Twin Piston Take-off and Single Engine Operations

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McDonnell-Douglas
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Twin Piston Take-off and Single Engine Operations

Post by McDonnell-Douglas »

In my preparation for an eventual Accusim twin piston in MSFS, yes I am hopeful :P , I had some queries that were best clarified by the community.

What is the recommended procedure for determining safe take-off speed in a twin piston aircraft such as the Beechcraft 58 Baron or Aerostar 600?
On the 58 Baron Vmc (minimum control speed) and Vr (rotation) is 85 KIAS, Vs1 (stall, clean) is 84 KIAS, and Vyse (best rate of climb, single engine) is 105 KIAS with Vxse (best angle of climb, single engine) at 95 KIAS.
I am not an aviator, unless you include simulation, or an expert in general aviation/aeronautics but it would appear risky to me to rotate and take-off in the wide margin between Vmc and Vyse i.e. 85-105 KIAS.
Would it not be safer to rotate at 92-95 KIAS or higher and ensure you were at least at Vxse after take-off? Gear retraction in the Baron is three seconds and flaps not much longer, so the clean-up and acceleration to Vyse would be quick; hopefully before complete single engine failure.

Single engine failure in a light twin have been demonstrated safely consistently except under take-off, where the majority of single engine incidents and fatalities occur.
What is the recommended procedure for single engine failure on the engine before reaching Vyse and after?
My assumption was that below Vyse, your only option is to put the aircraft down; better to put it down or crash into the trees than do so inverted :lol:
Above Vyse, apply opposite rudder to that of asymmetric thrust, turn five degrees into the operative engine and feather the inoperative engine. After which I assume you would contact ATC, climb above Vyse only and plan for a landing; a runway if you can.
Aircraft such as the Baron and Aerostar have sufficient power on one engine to at least maintain level flight on one engine.

Is the procedure for countering asymmetric thrust with the rudder aided by experience in high performance single aircraft. I ask this because my natural inclination to counter my aircraft rotating on the X axis and Z axis is immediate rudder in the opposite direction followed by aileron correction. I have no experience in aircraft such as the Cessna 172 or Bonanza but in the A2A Mustang or Spitfire you learn this lesson very quickly :mrgreen:
Dead engine, dead foot would not be my first thought but I would inevitably apply the method; I would simply seek to counter the force acting on my aircraft.

My takeaway from the aviation safety network statistics is that light twin pistons are a double-edged sword.
In theory when flown competently and the correct inputs are made a light twin piston is safer than a single; having more options. However, the margins for error in a light twin are much thinner and the consequences more severe i.e. Vmc rollover (certain death). Thus, a pilot has to be on their ‘a-game’ a much higher percentage of the flight time, minimise errors and correct errors quickly and sufficiently. As a result, in practice it is a mixed bag.

Successful handling of inflight single engine failure in a Baron:
https://www.youtube.com/watch?v=9n7B6cURtwE

The case for increasing Vmc and take-off speeds:
https://www.youtube.com/watch?v=Wbu6X0hSnBY

Best Regards,
Colin

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AKar
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Re: Twin Piston Take-off and Single Engine Operations

Post by AKar »

I am not an active pilot, and never really flown a piston twin properly at controls (though I have flown just some things somewhat actively some time back). But viewing the matter from technical and certifying point-of-view, light piston twins are generally not capable of continued takeoff with a failed engine. Yes, some may be, at least in very favorable circumstances, but generally they are not, nor are they required to be. OEI performance requirements can be thought of being like allowing for continued cruise flight. As a bonus, if clean and flown with astronomical accuracy, some may give out almost usable rate of climb.

The thing is really that after liftoff, there ought to remain sufficient obstacle-free forward sector (some runway would be nice) to get back down on should an engine fail before getting the aircraft up to a good climb speed, completely clean, and up to some height. Of course, after lifting off and before being out of landable real estate, the priority ought to be that of fulfilling the performance goals listed before.

-Esa

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Paughco
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Re: Twin Piston Take-off and Single Engine Operations

Post by Paughco »

Here are a couple good videos on single engine operations with a twin engine aircraft:

Part 1 https://www.youtube.com/watch?v=L_KGu2CFUU4&t=6s and Part 2 https://www.youtube.com/watch?v=VcEg39NmxY4.

Part 2 really gets into Vmc (the blue line) and what happens if you drop below that speed on one engine. Pretty serious.

Seeya
ATB
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McDonnell-Douglas
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Re: Twin Piston Take-off and Single Engine Operations

Post by McDonnell-Douglas »

Esa,
That was my initial observation. Single engine performance on light twins after take-off is sufficient but far from ideal; possible not fun :lol:
If you compare this to the Super King Air 200 series, the twin turboprops offer enough thrust that the aircraft is likely to reach Vyse very shortly after takeoff. In fact, I believe it is certified for continued take-off after reaching V1.

I would personally prefer a longer runaway or an obstacle free forward sector myself for both scenarios; coming down or the option to lower the nose for Vyse plus 5/10.

Paughco,
Fantastic youtube link. Doug Rozendaal is appears to be a popular guy, a bit of a legend.
The discussion on rudder design and Vmc is definitely worth viewing. The Baron offers power and significant single engine climb rate but one must react fast to any yawing.

Doug never mentioned it specifically but in line with Esa's thoughts I assume that in the scenario where the gear is in transition or retracted but you cannot clear the obstacles or change in height of the forward area terrain one would have no choice but to land gear up in front; if necessary in the obstacle. The latter still being preferable to doing so stalled and inverted?

Best Regards,
Colin

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AKar
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Joined: 26 May 2013, 05:03

Re: Twin Piston Take-off and Single Engine Operations

Post by AKar »

McDonnell-Douglas wrote: 16 Mar 2022, 08:05 Esa,
That was my initial observation. Single engine performance on light twins after take-off is sufficient but far from ideal; possible not fun :lol:
If you compare this to the Super King Air 200 series, the twin turboprops offer enough thrust that the aircraft is likely to reach Vyse very shortly after takeoff. In fact, I believe it is certified for continued take-off after reaching V1.

I would personally prefer a longer runaway or an obstacle free forward sector myself for both scenarios; coming down or the option to lower the nose for Vyse plus 5/10.
Colin,

unfortunately I am in the middle of some things, so I can't quickly refer into things I have in the back of my mind. Yet, I think (and could be wrong) that many of the King Air series were certified under FAR 23 into commuter category when it still was a thing. Even those specifications have changed over time, thus they are likely different in the latest ones from the time the aircraft was certified. Regardless, light twin turboprops are usually of very good thrust-to-weight ratio, and have respectable OEI performance (though they can be, rather dangerously, rudder-limited!). They can very well be capable of continued single-engine takeoff, however, they are not generally certified (and thus documented) to perform the airliner-like V1-VR-V2 -takeoff sequence. Note that such would require rather specific takeoff performance calculations for each takeoff, not necessarily feasible for all the light twin turboprops, given their scope of applications. After all, just having to fit the requirements to be legal is generally a liability in terms of getting some things done, even if it increased the possibility of having the things actually getting done very safely. Hence, the trade-off of having categories!

This having been said, the aircraft itself may be very well capable of continuing the takeoff climb performance vice, even if not held to the same criteria that the things such as airliners are.

I am more familiar with EASA regulations than the FAA ones, here's the CS-23 initial issue in a bookmarked PDF. Obviously these don't apply to the airplanes certified against a different standard, but take the chapters on applicable performance figures for what they are worth.

-Esa

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