King Air C90 2nd Engine Flame Out Procedure

[Turbinator_PT6A]

Greeting fellow pilots.
This is a question to any experienced King Air/Turbo prop pilots, The 2nd engine Flame out Procedure as per the manual requires the following response:
1. Power Lever---Idle
2.Props----- ****DO NOT FEATHER***
3. Condition lever---- Cut off
4. Conduct Air start procedures.

Now my question is regarding the Propellers in this case, the action expected is not to Feather the prop, wouldn't loss of oil pressure due to loss in engine power drive the prop toward feather in the first place?

What is the significance of not feathering the prop, especially in the King Air engine which is a free turbine engine, so would being feathered or unfeathered make any difference in the ease of air start since the prop is not connected to the gas generator shaft anyways?

Just a question i ve been pondering upon, if any of you experienced pilots can shed some light, would be much appreciated.
Thank you for reading and sharing.

[Desert185]

1. Power Lever---Idle
2.Props----- ****DO NOT FEATHER***
3. Condition lever---- Cut off
4. Conduct Air start procedures.



I fly a Twin Otter, which has the PT6's also. We don't have a similar checklist, but are told to feather both engines in the event of both engines failing. The AIRSTART checklist calls for the prop lever to be in the feather position prior to the start.



Now my question is regarding the Propellers in this case, the action expected is not to Feather the prop, wouldn't loss of oil pressure due to loss in engine power drive the prop toward feather in the first place?



Yes. With no engine oil pressure the springs and counterweights will feather the prop.



What is the significance of not feathering the prop, especially in the King Air engine which is a free turbine engine, so would being feathered or unfeathered make any difference in the ease of air start since the prop is not connected to the gas generator shaft anyways?



I would assume your AIRSTART checklist would be the same as the one in our Twin Otter, i.e. the prop would be feathered prior to the start.

BTW, the Twin Otter has Power, Prop and Fuel levers. No condition levers.

If the end result was to have both engines out, without a hope for either or both engines being restarted, you definitely want them both feathered to extend the glide...and that does make an enormous difference.

[bobrun]

Hi Desert185,

May I ask you a question regarding the twin otter?

From my understanding, the drill for an engine out after take-off is to select max power and flap 10.

Now, let's say the engine fails just after you have retracted the flaps on take-off and you're at about 500 ft. Would you then re-extend them to 10 or leave them up?

Thanks

[Air Soul]

Isn't the oil pump driven from the accessory gearbox, which is driven by the power section - which is connected to the propeller?

AS

[werbil]

Nope, accessory section in a PT6 is driven by the compressor turbine.

In the C208, different airspeeds apply for an air start without starter assist depending on whether the propeller is feathered or not. In this case I suspect the reason is the wind milling propeller drives the power turbine drawing more air through the engine.