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The altitude
available is, in many ways, the controlling
factor in the successful accomplishment of an
emergency landing. If an actual engine failure
should occur immediately after takeoff and before
a safe maneuvering altitude is attained, it
is usually inadvisable to attempt to turn back
to the field from where the takeoff was made.
Instead, it is safer to immediately establish
the proper glide attitude, and select a field
directly ahead or slightly too either side of
the takeoff path.
The decision to continue straight ahead is often
difficult to make unless the problems involved
in attempting to turn back are seriously considered.
In the first place, the takeoff was in all probability
made into the wind. To get back to the takeoff
field, a downwind turn must be made. This increases
the groundspeed and rushes the pilot even more
in the performance of procedures and in planning
the landing approach. Secondly, the airplane
is losing considerable altitude during the turn
and might still be in a bank when the ground
is contacted, resulting in the airplane cartwheeling
(which would be a catastrophe for the occupants,
as well as the airplane). After turning downwind,
the apparent increase: in groundspeed could
mislead the pilot into attempting to prematurely
slow down the airplane and cause it to stall.
On the other hand, continuing straight ahead
or making a slight turn allows the pilot more
time to establish a safe landing attitude, and
the landing can be made as slowly as possible,
but more importantly, the airplane can be landed
while under control.
Concerning the subject of turning back to the
runway following an engine failure on takeoff,
the pilot should determine the minimum altitude
an attempt of such a maneuver should be made
in a particular airplane. Experimentation at
a safe altitude should give the pilot an approximation
of height lost in a descending 180° turn
at idle power. By adding a safety factor of
about 25 percent, the pilot should arrive at
a practical decision height. The ability to
make a 180° turn does not necessarily mean
that the departure runway can be reached in
a power-off glide; this depends on the wind,
the distance traveled during the climb, the
height reached, and the glide distance of the
airplane without power. The pilot should also
remember that a turn back to the departure runway
may in fact require more than a 180° change
in direction.
Consider the following example of an airplane
which has taken off and climbed to an altitude
of 300 feet above ground level (AGL) when the
engine fails. After a typical 4 second reaction
time, the pilot elects to turn back to the runway.
Using a standard rate (3° change in direction
per second) turn, it takes 1 minute to turn
180°. At a glide speed of 65 knots, the
radius of the turn is 2,100 feet, so at the
completion of the turn, the airplane is 4,200
feet to one side of the runway. The pilot must
turn another 45° to head the airplane toward
the runway. By this time, the total change in
direction is 225° equating to 75 seconds
plus the 4 second reaction time. If the airplane
in a poweroff glide descends at approximately
1,000 fpm, it has descended 1,316, feet placing
it 1,016 feet below the runway.
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