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6. TP 14371 - Transport Canada Aeronautical Information Manual (TC AIM)
7. TC AIM - AIR - AIRMANSHIP
8. AIR - 1.0 GENERAL INFORMATION

AIR - 1.0 GENERAL INFORMATION

• 1.1 General
• 1.2 Pilot Vital Action Checklists
• 1.3 Aviation Fuels
  • 1.3.1 Fuel Grades
  • 1.3.2 Aviation Fuel Handling
  • 1.3.3 Fuel Anti-icing Additives
  • 1.3.4 Fires and Explosions
• 1.4 Aircraft Hand Fire Extinguishers
  • 1.4.1 General
  • 1.4.2 Classification of Fires
  • 1.4.3 Types of Extinguishers
• 1.5 Pressure Altimeter
  • 1.5.1 General
  • 1.5.2 Calibration of the Pressure Altimeter
  • 1.5.3 Incorrect Setting on the Subscale of the Altimeter
  • 1.5.4 Non-Standard Temperatures
  • 1.5.5 Standard Pressure Region
  • 1.5.6 Effect of Mountains
  • 1.5.7 Downdraft and Turbulence
  • 1.5.8 Pressure Drop
  • 1.5.9 Abnormally High Altimeter Settings
• 1.6 Canadian Runway Friction Index
  • 1.6.1 General
  • 1.6.2 Reduced Runway Coefficients of Friction and Aircraft Performance
  • 1.6.3 Description of Canadian Runway Friction Index (CRFI) and Method of Measurement
  • 1.6.4 Aircraft Movement Surface Condition Reports (AMSCR)
  • 1.6.5 Wet Runways
  • 1.6.6 CRFI Application to Aircraft Performance
• 1.7 Jet and Propeller Blast Danger
• 1.8 Marshalling Signals

1.1 General

Airmanship is the application of flying knowledge, skill and experience which fosters safe and efficient flying operations. Airmanship is acquired through experience and knowledge. This section contains information and advice on various topics which help to increase knowledge.

1.2 Pilot Vital Action Checklists

A number of aircraft accidents have been directly attributed to the lack of proper vital action checks by the pilots concerned. It is essential that pretakeoff, prelanding and other necessary vital action checks be performed with care.

While Transport Canada does not prescribe standard checks to be performed by pilots, it is strongly recommended that owners equip their aircraft with the manufacturer’s recommended checklists. For any specific type of aircraft, only relevant items should be included in the checklists which should be arranged in an orderly sequence having regard to the cockpit layout.

1.3 Aviation Fuels

1.3.1 Fuel Grades

The use of aviation fuel other than specified is contrary to a condition of the Certificate of Airworthiness and, therefore, a contravention of regulations. A fuel which does not meet the specifications recommended for the aircraft may seriously damage the engine and result in an inflight failure. In Canada, fuels are controlled by government specifications. Aviation fuel can usually be identified by its colour.

FUEL	COLOUR
AVGAS 80/87 AVGAS 100/130 100 LL Aviation Turbine Fuels MOGAS P 87-90 (see NOTE 2) MOGAS R 84-87 (see NOTE 2)	red green blue straw-coloured or undyed green undyed

NOTES
1: Good airmanship ensures that positive identification of the type and grade of aviation fuel is established before fuelling.

2: Transport Canada now approves the use of automotive gasoline for certain aircraft types under specific conditions. For additional information, refer to TP 10737E – Use of Automotive Gasoline (MOGAS) for General Aviation Aircraft, available from your TC Airworthiness Regional office. (See GEN 1.1.2 for addresses.)

1.3.2 Aviation Fuel Handling

A company supplying aviation fuel for use in civil aircraft is responsible for the quality and specifications of its products up to the point of actual delivery. Following delivery, the operator is responsible for the correct storage, handling, and usage of aviation fuel. A fuel dispensing system must have an approved filter, water separator or monitor to prevent water or sediment from entering aircraft fuel tanks. The use of temporary fuelling facilities such as drums or cans are discouraged. However, if such facilities are necessary, always filter aviation fuel using a proper filter and water separator with a portable pump bonded to the drum before bungs are removed.

The aircraft and fuelling equipment through which fuel passes all require bonding. The hose nozzle must be bonded to the aircraft before the tank cap is removed in over-wing fuelling. All funnels or filters used in fuelling are to be bonded together with the aircraft. Bonding prevents sparks by equalizing or draining the electric potentials.

During the preflight check, a reasonable quantity of fuel should be drawn from the lowest point in the fuel system into a clear glass jar. A “clear and bright” visual test should be made to establish that the fuel is completely free of visible solid contamination and water (including any resting on the bottom or sides of the container), and that the fuel possesses an inherent brilliance and sparkle in the presence of light. Cloudy or hazy fuel is usually caused by free and dispersed water, but can also occur because of finely divided dirt particles. Free water may also be detected by the use of water-finding paste available from oil companies. If there is any suspicion that water exists in an aircraft’s fuel system detailed checking of the entire system should be carried out until it is proven clear of contamination. Analysis by an approved laboratory is the only way to ensure positive proof of compliance if doubt exists.

1.3.3 Fuel Anti-icing Additives

All aviation fuels absorb moisture from the air and contain water in both suspended particles and liquid form. The amount of suspended particles varies with the temperature of the fuel. When the temperature of the fuel is decreased, some of the suspended particles are drawn out of the solution and slowly fall to the bottom on the tank. When the temperature of the fuel increases, water particles from the atmosphere are absorbed to maintain a saturated solution.

As stated in AIR 1.3.2, water should be drained from aircraft fuel systems before flight. However, even with this precaution water particles in suspension will remain in the fuel. While this is not normally a problem it becomes so when fuel cools to the freezing level of water and the water particles change to ice crystals. These may accumulate in fuel filters, bends in fuel lines, and in some fuel-selectors and eventually may block the fuel line causing an engine stoppage. Fuel anti-icing additives will inhibit ice crystal formation. Manufacturer approved additives, such as ethylene-glycol-monomethyl-ether (EGME), used in the prescribed manner have proven quite successful. The aircraft manufacturer’s instructions for the use of anti-icing fuel additives should therefore be consulted and carefully followed.

1.3.4 Fires and Explosions

Pound for pound aviation fuel is more explosive than dynamite. However, the explosive range of fuel is comparatively narrow. To be explosive, the mixture must contain 1 to 6% fuel vapor by volume when combined with air. Mixtures below this range are too weak and those above are too rich to explode.

The mixture in the space above the fuel in a gas-tight compartment is usually too rich for combustion, but in extremely cold conditions there may be a mixture lean enough to be explosive.

In sub-freezing weather conditions static charges can build up more readily than in warmer conditions. Untreated turbo fuel, when agitated as in refuelling operations, can build up greater static electricity charges than gasoline and is therefore, under certain conditions, potentially more dangerous. Most turbo fuel supplied in Canada contains an anti-static additive.

To avoid fires and explosions there should be effective electrical bonding between the aircraft, the fuel source, piping or funnel and the ground before refuelling is undertaken.

NOTES 1: Incidents have occurred involving death and injury resulting from fuelling in enclosed spaces, and with inadequate bonding. At low temperatures and humidity, a blower-heater could build up statically-charged dust particles to combine with fuel vapours with catastrophic results.

2: The increasing use of small plastic fuel containers which cannot be properly bonded or grounded increases the chance of explosion and fire.

 

1.4 Aircraft Hand Fire Extinguishers

1.4.1 General

When selecting a hand fire extinguisher for use in aircraft, consider the most appropriate extinguishing agent for the type and location of fires likely to be encountered. Take account of the agent’s toxicity, extinguishing ability, corrosive properties, freezing point, etc.

The toxicity ratings listed by the Underwriters’ Laboratories for some of the commonly known fire extinguisher chemicals are as follows:

Bromotrifluoromethane (Halon 1301)	– Group 6
Bromochlorodifluoromethane (Halon 1211)	– Group 5a
Carbon dioxide	– Group 5a
Common Dry Chemicals	– Group 5a
Dibromidifluoromethane (Halon 1202)	– Group 4*
Bromochlormethane (Halon 1011)	– Group 4*
Carbon Tetrachloride (Halon 104)	– Group 3*
Methyl bromide (Halon 1001)	– Group 2*

*Should not be installed in an aircraft

It is generally realized that virtually any fire extinguishing agent is a compromise between the hazards of fire, smoke, fumes and a possible increase in hazard due to the toxicity of the extinguishing agent used. Hand fire extinguishers using agents having a rating in toxicity Groups 2 to 4 inclusive should not be installed in aircraft. Extinguishers in some of the older types of aircraft do not meet this standard and for such aircraft it is recommended that hand fire extinguishers employing agents in toxicity Group 5 or above be installed when renewing or replacing units and that they be of a type and group approved by the Underwriters’ Laboratories. It is further recommended that instruction in the proper use, care and cautions to be followed be obtained from the manufacturer and the local fire protection agency.

1.4.2 Classification of Fires

Class A fires:	Fires in ordinary combustible materials. On these, water or solutions containing large percentages of water are most effective.
Class B fires:	Fires in flammable liquids, greases, etc. On these a blanketing effect is essential.
Class C fires:	Fires in electrical equipment. On these the use of a nonconducting extinguishing agent is of first importance.

1.4.3 Types of Extinguishers

1. Carbon Dioxide Extinguishers: Carbon dioxide extinguishers are acceptable when the principal hazard is a Class B or Class C fire. Carbon dioxide portable installations should not exceed five pounds of agent per unit to ensure extinguisher portability and to minimize crew compartment CO2 concentrations.
2. Water Extinguishers: Water extinguishers are acceptable when the principal hazard is a Class A fire and where a fire might smolder if attacked solely by such agents as carbon dioxide or dry chemical. If water extinguishers will be subject to temperatures below freezing, the water extinguisher must be winterized by addition of a suitable anti-freeze.
3. Vaporizing Liquid Extinguishers: Vaporizing liquid type fire extinguishers are acceptable when the principal hazard is a Class B or Class C fire.
4. Dry Chemical Extinguishers: Dry chemical extinguishers using a bi-carbonate of sodium extinguishing agent or potassium bi-carbonate powder are acceptable where the principal hazard is a Class B or Class C fire.
   
   Dry chemical extinguishers using a so-called All Purpose Monoammonium Phosphate are acceptable where the hazard includes a Class A fire as well as Class B and Class C.
   
   The size of the dry chemical extinguisher should not be less than two lbs. Only an extinguisher with a nozzle that can be operated either intermittently or totally by the operator should be installed.
   
   Some abrasion or corrosion of the insulation on electrical instruments, contacts or wiring may take place as a result of using this extinguisher. Cleaning and inspection of components should be carried out as soon as possible.
   
   Care should be taken when using this extinguisher in crew compartments because the chemical can interfere with visibility while it is being used and because the nonconductive powders may be deposited on electrical contacts not involved in the fire. This can cause equipment failure.
5. Halon Extinguishers: Halon 1211 is a colourless liquefied gas which evaporates rapidly, does not freeze or cause cold burn, does not stain fabrics nor cause corrosive damage. It is equally effective on an A, B or C class fire and has proven to be the most effective extinguishant on gasoline based upholstery fires. The size of a Halon 1211 extinguisher for a given cubic space should not result in a concentration of more than 5%. Halon 1211 is at least twice as effective as CO2 and is heavier than air (so it “sinks”). Decomposed Halon 1211 “stinks” so it is not likely to be breathed unknowingly.
   
   Halon 1301 is less toxic than Halon 1211 but it is also less effective and is excellent for B or C class fires. A short-coming appears to be the lack of a visible “stream” on discharge; Halon 1301 turns into an invisible gas as it discharges.

 

1.5 Pressure Altimeter

1.5.1 General

The pressure altimeter used in aircraft is a relatively accurate instrument for measuring flight level pressure but the altitude information indicated by an altimeter, although technically “correct” as a measure of pressure, may differ greatly from the actual height of the aircraft above mean sea level or above ground. In instances of aircraft flying high above the earth’s surface, knowledge of the actual distance between the aircraft and the earth’s surface is of little immediate value to the pilot except, perhaps, when navigating by pressure pattern techniques. In instances of aircraft operating close to the ground or above the highest obstacle en route, especially when on instruments, knowledge of actual ground separation or of “error” in the altimeter indication, is of prime importance if such separation is less than what would be assumed from the indicated altitude.

An aircraft altimeter which has the current altimeter setting applied to the subscale should not have an error of more than ±50 feet when compared on the ground against a known aerodrome or runway elevation. If the error is more than ±50 feet, the altimeter should be checked by maintenance as referenced in AIR 1.5.2.

1.5.2 Calibration of the Pressure Altimeter

Pressure altimeters are calibrated to indicate the “true” altitude in the ICAO Standard Atmosphere. The maximum allowable tolerance is ±20 feet at sea level for a calibrated altimeter. This tolerance increases with altitude.

The ICAO Standard Atmosphere conditions are:

1. air is a perfectly dry gas;
2. mean sea level pressure of 29.92 inches of mercury;
3. mean sea level temperature of 15°C; and
4. rate of decrease of temperature with height is 1.98°C per 1 000 feet to the height at which the temperature becomes -56.5°C and then remains constant.

1.5.3 Incorrect Setting on the Subscale of the Altimeter

Although altimeters are calibrated using the Standard Atmosphere sea level pressure of 29.92 inches of mercury, the actual sea level pressure varies hour to hour, and place to place. To enable the “zero” reference to be correctly set for sea level at any pressure within a range of 28.0 to 31.0 inches of mercury, altimeters incorporate a controllable device and subscale. Whether a pilot inadvertently sets an incorrect pressure on the altimeter subscale or sets the correct pressure for one area and then, without altering the setting, flies to an area where the pressure differs, the result is the same – the “zero” reference to the altimeter will not be where it should be but will be “displaced” by an amount proportional to 1 000 feet indicated altitude per 1 inch of mercury that the subscale setting is in error. As pressure decreases with altitude, a subscale setting that is higher than it should be will “start” the altimeter at a lower level, therefore, A TOO HIGH SUBSCALE SETTING MEANS A TOO HIGH ALTIMETER READING, that is the aircraft would be at a level lower than the altimeter indicates; A TOO LOW SUBSCALE SETTING MEANS A TOO LOW ALTIMETER READING, that is the aircraft would be at a level higher than the altimeter indicates. As the first instance is the more dangerous, an example follows:

A pilot at Airport A, 500 feet ASL, sets the altimeter to the airport’s altimeter setting of 29.80 inches of mercury prior to departure for Airport B, 1 000 feet ASL, some 400 NM away. A flight altitude of 6 000 feet is selected for the westbound flight so as to clear a 4 800-foot mountain ridge lying across track about 40 NM from B. The pilot does not change the altimeter subscale reading until he makes radio contact with B when 25 NM out and receives an altimeter setting of 29.20 inches of mercury. Ignoring other possible errors (see below), when the aircraft crossed the mountain ridge the actual ground clearance was only 600 feet, not 1 200 feet as expected by the pilot. This illustrates the importance of having the altimeter setting of the nearest airport along the route set on the instrument.

1.5.4 Non-Standard Temperatures

1. The only time that an altimeter will indicate the “true” altitude of an aircraft at all levels is when ICAO Standard Atmosphere conditions exist.
2. When the current altimeter setting of an airport is set on the subscale of an altimeter, the only time a pilot can be certain that the altimeter indicates the “true” altitude is when the aircraft is on the ground at that airport.
3. When 29.92 inches of mercury is set on the subscale of an altimeter within the Standard Pressure Setting Region, the altimeter will indicate “true” altitude if ICAO Standard Atmosphere conditions exist or if the aircraft is flying at that particular level for which 29.92 inches of mercury would be the altimeter setting.

In general, it can be assumed that the altitude indication of an altimeter is always in error due to temperature when an aircraft is in flight.

The amount of error will be approximately 4% of the indicated altitude for every 11°C that the average temperature of the air column between the aircraft and the “ground” differs from the average temperature of the Standard Atmosphere for the same air column. In practice, the average temperature of the air column is not known and “true” altitude is arrived at from knowledge of the outside air temperature (OAT) at flight level and use of a computer. The “true” altitude found by this method will be reasonably accurate when the actual lapse rate is, or is near, that of the Standard Atmosphere, i.e., 2°C per 1 000 feet. During the winter when “strong” inversions in the lower levels are likely and altimeters “habitually” over-read, in any situation where ground separation is marginal, a pilot would be well advised to increase the altimeter error found using flight level temperature by 50%. Consider the aircraft in the above example; assume that the OAT at flight level in the vicinity of the mountain ridge was -20°C; what was the likely “true” altitude of the aircraft over the mountain ridge?

To calculate “true” altitude using a computer, the pressure altitude is required. In this case, the altimeter indicates 6 000 feet with 29.80 inches of mercury set on the subscale, therefore, if the pilot altered the subscale to 29.92 inches of mercury momentarily, the pilot would read a pressure altitude of 6 120 feet. Although the indicated altitude is 6 000 feet, if the altimeter setting of the nearest airport (B) was set, the indicated altitude would be 5 400 feet. With 29.20 inches of mercury set on the altimeter subscale if the aircraft was on the ground at B, the altimeter would indicate the “true” altitude of 1 000 feet; assuming no pressure difference, it can be taken that the altimeter set to 29.20 inches of mercury would indicate the 1 000-foot level at the mountain with no error due to temperature, therefore temperature error will occur only between the 1 000-foot level and the 5 400-foot level, i.e., 4 400 feet of airspace.

1. Set pressure altitude, 6 120 feet, against OAT, -20°C, in the appropriate computer window.
2. Opposite 4 400 feet (44) on the inner scale read 4 020 feet (40.2) on the outer scale.
3. Add the 1 000 feet previously deducted as being errorless and find the “true” altitude of 4 020 feet + 1 000 feet = 5 020 feet ASL. The margin of safety is now just over 200 feet, but this does not take into account variables which may prevail as outlined immediately above and due to mountain effect as explained below.

1.5.5 Standard Pressure Region

When flying within this region, the altimeter must be reset, momentarily, to the altimeter setting of the nearest airport along the route to obtain indicated altitude, or indicated altitude calculated from the altimeter setting, and the steps given above followed, or, when over large expanses of water or barren lands where there are no airports, the forecast mean sea level pressure for the time and place must be used to get indicated altitude. In the other instance, “airport” level would be zero, therefore subtraction and addition of airport elevation would not be done. The “true” altitude determined in such a case would be “true” only if the forecast pressure used approximates the actual sea level pressure. (If sea level pressure is not known and pressure altitude is used also as indicated altitude, the resultant “true” altitude will be the “true” altitude above the 29.92 level, wherever it may be in relation to actual mean sea level).

1.5.6 Effect of Mountains

Winds which are deflected around large single mountain peaks or through the valleys of mountain ranges tend to increase speed which results in a local decrease in pressure (Bernoulli’s Principle). A pressure altimeter within such an airflow would be subject to an increased error in altitude indication by reason of this decrease in pressure. This error will be present until the airflow returns to “normal” speed some distance away from the mountain or mountain range.

Winds blowing over a mountain range at speeds in excess of about 50 KT and in a direction perpendicular (within 30°) to the main axis of the mountain range often create the phenomena known as “Mountain” or “Standing Wave”. The effect of a mountain wave often extends as far as 100 NM downwind of the mountains and to altitudes many times higher than the mountain elevation. Although most likely to occur in the vicinity of high mountain ranges such as the Rockies, mountain waves have occurred in the Appalachians, elevation about 4 500 feet ASL (the height of the ridge of our example). Aware and the Air Command Weather Manual (TP 9352E) cover the mountain wave phenomena in some detail; however, aspects directly affecting aircraft “altitude” follow.

1.5.7 Downdraft and Turbulence

Downdrafts are most severe near a mountain and at about the same height as the top of the summit. These downdrafts may reach an intensity of about 83 ft. per second (5 000 ft. per minute) to the lee of high mountain ranges, such as the Rockies. Although mountain waves often generate severe turbulence, at times flight through waves may be remarkably “smooth” even when the intensity of downdrafts and updrafts is considerable. As these smooth conditions may occur at night, or when an overcast exists, or when no distinctive cloud has formed, the danger to aircraft is enhanced by the lack of warning of the unusual flight conditions.

Consider the circumstances of an aircraft flying parallel to a mountain ridge on the downwind side and entering a smooth downdraft. Although the aircraft starts descending because of the downdraft, as a result of the local drop in pressure associated with the wave, both the rate of climb indicator and the altimeter will not indicate a descent until the aircraft actually descends through a layer equal to the altimeter error caused by the mountain wave, and, in fact, both instruments may actually indicate a “climb” for part of this descent; thus the fact that the aircraft is in a downdraft may not be recognized until after the aircraft passes through the original flight pressure level which, in the downdraft, is closer to the ground than previous to entering the wave.

1.5.8 Pressure Drop

The “drop” in pressure associated with the increase in wind speeds extends throughout the mountain wave, that is downwind and to “heights” well above the mountains. Isolating the altimeter error caused solely by the mountain wave from error caused by non-standard temperatures would be of little value to a pilot. Of main importance is that the combination of mountain waves and non-standard temperature may result IN AN ALTIMETER OVERREADING BY AS MUCH AS 3 000 FT. If the aircraft in our example had been flying upwind on a windy day, the actual ground separation on passing over the crest of the ridge may well have been very small.

1.5.9 Abnormally High Altimeter Settings

Cold dry air masses can produce barometric pressures in excess of 31.00 in. of mercury. Because barometric readings of 31.00 in. of mercury or higher rarely occur, most standard altimeters do not permit setting of barometric pressures above that level and are not calibrated to indicate accurate aircraft altitude above 31.00 in. of mercury. As a result, most aircraft altimeters cannot be set to provide accurate altitude readouts to the pilot in these situations.

When aircraft operate in areas where the altimeter setting is in excess of 31.00 in. of mercury and the aircraft altimeter cannot be set above 31.00 in. of mercury, the true altitude of the aircraft will be HIGHER than the indicated altitude.

Procedures for conducting flight operations in areas of abnormally high altimeter settings are detailed in RAC 12.12.

 

1.6 Canadian Runway Friction Index

1.6.1 General

The following paragraphs discuss the slippery runway problem and suggest methods of applying runway coefficient of friction information to flight manual data.

1.6.2 Reduced Runway Coefficients of Friction and Aircraft Performance

The accelerate-stop distance, landing distance and crosswind limitations (if applicable) contained in the aircraft flight manual are demonstrated in accordance with specified performance criteria on runways that are bare, dry, and that have high surface friction characteristics. Unless some factor has been applied, these distances are valid only under similar runway conditions. Whenever a contaminant, such as water, snow or ice, is introduced to the runway surface, the effective coefficient of friction between the aircraft tire and runway is substantially reduced. The stop portion of the accelerate-stop distance will increase, the landing distance will increase and a crosswind may present directional control difficulties. The problem has been to identify, with some accuracy, the effect that the contaminant has had on reducing the runway coefficient of friction and to provide meaningful information to the pilot, e.g., how much more runway is needed to stop and what maximum crosswind can be accepted.

1.6.3 Description of Canadian Runway Friction Index (CRFI) and Method of Measurement

The decelerometer is an instrument that is mounted in a test vehicle and measures the decelerating forces acting on the vehicle when the brakes are applied. The instrument is graduated in increments from 0 to 1, the top number being equivalent to the theoretical maximum decelerating capability of the vehicle on a dry surface. These numbers are referred to as the CRFI. It is evident that small numbers represent low braking coefficients of friction while numbers on the order of 0.8 and above indicate the braking coefficients to be expected on bare and dry runways.

The brakes are applied on the test vehicle at 300-m (1000-ft) intervals along the runway within a distance of 10 m (30 ft) from each side of the runway centreline at that distance from the centreline where the majority of aircraft operations take place at each given site. The readings taken are averaged and reported as the CRFI number.

1.6.4 Aircraft Movement Surface Condition Reports (AMSCR)

1.6.5 Wet Runways

Runway friction values during the summer period and when it is raining are not provided at this time. Consequently, some discussion of wet runways is in order to assist pilots in developing handling procedures when these conditions are encountered.

A packed snow or ice condition at a fixed temperature presents a relatively constant coefficient of friction with speed, but this is not the case for a liquid (water or slush) state. This is because water cannot be completely squeezed out from between the tire and the runway and, as a result, there is only partial tire-to-runway contact. As the aircraft speed is increased, the time in contact is reduced further, thus braking friction coefficients on wet surfaces fall as the speed increases, i.e., the conditions in effect become relatively more slippery, but will again improve as the aircraft slows down. The situation is further complicated by the susceptibility of aircraft tires to hydroplane on wet runways.

Hydroplaning is a function of the water depth, tire pressure and speed. Moreover, the minimum speed at which a non-rotating tire will begin to hydroplane is lower than the speed at which a rotating tire will begin to hydroplane because a build up of water under the non-rotating tire increases the hydroplaning effect. Pilots should therefore be aware of this since it will result in a substantial difference between the takeoff and landing roll aircraft performance under the same runway conditions. The minimum speed, in knots, at which hydroplaning will commence can be calculated by multiplying the square root of the tire pressure (PSI) by 7.7 for a non-rotating tire, or by 9 for a rotating tire.

This equation gives an approximation of the minimum speed necessary to hydroplane on a smooth, wet surface with tires that are bald or have no tread. For example, the minimum hydroplaning speeds for an aircraft with tires inflated to 49 PSI are calculated as:

NON-ROTATING TIRE: 7.7 X v49 = 54 KT.; or
ROTATING TIRE: 9 X v49 = 63 KT.

When hydroplaning occurs, the tires of the aircraft are completely separated from the actual runway surface by a thin water film and they will continue to hydroplane until a reduction in speed permits the tire to regain contact with the runway. This speed will be considerably below the speed at which hydroplaning commences. Under these conditions, the tire traction drops to almost negligible values and in some cases the wheel will stop rotating entirely. The tires will provide no braking capability and will not contribute to the directional control of the aircraft. The resultant increase in stopping distance is impossible to predict accurately, but it has been estimated to increase as much as 700 percent. Further, it is known that a 10-kt. crosswind will drift an aircraft off the side of a 200-ft wide runway in approximately 7 sec under hydroplaning conditions.

Notwithstanding the fact that friction values cannot be given for a wet runway and that hydroplaning can cause pilots serious difficulties, it has been found that the well-drained runways at most major Canadian airports seldom allow pooling of sufficient water for hydroplaning to occur. The wet condition associated with rain may produce friction values on the order of a CRFI of 0.3 on a poorly maintained or poorly drained runway, but normally produces a value of 0.5. These figures can be used as a guide in conjunction with pilot and other reports.

1.6.6 CRFI Application to Aircraft Performance

The information contained in Tables 1 and 2 has been compiled and is considered to be the best data available at this time, because it is based upon extensive field test performance data of aircraft braking on winter-contaminated surfaces. The information should provide a useful guide to pilots when estimating aircraft performance under adverse runway conditions. The onus for the production of information, guidance or advice on the operation of aircraft on a wet and/or contaminated runway rests with the aircraft manufacturer. The information published in this TC AIM does not change, create any additional, authorize changes in, or permit deviations from regulatory requirements. These tables are intended to be used at the pilot’s discretion.

Because of the many variables associated with computing accelerate-stop distances and balanced field lengths, it has not been possible to reduce the available data to the point where CRFI corrections can be provided, which would be applicable to all types of operations. Consequently, only corrections for landing distances and crosswinds are included pending further study of the take-off problem.

It should be noted that in all cases the tables are based on corrections to flight manual dry runway data and that the certification criteria does not allow consideration of the extra decelerating forces provided by reverse thrust or propeller reversing. On dry runways, thrust reversers provide only a small portion of the total decelerating forces when compared to wheel braking. However, as wheel braking becomes less effective, the portion of the stopping distance attributable to thrust reversing becomes greater. For this reason, if reversing is employed when a low CRFI is reported, a comparison of the actual stopping distance with that shown in Table 1 will make the estimates appear overly conservative. Nevertheless, there are circumstances, such as crosswind conditions, engine-out situations or reverser malfunctions, that may preclude their use.

Table 1 recommended landing distances are intended to be used for aeroplanes with no discing and/or reverse thrust capability and are based on statistical variation measured during actual flight tests.

Notwithstanding the above comments on the use of discing and/or reverse thrust, Table 2 may be used for aeroplanes with discing and/or reverse thrust capability and is based on the Table 1 recommended landing distances with additional calculations that give credit for discing and/or reverse thrust. In calculating the distances in Table 2, the air distance from the screen height of 50 ft to touchdown and the delay distance from touchdown to the application of full braking remain unchanged from Table 1. The effects of discing and/or reverse thrust were used only to reduce the stopping distance from the application of full braking to a complete stop.

The recommended landing distances stated in Table 2 take into account the reduction in landing distances obtained with the use of discing and/or reverse thrust capability for a turboprop-powered aeroplane and with the use of reverse thrust for a turbojet-powered aeroplane. Representative low values of discing and/or reverse thrust effect have been assumed and; therefore, the data may be conservative for properly executed landings by some aeroplanes with highly effective discing and/or thrust reversing systems.

The crosswind limits for CRFI shown at Table 3 contain a slightly different display range of runway friction index values from those listed for Tables 1 and 2. However, the CRFI values used for Table 3 are exactly the same as used for Tables 1 and 2 and are appropriate for the index value increments indicated.

TABLE 1
Canadian Runway Friction Index (CRFI) Recommended
Landing Distances (No Discing/Reverse Thrust)

Reported Canadian Runway Friction Index (CRFI)
Landing Distance (Feet) Bare and Dry Unfactored	0.60	0.55	0.50	0.45	0.40	0.35	0.30	0.27	0.25	0.22	0.20	0.18	Landing Field Length (Feet) Bare and Dry	Landing Field Length (Feet) Bare and Dry
	Recommended Landing Distances (Discing/Reverse Thrust)												60% Factor	70% Factor
1 800	3 120	3 200	3 300	3 410	3 540	3 700	3 900	4 040	4 150	4 330	4 470	4 620	3 000	2 571
2 000	3 480	3 580	3 690	3 830	3 980	4 170	4 410	4 570	4 700	4 910	5 070	5 250	3 333	2 857
2 200	3 720	3 830	3 960	4 110	4 280	4 500	4 750	4 940	5 080	5 310	5 490	5 700	3 667	3 143
2 400	4 100	4 230	4 370	4 540	4 740	4 980	5 260	5 470	5 620	5 880	6 080	6 300	4 000	3 429
2 600	4 450	4 590	4 750	4 940	5 160	5 420	5 740	5 960	6 130	6 410	6 630	6 870	4 333	3 714
2 800	4 760	4 910	5 090	5 290	5 530	5 810	6 150	6 390	6 570	6 880	7 110	7 360	4 667	4 000
3 000	5 070	5 240	5 430	5 650	5 910	6 220	6 590	6 860	7 060	7 390	7 640	7 920	5 000	4 286
3 200	5 450	5 630	5 840	6 090	6 370	6 720	7 130	7 420	7 640	8 010	8 290	8 600	5 333	4 571
3 400	5 740	5 940	6 170	6 430	6 740	7 110	7 550	7 870	8 100	8 500	8 800	9 130	5 667	4 857
3 600	6 050	6 260	6 500	6 780	7 120	7 510	7 990	8 330	8 580	9 000	9 320	9 680	6 000	5 143
3 800	6 340	6 570	6 830	7 130	7 480	7 900	8 410	8 770	9 040	9 490	9 840	10 220	6 333	5 429
4 000	6 550	6 780	7 050	7 370	7 730	8 170	8 700	9 080	9 360	9 830	10 180	10 580	6 667	5 714

Application of the Canadian Runway Friction Index (CRFI)

1. The recommended landing distances in Table 1 are based on a 95 percent level of confidence. A 95 percent level of confidence means that in more than 19 landings out of 20, the stated distance in Table 1 will be conservative for properly executed landings with all systems serviceable on runway surfaces with the reported CRFI.
2. Table 1 will also be conservative for turbojet and turboprop–powered aeroplanes with reverse thrust, and additionally, in the case of turboprop–powered aeroplanes, with the effect obtained from discing.
3. The recommended landing distances in the CRFI Table 1 are based on standard pilot techniques for the minimum distance landings from 50 ft, including a stabilized approach at V_ref using a glideslope of 3° to 50 ft or lower, a firm touchdown, minimum delay to nose lowering, minimum delay time to deployment of ground lift dump devices and application of brakes, and sustained maximum antiskid braking until stopped.
4. Landing field length is the landing distance divided by 0.6 (turbojets) or 0.7 (turboprops). If the Aeroplane Flight Manual (AFM) expresses landing performance in terms of landing distance, enter the table from the left-hand column. However, if the AFM expresses landing performance in terms of landing field length, enter the table from one of the right-hand columns, after first verifying which factor has been used in the AFM.

TABLE 2
Canadian Runway Friction Index (CRFI) Recommended
Landing Distances (Discing/Reverse Thrust)

Reported Canadian Runway Friction Index (CRFI)
Landing Distance (Feet) Bare and Dry Unfactored	0.60	0.55	0.50	0.45	0.40	0.35	0.30	0.27	0.25	0.22	0.20	0.18	Landing Field Length (Feet) Bare and Dry	Landing Field Length (Feet) Bare and Dry
	Recommended Landing Distances (Discing/Reverse Thrust)												60% Factor	70% Factor
1 200	2 000	2 040	2 080	2 120	2 170	2 220	2 280	2 340	2 380	2 440	2 490	2 540	2 000	1 714
1 400	2 340	2 390	2 440	2 500	2 580	2 660	2 750	2 820	2 870	2 950	3 010	3 080	2 333	2 000
1 600	2 670	2 730	2 800	2 880	2 970	3 070	3 190	3 280	3 360	3 460	3 540	3 630	2 667	2 286
1 800	3 010	3 080	3 160	3 250	3 350	3 480	3 630	3 730	3 810	3 930	4 030	4 130	3 000	2 571
2 000	3 340	3 420	3 520	3 620	3 740	3 880	4 050	4 170	4 260	4 400	4 510	4 630	3 333	2 857
2 200	3 570	3 660	3 760	3 880	4 020	4 170	4 360	4 490	4 590	4 750	4 870	5 000	3 667	3 143
2 400	3 900	4 000	4 110	4 230	4 380	4 550	4 750	4 880	4 980	5 150	5 270	5 410	4 000	3 429
2 600	4 200	4 300	4 420	4 560	4 710	4 890	5 100	5 240	5 350	5 520	5 650	5 790	4 333	3 714
2 800	4 460	4 570	4 700	4 840	5 000	5 190	5 410	5 560	5 670	5 850	5 980	6 130	4 667	4 000
3 000	4 740	4 860	5 000	5 160	5 340	5 550	5 790	5 950	6 070	6 270	6 420	6 580	5 000	4 286
3 200	5 080	5 220	5 370	5 550	5 740	5 970	6 240	6 420	6 560	6 770	6 940	7 110	5 333	4 571
3 400	5 350	5 500	5 660	5 850	6 060	6 310	6 590	6 790	6 930	7 170	7 340	7 530	5 667	4 857
3 600	5 620	5 780	5 960	6 160	6 390	6 650	6 960	7 170	7 320	7 570	7 750	7 950	6 000	5 143
3 800	5 890	6 060	6 250	6 460	6 700	6 980	7 310	7 540	7 700	7 970	8 160	8 380	6 333	5 429
4 000	6 070	6 250	6 440	6 660	6 910	7 210	7 540	7 780	7 950	8 220	8 430	8 650	6 667	5 714

Application of the Canadian Runway Friction Index (CRFI)

1. The recommended landing distances in Table 2 are based on a 95% level of confidence. A 95% level of confidence means that in more than 19 landings out of 20, the stated distance in Table 2 will be conservative for properly executed landings with all systems serviceable on runway surfaces with the reported CRFI.
2. The recommended landing distances in Table 2 take into account the reduction in landing distances obtained with the use of discing and/or reverse thrust capability for a turboprop-powered aeroplane and with the use of reverse thrust for a turbojet-powered aeroplane. Table 2 is based on the Table 1 recommended landing distances with additional calculations that give credit for discing and/or reverse thrust. Representative low values of discing and/or reverse thrust effect have been assumed, hence the data will be conservative for properly executed landings by some aeroplanes with highly effective discing and/or thrust reversing systems.
3. The recommended landing distances in CRFI Table 2 are based on standard pilot techniques for the minimum distance landings from 50 ft, including a stabilized approach at Vref using a glideslope of three degrees to 50 ft or lower, a firm touchdown, minimum delay to nose lowering, minimum delay time to deployment of ground lift dump devices and application of brakes and discing and/or reverse thrust, and sustained maximum antiskid braking until stopped. In Table 2, the air distance from the screen height of 50 ft to touchdown and the delay distance from touchdown to the application of full braking remain unchanged from Table 1. The effects of discing/reverse thrust were used only to reduce the stopping distance from the application of full braking to a complete stop.
4. Landing field length is the landing distance divided by 0.6 (turbojets) or 0.7 (turboprops). If the AFM expresses landing performance in terms of landing distance, enter the table from the left-hand column. However, if the AFM expresses landing performance in terms of landing field length, enter the table from one of the right-hand columns, after first verifying which factor has been used in the AFM.

 

TABLE 3
CROSSWIND LIMITS FOR CANADIAN
RUNWAY FRICTION INDEX (CRFI)

This chart provides information for calculating headwind and crosswind components and the vertical lines indicate the recommended maximum crosswind component for reported CRFI.

Example: CYOW CRFI RWY 07/25 - 4 .3 930119l200

Tower Wind 110° 20 KT.

The wind is 40° off the runway heading and produces a headwind component of l5 kt. and a crosswind component of l3 kt. The recommended minimum CRFI for a l3-kt crosswind component is .35. A takeoff or landing with a CRFI of .3 could result in uncontrollable drifting and yawing.

The CRFI depends on the surface type, as shown in Table 4a. It should be noted that:

1. the CRFI values given in Table 4a are applicable to all temperatures. Extensive measurements have shown that there is no correlation between the CRFI and the surface temperature. The case where the surface temperature is just at the melting point (i.e. about 0°C) may be an exception, as a water film may form from surface melting, which could induce slippery conditions with CRFIs less than those in Table 4a.
2. the CRFI may span a range of values for various reasons, such as variations in texture among surfaces within a given surface class. The expected maximum and minimum CRFIs for various surfaces are listed in Table 4b. Note that these values are based on a combination of analyses of extensive measurements and sound engineering judgment.
3. the largest range in CRFI is to be expected for a thin layer (3 mm or less in thickness) of loose snow on pavement (Table 4a). This variation may occur due to: (i) non-uniform snow coverage; and/or (ii) the tires breaking through the thin layer. In either case, the surface presented to the aircraft may range from snow to pavement.

Table 4a
Expected Range of CRFIs by Surface Type

Table 4b
Minimum and Maximum CRFIs for Various Surfaces

SURFACE	LOWER CFRI LIMIT	UPPER CRFI LIMIT
Bare Ice	No Limit	0.3
Bare Packed Snow	0.1	0.4
Sanded Ice	0.1	0.4
Sanded Packed Snow	0.1	0.5
Loose Snow on Ice (depth 3 mm or less)	No Limit	0.4
Loose Snow on Ice (depth 3 to 25 mm)	No Limit	0.4
Loose Snow on Packed Snow (depth 3 mm or less)	0.1	0.4
Loose Snow on Packed Snow (depth 3 to 25 mm)	0.1	0.4
Loose Snow on Pavement (depth 3 mm or less)	0.1	Dry Pavement
Loose Snow on Pavement (depth 3 mm to 25 mm)	0.1	Dry Pavement

 

1.7 Jet and Propeller Blast Danger

Jet aircraft are classified into three categories according to engine size. The danger areas are similar to those shown in Figure 1.1 and are used by ground control personnel and pilots. The danger areas have been determined for ground idle and take-off thrust settings associated with each category.

As newer aircraft are designed to handle more weight, larger engines are being used. Executive jets may have thrusts of up to 15 000 lbs; medium jets may have thrusts of up to 35 000 lbs; and some jumbo jets now have thrusts in excess of 100 000 lbs. Therefore, caution should be used when interpreting the danger areas for ground idle and take-off thrust settings, as some of the distances shown in Figure 1.1 may need to be increased significantly.

Pilots should exercise caution when operating near active runways and taxiways. With the use of intersecting runways, there is an increased possibility of jet blast or propeller wash affecting other aircraft at the aerodrome. This can occur while both aircraft are on the ground or about to take off or land. Pilots taxiing in close proximity to active runways should be careful when their jet blast or propeller wash is directed towards an active runway. Pilots operating behind a large aircraft, whether on the ground or in the take-off or landing phase, should be aware of the possibility of encountering localized high wind velocities.

No information is available for supersonic transport aircraft or for military jet aircraft. Many of these aircraft are pure-jet aircraft with high exhaust velocities for their size, and may or may not use afterburner during the take-off phase. Thus, great caution should be used when operating near these aircraft.

Lastly, it should be noted that light aircraft with high wings and narrow-track undercarriages are more susceptible to jet blast and propeller wash related hazards than heavier aircraft with low wings and wide-track undercarriages.

The following is a table showing the expected speed of the blast created by large turbo-prop aeroplanes:

DISTANCE BEHIND PROPELLERS	LEAVING PARKED AREA	TAXIING	TAKING OFF
ft	kt	kt	kt
60	59	45	–
80	47	36	60–70
100	47	36	50–60
120	36	28	40–50
140	36	28	35–45
180	–	–	20–30

Figure 1.1—Jet Blast Danger Areas (Not to scale)

 

1.8 Marshalling Signals

Marshalling signals for the guidance of aircraft on the ground are set out in section 5 of ICAO Annex 2-Rules of the Air. These signals should be used in order to standardize signalling between ground and flight personnel when required for aircraft entering, departing or manoeuvring within the movement area of an aerodrome.

Note 1: Marshalling signals are designed for use by the marshaller, with hands illuminated as necessary to facilitate observation by the pilot, and facing the aircraft in a position:

1. for fixed-wing aircraft, on the left side of the aircraft, where best seen by the pilot; and
2. for helicopters, where the marshaller can best be seen by the pilot.

Note 2: The aircraft engines are numbered from left to right, with the No. 1 engine being the left outer engine. That is right to left for a marshaller facing the aircraft.

Note 3: Signals marked with an asterisk (*) are designed for use with hovering helicopters.

Marshalling Signals Diagram

Signal	Description
	Wingwalker/guide Raise right hand above head level with wand pointing up; move left-hand wand pointing down toward body. Note: This signal provides an indication by a person positioned at the aircraft wing tip, to the pilot/ marshaller/push-back operator, that the aircraft movement on/off a parking position would be unobstructed.
	Identify gate Raise fully extended arms straight above head with wands pointing up.
	Proceed to next marshaller as directed by tower/ground control Point both arms upward; move and extend arms outward to sides of body and point with wands to direction of next marshaller or taxi area.
	Straight ahead Bend extended arms at elbows and move wands up and down from chest height to head.
	Turn left (from pilot’s point of view) With right arm and wand extended at a 90-degree angle to body, make “come ahead” signal with left hand. The rate of signal motion indicates to pilot the rate of aircraft turn.
	Turn right(from pilot’s point of view) With left arm and wand extended at a 90-degree angle to body, make “come ahead” signal with right hand. The rate of signal motion indicates to pilot the rate of aircraft turn.
	Normal stop Fully extend arms and wands at a 90-degree angle to sides and slowly move to above head until wands cross.
	Emergency stop Abruptly extend arms and wands to top of head, crossing wands.
	Set brakes Raise hand just above shoulder height with open palm. Ensuring eye contact with flight crew, close hand into a fist. Do not move until receipt of “thumbs up” acknowledgement from flight crew.
	Release brakes Raise hand just above shoulder height with hand closed in a fist. Ensuring eye contact with flight crew, open palm. Do not move until receipt of “thumbs up” acknowledgement from flight crew.
	Chocks inserted With arms and wands fully extended above head, move wands inward in a “jabbing” motion until wands touch. Ensure acknowledgement is received from flight crew.
	Chocks removed With arms and wands fully extended above head, move wands outward in a “jabbing” motion. Do not remove chocks until authorized by flight crew.
	Start engine(s) Raise right arm to head level with wand pointing up and start a circular motion with hand; at the same time, with left arm raised above head level, point to engine to be started.
	Cut engines Extend arm with wand forward of body at shoulder level; move hand and wand to top of left shoulder and draw wand to top of right shoulder in a slicing motion across throat.
	Slow down Move extended arms downwards in a “patting” gesture, moving wands up and down from waist to knees.
	Slow down engine(s) on indicated side With arms down and wands toward ground, wave either right or left wand up and down indicating engine(s) on left or right side respectively should be slowed down.
	Move back With arms in front of body at waist height, rotate arms in a forward motion. To stop rearward movement, use signal 6.a) or 6.b).
	Turns while backing (for tail to starboard) Point left arm with wand down and bring right arm from overhead vertical position to horizontal forward position, repeating right-arm movement.
	Turns while backing (for tail to port) Point right arm with wand down and bring left arm from overhead vertical position to horizontal forward position, repeating left-arm movement.
	Affirmative / all clear Raise right arm to head level with wand pointing up or display hand with “thumbs up”; left arm remains at side by knee. Note: This signal is also used as a technical/servicing communication signal.
	Hover Fully extend arms and wands at a 90-degree angle to sides.
	Move upwards Fully extend arms and wands at a 90-degree angle to sides and, with palms turned up, move hands upwards. Speed of movement indicates rate of ascent.
	Move downwards Fully extend arms and wands at a 90-degree angle to sides and, with palms turned down, move hands down-wards. Speed of movement indicates rate of descent.
	Move horizontally left (from pilot’s point of view) Extend arm horizontally at a 90-degree angle to right side of body. Move other arm in same direction in a sweeping motion.
	Move horizontally right (from pilot’s point of view) Extend arm horizontally at a 90-degree angle to left side of body. Move other arm in same direction in a sweeping motion.
	Land Cross arms with wands downwards and in front of body.
	Fire Move right-hand wand in a “fanning” motion from shoulder to knee, while at the same time pointing with left-hand wand to area of fire.
	Hold position / stand by Fully extend arms and wands downwards at a 45-degree angle to sides. Hold position until aircraft is clear for next manoeuvre.
	Dispatch aircraft Perform a standard salute with right hand and/or wand to dispatch the aircraft. Maintain eye contact with flight crew until aircraft has begun to taxi.
	Do not touch controls (technical / servicing communication signal) Extend right arm fully above head and close fist or hold wand in horizontal position; left arm remains at side by knee.
	Connect ground power (technical / servicing communication signal) Hold arms fully extended above head; open left hand horizontally and move finger tips of right hand into and touch open palm of left hand (forming a “T”). At night, illuminated wands can also be used to form the “T” above head.
	Disconnect power (technical / servicing communication signal) Hold arms fully extended above head with finger tips of right hand touching open horizontal palm of left hand (forming a “T”); then move right hand away from the left. Do not disconnect power until authorized by flight crew. At night, illuminated wands can also be used to form the “T” above head.
	Negative (technical / servicing communication signal) Hold right arm straight out at 90 degrees from shoulder and point wand down to ground or display hand with “thumbs down”; left hand remains at side by knee.
	Establish communication via interphone (technical / servicing communication signal) Extend both arms at 90 degrees from body and move hands to cup both ears.
	Open/close stairs (technical / servicing communication signal) With right arm at side and left arm raised above head at a 45-degree angle, move right arm in a sweeping motion towards top of left shoulder. Note: This signal is intended mainly for aircraft with the set of integral stairs at the front.

Marshalling signals from the pilot of an aircraft to a marshaller

Meaning of Signal	Description of Signal
Brakes engaged	Raise arm and hand, with fingers extended, horizontally in front of face, then clench fist.
Brakes released	Raise arm, with fist clenched, horizontally in front of face, then extend fingers.
Insert chocks	Arms extended, palms outwards, move hands inwards to cross in front of face.
Remove chocks	Hands crossed in front of face, palms outwards, move arms outwards.
Ready to start engine	Raise the appropriate number of fingers on one hand indicating the number of the engine to be started.

Date modified:

2012-01-16

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