wouldn’t both engines be critical
Had a similar debate with my CFI. It is not just yaw from the thrust asymmetry, you also get yaw from:
-asym thrust.. okay this one is obvious
-torque.. less obvious, but the running engine is trying to turn the wing, which in turn tries to turn the plane along its roll axis
-spiraling slipstream.. the reason we apply rudder on T/O in SE)
-accel slipstream.. the descending/vs ascending propeller will generate more adverse yaw because of this.. the center of thrust, so to speak, is actually further out on the wing (or closer in, depending on engine)
**in a perfect world both engines turn inward center of thrust close to plane, etc.. the Duchess for example has no critical engine because of this. On some Aerostars both turn outward.. so both are critical (or are neither?). Why they did that? I have no idea. That's a good question about certification though..
but at blue line you will not VMC roll
Isn't that red line? In the Duchess I learned on and the Aztec I fly now red line is the Vmc speed and blue line is Vyse. We pitch for blue so that if you have an engine failure on departure you are already at best climb speed and you have some margin before you degrade to Vmc. In the Aztec there's a pretty big delta in the two.. Vmc of 70 knots and Yyse of 89 knots, with a Vy of 102 knots. I rotate over red line, (around 80 knots).. go to Vyse.. and with sufficient altitude go to 100-120 knot cruise climb with 24/24 for the power
One thing I saw results of and it impressed me greatly was an engine failure soon after takeoff, no runway remaining - this was DA of 7500, light twin, decent load, in a mountainous bowl.
Pilot pulled both back and bellied in to a pasture, they walked away.
This could have turned out so. much. worse. Like so many others which ended upside down or augered in.
The best option is not always to try to keep on going, on one engine.
"Fly The Airplane" includes doing so by purposely pulling both engines back in order to maintain aircraft control. I don't think this is taught enough.
They teach that you will be a perfect pilot and do everything right during OEI events and land on a runway. Well, we know how that's turned out statistically.
We did a fair amount of Vmc demo work.. it actually was very good at training my first response to (oh crap we're going over) to just closing both throttles. It's like a panacea.. once you are back over red line and stabilized you can asses your options. I'd *like to think* that should I be unfortunate enough to get in the situation of "she's going over!" I'll close them both. Ideally you never get anywhere near Vmc. Mind you, the Aztec and the Duchess are such dopey planes that you've got to really get behind the airplane I'd like to think. Planes without such fat wings (310? / Aerostar?) might have more brisk stall / VMC characteristics