Question For "Van" Drivers

Griff

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Pardon my ignorance. The red emergency power lever on the quadrant does what? The reason I ask is because I recently had a FCU quit on a PW-530, it was sure nice having that second engine. The engine packed it in just like you were shutting it down on the ramp, done, finished, no way to restart..... No fuel flow period. I am curious and looking into the caravan. So, if the pt-6 FCU goes T.U. does that red lever thingy bypass it. Popular opinion is that single engine turbine is very safe, this event is still fresh in my mind so I am a little wary. Thanks for any help.!
 

goodgig

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It manually overrides the main metering valve in the fuel control, which is normally controlled by pneumatics and monkey motion.
 

Griff

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Thanks goodgig. So the fire should keep burning. Nice little piece of mind. Take Care!
 

Princedietrich

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The FCU, as controlled by the power lever, is driven by P3 bleed air that is tapped downstream of the axial compressor and just upstream of the burner can. It allows for very precise fuel control and greater fuel efficiency for the engine in addition to providing some overspeed governor protection for the engine. If for some reason you happen to lose the P3 bleed (the plumbing is kinda flimsy, plus crap does happen) you'll lose control over that metering valve and the engine will roll back to the mechancial idle stop (around 48% if I remember correctly) but it won't die. This is when you grab the emergency power lever and take direct physical control of that metering valve. It won't be as precise or fuel efficient but it will at least bring the engine back to power. Use caution because it's EXTREMELY sensitive and just barely moving it can cause power surges if you're not careful. You also lose one of your overspeed governors since you no longer have the bleed air input.

Technically you also lose the ability to use reverse thrust, but there is a way you can do it. It's not advocated or recommended or even published in the manual, but it'll work in a pinch.

I used to teach this particular aircraft, although I'm 2.5 years out of practice.
 

SinglePliot135

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The same lever is present in the PC12 and TBM700 with the larger PT6As. I wonder why they didn't include it in twins?

Works good in the sim, but watching the video of the Swiss test pilot doing it for real in the PC12-- you gotta be ready because it rolls back FAST, especially at low altitudes.
 

goodgig

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Yeah, but it just rolls to low idle. Unless you are short final, should not be a problem.
 
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