Flight In Icing Conditions; Static Source Blocked; Recovery From A Spiral Dive - Cessna 172N Pilot Operating Handbook

SECTION
3
EMERGENCY PROCEDURES
CESSN11 CESSNA
MODEL
172~
1VIODEL 172N
SECTION 3
EMERGENCY PROCEDURES
1.
2.
3.
4.
Apply full rich mixture.
Use full carburetor heat.
Reduce power to set up a 500 to 800 ft/min rate of descent.
Adjust the elevator trim and rudder trim (if installed) for
1
stabilized descent at 70-80 KIAS.
Keep hands off the control wheel.
NOTE
In an emergency on airplanes not equipped with an
alternate static source, cabin pressure can be supplied to
the static pressure instruments by breaking the
g~ass
in
the face of the rate-of-climb indicator.
5.
6.
7.
Monitor turn coordinator and make corrections by rudder alone.
Check trend of compass card movement and make cautiou
1
With the alternate static source on, adjust indicated airspeed slightly
corrections with rudder to stop the turn. during climb or approach according to the alternate static source airspeed
8.
Upon breaking out of clouds, resume normal cruising flight. calibration table in Section 5, appropriate to vent/window(s) configura-
RECOVERY FROM A SPIRAL DIVE
If a spiral is encountered, proceed as follows:
tion, causing the airplane to be flown at the normal operating speeds.
Maxim um airspeed and altimeter variation from normal is
4
knots and
30
feet over the normal operating range with the window(s) closed. With
1.
2.
window(s) open, larger variations occur near stall speed. However,
Close the throttle. maximum altimeter variation remains within 50 feet of normal.
Stop the turn by using coordinated aileron and rudder control tc
align the symbolic airplane in the turn coordinator with the
horizon reference line.
3.
Cautiously apply elevator back pressure to slowly reduce the
S Pl NS
airspeed to 80 KIAS.
4.
5.
Adjust the elevator trim control to maintain an 80 KIAS glide. Should an inadvertent spin occur, the following recovery procedure
Keep hands off the control wheel, using rudder control to hold
a
should be used:
6.
7.
8.
straight heading. Adjust rudder trim (if installed) to relieve
unbalanced rudder force.
Apply carburetor heat.
Clear engine occasionally, but avoid using enough power tc
disturb the trimmed glide.
Upon breaking out of clouds, resume normal cruising flight.
FLIGHT IN ICING CONDITIONS
Flight into icing conditions is prohibited. An inadvertent encounter
with these conditions can best be handled using the checklist procedures
The best procedure, of course, is to turn back or change altitude to escape
icing conditions.
STATIC SOURCE BLOCKED
If erroneous readings of the static source instruments (airspeed
altimeter and rate-of-climb) are suspected, the alternate static sourc<
valve should be pulled on, thereby supplying static pressure to thes<
instruments from the cabin.
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1.
2.
3.
4.
5.
6.
RETARD THROTTLE TO IDLE POSITION.
PLACE AILERONS IN NEUTRAL POSITION.
APPLY AND HOLD FULL RUDDER OPPOSITE TO THE DIREC-
TION OF ROTATION.
JUST AFTER THE RUDDER REACHES THE STOP, MOVE THE
CONTROL WHEEL BRISKLY FORWARD FAR ENOUGH TO
BREAK THE STALL. Full down elevator may be required at aft
center of gravity loadings to assure optimum recoveries.
HOLD THESE CONTROL INPUTS UNTIL ROTATION STOPS.
Premature relaxation of the control inputs may extend the recov-
ery.
AS ROTATION STOPS, NEUTRALIZE RUDDER, AND MAKE A
SMOOTH RECOVERY FROM THE RESULTING DIVE.
NOTE
If disorientation precludes a visual determination of the
direction of rotation, the symbolic airplane in the turn
coordinator may be referred to for this information.
For additional information on spins and spin recovery, see the discus-
sion under SPINS in Normal Procedures (Section
4).
3-15