Chapter 12—Transition to Multiengine Airplanes

Table of Contents
Multiengine Flight
Terms and Definitions
Operation of Systems
    Propeller Synchronization
    Fuel Crossfeed
    Combustion Heater
    Flight Director / Autopilot
    Yaw Damper
    Alternator / Generator
    Nose Baggage Compartment
    Anti-Icing / Deicing
Performance and Limitations
Weight and Balance
Ground Operation
Normal and Crosswind Takeoff and Climb
Level Off and Cruise
Normal Approach and Landing
Crosswind Approach and Landing
Short-Field Takeoff and Climb
Short-Field Approach and Landing
Rejected Takeoff
Engine Failure After Lift-Off
Engine Failure During Flight
Engine Inoperative Approach Landing
Engine Inoperative Flight Principles
Slow Flight
    Power-Off Stalls (Approach and Landing)

    Power-On Stalls (Takeoff and Departure)
    Spin Awareness
Engine Inoperative—Loss of Directional Control Demonstration
Multiengine Training Considerations


Fuel crossfeed systems are also unique to multiengine airplanes. Using crossfeed, an engine can draw fuel from a fuel tank located in the opposite wing.

On most multiengine airplanes, operation in the cross- feed mode is an emergency procedure used to extend airplane range and endurance in OEI flight. There are a few models that permit crossfeed as a normal, fuel balancing technique in normal operation, but these are not common. The AFM/POH will describe crossfeed limitations and procedures, which vary significantly among multiengine airplanes.

Checking crossfeed operation on the ground with a quick repositioning of the fuel selectors does nothing more than ensure freedom of motion of the handle. To actually check crossfeed operation, a complete, functional crossfeed system check should be accomplished. To do this, each engine should be operated from its crossfeed position during the runup. The engines should be checked individually, and allowed to run at moderate power (1,500 r.p.m. minimum) for at least 1 minute to ensure that fuel flow can be established from the crossfeed source. Upon completion of the check, each engine should be operated for at least 1 minute at moderate power from the main (takeoff) fuel tanks to reconfirm fuel flow prior to takeoff.

This suggested check is not required prior to every flight. Infrequently used, however, crossfeed lines are ideal places for water and debris to accumulate unless they are used from time to time and drained using their external drains during preflight. Crossfeed is ordinarily not used for completing single-engine flights when an alternate airport is readily at hand, and it is never used during takeoff or landings.


Combustion heaters are common on multiengine airplanes. A combustion heater is best described as a small furnace that burns gasoline to produce heated air for occupant comfort and windshield defogging. Most are thermostatically operated, and have a separate hour meter to record time in service for maintenance purposes. Automatic overtemperature protection is provided by a thermal switch mounted on the unit, which cannot be accessed in flight. This requires the pilot or mechanic to actually visually inspect the unit for possible heat damage in order to reset the switch.

When finished with the combustion heater, a cool down period is required. Most heaters require that outside air be permitted to circulate through the unit for at least 15 seconds in flight, or that the ventilation fan be operated for at least 2 minutes on the ground. Failure to provide an adequate cool down will usually trip the thermal switch and render the heater inoperative until the switch is reset.

Ch 12.qxd 5/7/04 9:54 AM Page 12-6

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PED Publication