Avicon,
The following is provided for information only - please get proper instruction, in an aircraft, from a multi-engine instructor, as part of an approved course!
Other instructors may do this slightly differently, but here's how I do it:
- Perform relevant airmanship actions - safe altituden, appropriate area, good lookout.
- I have control of the aircraft; however, you have control of the rudder.
- Please use the rudder to prevent yaw (using a distant visual feature as a reference, as taught on previous exercises).
- Whilst maintaining pitch, and keeping wings level with ailerons, I gradually close one throttle, expecting you to apply rudder (and trim) to prevent yaw. I then increase power on the other engine until it's at maximum power, again expecting you to apply rudder to prevent yaw.
- I point out to you our current airspeed.
- I pitch the aircraft up, a little at a time, in order to gradually reduce airspeed. After each change in pitch, I wait for you to increase rudder as necessary, and re-trim the rudder, then we look at the new, lower airspeed.
- I repeat this as many times as necessary until you run out of rudder, at which point we note the speed - this is Vmc.
Everything up to this point is a repeat of a previous exercise we've already done, to demonstrate the connection between airspeed and rudder.
- I then pitch up once more, just a tiny bit this time to decrease speed by only a couple of knots. I encourage you to apply more rudder to prevent the yaw, but of course you are unable. Over the next few seconds, the yaw develops into a spiral dive.
- I take control of the rudder ("I have control"), then demonstrate the recovery: close both throttles, lower the nose, then recover to the desired attitude.
Depending on circumstances (student ability, weather, aircraft type, etc), I might repeat this a few times with different scenarios: wings level vs 5 degrees of bank is my favourite, but also critical vs non-critical engine, zero thrust vs windmilling, noting what difference the change makes to Vmc.
FFF
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