Multi-Engine Flight Flashcards
Describe the factors which cause yaw and roll toward the inoperative engine.
Yaw is caused by the asymmetric thrust condition.
Roll is produced by several factors.
The reduced flow over the wing from the inoperative engine reduces lift on that wing resulting in differential lift.
Drag increases on the side of the inoperative engine increasing roll and yaw to the inoperative side
Yaw leads to roll
What is a critical engine?
The critical engine is the engine who’s failure most adversely affects the performance and handling characteristics of the aircraft.
How is side-slip eliminated in an engine out situation?
By applying approximately 5 degrees of bank to the live engine. The slight horizontal component of lift counteracts the side slip
What factors lower Vmc?
An increase in weight produces more lift which means a lower speed is required to produce the sideways component of lift to counteract the side slip.
The performance reduction operating at maximum weight may counter the benefit of a reduced Vmc.
Forward CoG increases the moment from the vertical stabiliser which means more asymmetric thrust may be balanced with rudder deflection.
Flap extension reduces Vmc but degrades climb performance
A reduction in power will reduce Vmc but degrade climb performance
While Vmc reduces with an increase in density altitude, stall speed increases.
What are the performance requirements for:
Take Off
En-route climb
Landing climb
Take off
In the take-off configuration with landing gear extended, an aeroplane must have the ability to achieve a climb gradient of 6% at take-off safety speed, without ground effect, and with all engines operating at take-off power.
En-Route Climb
Multi-engined aeroplanes engaged in charter operations under the Instrument Flight Rules or aerial work operations under the Instrument Flight Rules must have the ability to climb with a critical engine inoperative at a gradient of 1% at all heights up to 5 000 feet in the standard atmosphere in the following configuration:
(a) propeller of inoperative engine stopped;
(b) undercarriage (if retractable) and flaps retracted;
c) remaining engine(s) operating at maximum continuous power;
(d) airspeed not less than 1.2 VS.
Landing Climb
In the landing configuration with all engines operating at take-off power an aeroplane must have the ability to climb at a gradient of 3.2% in standard atmospheric conditions at a speed not exceeding 1.3VS.
Define Vmc
The lowest airspeed at which rudder authority can equal unbalanced thrust
What is the difference between published Vmc and actual Vmc?
Actual Vmc is the Vmc based on actual conditions at the time of engine failure.
Published Vmc is the red line speed published in the aircrafts POH. It is based on flight under the conditions in the FARs.
VMC is the calibrated airspeed at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane with that engine still inoperative, and thereafter maintain straight flight at the same speed with an angle of bank of not more than 5 degrees. The method used to simulate critical engine failure must represent the most critical mode of powerplant failure expected in service with respect to controllability.
(b) VMC for takeoff must not exceed 1.2 VS1, where VS1 is determined at the maximum takeoff weight. VMC must be determined with the most unfavorable weight and center of gravity position and with the airplane airborne and the ground effect negligible, for the takeoff configuration(s) with—
(1) Maximum available takeoff power initially on each engine;
(2) The airplane trimmed for takeoff;
(3) Flaps in the takeoff position(s);
(4) Landing gear retracted; and
(5) All propeller controls in the recommended takeoff position throughout.
150lb force on rudder pedals
When is the effects of the critical engine most pronounced?
At low speeds and high power
Why is using only rudder to maintain direction with OEI inefficient?
It causes the aircraft to side slip which increases drag, reduces effective airflow over the rudder and airflow pushes against the vertical stabiliser adding the the yaw to the side on the inoperative engine.
What effect does turning have in an OEI situation?
Turning increases induced drag and so degrade aircraft performance
