Principles Of Flight-Engine Inoperative Flashcards
Effects of density altitude on VMC demo?
As the density altitude is increased, or you climb in altitude, this decreases the performance of the operating engine, which actually decreases VMC speed (which is good). This is why you may encounter stall conditions prior to losing directional control. To prevent the stall conditions, an instructor will often times place there foot behind the right rudder (simulating the no more than 150 lbs of rudder force) limiting rudder authority and causing a loss of directional control.
Meaning of the term Critical Engine?
The engine whose failure would most adversely affect the performance of the aircraft.
Airplane weight and CG on VMC?
As weight is increased the right engine has a harder time moving mass. This decreases VMC speed which is good.
As the CG moves aft, the arm and therefore moment is decreased. This results in less rudder authority which increases VMC (bad).
Effects of angle of bank on VMC?
Banking helps lower VMC which is good. More than 5 degrees lowers VMC even more becomes the more you bank, the closer you bring the moment of that operating engine closer to the longitudinal COG. So, while you may lower your VMC speed, you vertical lift component drops drops dramatically, not good. Up to 5 degrees of bank allows for increased performance and a decrease in VMC which both are good. This allows for zero side slip.
Relationship of VMC to stall speed?
VMC must not exceed 1.2 Stall speed Vs1
This chart is depicted with DA up the left hand side and airspeed along the bottom. Stall speed line goes straight up from stall speed. Let’s say 84. The VMC line is curved going bisecting Vs half way down. The area above and left is the stall first area. The area below and right is the yaw first area.
With normally aspirated engines, as DA increases, VMC decreases. A stall will occur prior to losing directional control. If lower DA, then you will lose dir control first.
The “critical” density altitude is right in the middle of the chart where the stall speed and VMC are the same which can result in a spin.
Reasons for loss of directional control?
PAST
P p-factor. The descending blade on high angles of attack creates more thrust on the right engine because it has a greater arm which creates more moment=potential rotational force
A accelerated slip stream. Again, the descending blades create more thrust which on the right engine is acting upon an area of the right wing which if further outboard than the area on the left wing. Greater arm and moment.
S spiraling slip stream. On a conventional twin, more of the slip stream, or prop wash of the critical engine hits the rudder and elevator (empennage). With the loss of left engine you have less rudder and elevator authority simply due to the reduction of air flow
T torque. Newton’s first law, for every action there is an equal and opposite reaction. The prop spinning right makes the aircraft roll to the left. More so if you lose the left engine because the right, which has greater arm and moment, is still operative. Also, when it comes to center of gravity (looking at the airplane from the back), the torque from the left engine lifts up on the COG where as the torque of the right pushes down on the COG. Losing the left looses that lifting effect decreasing performance.
Indications of loss of directional control?
Explain VMC demo
Slow to 122 mph and reduce power on CE. Pitch to lose 1 mph/sec. Recover when unable to maintain dir control or stall conditions (horn)
No more than 5 degrees and 150 lbs, unable +- 20 degrees
Importance of maintaining proper pitch and bank attitude, and proper coordination of controls?
Describe zero side slip
Zero side slip (coordinated flight) is done by simply keeping the ball centered with both engines operative. However when you lose one engine this is not the case. In order to keep the aircraft in straight and level flight you must bank towards operative engine or “raise the dead” engine “lift” by approx 2 degrees. This creates a new bottom or low area in the inclinometer where the ball must be in order to have zero slide slip. By using your rudder to place approx 1/2 of the ball on the line of the inclinometer closest to operative engine you have allowed for zero side slip which gives you best performance under circumstance.
Loss of directional control recovery procedure?
Describe VMC demo recovery.
Within +-20 degrees, Reduce power on op engine and pitch for blue line, then power full on op engine maintaining blue line.
Explain engine failure during takeoff including planning, decisions and single-engine operations.
Essentially your takeoff brief.
If engine failure on takeoff roll, reduce power and brake as req and get off rwy ASAP
If failure at lift off and gear down then land straight ahead
If failure after lift off and gear and flaps run the saying, mixture, props, power (full) gear up, flaps up, fix or feather (feather in this case) and enter the pattern and land. Remember speeds and procedures are much the same until short final, flaps 15 at perch helps with lift. Short final when rwy ensured slow to 105 and flaps 30 as required…pull both throttles back at oper reduction.
What acronym describes performance reducing elements of losing the critical engine?
PAST
P p-factor. The descending blade on high angles of attack creates more thrust on the right engine because it has a greater arm which creates more moment=potential rotational force
A accelerated slip stream. Again, the descending blades create more thrust which on the right engine is acting upon an area of the right wing which if further outboard than the area on the left wing. Greater arm and moment.
S spiraling slip stream. On a conventional twin, only the slip stream, or prop wash, hits the rudder and elevator (empennage). With the loss of left engine you have less rudder and elevator authority simply due to the reduction of air flow
T torque. Newton’s first law, for every action there is an equal and opposite reaction. The prop spinning right makes the aircraft roll to the left because the force pushes down on the center of gravity. More so if you lose the left engine because the right, which has greater arm and moment, is still operative. If you loose the right engine, the rotational force of the torque of the left engine actually helps lift the center of gravity.
What are Vyse, VMC, Vsse speeds of C310?
VMC 80 air, 95 ground
Vyse 111
Vsse 95 single engine safe speed, slightly higher than VMC to provide safety margin
How much performance is lost when losing an engine?
50% power but 80% in performance
Due to loss of performance of losing an engine, it is important to establish _________, which done by?
Zero side slip (coordinated flight) is done by simply keeping the ball centered with both engines operative. However when you lose one engine this is not the case. In order to keep the aircraft in straight and level flight you must bank towards operative engine or “raise the dead” engine “lift” by approx 2 degrees. This creates a new bottom or low area in the inclinometer where the ball must be in order to have zero slide slip. By using your rudder to place approx 1/2 of the ball on the line of the inclinometer closest to operative engine you have allowed for zero side slip which gives you best performance under circumstance.
Describe the FAA standard for factors in determining VMC speed for takeoff.
A good acronym is SMACFUM
S-standard day M-max power on operating engine A-aft CG or most adverse CG C-critical engine not feathered F-flaps and gear up (flaps provide drag and gear and gear doors act like a keen on a boat providing directional control U-up to 5 degrees of bank and 1/2 ball M-most unfavorable weight (light)
Must be able to maintain within 20 degrees and no more than 150lbs rudder force
