PC-12 Shutdown in Flight

I wonder what the insurer would think of this...(or perhaps it's required training?)

Seems a little risky but I'm not familiar with the PC12. Suppose they screw something up during the first start attempt, do they still have the battery power for additional starts? Can they do a windmilling start/will the prop unfeather?

I'd imagine they were very close to an airport so worst case would have been a dead stick landing after circling over the field'.
 
meritflyer said:
Thought this was a little odd. I mean, it's only a $2-3MM airplane. What's the big deal if you can't get it re-lit.

For you that fly a PC-12, is this something you do during training (actually in the plane)?

http://www.youtube.com/watch?v=LwZaIB71v_4
Click to expand...

I imagine these are Pilatus test pilots, as the shutdown was done over Lake Lucerne, Switzerland, where Stans & the Pilatus factory are located.

I have over 900 hours in the PC-12, and have never heard it done in any training program. Engine failures are of course practiced in the sim.

Notice how after shutting down the engine he utilizes the autopilot to maintain his airspeed, using the "nose up/nose down" toggle switch on the left side of the A/P controller. The PC-12 has a great wing, at altitude you may have twenty minutes to thirty minutes to contemplate your impending doom, should you lose an engine. Of course, you have plenty of time to pick a suitable landing site, and get set up for it. Attempting a relight is a possibility. In the sim, you will do an engine failure from the flight levels down to a deadstick ILS approach. Fun stuff!
 
Baronman said:
I wonder what the insurer would think of this...(or perhaps it's required training?)

Seems a little risky but I'm not familiar with the PC12. Suppose they screw something up during the first start attempt, do they still have the battery power for additional starts? Can they do a windmilling start/will the prop unfeather?

I'd imagine they were very close to an airport so worst case would have been a dead stick landing after circling over the field'.
Click to expand...

As for battery power for a second (or third) attempt, I would imagine so. Of course this could depend on whether they have a second battery installation, condition of those batteries, etc. There are limitations on the ground for letting the starter cool between start attempts (60 seconds, 60 seconds, 30 minutes).

Oh, and there is no way for a windmilling start, the PT-6 is a free turbine, so the prop does not turn the engine.
 
Stonefly said:
As for battery power for a second (or third) attempt, I would imagine so. Of course this could depend on whether they have a second battery installation, condition of those batteries, etc. There are limitations on the ground for letting the starter cool between start attempts (60 seconds, 60 seconds, 30 minutes).

Oh, and there is no way for a windmilling start, the PT-6 is a free turbine, so the prop does not turn the engine.
Click to expand...

Airflow through the engine would, though, wouldn't it?
 
Stonefly said:
Oh, and there is no way for a windmilling start, the PT-6 is a free turbine, so the prop does not turn the engine.
Click to expand...
Airflow through the engine windmills the engine...rotates it...you can start that way, but you need the speed up quite a bit.

-mini
 
trafficinsight said:
Airflow through the engine would, though, wouldn't it?
Click to expand...


Wouldn't that take a buttload of airflow into the inlet? To generate the sort of RPMs necessary to turn the compressor?

Especially after the first turn in the intake.. seems like you'd lose a lot of wind velocity from the ram air.

(This is just me thinking out loud about Traffic's idea- the subtleties of reverse flow turbine inlets is way beyond my button-mashing understanding.)
 
Stonefly said:
Oh, and there is no way for a windmilling start, the PT-6 is a free turbine, so the prop does not turn the engine.
Click to expand...

I've done it in a BE20. Airspeed (min 140 KIAS) provides the ram air for N1 rotation and with the prop turning (FYI: with the Raisbeck 4-bl props, the prop will not stop), you are good to go for a "no starter assist" restart.
 
deadstick said:
I've done it in a BE20. Airspeed (min 140 KIAS) provides the ram air for N1 rotation and with the prop turning (FYI: with the Raisbeck 4-bl props, the prop will not stop), you are good to go for a "no starter assist" restart.
Click to expand...

140kts isn't much. What model PT-6 was that?
 
Stonefly said:
As for battery power for a second (or third) attempt, I would imagine so. Of course this could depend on whether they have a second battery installation, condition of those batteries, etc. There are limitations on the ground for letting the starter cool between start attempts (60 seconds, 60 seconds, 30 minutes).

Oh, and there is no way for a windmilling start, the PT-6 is a free turbine, so the prop does not turn the engine.
Click to expand...


I have to correct myself on this. The EP for airstart (I went back to review it), has a warning to only attempt one airstart, so as not to drain the batt(s) to a point where you lose sufficient power to operate your other electrical systems that you'll need to use to shoot an approach.
 
Baronman said:
I wonder what the insurer would think of this...(or perhaps it's required training?)

Seems a little risky but I'm not familiar with the PC12. Suppose they screw something up during the first start attempt, do they still have the battery power for additional starts? Can they do a windmilling start/will the prop unfeather?

I'd imagine they were very close to an airport so worst case would have been a dead stick landing after circling over the field'.
Click to expand...

Going back to this post, if you don't have batt power left to energize the starter, then you don't have power for the igniters.

In a King Air, you've got that second motor out there with a generator that's making electricity.
 
I would try an airstart first before a bat start. I wouldn't like to lose the autopilot and efis while starting in IFR. 150kts should give you a good NG. Never done it however so I can't tell you if it would work or not. It is a Very big PT-6 up front so it may take some juice to get going.
 
I am not too concerned about doing a in air restart of a T-prop or Jet. I've had more problems restarting pistons that turbines. As long as the ignitors don't crap out the Jet will relight (except in the sim).
 
just thinking out loud here but... has anyone here ever had an engine problem in a turbine that was able to restart it?

aircraft engines aren't the type to die for no reason really....
 
trafficinsight said:
just thinking out loud here but... has anyone here ever had an engine problem in a turbine that was able to restart it?

aircraft engines aren't the type to die for no reason really....
Click to expand...

Agreed. Unless someone bumped something. Had a lady knee my mixture at night in a 172 doing a courtesy flight for a coworker. I started looking at what happened. Saw mixture in and flaps 5 down. Asked her if she bumped them and she said "I didn't think it was a big deal."
 
Stonefly said:
Oh, and there is no way for a windmilling start, the PT-6 is a free turbine, so the prop does not turn the engine.
Click to expand...

As mentioned, yes there is a air start assist procedure of the PT6

Stonefly said:
I have to correct myself on this. The EP for airstart (I went back to review it), has a warning to only attempt one airstart, so as not to drain the batt(s) to a point where you lose sufficient power to operate your other electrical systems that you'll need to use to shoot an approach.
Click to expand...

I'm going to call you out. I don't usually do this often, but with having over 900 hours on a PT6, your posts just don't jive with me. I think you're pulling your info off the internets and posting here to try to seem educated. Correct me if I'm wrong.

I think most pilots would agree, that they would rather re-light the fire than worry about draining the bat. It's a classic case of a practical scenario vs. textbook scenario.

I'm with acknight here. I'd do an air start assist before a bat start. IMHO it's an easy procedure and you don't loose much altitude to keep 120 kts.

ackeight said:
I would try an airstart first before a bat start. I wouldn't like to lose the autopilot and efis while starting in IFR. 150kts should give you a good NG. Never done it however so I can't tell you if it would work or not. It is a Very big PT-6 up front so it may take some juice to get going.
Click to expand...
 
You must log in or register to reply here.
Back
Top