Cessna Hawk XP - Rough Engine Operation or Loss of Power; Engine-Driven Fuel Pump Failure; Low Oil Pressure

SECTION 3
EMERGENCY PROCEDURES
CESSNA
MODEL R172K
NOTE
If disorientation precludes . . .
direction of rotati a visual determmat10n of the
coordinator or theon, the symbolic airplane in the turn
needle of th t · d' t
may be referred to f . . e urn and bank in ica or
or
this mformation.
For additional information on . .
cussion under SPINS in No
1
spms and spm recovery , see the dis-
rma Procedures (Section 4).
ROUGH ENGINE OPERATION OR LOSS OF
POWER
SPARK PLUG FOULING
A slight engine roughness in fli ht m
spark plugs becoming fouled by ca gb ayl be caused by one or more
' f' d r on or ead deposits Th . b
ven 18 by turning the ignition ·t h . . is may e
either L or R position An obvi swi c mof1entanly from BOTH to
tion is evidence of sp~rk plug
0
~~i;r:~~ t~~~~~~ingle ig~ition opera-
spark plugs are the more likely cause lean the mix~~:~mmg that
mended lean setting for cruising flight. If the roble o the recom-
~p m several minutes, determine if a richer mi~ture :t~~~s n?~ clear
uce. smoo.ther operation. If not, proceed to the nearest air wi pro-
repairs usmg the BOTH position of the ignition switch unl~ort for
roughness dictates the use of a single ignition position. ss extreme
MAGNETO MALFUNCTION
A sudden engine roughness or misfiring is usually eviden f
ma.gneto pro.blems. Switching from BOTH to either L or R i c~ .°
switch posit10n will identify which magneto is malfunctioningmtion
different power settmgs and enrichen the mixture to deter · g .. Select
tinued operation on BOTH magnetos is practicable If n tmm~ if con-
the good t ·
0
•
switch to
magne o and proceed to the nearest airport for repairs.
If ignition system malfunctions occur at high altitude and h .
power, as evidenced by roughness and possible backfiring igh
both t on one or
. .magn.e os, t~e power should be reduced as required . This c .
tio:q. is an ~ndicat10n of excessive spark plug gaps which, in turnondi-
causes arcing across the magneto points. '
3-14
r
CESSNA
MODEL R172K
SECTION 3
EMERGENCY PROCEDURES
ENGINE-DRIVEN FUEL PUMP FAILURE
Failure of the engine-driven fuel pump will be evidenced by a sud-
den reduction in the fuel flow indication prior to a loss of power , while
operating with adequate fuel in either or both fuel tanks .
In the event of an engine-driven fuel pump failure during takeoff ,
immediately hold the auxiliary fuel pump switch in the HIGH position
until the airplane is well clear of obstacles. Upon reaching a safe
altitude , and reducing power to cruise settings , placing the switch in
the LOW position will then provide sufficient fuel flow to maintain
engine operation while maneuvering for a landing.
If an engine-driven fuel pump failure occurs during cruising flight,
apply full rich mixture and hold the auxiliary fuel pump switch in the
HIGH position to re-establish fuel flow. Then the LOW position of the
fuel pump switch may be used to sustain level flight. If necessary,
additional fuel flow is obtainable by holding the pump switch in the
HIGH position. If either LOW or HIGH fuel pump switch positions
results in rough engine operation, lean the mixture as required for
smooth operation.
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
precautionary landing because an orifice in this line will prevent a
sudden loss of oil from the engine sump. However, a landing at the
nearest airport would be advisable to inspect the source of trouble.
If a total loss of oil pressure is accompanied by a rise in oil temper-
ature , there is good reason to suspect an engine failure is imminent .
Reduce engine power immediately and select a suitable forced landing
field. Use only the minimum power required to reach the desired
touchdown spot.
ELECTRICAL POWER SUPPLY SYSTEM MAL-
FUNCTIONS
Malfunctions in the electrical power supply system can be detected
by periodi c monitoring of the ammeter and over-voltage warning light;
however, the cause of these malfunctions is usually difficult to deter-
mine . A broken alternator drive belt or wiring is most likely the cause
of a ltern a tor failures, although other factors could cause the problem .
3-15