Part V - Airworthiness Manual Chapter 522 - Gliders and Powered Gliders

Canadian Aviation Regulations (CARs) 2017-2

Content last revised: 2010/12/01

Preamble

SUBCHAPTERS 

  • A (522.1-522.3), 
  • B (522.21-522.255), 
  • C (522.301-522.597), 
  • D (522.601-522.885), 
  • E (522.901-522.1193), 
  • F (522.1301-522.1449),
  • G (522.1501-523.1589),
  • H (522.1801-523.1857),
  • J (522.1901-523.1947)

(2007/12/30)

SUBCHAPTER C STRUCTURE GENERAL

522.301 Loads

  1. (a) Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and ultimate loads (limit loads multiplied by prescribed factors of safety). Unless otherwise provided, prescribed loads are limit loads. 

  2. (b) Unless otherwise provided, the air and ground loads must be placed in equilibrium with inertia forces, considering each item of mass in the glider. These loads must be distributed so as to represent actual conditions or a conservative approximation to them.

  3. (c) If deflections under load would significantly change the distribution of external or internal loads, this redistribution must be taken into account.

522.303 Factor of Safety

Unless otherwise provided, a factor of safety of 1.5 must be used.

522.305 Strength and Deformation

  1. (a) The structure must be able to support limit loads without permanent deformation. At any load up to limit loads, the deformation may not interfere with safe operation. This applies in particular to the control system.

  2. (b) The structure must be able to support ultimate loads without failure for at least three seconds.

However, when proof of strength is shown by dynamic tests simulating actual load conditions, the three second limit does not apply.

522.307 Proof of Structure

  1. (a) Compliance with the strength and deformation requirements of 522.305 must be shown for each critical load condition. Structural analysis may be used only if the structure conforms to those for which experience has shown this method to be reliable. In other cases, substantiating load tests must be made.

  2. (b) Certain parts of the structure must be tested as specified in Sub chapter D of this Chapter.

Note: Structural requirements contained in Subchapter C do not constitute all the structural requirements necessary to show compliance with Chapter 522.

Flight Loads

522.321 General

  1. (a) Flight load factors represent the ratio of the aerodynamic force component (acting normal to the flight path of the glider) to the weight of the glider. A positive flight load factor is one in which the aerodynamic force acts upward, with respect to the glider.

  2. (b) Compliance with the flight load requirements of this Subchapter must be shown:

    1. (1) At each critical altitude within the range in which the glider may be expected to operate; and

    2. (2) At each practicable combination of weight and disposable load.

522.331 Symmetrical Flight Conditions

  1. (a) The appropriate balancing horizontal tail load must be accounted for in a rational or conservative manner when determining the wing loads and linear inertia loads corresponding to any of the symmetrical flight conditions specified in 522.333 through 522.345.

  2. (b) The incremental horizontal tail loads due to manoeuvring and gusts must be reacted by the angular inertia of the glider in a rational or conservative manner.

  3. (c) In computing the loads arising in the prescribed conditions, the angle of attack is assumed to be changed suddenly without loss of flight speed until the prescribed load factor is attained. Angular accelerations may be disregarded.

  4. (d) Aerodynamic data required for the establishment of the loading conditions must be verified by tests, calculations or by conservative estimation.

    1. (1) In the absence of better information the maximum negative lift coefficient in the normal configuration may be taken as -0.8.

    2. (2) If the pitching moment coefficient Cmo is less than ±0.025, a coefficient of at least -0.025 must be used for the wing and horizontal tail.
      (amended 2007/07/16)

522.333 Flight Envelope

  1. (a) General. Compliance with the strength requirements of this Subchapter must be shown at any combination of air speed and load factor on and within the boundaries of the flight envelopes specified by the manoeuvring and gust criteria of subparagraphs (b) and (c) of this paragraph respectively.

  2. (b) Manoeuvring envelope. Wingflaps in the en route setting, air brakes closed.
    (See Figure 1.)

Figure 1 Manoeuvring envelope

  1. (c) Gust envelope. Wing-flaps in the en route setting. (See Figure 2.)

Figure 2 - Gust Envelope

Figure 2 - Gust Envelope

  1. (1) At the design gust speed VB, the glider must be capable of withstanding positive (up) and negative (down) gusts of 15 m/s acting normal to the flight path.
    (amended 2007/07/16)

  2. (2) At the design maximum speed VD, the glider must be capable of withstanding positive (up) and negative (down) gusts of 7.5 m/s acting normal to the flight path.

522.335 Design Air Speeds

The selected design air speeds are equivalent air speeds (EAS):

  1. (a) Design manoeuvring speed VA

where:

VS1 = estimated stalling speed at design maximum weight with wing-flaps neutral and air brakes retracted.

  1. (b) Design flap speed, VF

    1. (1) For each landing setting, VF must not be less than the greater of:

      1. (i) 1.4 VS1, where VS1 is the computed stalling speed with wing-flaps neutral at the maximum weight.

      2. (ii) 2.0 VSF, where VSF is the computed stalling speed with wing-flaps fully extended at the maximum weight.

    2. (2) For each positive en-route setting, VF must not be less then the greater of:

      1. (i) 2.7 VS1, where VS1 is the computed stalling speed at design maximum weight with wing flaps in the particular positive en-route setting.

      2. (ii) 1.05 VA, where VA is determined in accordance with subparagraph (a) of this paragraph, i.e. for wingflaps neutral.

    3. (3) For all other settings, VF must equal VD,

  2. (c) Design Gust Speed VB. VB must not be less than VA.

  3. (d) Design Aerotow Speed VT. VT must not be less than 125 km/h.

  4. (e) Design Winch-launching Speed VW. VW must not be less than 110 km/h.

  5. (f) Design Maximum Speed VD. The design maximum speed may be chosen by the applicant but must not be lower than:

(km/h) for gliders of Category U.

(km/h) for gliders of Category A.

where:

W/S = wing loading (daN/m2) at design S maximum weight.

Cdmin = the lowest possible drag coefficient of the glider.

For a powered glider, VD must also not be lower than 1.35 VH.

(Change 522-1 (87-08-31))
(Change 522-2 (93-06-30))

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