EC-135 Power Assurance Check
 

My EC-135T2 fails the PWR Assurance Check: (Pa-250' OAT 20 degrees)
Limits with Tq at 75% (Gen and Bleed off)= N1 95,4% and 805 degrees
Values found on Engine 1 N1 94,6% and 810 degrees
on Engine 2 N1 93,9% and 825 degrees
The engines will be replaced in the near future. Would you fly the machine on a HEMS mission? Just a question from a HEMS pilot on a quiet morning.

Cheers, Rakker

Rakker,
By my calcs, you are under on the ToT on both engines. Will check with our engineer later but I think the first step would be to do a compwash and a further power check. Once that is done, if the figures are still out then no, I wouldn't fly it - HEMS mission or not. The Number 2 engine is some 30 degrees under and I don't think a compwash could recover that much. Have the engines gone the full 4000 hours?

Thanks Fortyodd2, the engines have had a very recent compwash, only 1200hrs time total each and several recent PWR checks done.

In which case I'd not take it flying at all. Sounds like you've possibly got some FOD damage in there - your trend charts should help to tell the story - whether it's been a gradual decline or whether there was a specific event. Are you close to the sea? Do you do a daily or weekly rinse?

Don't know the setup for 135 engines but check any bleeds from the engines for missing/damaged gaskets.

NST

According to the FOM ( 9.1 Limitations ) CAT A Procedures are prohibited if power check is not satisfactory. And this one definitely is not...

skadi

Thanks for the replies, we are close to the sea and do a wash every three days, we have seen a gradual decline in performance. I think we have to call Maintenance.

Havent flown a 135 for a couple of years, but certainly on the T1, Turbomeca instituted a requirement in "salt-laden environments" (which included the whole of the UK) to perform a fresh-water rinse on the engines every day with de-ionised water. You may want to look at that?

From a engineering pov. Engines should be fresh water washed everyday if operating in a salt water enviroment. I would have also thought asking your engineers would be the first step not posting on the internet (although I know the answers to all lifes problems can be solved online :rolleyes:)

If the engine is failing by a large margin and you are aware of that its more an engineering matter. However I would revise your SOP's and start washing everyday, I previously worked for a company where all our engines reached overhaul with no problems, Turbomeca believe this was partly due to our washing routine.

HTH

Thank you all for the replies, A daily wash will be SOP in the next few months.

Compressor washing will not sort this one out, though daily water rinses are the way to go if you are near the sea.

When were both engines fuel injector manifolds and preference injector last changed or cleaned?

It is a common problem with the Arrius 2B2........fit clean injectors and you will notice a significant reduction in your TOT. :ok:

If the engines still fail their grd power checks, get the boroscope out.