Unusual Attitudes/Recoveries
Familiarization
If the aircraft recovery is not initiated by 120 KIAS or the airspeed bleeds off below 85 KIAS, perform a
zero airspeed recovery:
*
Reduce the power to IDLE.
*
Neutralize the flight controls.
*
Allow the aircraft to fall through the horizon until you achieve a nose-low attitude.
*
Hold the nose-low attitude and increase the power as necessary to increase airspeed to 150 KIAS.
*
Roll wings level in the shorter direction and then smoothly raise the nose to the horizon without
exceeding g limits or optimum AOA (17 units).
COMPRESSOR STALL DURING VERTICAL RECOVERY
Before or during any vertical or nose-high unusual attitude recovery, a compressor stall might occur.
CAUSES
A compressor stall may occur when the aircraft is at high AOA and low airspeeds with high power settings,
during unusual flight attitudes that interrupt airflow through the compressor, or because of abrupt throttle
movements at high altitudes and low airspeeds.
INDICATIONS
A compressor stall may be indicated by a “pop” or “bang” followed by a “buzzing” sound and vibration.
These indications are accompanied by a rapid drop in rpm and a sudden increase in EGT.
CLEARING AN ENGINE STALL
To prevent a flameout and/or damage to the engine, neutralize controls, throttle to idle, monitor EGT, RPM,
and fuel flow. If the engine isn’t cleared by going to IDLE, shut it down and perform an immediate airstart
IAW NATOPS. However, if the throttle is at IDLE when an engine stall occurs, it may not be apparent in
some situations until the throttle is advanced above IDLE.
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