Switched to ultrasonic cleaning for fuel nozzles and saw a 15% drop in EGT within 2 flights

We had a PT6 that was running hot on number 2 bearing. Tried the bench flow test and it passed fine. But I sent the fuel nozzles out for ultrasonic cleaning anyway. Put them back in last thursday and the exhaust gas temp dropped 15% by the second flight. The old soak and blow method just wasnt getting the varnish out. Has anyone else seen that big a change from just cleaning the nozzles?

3 comments

3 Comments

skylerm556d ago

That "just a couple cycles" thing reminds me of the time I changed oil filters mid-trip.

cooper.max6d ago

15% drop is too much for just cleaning nozzles unless they were basically plugged solid before. Ultrasonic cleaning is fine but people act like its some kind of magic bullet when really it just removes stuff that a good solvent soak would also get. Ive seen shops push ultrasonic cleaning as a upsell when the old method still works fine. Plus you changed them on a Thursday and saw results by the next flight, thats only a couple cycles. Could be you just seated the new gaskets better or torqued them down different.

sethr116d ago

The Thursday thing is whatever. People get super hung up on what day work gets done like it matters. You could do it on a Wednesday and still see a drop by Friday if the sealant hadn't fully cured or something. I'd wait a few more cycles before calling it a fix.