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martinlest2

Arming the autofeather?

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I know what the autofeather does (basically, in layman's terms, at least) but what I don't see is under what conditions it would be set to 'Armed', as if the pilots were always anticipating problems.

 

I had a nice real-world experience recently. I was travelling from Jaffna to Colombo via Trincomallee (Sri Lanka) and appalling weather prevented us from completing the flight the same day. The airline put us up in a hotel and I got chatting with the pilots, who came round to all the passengers during the course of the evening. Of course I mentioned MSFS and they seemed quite interested to talk to me (and a bit surprised at my knowledge - such as it is!). They asked if I would like to complete the journey in the cockpit the next day (in an MA60), which I duly did. I noticed they didn't arm the autofeather and I asked about it. They didn't give much of an reply, other than that it wasn't needed, and I didn't ask further about it.

 

But why do some pilots set the autofeather to 'arm'. Maybe it's no big deal, and it hardly matters, perhaps airline policy, but any turboprop pilots out there, I'd be interested to know any more about it.

 

Martin

 

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So that if the engine fails, the affected prop feathers automatically to reduce drag. If it weren't armed, then they would have to feather the prop manually. The better question is, why wouldn't you arm the auto-feather? 

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Basically, its armed during take-off, climb and landing. You definitely want it on during take-off and landing, because if an engine cans, you don't have to worry about feathering the prop manually, which could take time away from trying to get the aircraft under control. If you're right at V1 and the engine fails without feathering, you're going to have a fun time. Same goes for landing.

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Yes, that makes sense of course. The flight I was on was flown by Sri Lankan Air Force pilots, so maybe they have different habits??? I wonder if some airlines include it as part of standard procedures and others not.

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Some of the transport turboprops I flew required it.  If it was inoperative, you took a substantial weight hit.  I would guess that even if you are expecting something, the machine will always feather the prop faster than the human.  Also, I don't think they want you throwing levers 50' off the ground.  See the Trans Asia accident in Taiwan for what happens when you do.

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I fly with it everyday and my MEL will not allow me to fly without it. The certification process for most turboprob aircraft in the US require autofeather in order to meet certification.  The amount of drag that the unfeathered prop has on the aircraft is significant and something like a V1 cut with a non feathered prop can get hairy to say the least, well in the sim that is which is the only place I have practiced it.

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You mean you can't fly without feathering 'on', or that you always arm the feathering, Nick? You mean in FS, not real world, I guess?

 

To be honest, the airline in Sri Lanka apparently had no proper certification, and the British ambassador, when he found out, banned all British officials from using them. I had a special clause in my contract however giving me free flights between Colombo and Jaffna (where I worked), as the road and train journeys were SO long, so they had to honour that, but I had to sign an 'AYOR' waiver! Maybe the pilots should have been arming the auto-feather!! Well., maybe they do now, after I brought the subject up in the cockpit! :P Haha ....

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