Roger Roger
Bottom of the list
Yeah, but it will NTS which is in effect very similar
King Air crashed into FSI Witchita
- Thread starter tlewis95
- Start date
Cherokee_Cruiser
Bronteroc
Well that's what I mean though --- say it does go the complete opposite direction of feather. Say if feather means 100% into the wind, imagine the reverse failure with 2%, meaning the prop is flat and basically a full-face head on to the wind. Even if you cut the power to this engine, cut the fuel, and use the power on the other engine, is this survivable on an E120? Dash 8? Q400? And this particular King Air?
CFI A&P
Exploring the world one toilet at a time.
Without it feathering it is as bad as a sewer cover in front of that engine, A=πr2.
A few years ago I worked an aerodynamics scenario if the prop didn't feather on a C421 and if I remember correctly it was something equivalent to 40 or 80 square feet of additional drag to the airframe.
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AAPalmTree
Well-Known Member
Won't do much until feathered. I didn't care for it.
Roger Roger
Bottom of the list
I guess I wouldn't know, being single engine we don't do NTS shutdowns ever.
AAPalmTree
Well-Known Member
Now I'm lost. You won't shut down with a failure SE?
Roger Roger
Bottom of the list
Our Garrett machines are all single engine. Therefore we never do NTS shutdowns in training or for maintenance purposes. There are several ground checks we do both in the hangar and running and if you go flight idle at high airspeed you will get an NTS but we don't take let it NTS to 38% or wherever it is that you have to pull the feather handle by.
z987k
Well-Known Member
No but it goes in the right direction, and if you did remove all oil pressure, it would go to feather. Ever forget to put it on the locks?
z987k
Well-Known Member
If you cut the fuel to a pt6, which will remove the oil pressure as well, the engine will eventually feather even if autofeather doesn't work... and at high power settings outside TO and landing is probably off anyways.
USMCmech
Well-Known Member
Nope,
In the event of a malfunction that leaves the engine producing any amount of thrust, you burn up the engine if need be to get to a safe landing site. The only checklist that called for a in flight shut down is a confirmed engine fire (fire warnings by themselves did not). Hot sections are cheap, airplanes and pilots are expensive.
In a twin, you have the luxury of performing a precautionary shutdown which is the cause of most engine "failures". In practice, most precautionary shutdowns turn out to be malfunctions that would not lead to an actual failure of the powerplant.
AAPalmTree
Well-Known Member
Yes, everyone laughed at me.
Roger Roger
Bottom of the list
Knock on wood I've never forgotten the locks, though on pre and post mx runs we do a lot of intentional unlocked shutdowns. Also first time you kill one with the red knob (at least in a caravan) it's pretty shocking.
milleR
Well-Known Member
NTS is ok but not great, it needs to be feathered to get any kind of single engine climb performance. I just did two inflight NTS shutdowns and while it'll buy you a couple of seconds on departure it's just not the same as being fully feathered.
On the Dash there is a (DC powered) feathering pump that draws off a separate reservoir to drive the blades to full feather in the event of an engine failure or loss of oil pressure.
On the Dash there is a (DC powered) feathering pump that draws off a separate reservoir to drive the blades to full feather in the event of an engine failure or loss of oil pressure.
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Capt. Chaos
Well-Known Member
Yours not rigged with a small space between fuel shut off and feather?
msmspilot
Well-Known Member
It's actually worse than the area formula you posted. Depending on the blade angle, it can actively produce negative thrust. A flat prop will definitely produce a negative thrust vector.
Roger Roger
Bottom of the list
Oh, it is, but you have to check the feather function once in a while too. Typically to prevent a really ugly smoky event we will get a normal purge going then yank the red knob.
Roger Roger
Bottom of the list
Yes, but depending how tight your beta system is it might take 5 minutes to get there.
gotWXdagain
Polished Member
Not sure about all PT6 engines but the PC12 has a setup whereby an electrical signal opens a valve in the primary governor to allow feathering.
Edited previous post in light of me studying my prop system a little further...
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PhilosopherPilot
Well-Known Member
In that accident the prop ran away due to dissimilar metals causing metal fatigue/failure in the prop actuator. ASA had a few of those, but this one happened at exactly the wrong time, base to final into Brunswick. From loss of prop control to impact was seconds, and there was little the crew could do. It was low altitude, and that much sudden drag at low speed caused an immediate loss of control.
My friends dad (also ASA) had one do the exact same thing into CLT. Luckily he was higher, and it was only a partial failure. They got it on the ground.
MaRiO FDZ
JJ Abrams you Insensitive Bastard.
This is why the PT-6 is King. The issue on it is DON'T FORGET TO ARM THE AUTOFEATHER, because it cought me more than once in training on it on engine failure after takeoff and I was just waiting for it to kick in.... IIRC the big Turboprops have something called Reverse Torque sensing, and once that goes you're supposed to feather by hand. But then again, I haven't flown anything larger than a King Air 200.
Thanks for posting those links, @JeppUpdater !!
Take Care
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