Static Source Blocked; Spins - Cessna 172S Nav III Information Manual

SECTION 3 CESSNA
EMERGENCY PROCEDURES MODEL 172S NAV 111
STATIC SOURCE BLOCKED
If erroneous readings of the static source instruments (airspeed,
altimeter and vertical speed) are suspected, the ALT STATIC AIR
valve should be pulled ON, thereby supplying static pressure to
these instruments from the cabin.
When the ALT STATIC AIR valve is ON, the maximum airspeed
variation from normal static source operation is 11 knots and the
maximum altimeter variation is less than 50 feet (all windows
closed). Refer to Section 5, Airspeed Calibration and Altimeter
Correction tables for Alternate Static Source for additional details.
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
DIRECTION 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 recovery.
6. AS ROTATION STOPS, NEUTRALIZE RUDDER. AND MAKE
A SMOOTH RECOVERY FROM THE RESULTING DIVE.
NOTE
If the rate of the spin makes determining the
direction of rotation difficult, the magenta turn rate
indicator at the top of the HSI compass card will
show the rate and direction of the turn. The HSI
compass card will rotate in the opposite direction.
Hold opposite rudder to the turn vector direction.
For additional information on spins and spin recovery, see the
discussion under SPINS in Normal Procedures (Section 4).
3-30 U.S. 172SPHAUS-03