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wheels near the edge
of the taxi surface.
October 31, 2006
777/787 Flight Crew Training Manual
Ground Operations
Copyright © The Boeing Company. See title page for details.
FCT 777/787 Preliminary (TM) 2.15
Recommended Pivot Turn Technique
If possible, choose the turn direction and location to minimize the potential for
engine foreign object damage, jet blast damage and pavement damage during the
turn.
Lineup the outside tires of the main landing gear near the outside edge of the edge
of the taxi surface or runway. Bring the airplane to a complete stop with engines
at idle thrust. If available, use a ground observer or ground maneuver camera to
help accurately establish the airplane at the edge of the taxi surface prior to
initiating the turn. If an observer is used to guide the lineup, the observer should
be well clear of the area before the pivot turn is started.
Turn the tiller to the maximum steering angle and hold maximum steering angle
until the nose wheels have cleared the far side of the pavement. Apply full braking
pressure to the main gear on the side toward the inside of the turn. The braked
landing gear truck must be locked until the nose wheels clear the far edge of the
pavement. Apply sufficient thrust to the engine on the outside of the turn to pivot
the airplane about the locked gear. The engine on the inside of the turn should
remain at idle thrust.
Other considerations include:
• approximate pavement width required if the above method is used:
777-200, 777-200LR
• 126.0 feet (38.4 m)
777-300
• 143.1 feet (43.6 m)
777-300ER
• 143.2 feet (43.7m)
777-300, 777-300ER
Note: If the airplane is not initially lined up within approximately one foot
(1/3 m) of the starting edge of the pavement, or if the inside main wheel
brake is not locked throughout the turn, the turn may not be completed
within the width of a 147.6 foot (45 m) pavement.
• large tire deflections and rubber trails are normal
• inspection of the main gear tires, the nose gear tires, and the pavement
surface is recommended after completion of the pivot turn
• the resulting engine thrust on the outside engine may damage the runway
shoulder surface, especially if it is unpaved
• the nose wheels may produce a scrubbing noise and vibration on the flight
deck
October 31, 2006
777/787 Flight Crew Training Manual
Ground Operations
Copyright © The Boeing Company. See title page for details.
2.16 FCT 777/787 Preliminary (TM)
• pivot turns on pavements that are not sound may cause pavement damage.
In addition, if the pavement fails in such a way as to increase the forces
between the pavement surface and the tires, gear and tire design loads
may be exceeded with the potential for tire or gear damage
• loose debris may result in tire cuts which could lead to premature tire
failure.
Taxi - Adverse Weather
Taxi under adverse weather conditions requires more awareness of surface
conditions.
When taxiing on a slippery or contaminated surface, particularly with strong
crosswinds, use reduced speeds. Use of differential engine thrust assists in
maintaining airplane momentum through the turn. When nearing turn completion,
placing both engines to idle thrust reduces the potential for nose gear skidding.
Avoid using large nose wheel steering inputs to correct for skidding. Differential
braking may be more effective than nose wheel steering on slippery or
contaminated surfaces. If speed is excessive, reduce speed prior to initiating a
turn.
Note: A slippery surface is any surface where the braking capability is less than
that on a dry surface. Therefore, a surface is considered “slippery” when it
is wet or contaminated with ice, standing water, slush, snow or any other
deposit that results in reduced braking capability.
During cold weather operations, nose gear steering should be exercised in both
directions during taxi. This circulates warm hydraulic fluid through the steering
cylinders and minimizes the steering lag caused by low temperatures. If icing
conditions are present, use anti-ice as required by the FCOM.
During prolonged ground operations, periodic engine run-ups should be
accomplished to minimize ice build-up. These engine run-ups should be
performed as defined in the FCOM.
Engine exhaust may form ice on the ramp and takeoff areas of the runway, or blow
snow or slush which may freeze on airplane surfaces. If the taxi route is through
slush or standing water in low temperatures, or if precipitation is falling with
temperatures below freezing, taxi with flaps up. Extended or prolonged taxi times
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787机组训练手册Flight Crew Training Manual 787(30)
