Exhaust Welding

[ellisr]

Hi

There is a crack in my Powerflow exhaust which needs welding. Does the actual welding have to be done by an aviation workshop that is FAA certified? Or can it legally be welded by any metal workshop?

Note an FAA mechanic will remove and reinstall once repaired and it would get a log book entry.

Thanks, Russ

[h20wrks]

I would call Darren at Power Flow, I had some issues with my exhaust and he went out of his way to resolve my issues.

Jimmy

[CFIDave]

Are you sure the crack can be repaired via welding? Back when I owned a DA40 with Powerflow I had a cracked exhaust riser and was forced to replace it with a replacement ordered from Powerflow.

The key point I learned the hard way with Powerflow exhausts is that they must be dismantled and put back together with anti-seize compound on the joints at EVERY annual to prevent cracks from occurring. This procedure is not listed in Diamond's DA40 Aircraft Maintenance Manual because the DA40 was originally certified without Powerflow exhaust. But the Powerflow STC maintenance instructions specify the application of anti-seize annually to keep the pipe joints flexible and thus to prevent cracking.

[Antoine]

Absolutely Dave.

The PowerFlow is a tricky airworthiness trap - comes standard with the 2007 and newer models but is NOT mentioned in the standard AMM as a required Continued Airworthiness item.

I had to dig out the ICAW pdf from PowerFlow and show it to my A&P before he would agree to do this work.
And then I had to explicitly ask the FAA A&P who signed off my annual (welcome to Europe, my A&P needs an A&P) to mention this work in the annual entry.

Hint: careful with the flexible "suspension" of the exhaust pipe. This has limited life and is prone to breaking, probably more so after removal and installation.
Mine broke off a few weeks after the exhaust was removed and I suspect it was related. This is made of engine baffling and I am at my third iteration of trying to achieve a final repair.
From now on I will have this part replaced at every annual...

[Steve]

The original exhaust design (non-Powerflow) was also prone to cracking of the exhaust risers near the attachment flanges. My exhaust was replaced under warranty within the first two years of ownership because of this. Subsequently, Diamond developed a Service Bulletin to install a brace on the muffler, which apparently relieved the stress on the risers. Since then (> 12 years), no cracks. I wonder if the Powerflow could benefit from a similar brace?

Steve

[Lance Murray]

Call Powerflow and they can advise but to answer your question it can be welded by anyone as long as your A&P signs off the work as airworthy.