with power off; and

(ii) VREF with enough power to maintain a 3 degree angle of descent.

(Change 523-1 (88-01-01))
(Change 523-4 (96-09-01))
(Change 523-5)

523.177   Static Directional and Lateral Stability

(a) The static directional stability, as shown by the tendency to recover from a wings level sideslip with the rudder free, must be positive for any landing gear and flap position appropriate to the takeoff, climb, cruise, approach, and landing configurations. This must be shown with symmetrical power up to maximum continuous power, and at speeds from 1.2 VS1 up to the maximum allowable speed for the condition being investigated. The angle of sideslip for these tests must be appropriate to the type of aeroplane. At larger angles of sideslip, up to that at which full rudder is used or a control force limit in 523.143 is reached, whichever occurs first, and at speeds from 1.2 VS1 to VO, the rudder pedal force must not reverse.

(b) The static lateral stability, as shown by the tendency to raise the low wing in a sideslip, must be positive for all landing gear and flap positions. This must be shown with symmetrical power up to 75 percent of maximum continuous power at speeds above 1.2 VS1 in the takeoff configuration(s) and at speeds above 1.3 VS1 in other configurations, up to the maximum allowable speed for the configuration being investigated, in the take-off, climb, cruise, and approach configurations. For the landing configuration, the power must be that necessary to maintain a 3 degree angle of descent in co-ordinated flight. The static lateral stability must not be negative at 1.2 VS1 in the takeoff configuration, or at 1.3 VS1 in other configurations. The angle of sideslip for these tests must be appropriate to the type of aeroplane, but in no case may the constant heading sideslip angle be less than that obtainable with a 10 degree bank, or if less, the maximum bank angle obtainable with full rudder deflection or 150 pound rudder force.

(c) Paragraph (b) of this section does not apply to aerobatic category aeroplanes certificated for inverted flight.

(d) In straight, steady slips at 1.2 VS1 for any landing gear and flap positions, and for any symmetrical power conditions up to 50 percent of maximum continuous power, the aileron and rudder control movements and forces must increase steadily, but not necessarily in constant proportion, as the angle of sideslip is increased up to the maximum appropriate to the type of aeroplane. At larger slip angles, up to the angle at which full rudder or aileron control is used or a control force limit contained in 523.143 is reached, the aileron and rudder control movements and forces must not reverse as the angle of sideslip is increased. Rapid entry into, and recovery from, a maximum sideslip considered appropriate for the aeroplane must not result in uncontrollable flight characteristics.

(Change 523-4 (96-09-01))
(Change 523-5)

523.179   Instrumented Stick Force Measurements (Removed)

(Change 523-4 (96-09-01))

523.181   Dynamic Stability

(a)  Any short period oscillation not including combined lateral-directional oscillations occurring between the stalling speed and the maximum allowable speed appropriate to the configuration of the aeroplane must be heavily damped with the primary controls:

(1)  Free; and

(2)  In a fixed position.

(b)  Any combined lateral-directional oscillations ("Dutch roll") occurring between the stalling speed and the maximum allowable speed appropriate to the configuration of the aeroplane must be damped to 1/10 amplitude in 7 cycles with the primary controls:

(1)  Free; and

(2)  In a fixed position.

(c)  If it is determined that the function of a stability augmentation system, reference 523.672, is needed to meet the flight characteristic requirements of this chapter, the primary control requirements of paragraphs (a)(2)(2) and (b)(2) of this section are not applicable to the tests needed to verify the acceptability of that system.

(d)  During the conditions as specified in 523.175, when the longitudinal control force required to maintain speeds differing from the trim speed by at least plus and minus 15 percent is suddenly released, the response of the aeroplane must not exhibit any dangerous characteristics nor be excessive in relation to the magnitude of the control force released. Any long-period oscillation of flight path, phugoid oscillation, that results must not be so unstable as to increase the pilot's workload or otherwise endanger the aeroplane.

(Change 523-4 (96-09-01))

Stalls

523.201   Wings Level Stall

(a) It must be possible to produce and to correct roll by unreversed use of the rolling control and to produce and to correct yaw by unreversed use of the directional control, up to the time the aeroplane stalls.

(b) The wings level stall characteristics must be demonstrated in flight as follows. Starting from a speed at least 10 knots above the stall speed, the elevator control must be pulled back so that the rate of speed reduction will not exceed one knot per second until a stall is produced, as shown by either:

(1) An uncontrollable downward pitching motion of the aeroplane;

(2) A downward pitching motion of the aeroplane that results from the activation of a stall avoidance device (for example, stick pusher); or

(3) The control reaching the stop.

(c) Normal use of elevator control for recovery is allowed after the downward pitching motion of paragraphs (b)(1) or (b)(2) of this section has unmistakably been produced, or after the control has been held against the stop for not less than the longer of two seconds or the time employed in the minimum steady flight speed determination of 523.49.
(amended 2005/06/03; previous version)

(d) During the entry into and the recovery from the manoeuvre, it must be possible to prevent more than 15 degrees of roll or yaw by the normal use of controls.

(e) Compliance with the requirements of this section must be shown under the following conditions:

(1) Wing flaps. Retracted, fully extended, and each intermediate normal operating position.

(2) Landing gear. Retracted and extended.

(3) Cowl flaps. Appropriate to configuration.

(4) Power:

(i) Power off; and

(ii) 75 percent of maximum continuous power. However, if the power-to-weight ratio at 75 percent of maximum continuous power result in extreme nose-up attitudes, the test may be carried out with the power required for level flight in the landing configuration at maximum landing weight and a speed of 1.4 VSO, except that the power may not be less than 50 percent of maximum continuous power.

(5) Trim. The aeroplane trimmed at a speed as near 1.5 VS1 as practicable.

(6) Propeller. Full increase r.p.m.. position for the power off condition.

(Change 523-4 (96-09-01))
(Change 523-5)

523.203   Turning Flight and Accelerated Turning Stalls

Turning flight and accelerated turning stalls must be demonstrated in tests as follows:

(a) Establish and maintain a co-ordinated turn in a 30 degree bank. Reduce speed by steadily and progressively tightening the turn with the elevator until the aeroplane is stalled, as defined in 523.201(b). The rate of speed reduction must be constant, and:

(1) For a turning flight stall, may not exceed one knot per second; and

(2) For an accelerated turning stall, be 3 to 5 knots per second with steadily increasing normal acceleration.

(b) After the aeroplane has stalled, as defined in 523.201(b), it must be possible to regain wings level flight by normal use of the flight controls, but without increasing power and without:

(1)  Excessive loss of altitude;

(2)  Undue pitch-up;

(3)  Uncontrollable tendency to spin;

(4) Exceeding a bank angle of 60 degrees in the original direction of the turn or 30 degrees in the opposite direction in the case of turning flight stalls;

(5) Exceeding a bank angle of 90 degrees in the original direction of the turn or 60 degrees in the opposite direction in the case of accelerated turning stalls; and

(6) Exceeding the maximum permissible speed or allowable limit load factor.

(c) Compliance with the requirements of this section must be shown under the following conditions:

(1) Wing flaps:  Retracted, fully extended, and each intermediate normal operating position;

(2)  Landing Gear:  Retracted and extended;

(3)  Cowl Flaps:  Appropriate to configuration;

(4) Power:

(i) Power off; and

(ii) 75 percent of maximum continuous power. However, if the power-to-weight ratio at 75 percent of maximum continuous power results in extreme nose-up attitudes, the test may be carried out with the power required for level flight in the landing configuration at maximum landing weight and a speed of 1.4 VSO, except that the power may not be less than 50 percent of maximum continuous power.

(5)  Trim:  The aeroplane trimmed at a speed as near l.5 VS1 as practicable.

(6) Propeller. Full increase r.p.m. position for the power off condition.

(Change 523-4 (96-09-01))
(Change 523-5)

523.205  Critical Engine Inoperative Stalls [Removed]

(Change 523-4 (96-09-01))
(Change 523-5)

523.207   Stall Warning

(a)  There must be a clear and distinctive stall warning, with the flaps and landing gear in any normal position, in straight and turning flight.

(b)  The stall warning may be furnished either through the inherent aerodynamic qualities of the aeroplane or by a device that will give clearly distinguishable indications under expected conditions of flight. However, a visual stall warning device that requires the attention of the crew within the cockpit is not acceptable by itself.

(c) During the stall tests required by 523.201(b) and 523.203(a)(1), the stall warning must begin at a speed exceeding the stalling speed by a margin of not less than 5 knots and must continue until the stall occurs.

(d) When following procedures furnished in accordance with 523.1585, the stall warning must not occur during a takeoff with all engines operating, a takeoff continued with one-engine-inoperative, or during an approach to landing.

(e) During the stall tests required by 523.203(a)(2), the stall warning must begin sufficiently in advance of the stall for the stall to be averted by pilot action taken after the stall warning first occurs.

(f) For aerobatic category aeroplanes, an artificial stall warning may be mutable, provided that it is armed automatically during takeoff and rearmed automatically in the approach configuration.

(Change 523-4 (96-09-01))
(Change 523-5)

Spinning

523.221   Spinning

(a) Normal category aeroplanes. A single-engine, normal category aeroplane must be able to recover from a one-turn spin or a three-second spin, whichever takes longer, in not more than one additional turn after initiation of the first control action for recovery, or demonstrate compliance with the optional spin resistant requirements of this section.

(1) The following apply to one turn or three second spins:

(i) For both the flaps-retracted and flaps-extended conditions, the applicable airspeed limit and positive limit manoeuvring load factor must not be exceeded;

(ii) No control forces or characteristic encountered during the spin or recovery may adversely affect prompt recovery;

(iii) It must be impossible to obtain unrecoverable spins with any use of the flight or engine power controls either at the entry into or during the spin; and

(iv) For the flaps-extended condition, the flaps may be retracted during the recovery but not before rotation has ceased.

(2) At the applicant's option, the aeroplane may be demonstrated to be spin resistant by the following:

(i) During the stall manoeuvre contained in 523.201, the pitch control must be pulled back and held against the stop. Then, using ailerons and rudders in the proper direction, it must be possible to maintain wings-level flight within 15 degrees of bank and to roll the aeroplane from a 30 degree bank in one direction to a 30 degree bank in the other direction;

(ii) Reduce the aeroplane speed using pitch control at a rate of approximately one knot per second until the pitch control reaches the stop; then, with the pitch control pulled back and held against the stop, apply full rudder control in a manner to promote spin entry for a period of seven seconds or through a 360 degree heading change, whichever occurs first. If the 360 degree heading change is reached first, it must have taken no fewer than four seconds. This manoeuvre must be performed first with the ailerons in the neutral position, and then with the ailerons deflected opposite the direction of turn in the most adverse manner. Power and aeroplane configuration must be set in accordance with 523.201(e) without change during the manoeuvre. At the end of seven seconds or a 360 degree heading change, the aeroplane must respond immediately and normally to primary flight controls applied to regain co-ordinated, unstalled flight without reversal of control effect and without exceeding the temporary control forces specified by 523.143(c); and

(iii) Compliance with 523.201 and 523.203 must be demonstrated with the aeroplane in uncoordinated flight, corresponding to one ball width displacement on a slip-skid indicator, unless one ball width displacement cannot be obtained with full rudder, in which case the demonstration must be with full rudder applied.

(b) Utility category aeroplanes. A utility category aeroplane must meet the requirements of paragraph (a) of this section. In addition, the requirements of paragraph (c) of this section and 523.807(b)(6) must be met if approval for spinning is requested.

(c) Aerobatic category aeroplanes. An aerobatic category aeroplane must meet the spin requirements of paragraph (a) of this section and 523.807(b)(6). In addition, the following requirements must be met in each configuration for which approval for spinning is requested:

(1) The aeroplane must recover from any point in a spin up to and including six turns, or any greater number of turns for which certification is requested, in not more than one and one-half additional turns after initiation of the first control action for recovery. However, beyond three turns, the spin may be discontinued if spiral characteristics appear.

(2) The applicable airspeed limits and limit manoeuvring load factors must not be exceeded. For flaps-extended configurations for which approval is requested, the flaps must not be retracted during the recovery.

(3) It must be impossible to obtain unrecoverable spins with any use of the flight or engine power controls either at the entry into or during the spin.

(4) There must be no characteristics during the spin (such as excessive rates of rotation or extreme oscillatory motion) that might prevent a successful recovery due to disorientation or incapacitation of the pilot.

(Change 523-3 (92-01-02))
(Change 523-5)

Ground and Water Handling Characteristics

523.231   Longitudinal Stability and Control

(a) A landplane may have no uncontrollable tendency to nose over in any reasonably expected operating condition, including rebound during landing or takeoff.  Wheel brakes must operate smoothly and may not induce any undue tendency to nose over.

(b) A seaplane or amphibian may not have dangerous or uncontrollable porpoising characteristics at any normal operating speed on the water.

523.233   Directional Stability and Control

(a) A 90 degree cross-component of wind velocity, demonstrated to be safe for taxiing, takeoff, and landing must be established and must be not less than 0.2 VSO.

(b) The aeroplane must be satisfactorily controllable in power-off landings at normal landing speed, without using brakes or engine power to maintain a straight path until the speed has decreased to at least 50 percent of the speed at touchdown.

(c) The aeroplane must have adequate directional control during taxiing.

(d) Seaplanes must demonstrate satisfactory directional stability and control for water operations up to the maximum wind velocity specified in paragraph (a) of this section.

(Change 523-4 (96-09-01))
(Change 523-5)

523.235   [Operation On Unpaved Surfaces

The aeroplane must be demonstrated to have satisfactory characteristics and the shock-absorbing mechanism must not damage the structure of the aeroplane when the aeroplane is taxied on the roughest ground that may reasonably be expected in normal operation and when takeoffs and landings are performed on unpaved runways having the roughest surface that may reasonably be expected in normal operation.

(Change 523-4 (96-09-01))
(Change 523-5)

[523.237   Operation On Water

A wave height, demonstrated to be safe for operation, and any necessary water handling procedures for seaplanes and amphibians must be established.

(Change 523-5)

523.239   Spray Characteristics

Spray may not dangerously obscure the vision of the pilots or damage the propellers or other parts of a seaplane or amphibian at any time during taxiing, takeoff, and landing.

Miscellaneous Flight Requirements

523.251   Vibration and Buffeting

There must be no vibration or buffeting severe enough to result in structural damage, and each part of the aeroplane must be free from excessive vibration, under any appropriate speed and power conditions up to VD/MD.  In addition, there must be no buffeting in any normal flight condition severe enough to interfere with the satisfactory control of the aeroplane or cause excessive fatigue to the flight crew.  Stall warning buffeting within these limits is allowable.

(Change 523-4 (96-09-01))

523.253   High Speed Characteristics

If a maximum operating speed VMO/MMO is established under 523.1505(c), the following speed increase and recovery characteristics must be met:

(a)  Operating conditions and characteristics likely to cause inadvertent speed increases (including upsets in pitch and roll) must be simulated with the aeroplane trimmed at any likely speed up to Vo VMO/MMO. These conditions and characteristics include gust upsets, inadvertent control movements, low stick force gradients in relation to control friction, passenger movement, levelling off from climb, and descent from Mach to airspeed limit altitude.

(b)  Allowing for pilot reaction time after occurrence of the effective inherent or artificial speed warning specified in 523.1303, it must be shown that the aeroplane can be recovered to a normal attitude and its speed reduced to VMO/MMO, without:

(1) Exceeding VD/MD, the maximum speed shown under 523.251, or the structural limitations; or

(2) Buffeting that would impair the pilot's ability to read the instruments or to control the aeroplane for recovery.

(c)  There may be no control reversal about any axis at any speed up to the maximum speed shown under 523.251.  Any reversal of elevator control force or tendency of the aeroplane to pitch, roll, or yaw must be mild and readily controllable, using normal piloting techniques.

(Change 523-4 (96-09-01))
(Change 523-5)