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extended flaps may result in asymmetrical flap failure
and slowing of the airplane. Keep a retractable gear up
unless the AFM/POH advises otherwise.
A landing in snow should be executed like a ditching,
in the same configuration and with the same regard for
loss of depth perception (white out) in reduced visibility
and on wide open terrain.
ENGINE FAILURE AFTER TAKEOFF
(SINGLE-ENGINE)
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 to 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 will be 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
AGL when the engine fails. [Figure 16-5 on next
page]. 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 will take 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 will be 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 f.p.m., it
Figure 16-4.Tree landing.
Ch 16.qxd 5/7/04 10:30 AM Page 16-5
16-6
will have descended 1,316, feet placing it 1,016 feet
below the runway.
EMERGENCY DESCENTS
An emergency descent is a maneuver for descending
as rapidly as possible to a lower altitude or to the
ground for an emergency landing. [Figure 16-6] The
need for this maneuver may result from an uncontrollable
fire, a sudden loss of cabin pressurization, or any
other situation demanding an immediate and rapid
descent. The objective is to descend the airplane as
soon and as rapidly as possible, within the structural
limitations of the airplane. Simulated emergency
descents should be made in a turn to check for other air
traffic below and to look around for a possible
emergency landing area. A radio call announcing
descent intentions may be appropriate to alert other
aircraft in the area. When initiating the descent, a bank
of approximately 30 to 45° should be established to
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AIRPLANE FLYING HANDBOOK 飞机飞行手册下(93)
