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is the lack of flight crew experience in the model being flown. Understanding the
factors that contribute to a tail strike can reduce the possibility of a tail strike
occurrence.
Note: Anytime fuselage contact is suspected or known to have occurred,
accomplish the appropriate NNC.
Takeoff Risk Factors
Any one of the following takeoff risk factors may precede a tail strike:
Mistrimmed Stabilizer
This usually results from using erroneous takeoff data, e.g., the wrong weights, or
an incorrect center of gravity (CG). In addition, sometimes accurate information
is entered incorrectly either in the flight management system (FMS) or set
incorrectly on the stabilizer. The flight crew can prevent this type of error and
correct the condition by challenging the reasonableness of the load sheet numbers.
Comparing the load sheet numbers against past experience in the aircraft can assist
in approximating numbers that are reasonable.
Rotation at Improper Speed
This situation can result in a tail strike and is usually caused by early rotation due
to some unusual situation, or rotation at too low an airspeed for the weight and/or
flap setting.
October 31, 2004
767 Flight Crew Training Manual
Non-Normal Operations
Copyright © The Boeing Company. See title page for details.
FCT 767 (TM) 8.23
Trimming during Rotation
Trimming the stabilizer during rotation may contribute to a tail strike. The pilot
flying may easily lose the feel of the elevator while the trim is running which may
result in an excessive rotation rate.
Excessive Rotation Rate
Flight crews operating an airplane model new to them, especially when
transitioning from an airplane with unpowered flight controls to one with
hydraulic assistance, are most vulnerable to using excessive rotation rate. The
amount of control input required to achieve the proper rotation rate varies from
one model to another. When transitioning to a new model, flight crews may not
realize that it does not respond to pitch input in exactly the same way as their
previous model.
Improper Use of the Flight Director
The flight director provides accurate pitch guidance only after the airplane is
airborne. With the proper rotation rate, the airplane reaches 35 feet with the
desired pitch attitude of about 15 degrees. However, an aggressive rotation into
the pitch bar at takeoff is not appropriate and can cause a tail strike.
Landing Risk Factors
A tail strike on landing tends to cause more serious damage than the same event
during takeoff and is usually more expensive and time consuming to repair. In the
worst case, the tail can strike the runway before the landing gear, thus absorbing
large amounts of energy for which it is not designed. The aft pressure bulkhead is
often damaged as a result.
Any one of the following landing risk factors may precede a tail strike:
Unstabilized Approach
An unstabilized approach is the biggest single cause of tail strike. Flight crews
should stabilize all approach variables - on centerline, on approach path, on speed,
and in the final landing configuration - by the time the airplane descends through
1,000 feet above ground level (AGL). This is not always possible. Under normal
conditions, if the airplane descends through 1,000 feet AGL (IMC), or 500 feet
AGL (VMC), with these approach variables not stabilized, a go-around should be
considered.
October 31, 2004
767 Flight Crew Training Manual
Non-Normal Operations
Copyright © The Boeing Company. See title page for details.
8.24 FCT 767 (TM)
Flight recorder data show that flight crews who continue with an unstabilized
condition below 500 feet seldom stabilize the approach. When the airplane arrives
in the flare, it often has either excessive or insufficient airspeed. The result is a
tendency toward large power and pitch corrections in the flare, often culminating
in a vigorous pitch change at touchdown resulting in tail strike shortly thereafter.
If the pitch is increased rapidly when touchdown occurs as ground spoilers deploy,
the spoilers add additional nose up pitch force, reducing pitch authority, which
increases the possibility of tail strike. Conversely, if the airplane is slow,
increasing the pitch attitude in the flare does not effectively reduce the sink rate;
and in some cases, may increase it.
A firm touchdown on the main gear is often preferable to a soft touchdown with
the nose rising rapidly. In this case, the momentary addition of power may aid in
preventing the tail strike. In addition, unstabilized approaches can result in landing
long or a runway over run.
Holding Off in the Flare
The second most common cause of a landing tail strike is an extended flare, with
　
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本文鏈接地址：767機組訓練手冊Flight Crew Training Manual (FCTM)767(125)