Controversial use of Transient engine rating in PT6

[svickova]

Good morning! First of all I want to thank you all for all the knowledge shared in this website.

I work in a firefighting company, operating the pt6a-67f. Some pilots (thanks God not so many) tend to use the transient torque engine rating limited to 20 seconds (but not limited in number of excedances) as a normal operation just to get some more performance (climbing stepper so they can get to dump to confined areas, loading a few more gallons when scooping etc).

Even if you are not a genious you can understand this is not an efficient and safe way to operate an engine, at least if you want not to degrade it earlier than normal. I was diving in the official documentation from EASA, FAA and Pratt & Whitney and was not able to find any statement saying "guys, do not go there voluntarily unless you need to save your life, never use it as a normal regime", maybe because it is so obvious...

Could you please provide me with any documentation just to discuss that way to operate?

Thanks a lot!

[ahwalk01]

Might be worth reaching out to these folks

https://www.turbine-training.com/air-tractor-training.html

[mustafagander]

Hey svickova I think you need to contact P&W to see what they think.

[meleagertoo]

I'm sure P & W's lawyers will agree with the OP in that "transient" excursions are regarded as unplanned momentary operational exceedences and should never be used wilfully or deliberately, let alone routinely. I'd be astonished if that were not so.A "transient" exceedence occurs in an unexpected event when the "Oh Christ oh shit oh dear" situation results in an input that produces a "woops!" response which is almost immediately cancelled/reduced. Seems pretty self-evident to me. And furthermore I'd hate to try arguing a defence of that practice against an FAA lawyer.

[Salusa]

This is my opinion only and I know others will differ.

Transient limits are never to be used during routine operations.

If using transient limits on a frequent basis then you have a problem with Op Specs or personnel skill/training.

[megan]

Some background.

https://www.ecfr.gov/current/title-14/chapter-I/subchapter-C/part-33/subpart-F/section-33.87

[rigpiggy]

I'm sure P & W's lawyers will agree with the OP in that "transient" excursions are regarded as unplanned momentary operational exceedences and should never be used wilfully or deliberately, let alone routinely. I'd be astonished if that were not so.A "transient" exceedence occurs in an unexpected event when the "Oh Christ oh shit oh dear" situation results in an input that produces a "woops!" response which is almost immediately cancelled/reduced. Seems pretty self-evident to me. And furthermore I'd hate to try arguing a defence of that practice against an FAA lawyer.

Many years ago we had a free with a torque guage failure fly the 1900 at something like 150% for a day prob 3 legs. The next crew immediately noticed and returned to gate, dumped the pax, and sent for MX..... It turns out they had been driving about 5 hours that way. They were company "problem children". They couldn't understand the higher speeds, fuelflow, temps or use of rudder. They pulled the engine e and sent to overhaul, it came back with fresh overhaul but no new parts.....They built the PT6 tough!