Further to Jack Webb's comments on the PT6, because the PT6 prop and compressor sections are not connected you cannot unfeather to restart a PT6. The gearbox will spin and the compressor will not.  You must either have battery power or accomplish an air restart with sufficient airspeed to spin the compressor.   My suggestion for your friend is to attend any of the free courses given by Pratt & Whitney for maintenance people and operators. Any owner of a PT6 is eligible to attend.  I've attend three so far in Montreal but they are held in a number of locations worldwide.  They are invaluable for someone intending to operate a PT6.  You can also find lots of info and register for courses at the site:

http://www.pwc.ca/en/service-support/customer-training

Paul Miller
PT6A-64

Mark Ravinski wrote:

Turbine types,

I met a fellow yesterday who is building a Seawind with a 550 hp PT-6.  It is complete except for paint.

He says he will not be able to unfeather the prop in flight if there is no oil pressure.  (engine not running)

It seems I've read here on the LML that some turbines are equipped with unfeathering accumulators.

Can anyone enlighten me about that for a PT-6?