Flight In Icing Conditions; Spins; Recovery From A Spiral Dive; Static Source Blocked - Cessna Hawk XP R172K Pilot Operating Handbook

SECTION 3
EMERGENCY PROCEDURES
CESSNA
MODEL R172K
CESSNA
MODEL R172K
a descent through a cloud deck to VFR conditions may be appropriate.
If possible, obtain radio clearance for an emergency descent through
clouds. To guard against a spiral dive. choose an easterly or westerly
heading to minimize compass card
sw
ings due to changing bank an-
gles. In addition, keep hands off the control wheel and steer a straight
course with rudder control by monitoring; the turn coordinator.
Occasionally check the compass heading; and make minor corrections
to hold an approximate course. Before descending into the clouds, set
up a stabilized let-down condition as follows:
(1) Reduce power to set up a. 500 to HOO ft./ min. rate of descent.
(2) Adjust the mixture as requ ired for smooth engine operation.
(3) Adjust the elevator and rudder trim for a stabilized descent at
75 KIAS.
(4) Keep hands off control whee I.
(5)
Monitor turn coordinator
and mu.k
o corrections by rudder alone.
(6) Adjust rudder trim to relieve unbalauoed rudder force, if pres-
ent.
(7) Check trend of compass card III()VI~mentand make cautious cor-
rections with rudder to stop turn.
(8) Upon breaking out of clouds. rusu m» normal cruising flight.
RECOVERY FROM A SPIRAL DIVE
If a spiral is encountered, proceed
a:,
follows:
(1) Close the throttle.
(2) Stop the turn by using coord i
II ;1,Lu(\
aileron and rudder control to
align the symbolic airplane in l.h«
\.11I'll
coordinator with the horizon
reference line.
(3) Cautiously apply elevator back prossu re to slowly reduce the
airspeed to 75 KIAS.
(4) Adjust the elevator trim control t.o rn a.inta.in a 75 KIAS glide.
(5) Keep hands off the control whoo l. w;ing rudder control to hold a
straight heading. Use rudder trim t.o rol ie ve unbalanced rudder
force, if present.
(6) Clear engine occasionally, but avoid using enough power to
disturb the trimmed glide.
(7) Upon breaking out of clouds, resume normal cruising flight.
F GHT IN ICING CONDITIONS
Intentional flight into known icing conditions is prohibited in this
airplane. During instrument flights, however, icing conditions may be
encountered inadvertently and therefore some corrective action will be
required as shown in the checklists. Initiation of a climb is usually the
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SECTION 3
EMERGENCY PROCEDURES
best ice avoidance action to take; however, alternatives are descent to
warmer air or to reverse course.
STATIC SOURCE BLOCKED
If erroneous instrument readings are suspected due to water, ice, or
other foreign matter in the pressure lines going to the standard exter-
nal static pressure sources, the alternate static source valve should be
pulled on.
A calibration table is provided in Section 5 to illustrate the effect of
the alternate static source on indicated airspeeds. With the windows
and vents closed the airspeed indicator may typically read as much as
4 knots slower and the altimeter 50 feet lower in cruise. With the vents
open and heater on, these variations increase to 7 knots slower and 50
feet lower respectively. If the alternate static source must be used for
landing, airspeed errors of up to 10 knots slower with vents open and 4
knots slower with vents closed can be expected. Altimeter errors re-
main 50 feet low.
NOTE
In an emergency on airplanes not equipped with an alter-
nate static source, cabin pressure can be supplied to the
static pressure instruments by breaking the glass in the
face of the rate-of-climb indicator.
SPINS
Should an inadvertent spin occur, the following recovery procedure
should be used:
(1) RETARD THROTTLE TO IDLE POSITION.
(2) PLACE AILERONS IN NEUTRAL POSITION.
(3) APPLY AND HOLD FULL RUDDER OPPOSITE TO THE DI-
RECTION OF ROTATION.
(4) 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.
(5) HOLD THESE CONTROL INPUTS UNTIL ROTATION STOPS.
Premature relaxation of the control inputs may extend the recov-
ery.
(6) AS ROTATION STOPS, NEUTRALIZE RUDDER, AND MAKE
A SMOOTH RECOVERY FROM THE RESULTING DIVE.
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