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5 Answers

Multi-Engine (random question)

Asked by: 2518 views General Aviation

Ok, so skip all the politics of you should never be in this situation. But, hypothetically speaking if you were flying a multi engine aircraft and were running low on fuel could you shut one engine off and conserve fuel....or would it cut down to much on performance for the benefit(if any). 😏 ..... I think multi training may be getting to me! 

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5 Answers



  1. fugae fuit malleator on May 03, 2017

    Every time I’ve done single-engine work it was all I could do to maintain altitude just above blue line. That was with a considerably higher fuel flow on the remaining engine. Not the most efficient use of every drop of fuel if you ask me.

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  2. Wes Beard on May 04, 2017

    If everything is the same, the same amount of power from two engines would be required on a single engine. Again, if everything was the same, that would also equate to the same amount of fuel being burned per hiur whether on one engine or two. In fact, most jets I fly will double the fuel flow for the same airspeed as a good rule of thumb.

    For propeller powered airplanes… everything is not equal. First, power is not linear. The prop definitely has a range where it is most efficient. This can be overcome somewhat with a constant speed propeller. Second, even though the prop is feathered it is still creating drag increasing power required to maintain airspeed and altitude. Third, you aren’t coordinated which increases form drag. The ball should be halfway out and up to 5 degrees of bank is the most efficient but still creates drag.

    To answer your question. Under no airplane I am aware of would this technique conserve fuel. I do applaud you for thinking outside the box and considering the best alternerative

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  3. John Schreiber on May 05, 2017

    With the exception of centerline thrust aircraft, you most likely will not gain range. Especially if you have a headwind. ( see Voyager, a Rutan twin that circumnavigated nonstop, mostly on one engine). I think I saw a Riley Skyrocket ad many years ago bragging about single engine range on their modified Skymaster. For most aircraft it is probably a wash, unless you are far under gross weight.

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  4. Kris Kortokrax on May 07, 2017

    OK. From my King Air 300 POH performance charts:

    Two engine Maximum Cruise (100% torque, 1500 RPM) at 18,000′ and 14,000 # weight,
    you would burn 902 #/hour (451# per engine). This would give you a TAS of 306 knots.

    Single engine Maximum Cruise (81% torque, 1700 RPM) at 18,000′ and 14,000 weight,
    you would burn 443 #/hour. This would give you a TAS of 210 knots.

    You can do the math and answer your question for one airplane, the King Air 300.

    The ultimate answer is that it depends on the airplane. One size (and one answer) doesn’t fit all. See what info you can find in the POH for the airplane you are training in.

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  5. Max on May 24, 2017

    I’d always heard that the Navy would shut down an engine on their P-3s to increase endurance. Here’s a video showing that.
    https://www.youtube.com/watch?v=07r6b_YvaE0

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