Multi Engine Considerations Flashcards
How is the Critical Engine defined?
The engine whose failure would most adversely affect the performance or handling qualities of an aircraft.
P.A.S.T.
FAR 1.1
What are the criteria for certifying & establishing Vmc?
COMBATS
C - Critical Engine inop
O - Operating engine full power
M - Most unfavorable weight
B - Bank 5 degrees into operative
A - Aft most allowable CG
T - Takeoff configuration: Flaps & Gear up, fine pitch on the prop
S - Standard Atmospheric conditioins
AND
1. Be able to stop the turn within 20 degrees of original HDG
Found in FAR part 23.149
Define Vmc
- The calibrated airspeed at which..
- When the Critical Engine suddenly becomes inoporative..
- It is possible to maintain control of the airplane with that engine still inoporative..
- And thereafter maintain straight flight..
- At the same speed with….
- An angle of bank of not more than 5 degrees
FAR 23.149 (airworthiness standards)
What is it called when you fly at VYse above the aircrafts Absolute Ceiling?
VYse will deliver your Minimum Sink rate
What is Minimum Sink rate?
Minimum sink rate is the lowest rate of descent for an aircraft, or the speed at which an aircraft loses altitude the slowest
- It occurs at VYse when above the aircrafts absolute ceiling
What is Absolute ceiling?
The altitude at which the Aircraft will no longer climb
What is Service Ceiling?
The alitutde at which an aircraft can maintain a 100 FPM climb
Source: AFH Glossary
What is OEI Service Ceiling?
The altitude that a twin engine airplane can no longer climb at a rate greater than 50 FPM with one engine inoperative AT max takeoff weight
Source: AFH Glossary
Which FAR governs the certification of Vmc speed in light twins prior to 2011?
FAR 23.149
- The DA42 was certified in 2010, so its Vmc falls under this defintion
The new Vmc definition can be found in FAR 23.2135
The in depth details are laid out in AC 22-8C
Which FAR governs certification of Vmc after 2011?
FAR 23.2135
If no Vr speed is published for the aircraft, what speed should be used?
Vmc + 5 kts
Because an twin engine aircraft should not be airborn prior to Vmc. Its unsafe
When should the landing gear be retracted on take off?
The landing gear should be retracted as soon as a positive rate is acheived AND a safe landing can no longer be made
Source: Flying Twins Safely
What are the 6 main elements of the Vmc definition in FAR 23.149
- Calibrated airspeed
- Critical engine suddenly made inop
- Maintain aircraft control
- Straight flight
- Same airspeed
- Bank of not more than 5 degrees
Explain why we need rudder and aileron when our engine dies
- Rudder to counteract the YAW created by the Asymmetrical Thrust
- Aileron to counteract the Roll created by Accelerated Slip Stream due to propeller blast being eliminated on the dead engines wing
What is meant by Zero Sideslip when flying the airplane with one engine inoporative?
Side slip is the angle where the relative wind meets the longituinal axis of the airplane
Achieving Zero Side Slip occurs when the longitudinal axis of the airplane is lined up with the direction of travel through the use of Aileron & Rudder
What is important to remember about how Vmc changes with bank angle?
Vmc may increase by as much as 3 kts for every degree of bank below 5 degrees
Source: Flying Twins Safely
Is VXse higher or lower than VYse? Why dont we use it?
- Slower than VYse, & may be just a few kts above Vmc
- We dont use it because your climb rate will be too low, less than Vy
What is the Blue line on the Airspeed indicator
VYSe - Best rate of climb single engine
85 kts
What is the Red line on the airpseed indicator?
Vmc - Minimum Control speed
What is the speed limit for a Starter assisted engine restart?
Max 100kts
When shutting down the engine for manuevering, what should you remember to do?
START A TIMER!
This will keep you from exceeding the max restart time based on your OAT
What is Accelerate Stop distance?
The amount of runway needed to accelerate to Vr, and come to a complete stop after an engine failure
What is Accelerate Go distance?
The runway required to accelerate to Vr, have an engine fail, and continue take off and climb to a height of 50 ft with a single engine
What happens to performance and thrust when we lose an engine?
We lose 50% of our thrust, but 80-90% of our climb performance
What is the diffence between a Rate of Climb and a climb Gradient?
Rate of climb
* A measure of altitude gained over a unit of time
* Example: Feet Per Minute
Climb Gradient
* The amount of altitude gained over a specified distance, usually 100ft.
* Example: A climb gradient of 1.5% means that that 1.5ft of altitude has been gained over 100ft horizontal distance.
Is there a certification requirment for a light twin to be able to climb with OEI?
No
What is an important consideration regarding flight planning & your OEI Service Ceiling?
You will want to know what altitudes you will be able to maintain while OEI. Can you maintain your selected IFR or VFR altitude?
How should an engine failure after lift off be handled?
Gear Down + Rwy or Overrun remaining
* Power idle and land
Gear up, Negative climb
* Catch and secure the engine
* Land ahead, within a 30 degree window left or right of the nose
Gear up, Positive climb
* Catch the aircraft and secure the engine
* Return for landing
What should be your ‘big picture’ priorities after an engine has failed
- Catch the aircraft to prevent a Vmc spin - RAPAFLIVE (if above 3000ft AGL, run the engine troubleshooting checklist after this step)
- Secure the inoporative engine - IMAPS
- Find a suitable airport to land and begin performing the Landing with One Engine Inoporative Checklist
- Run your engine catching and engine securing checklists
- Squawk 7700 & notify ATC
How do we recover from a stall in a twin engine aircraft?
PREAF RE
P - PWR Idle
R - Rudder opposite direction of turn
A - Aileron Neutral
E - Elevator full forward
F - Flaps Up
——- TURN HAS CEASED——
R - Rudder Nuetral
E - Elevator Up slowlyyy
Acronym: PREAF RE
What are the main differences between stall recovery in a single vs a twin?
- Power goes to idle
- Flaps go up before stopping the turn
Why is a Go-Around to be avoided at all cost durring an OEI landing?
From a landing configuration with any degree of flaps, a light twin will use up an excessive amount of altitude to make the transition from a descent to a climb with gear and flaps down.
* No GO-AROUNDS below 800ft AGL per AFM 3-41
Every effort should be made to execute the approach & landing succesfully the first time
What is important to understand about the relationship between Vmc and stall speed?
Vmc will decrease with altitude, and eventually may fall below stall speed
You may experience a stall warning horn activation prior to Vmc on durring the Vmc demonstration. Recover at the first sign directional control has been lost, OR stall horn
What purpose does the Vmc demonstration serve?
- To demonstrate recognition of the loss of directional control due to slowing below Vmc speed durring OEI operation
- To demonstrate propery recovery technique from a loss of directional control
How should flaps be used when landing OEI?
Flaps should not be used until landing is assured, avoid the use of full flaps
* Flaps may be used on final especially if you are above airspeed.
* It is perfeclty acceptable to land with partial flaps (flaps APP)
What is the difference between OEI operations above and below 3,000ft AGL?
Above 3,000ft AGL
* Catch the aircraft (RAPAFLIVE), and then trouble shoot the problem.
Below 3,000ft AGL
* Catch the aircraft (RAPAFLIVE) and immediately secure the inoporative engine (IMAPS)
Why are you NOT supposed to touch flaps while on the runway after landing in a twin?
A striking number of inadvertent landing gear retractions have occurred when the pilot meant to touch the flaps.
Source: Flying Twins Safely
Dont touch the flaps unless there is a clear operational need to do so
When are you REQUIRED to fly with 5 degrees of bank into the inoporative engine?
Durring the Vmc Demonstration
Source: Flying Twins Safely
What limitations might exist to your Commercial Multi-Engine rating?
No IR
* No pax at night or beyond 50 nm
Type Ratings
* Large aircraft ( > 12,000lbs MTOW)
* Complex aircraft (Flaps, Retractable LDG, Constant pitch prop)
* High Performance aircraft (>200 HP engine)
* TurboJet aircraft
* High Altitude aircraft (service/operating ceiling >FL250)
* Any other aircraft determined by the FAA
Which Advisory Circular goes into detail on Vmc certification?
AC 23-8C
* States that Vmc for light twins is certified at most unfavorable weight: light
Where can the new definition of Vmc be found?
FAR 25.149
What does the AFM state about go-arounds on an OEI landing?
Go-Arounds are NOT recommended below 800 AGL as climb performance may be insufficient
* The better scenario may be to continue the landing, even under IFR conditions..
AFM 3-41
What is recommended if we need to use the Emergency Gear Extension Lever and we don’t have all three lights green?
Slow below 110kts and apply moderate yawing and pitching to attempt gear locking
AFM 3-50
What important Memory Items are located on the DA42 QRC
Emergency Checklists:
1. Engine Failure in Flight - Detect. (Follow up with Engine Troubleshooting if above 3000ft AGL)
2. Engine Securing
3. Engine Fire
4. Electrical Fire (think of this as smoke in the cabine for the DA42)
5. Spin Recovery (PREAF-RE)
6. AP/Trim Malfunction (AP disc)
Besides the memory items, what other important emergency checklists are on the DA42 QRC?
- Landing OEI
- Emergency Descent
- Unitentional Flight into Icing
- Alternator Failure single/dual
What would your decision process look like if you saw that the left main light did not illuminate durring a landing?
- Refer to appropriate checklist
- Re-cycle the gear
- Use the emergency gear extension
- slow below 110kts & shake the airplane using moderate yaw & pitch movements to try and lock it into place
- Proceed with Landing with Gear Up checklist if above has failed
What would you do if on takeoff your gear did not retract?
It would be wise to return and land, however, the AFM does state that it is possible to continue flight with the gear down.
* Keep in mind that your performance will be reduced and you will experience increased fuel consumption & ETE/ETA
AFM 3-48 (note)
At what point should the the landing gear be retracted after take off?
Only after a positive rate has been achieved AND there is not enough runway remaining to land on
What point will you use to determine your Acelerate-Go distance?
Gear up, negative rwy/overrun remaining
