Maneuvering with one engine inop guidance..

middies10

middies10

Well-Known Member
Hey guys,

I working on developing outlines and lesson plans for the MEI topics. For some reason this topic is giving my particular trouble. I just don't know where to start. I already discussed sideslip vs. zero sideslip but thats all i can really come up with.

Can someone say something that could kick my butt into gear? A topic or something worth discussing..

Thanks!!
 
You should include the asymmetric thrust, asymmetric drag, asymmetric lift, and aerodynamic coupling that causes the yawing and rolling tendencies in an OEI situation. Then you can discuss the critical engine concept. And don't forget about the new V speeds, Vyse and Vmc. With the Vmc, you can talk about the factors that were used to create the published Vmc speed, and how any change in those factors will affect the actual Vmc speed of the aircraft. You want to also teach your students the relationship of controllability to airspeed. Another thing you should include is what they should do in an OEI situation, when they do start to lose directional control, or get close to a stall. The last part, is have a good flow for them to use immediately following an engine failure. Mine is:
  • Maintain Directional Control (i.e. heading)
  • Pitch for Vyse
  • Maximum Power on the Operating Engine
  • Verify Gear Up, Flaps Up
  • Then Decide: Fix (Troubleshoot) or Feather
I also spend a lot of time on single engine performance, and make then set their own personal minimums. Minimums like a minimum fix altitude (anything below that they instantly feather), and minimum maneuvering altitude (anything below they will continue to climb straight ahead to get altitude before maneuvering), make their decision making process happen on the ground, so they don't have to try to decide on a course of action while dealing with everything else going.

Since all of my multi-engine students are instrument rated, I spend some time talking about how to handle engine failures in IMC (no different than VMC really), but more importantly how the performance numbers will compare to instrument procedures, especially with minimum climb gradients. Also, since I fly in very mountainous terrain, drift down is critical, especially when picking IFR routes with high MEAs (some around 16,000 ft.).

Hopefully this helps you out. All but one of my students are multi-engine students, so I teach this on a pretty regular basis (understatement of the year). Let me know if you need any more help with this one. Gook luck.
 
To elaborate on the above, let’s put Vmc factors into perspective with real world application…


I’m have been both a skydive pilot in a King Air and Survey pilot in suped up Cessna 310s and Navejos.

Max T/O Power @ SL – Both jobs required high power settings in phases of flight other than take off with nearly full or full power. Skydiving you’re paid by the load and need to get to altitude ASAP. How do you do that? Max continuous power. In survey you mow lines in the sky, many times as fast as the shutter speed can handle. Many times that’s at max continuous power.

At Gross Weight – yeah both jobs are pretty much at max gross weight during each sortie. I wont say that either of these jobs regularly operated over max gross weight, because that would just be silly. No one has ever operated an airplane over max gross weight.

Most adverse CG – In skydiving I have 15 people onboard, all wanting to be the first one out the door or a part of a BIG WEIGH. A big weigh is when as many people as possible are holding on to the airframe so they all can release together. Yeah, I’m flying as slow as I can with 5 people in the door, 4 outside, and 6 ready to run out behind the people in the door. The door is at the rear of the plane… With survey, the camera weighs 200 pounds, The operator sits behind the camera monitoring the computer equipment – that’s 400 pounds at the rear of the plane – about as far aft CG as is in the envelope…

Gear up – Yep, it’s mostly up in both operations

Take off flaps – Dropping meat missiles you fly as slow as you can so they don’t get ripped off the side of the airplane, that means take off flaps. Flying survey, when flying low many times I am speed restricted because of shutter speed – that means take off flaps to slow me down enough to get the shot.

Prop windmilling – no autofeather on either plane, so it’s going to be windmilling until I get it secured and I’m only an average pilot.

Out of ground effect – yep – most of the time.

5 degree bank – like I said, I’m average. I’m probably going to be amped up with the engine chunking and wont remember the bank until after I’ve secured the enging. We’ll see.


So as you can see for the past 3,000 hours of flying I have been operating with the most unfavorable factors which affect Vmc. I would recommend talking to your students about the realities of flying when you’re not in a 121 or 135 operation.
 
Exactly what Moxie said. Having a good knowledge of your Vmc speed, and the things that affect it are crucial for all multi-engine pilots. I want my student to know exactly whats happening with their aircraft during an OEI situation, and be able to apply and correlate their knowledge to have a good idea of how the factors, they are currently in, will affect the actual Vmc speed.

The acronym I teach for Vmc Factors (published Vmc Speed) is SMACTUM:
  • Sea-Level Pressure and Standard Temp (Density Altitude)
  • Maximum Power on the Operating Engine
  • Aft Legal C.G.
  • Critical Engine Windmilling
  • Takeoff Configuration, Out of Ground Effect
  • Up to 5 degrees of bank towards the Operating Engine
  • Most Unfavorable Weight (Light Weight)
It's all about controllability, and if they have done the weight and balance/performance for the flight, they can run through this entire list and get an idea of where the actual Vmc speed will be in relation to the published Vmc. Always good to know prior to any flight! You can go through this list and discuss how any changes in these factors will change the actual Vmc speed for your aircraft.

Also, if your twins have turbo chargers, that changes things up as well.
 
moxiepilot said:
So as you can see for the past 3,000 hours of flying I have been operating with the most unfavorable factors which affect Vmc. I would recommend talking to your students about the realities of flying when you’re not in a 121 or 135 operation.
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...or even in a 121 operation:
1233102.jpg

The aerodynamics involved are the same...and let's talk about just how "critical" that left engine is, with the right engine center of thrust 5.25 feet further out thanks to the miracle of P-factor. (Or how critical prop feathering is at any airspeed when a 10.5'-diameter disc suddenly, uh, discs.)


Of course, the customer (and the government) demands a safer sandbox.


middies10 said:
Hey guys,

I working on developing outlines and lesson plans for the MEI topics. For some reason this topic is giving my particular trouble. I just don't know where to start. I already discussed sideslip vs. zero sideslip but thats all i can really come up with.

Can someone say something that could kick my butt into gear? A topic or something worth discussing..

Thanks!!
Click to expand...
"Speed is life." It sounds like a stupid platitude, but it is fact: there's not an average private-multi-instrument guy on the planet who can handle an unexpected engine failure at Vmca without a snaproll. Vmca is certification; reality demands more speed.


As far as actual useful operational advice, Always run your twin as if it's already on one engine and you will live.
p1l07m4n said:
  • Maintain Directional Control (i.e. heading)
  • Pitch for Vyse
  • Maximum Power on the Operating Engine
  • Verify Gear Up, Flaps Up
  • Then Decide: Fix (Troubleshoot) or Feather
Click to expand...
It's implied, but it should be clearly stated: if the gear is still down during initial climb in your average light twin, you're better off chopping, dropping, and stopping.
 
Autothrust Blue said:
It's implied, but it should be clearly stated: if the gear is still down during initial climb in your average light twin, you're better off chopping, dropping, and stopping.
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Oh, yeah, this ^ definitely! At our school, we teach our students not to bring the gear up until you are out of useable runway and have a positive rate of climb. Unfortunately, just past 3 out of 4 of our runways is water...a massive lake.

However, if you still have plenty of runway, you can easily set it back down on the runway remaining. That just reiterates the need for accurate performance numbers prior to each flight, along with the accelerate stop and accelerate go distances (if you have that, our twins can't go). Luckily we have a sim that accurately simulates our twins, so I spend a bunch of time in the sims with my students before even letting them near the aircraft. The way I tell it to my students, "I'd much rather lose and engine, and put it back on the runway, and go off the end at 5-10 kts., rather than end up putting it into the lake (or the neighborhood off our other runway)."
 
p1l07m4n said:
Oh, yeah, this ^ definitely! At our school, we teach our students not to bring the gear up until you are out of useable runway and have a positive rate of climb. Unfortunately, just past 3 out of 4 of our runways is water...a massive lake.

However, if you still have plenty of runway, you can easily set it back down on the runway remaining. That just reiterates the need for accurate performance numbers prior to each flight, along with the accelerate stop and accelerate go distances (if you have that, our twins can't go). Luckily we have a sim that accurately simulates our twins, so I spend a bunch of time in the sims with my students before even letting them near the aircraft. The way I tell it to my students, "I'd much rather lose and engine, and put it back on the runway, and go off the end at 5-10 kts., rather than end up putting it into the lake (or the neighborhood off our other runway)."
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How cute, a light twin with performance data? (I heart CAR 3. :D )

As Vr increases this advice is no longer valid, but as that happens you tend to have more power (and fewer problems, actually).

One of my instructors did a really neat thing that illustrated why your typical 360-hp Seminole turns into a dog (and loses much more than 50% of its performance) when an engine quits. I don't think I have it written down anywhere anymore, but they took the 360 horsepower budget, and broke it down into the various "consumers" of that power (drag, maintaining altitude, etc.). Sort of an eye-opening way to start your first day of twin training.
 
Autothrust Blue said:
One of my instructors did a really neat thing that illustrated why your typical 360-hp Seminole turns into a dog (and loses much more than 50% of its performance) when an engine quits. I don't think I have it written down anywhere anymore, but they took the 360 horsepower budget, and broke it down into the various "consumers" of that power (drag, maintaining altitude, etc.). Sort of an eye-opening way to start your first day of twin training.
Click to expand...

Yeah, I guess we have nothing else to call it. :) 180 feet per minute rate of climb OEI is the about the highest I've seen. Not very good in mountainous areas.

I do something like that with my students, but just climb rates vs. airspeed on a graph. I include two engines, zero engine, and the infamous OEI. They are always surprised that a 50% loss of power can easily equal an 80% loss in climb performance. I would love to get my hands on the sort of info your instructor gave you. I guess I will have to hit the books, and bug the manufacturer again. That would be really cool to show to my students.
 
TwoTwoLeft said:
Just don't feather the good one....
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Yeah, no joke. I teach my student to identify the failed engine, verify it, confirm it. Then when actually shutting it down to identify, verify confirm each control/switch/lever prior to executing the movement. I had one student fail his private add-on because he secured the wrong engine (after saying the correct engine, but pointing to the wrong master switch). Pisses me off to this day because he had never done that before. Oh, well. Now he never secures the wrong one, so I guess he took something away from it.
 
p1l07m4n said:
Yeah, no joke. I teach my student to identify the failed engine, verify it, confirm it. Then when actually shutting it down to identify, verify confirm each control/switch/lever prior to executing the movement. I had one student fail his private add-on because he secured the wrong engine (after saying the correct engine, but pointing to the wrong master switch). Pisses me off to this day because he had never done that before. Oh, well. Now he never secures the wrong one, so I guess he took something away from it.
Click to expand...

Don't sweat it too much. As if the training environment wasn't unrealistic enough, the checkride is even worse. What I found I end up doing during REAL emergency situations is spending the first few moments cussing out the airplane. Once I get all that out, I tend to slow down and focus on the task at hand.
 
Now that I've had time to read through, I was pressed for time yesterday, there is a big one missing. Talking about side slip and zero side slip is great. Pointing out that banking beyond zero side slip greatly improves controllability can be equally important. Also how cutting power guarantees normal controllability again (assuming you've not jacked up your rudder trim).

Keep in mind that the game for control often has the consequence of decreasing your performance. Both scenarios above (bank past zero side slip and reducing power) will greatly diminish your performance; sometimes that's a necessary evil to give you enough control to avoid laying on your back.

Summary: Three key ways to get control back when you've run out of rudder --

  • Reduce AOA
  • Reduce power (to idle if the situation is severe enough
  • Bank more into the good engine
 
I'm in the middle of my MEI ride right now (supposed to finish tomorrow, discontinued for wx on Monday). This is all good info! Make sure to teach them never to give up controllability to gain performance. How does zero-sideslip help control or performance, etc, etc.

I'm sure I'll gain experience and knowledge as I go along, it will definitely be a nice change of pace from primary and instrument instruction!
 
When the engine goes, especially if it goes on takeoff, don't freak out and start panic-pulling levers just to be pulling levers, if you are past the "point of no return" (that is, gear is up). This is where it comes in very handy to know not only your OEI climb performance and your drag penalties. In the 'nole at our airport, even on a summer day at average weights, the charted rate-of-climb is more up than the windmilling propeller is down. If you're on climbout and an engine gives up the ghost, pitch for 88 and take a few deep breaths to allow your head to wrap itself around the situation. Then let your training take over.
 
gotWXdagain said:
When the engine goes, especially if it goes on takeoff, don't freak out and start panic-pulling levers just to be pulling levers, if you are past the "point of no return" (that is, gear is up). This is where it comes in very handy to know not only your OEI climb performance and your drag penalties. In the 'nole at our airport, even on a summer day at average weights, the charted rate-of-climb is more up than the windmilling propeller is down. If you're on climbout and an engine gives up the ghost, pitch for 88 and take a few deep breaths to allow your head to wrap itself around the situation. Then let your training take over.
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Yes that. You should never be rushing anything in a twin. Take your time, and do it right the first time!
 
Passed my MEI yesterday, time to put this stuff to work! :) Thank you to everyone who shared good tips and guidance. I'm sure middies10 will appreciate it when he has to do his ride.
 
Turning while banking isn't as big of a deal doing it as it is in the classroom. IF you happen to be in a "fine piece of crap" such as a piper semenhole, you'll notice that you can do steep turns and do it just fine.... if you're in a conventional twin, i'd advice strongly against what I just said...
 
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