TAXIING: AIR EXERCISE ( Refer to Briefing 2 )
1.CHECKS
Before taxiing
- Engine instruments / Brakes on / Adjust friction control lever / RT clearance
- Taxi brief / Note wind velocity
During taxiing
- Brake check / Full rudder movement and nose wheel steering / Engine and gyro instruments / Lookout
2.STARTING AND STOPPING
Starting
- Throttle closed
- Toe brakes – ON
- Parking brake – OFF
- Toe brakes – OFF
- Power as required – Danger of misuse of power
Stopping
- Close throttle
- Apply toe brakes evenly – Danger of harsh braking
- Apply parking brake when aircraft stationary
3.CONTROL AND DIRECTION OF TURNING
Use Of Nose Wheel Steering
- Normal radius turns – nose wheel steering effective
Across Wind
- Weathercock tendency / Turns into wind tend to tighten / Aircraft is less willing to turn out of wind
4.CONTROL OF SPEED
Judging Correct Speed
Control of Speed with:
- Power / Brake
Factors Affecting Speed
- Surface gradient
- Nature of surface
- Change of Surface
- Wind
- Smooth use of throttle
5.RESTRICTED RADIUS TURNS
- Low speed
- Small radius turns – toe brake to assist nose wheel steering and cadence braking
- Power to maintain speed when the toe brakes are used
Avoid turning on locked wheel Use of differential brake with full nose wheel steering not permitted
6.LEAVING THE APRON
- If chocks in position, close throttle and have chocks removed. Chocks should be removed before starting the engine. Where this is impractical, removing chocks with the engine started must only be done as an agreed procedure and with the person removing the chocks being fully briefed by the pilot and being able to remove the chocks from behind the wing. Move off as in 2 – Starting
Use 1200RPM max with cold engine.
TAXIING: AMPLIFYING NOTES
GENERAL
- The elements of taxiing are introduced, in conjunction with flying exercises as soon as possible and the student should be given progressively more responsibility as his proficiency increases. Resist the temptation to take over control in order to save time but allow the student to gain the maximum amount of taxiing under supervision.
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The sequence in which the items of this exercise are taught depends on variables such as wind velocity, airfield layout and local regulations as well as the student’s ability. The lesson should, therefore, be adapted to the prevailing circumstances. Whenever possible, the initial lessons are best done in an open space on the airfield where there is plenty of room to maneuver.
BEFORE THE EXERCISE
PREPARATORY INSTRUCTION
Discuss the following subjects:
1. Effects of inertia and momentum
2. Use of controls
3. Use of power
4. Effect of wind
5. Use of brakes
6. Engine handling
7. Traffic rules
8. Taxi brief: where to, route
DURING THE EXERCISE
Emphasize the constant need for a careful lookout. Mention the following points:
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Distribution of the keel surface tends to make the aircraft weathercock into wind.
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There is a time lag between throttle movement and the aircraft responding.
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Brake must never be used against power. (This prevents brake overheat and consequent loss of effectiveness; in addition, overheating may cause tyre deflation or blow out).
THREAT AND ERROR MANAGEMENT
- Emphasize that the captain is ultimately responsible for the safety of the aircraft and that although, at larger airfields, any marshaller’s signals should normally be obeyed, the captain is at liberty to disregard them if he considers that the safety of the aircraft is endangered by following them. Consequently, lookout is essential; to spot obstacles and other aircraft not only ahead but also all around, both near and far.
- Flight instrument serviceability checks should be carried out during taxiing but always in areas clear of obstructions.
- Teach the practical applications of “Rules of the Air”, e.g. the requirement to give way to aircraft approaching to land or taking off.
- Note: Easy Access Rules for Standardized European Rules of the Air (SERA)
STARTING AND STOPPING
- Because of inertia, more power is required to start the aircraft than to keep it moving. Teach the need to reduce power as soon as the aeroplane starts to move and stress that throttle movements and brake applications should always be smooth. To stop the aircraft, first close the throttle, then brake gently until the aircraft stops and finally apply the parking brake.
CONTROL OF SPEED
- Teach that the correct taxiing speed is a brisk walking pace which should be judged by looking out and the apparent movement of the wing tips over the ground. Power changes should be anticipated in order to maintain a constant speed over varying surfaces.
DIRECTIONAL CONTROL AND TURNING
- Point out that it is easier to hold direction when looking well ahead and that, because of the inherent directional stability of nose wheel landing gear, the aircraft will maintain a given direction unless the wind is strong enough to cause a weathercock tendency. Turning is achieved by nose wheel steering, linked directly to the rudder bars. Stress that, as a result, students should never try to move the rudder when the aeroplane is stationary. When clear of the apron, apply full rudder in each direction to ensure that full, free and correct movement of the rudder is available and that the nose wheel steering is working correctly. Teach that foot loads can be high and differential brake can be used to assist in turning the aircraft in confined areas.
TURNING IN A CONFINED SPACE
- The tail can be made to swing quite sharply through a large angle, so emphasize the need to ensure that there are no obstacles in the path of the tail when turning in a confined space. Stress, too, that turning about a locked wheel must be avoided unless the safety of the aircraft is involved. In this case cadence braking (short ‘dabs’ of the ‘inside’ brake) is used to avoid locking the ‘inside’ wheel.
LEAVING THE APRON
- Ensure your student has had sufficient practice at taxiing in areas away from the apron to become reasonably competent before introducing this part of the exercise. Teach how to complete the brake check immediately the aircraft moves forward and stress that the aircraft should only be allowed to move slowly before applying the brakes in case they are unserviceable. If only one brake fails the aircraft may swing to one side.
USE OF CONTROL
- The yoke should be held neutral (fore and aft) at all times when taxiing on hard surfaces. On grass the yoke should be held fully aft in order to achieve the maximum propeller clearance.
EMERGENCIES
- Brake failure
Discuss the following points that affect the action to be taken if the brakes fail:
1. Proximity of obstacles and other aircraft.
2. Wind strength and direction.
3. Nature and gradient of the surface.
- Make clear that usually the safest course of action is to switch off the engine after steering the aircraft clear of danger. If only one toe brake fails, the aircraft can be stopped by use of the parking brake.
Nose wheel Steering Failure
- In the event of nose wheel steering failure, directional control can be maintained by use of differential braking. Emphasize that, in these circumstances, the aircraft should be stopped and towed back to the maintenance area.
- In the event of nose wheel steering failure, directional control can be maintained by use of differential braking. Emphasize that, in these circumstances, the aircraft should be stopped and towed back to the maintenance area.
COMMON FAULTS
- There is a growing tendency for students to become obsessed with technology and to concentrate on GPS to check their taxiing speed. Do not allow this to become a habit. Stress the vital importance of looking out, both to avoid obstacles and to judge speed by looking at the wingtips.
- As the student gains experience and confidence, he may tend to taxi too fast, particularly when solo. Stress the dangers of doing so.
- Not synchronized braking and too much force on the pedals during the taxiing when correcting trajectory. Check the feets position of the student