Welcome Guest. Sign in or Signup

5 Answers

Multi engine Question

Asked by: 3552 views Aerodynamics

If you were to have one engine fail in a Multi Engine aircraft of course you would feather the propeller of the failed engine. My question is, if you were to have the other engine fail after the first one (so a dual engine failure) would you also feather that propeller as well or should only one propeller be feathered in the event of dual engine failure? I believe I heard that in this situation that if you were to have a second engine failure that you should not feather the propeller and that only one propeller should be feathered. Can anyone explain why and aerodynamically what would happen if you experienced a dual engine failure and feathered both propellers?


Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

5 Answers

  1. John D Collins on Jan 19, 2014

    A windmilling propeller generates a lot of drag. If you want to glide the furthest distance and both engines have failed, feather both engines. A twin is often an excellent glider when both engines are feathered. For example a Bonanza has a book glide ratio of about 10 to 1. Its bigger brother, the Baron has the same basic wing and fuselage. With both engines feathered, the glide ratio is listed as 12 to 1. With one engine feathered, the glide ratio would drop substantially and with neither feathered, it would drop like a rock.

    +2 Votes Thumb up 2 Votes Thumb down 0 Votes

  2. Jim F. on Jan 19, 2014

    I’m absolutely with John that you want to reduce drag as much as possible by feathering both.. Do you remember the reasons you were told not to feather the second dead engine?

    0 Votes Thumb up 0 Votes Thumb down 0 Votes

  3. DS on Jan 19, 2014

    I wasn’t given any reasons as to why not feather the second dead engine. A King Air pilot told me this and I didn’t have a chance to ask any questions. I looked up a King Air Emergency checklist and sure enough it says for a second engine flame out to not feather the propeller.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes

  4. Kris Kortokrax on Jan 19, 2014

    You didn’t look far enough through the King Air checklist. It states to not feather the second propeller when you are contemplating a restart.

    In the checklist for Gliding (no successful restart), the checklist states to feather both propellers.

    +3 Votes Thumb up 3 Votes Thumb down 0 Votes

  5. Brian on Jan 25, 2014

    Agree with all that is here, only one thing to add. Piston twins will auto feather once oil pressure is gone. Their constant speed system is effectively opposite that of a piston single. Turbo props have auto feather unless disabled by the pilot. I believe it is disabled at cruise, but I’m not certain; perhaps someone else here can comment to that.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes

The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.