ROUGH ENGINE OPERATION OR LOSS OF POWER
An unexplained drop in manifold
pressure and eventual engine roughness may result from the formation of
carburetor ice. To clear the ice, apply full throttle and pull the carburetor
heat knob full out until the engine runs smoothly: then remove carburetor heat
and readjust the throttle. If conditions require the continued use of carburetor
heat in cruise flight, use the minimum amount of heat necessary to prevent ice
from forming and lean the mixture for smoothest engine operation.
SPARK PLUG FOULING
A slight engine roughness in
flight may be caused by one or more spark plugs becoming fouled by carbon or
lead deposits. This may be verified by turning the ignition switch momentarily
from BOTH to eitherL or H position. An obvious power loss in single ignition
operation is evidence of spark plug or magneto trouble. Assuming that spark
plugs are the more likely cause, lean the mixture to the recommended lean
setting for cruising flight. If the problem does not clear up in several
minutes, determine 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 single
A sudden engine roughness or
misfiring is usually evidence of magneto problems. Switching from BOTH to either
LB ignition switch position will identify which magneto is malfunctioning.
Select different power settings and enrichen the mixture to determine if
continued opera tion on BOTH magnetos is practicable. If not, switch to the good
magneto and proceed to the nearest airport for repairs.
ENGINE-DRIVEN FUEL PUMP FAILURE
In the event of an engine-driven
fuel pump failure, gravity flow will provide sufficient fuel flow for level or
descending flight. However, in a climbing attitude or anytime the fuel pressure
drops to 0.5 PSI, the auxiliary fuel pump should be turned on.
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 precau tionary landing because an orifice in this line will prevent a sudden loss of oil from the engine suinp. 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 tempera ture, 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.
LANDING GEAR MALFUNCTION PROCEDURES
In the event of possible landing gear retraction or extension malfunc tions, there are several general checks that should be made prior to initiating the steps outlined in the following paragraphs.
In analyzing a
landing gear malfunction, first check that the master switch is ON and the LDG
GEAR and GEAR PUMP circuit breakers are in; reset, if necessary. Also, check
both landing gear position indicator lights for operation by "pressing-to-test'
the light units and rotating them at the same time to check for open dimming
shutters. A burned-out bulb can be replaced in flight by using the bulb from the
remaining gear position indicator light.
If the landing
gear fails to retract normally, or an intermittent GEAR UP indicator light is
present, check the indicator light for proper operation and attempt to recycle the landing gear. Place
the landing gear lever in the GEAR DOWN position. When the GEAR DOWN light
illuminates, reposi tion the gear lever in the GEAR UP position for another
retraction attempt. If the GEAR UP indicator light still fails to illuminate,
the flight may be continued to an airport having maintenance facilities, if
practical. If gear motor operation is audible after a period of one minute
following gear lever retraction actuation, pull the GEAR PUMP circuit breaker
switch to prevent the electric motor from overheating. In this event, remember
to re engage the circuit breaker switch just prior to landing. Intermittent gear
motor operation may also be detected by momentary fluctuations of the ammeter
Normal landing gear extension time is approximately 5 seconds. If the landing gear will not extend normally, perform the general checks of circuit breakers and master switch and repeat the normal extension procedures at a reduced airspeed of 100 KIAS. The landing gear lever must be in the down position with the detent engaged. If efforts to extend and lock the gear through the normal landing gear system fail, the gear can be manually extended (as long as hydraulic system fluid has not been completely lost) by use of the emergency hand pump. The hand pump is located between the front seats.
A checklist is provided for step-by-step instructions for a manual gear extension.
If gear motor operation is
audible after a period of one minute following gear lever extension actuation,
pull the GEAR PUMP circuit breaker to prevent the electric motor from
overheating. In this event, remember to re-engage the circuit breaker just prior
GEAR UP LANDINGS
If the landing gear remains retracted
or is only partially extended, and all efforts to fully extend it (including
manual extension) have failed, plan a wheels-up landing. In preparation for
landing, reposition the landing gear lever to GEAR UP and push the LDG GEAR
and GEAR PUMP circuit breakers in to allow the landing gear to swing into the
gear wells at touchdown. Then proceed in accordance with the checklist.