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Old 11-29-2008, 10:31 AM
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Default Turboprop V1

Having never flown a multiengine turboprop this may be a dumb question, but here it is.

In a part 23 turboprop aircraft such as a King Air or Avanti how bad is a engine loss at V1? Can they meet most departure gradients even though they are not required to demonstrate it?

Thanks.
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Old 12-02-2008, 08:21 PM
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Originally Posted by rthompsonjr View Post
Having never flown a multiengine turboprop this may be a dumb question, but here it is.

In a part 23 turboprop aircraft such as a King Air or Avanti how bad is a engine loss at V1? Can they meet most departure gradients even though they are not required to demonstrate it?

Thanks.
Depends on what category those airplanes are in. It looks to me that Part 23 airplanes (at least commuter airplanes) must be 35 feet above the surface of the runway prior to V2 and have some type of climb performance.

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-Fatty
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Old 12-03-2008, 08:14 PM
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Most turboprops will have a positive climb performance. But when you get into the areas of high/hot/heavy you might not be able to depart IFR for not having the required climb gradient. The danger with props at V1 is when losing your critical engine (majority is the left engine) which will induce more yaw when compared to losing a jet engine on a Lear.

Min climb is 200'/nm which translates to 400 fpm at 120knots V2. Easy done in a King Air 200. Of course you need to look at the charts. Rule of thumb for turboprops is when you lose an engine you lose 50% of your power and 75% of your climb performance. Hope that helps.

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Old 12-04-2008, 12:41 PM
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In my opinion having flown the Q400, an engine loss at V1 with auto feather is managable, but pretty challenging. A engine loss at V1 without auto feather in the Q400 is one of the nastiest things I have ever had to deal with when it comes to engine failures in a sim.
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Old 12-04-2008, 02:49 PM
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Thanks for the answers. I was wondering about this sitting up in Eagle one day watching a Piaggio.
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Old 12-05-2008, 01:43 PM
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I fly Jetstream 31s and 32s and there's a good difference in the failure at V1. Either way, you are going flying. In a 31 though, we clean up as fast a we can because there is no guarantee on climb rate. In the 32, we're trained to wait for 400 AGL to do the memory items. In reality, you could do them immediately, but the biggest gotcha with that failure is controlling the airplane. If you maintain control of the airplane, you give yourself the best chance to survive.
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Old 12-06-2008, 10:49 AM
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Originally Posted by the King View Post
I fly Jetstream 31s and 32s and there's a good difference in the failure at V1. Either way, you are going flying. In a 31 though, we clean up as fast a we can because there is no guarantee on climb rate. In the 32, we're trained to wait for 400 AGL to do the memory items. In reality, you could do them immediately, but the biggest gotcha with that failure is controlling the airplane. If you maintain control of the airplane, you give yourself the best chance to survive.
When we go to recurrent for the SA227 Metroliner, most of our recurrent is focused on V1 cuts. The Metro doesn't have an auto-feather system per se. It has a Negative Torque Sensing (NTS) system. This system, hopefully properly working, senses if the engine is turning the prop or the prop is turning the engine. If the system NTSes, then it will slowly let oil out of the prop hub and move the prop to a feathered position. If the NTS system does not feather the prop then you have an 8' diameter prop disk out there trying to put you into the ground! After setting max power, rotating, and getting the gear up, you have to immediately manually feather the prop. If you don't you will run out of aileron and rudder authority and make a smoking a hole in the ground.
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Old 12-06-2008, 06:23 PM
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Originally Posted by freightdog View Post
When we go to recurrent for the SA227 Metroliner, most of our recurrent is focused on V1 cuts. The Metro doesn't have an auto-feather system per se. It has a Negative Torque Sensing (NTS) system. This system, hopefully properly working, senses if the engine is turning the prop or the prop is turning the engine. If the system NTSes, then it will slowly let oil out of the prop hub and move the prop to a feathered position. If the NTS system does not feather the prop then you have an 8' diameter prop disk out there trying to put you into the ground! After setting max power, rotating, and getting the gear up, you have to immediately manually feather the prop. If you don't you will run out of aileron and rudder authority and make a smoking a hole in the ground.
The NTS system will not feather the prop; it will only move the prop towards feather.
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Old 12-06-2008, 07:50 PM
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Originally Posted by Qtip View Post
The NTS system will not feather the prop; it will only move the prop towards feather.
Thanks for the exact wording, moving TOWARDS feather. :-)
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Old 12-31-2008, 05:05 AM
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Last recurrent in the P180 I did several "v1" cuts in the sim in ASE. If you follow the numbers and weight restrict yourself on summer days it can be done. If the autofeather does not work it will be very difficult to make it, but possible with a little practice reaching for the prop lever. SE climb is marginal but manageable out of EGE, ASE, etc. and our Ops. Specs. require high departure mins out of those airports.

Also with the derated engine we can use 20 seconds of max power (an additional 420 lbs. tq./side) if the need arises. This is not calculated in the climb performance.

Oh, no critical engine either.
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