Cessna 1973 172 - Landing Emergencies and Ditching

termine if a richer mixture setting will produce smoother operation. If
not, proceed to the nearest airport for repairs using the BOTH position
of the ignition switch unless extreme roughness dictates the use of a sin-
gle ignition position.
MAGNETO MALFUNCTION.
A sudden engine roughness or misfiring is usually evidence of mag-
neto problems. Switching from BOTH to either LEFT or RIGHT ignition
switch position will identify which magneto is malfunctioning. Select dif-
ferent power settings and enrichen the mixture to determine if continued
operation on BOTH magnetos is practicable. If not, switch to the good
magneto and proceed to the nearest airport for repairs.
LOW OIL PRESSURE.
If low oil pressure is accompanied by normal oil temperature, there
is a possibility the oil pressure gage or relief valve is malfunctioning. A
leak in the line to the gage is not necessarily cause for an immediate pre-
cautionary landing because an orifice in this line will prevent a sudden
loss of oil from the engine svunp. However, a landing at the nearest air-
port would be advisable to inspect the source of trouble.
If a total loss of oil pressure is accompanied by a rise in oil tempera-
ture, there is reason to suspect an engine failure is imminent. Reduce
engine power immediately and select a suitable forced landing field.
Leave the engine running at low power diu-ing the approach, using only
the minimum power required to reach the desired touchdown spot.
FORCED LANDINGS.
PRECAUTIONARY LANDING WITH ENGINE POWER.
Before attempting an "off airport" landing, one should drag the land-
ing area at a safe but low altitude to inspect the terrain for obstructions
and siu-face conditions, proceeding as follows:
(1) Drag over selected field with flaps 20° and 70 MPH airspeed,
noting the preferred area for touchdown for the next landing approach.
Then retract flaps after well clear of all obstacles.
(2) On downwind leg, turn off all switches except the ignition and
master switches.
3-3