Piper Navajo feathering

[spain]

First: English is not my native language. :D

Time ago, a friend (militar aeronautical engineer) told me about an spanish Air Force Piper Navajo accident due to right engine failure, followed by a crash landing. Both pilots did't think about feathering failed engine while flying 5000' AGL though. And that is the example I tell students when I talk them about prop windmilling drag increase. Later on, two other friends, (pilots) had similar failure on same aircraft due to an (unnadverted) unnusual high OAT that led to an engine overheat. They retarded failed engine to idle, and didn`t feather failed engine wich led them to a 3000' descent prior to power reestablishment. They told me they didn't trust about maintaining altitude with only one engine running.

So, my question is: should they have feathered that propeler?

Thanks folks!

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Do know dear Sancho, is not a man more than other, but makes more than other. D.Quijote de la Mancha, Miguel de Cervantes

[ 10 September 2001: Message edited by: spain ]

[eyeinthesky]

It seems to me that the two pilots you are talking about had either been badly taught or forgotten the basic aerodynamics you mention of windmilling engines.

The 'not trusting being able to maintain height on one engine' seems rather odd, especially as they lost 3000' trying to get the other one going again!

If the problem is simple like fuel mismanagement and altitude is not critical then perhaps there is no need to feather because it will soon get going again.

Short answer from the info you give: Yes they should have feathered it once they were sure the failure could not be quickly rectified. They could always unfeather it again later, although I would suggest a failure of any kind is probably a good suggestion that it might fail again, so best leave it off and land.

[blueline69]

The question you have to ask is : Is this engine going to feather? No point in leaving it windmilling while you try to sort out the problem and lose prescious altitude. Then when you want to feather , it doesn't. If you did it earlier , you would have more time to sort out your new problem. Rectify on the checlist is a few basic things and if it don't work FEATHER !!! :eek:

[spain]

Thanks for your kind replies.