Menu Sign In Contact FAQ
Welcome to our forums

Exhaust manifold material - inconel or stainless steel? And ceramic coatings?

The claim by Socata that their GT exhausts are inconel seems to be false. It is mostly stainless.

Shoreham EGKA, United Kingdom

Does anyone know roughly how much an inconel exhaust weld repair costs?
Mine is for two Apache exhausts, both broken in the middle so need approx 4 ft inconcel pipes welded x 2.

The quote is £3,000 for inconel pipes (global shortage bs) and £3,000 for specialist welding, an eye-watering £6,000.

Is this about right?


United Kingdom

The welder I used (UK) didn’t sound like inconel was hard to weld. I got a tube welded up (see linked thread) very cheaply. 3k is taking the p1ss. I can PM you his details.

An all-inconel exhaust is expensive – perhaps 2x of a stainless one. But it is worth every penny.

Shoreham EGKA, United Kingdom

Don’t know if this helps here but I got first rate service from Goodfabs in the UK.
They are experts at inconel welding, the welds are so clean and refined you can hardly see them.

LSGG, LFEY, Switzerland

Thanks. Just to update it turns out to be nearly all of the exhausts x 2 being replaced with new inconel tubes.
Hence the high cost. No off-the-shelf parts available.

United Kingdom

I would quite like to replace all of my downpipes with inconel ones. Unfortunately this requires some paperwork, I think. I wonder if @pilot_dar knows about the certification details.

Shoreham EGKA, United Kingdom

This paperwork topic is really confusing.
Before switching my plane’s exhaust line to Inconel on an owner-produced basis, I used to see frequent failures of downpipes. In a turbocharged high altitude engine, these are potentially severe events.
These were weld-repaired by Gomolzig in Germany, complete with paperwork and reinstalled by my shop.
And yet the Continental documents explicitly forbid any weld repairs on exhaust parts…

So on the one hand you have an owner produced part which is identical to the original except for the material…

And on the other you have a repair that blatantly breaches manufacturer guidance and yet gets signed off without any debate.

LSGG, LFEY, Switzerland

One answer is here – heavily defended by “the industry” as always

Fairly obviously the way this works is that the shop can do whatever work is within its CAA approval. So if you turned up with a piece of pipe from a nuclear submarine reactor, The shop would happily weld it up and issue paperwork IAW their approvals. The application is not their problem. In the case of a plane, whether the item can be legally installed will depend on which section of the MM it is states that repairs are not permitted. If the plane is N-reg then anything other than the Airworthiness Limitations can be ignored (potentially) because you are working IAW AC43-13 or whatever… In European reg planes, a lot of MM stipulations are implemented in the maintenance industry as restrictive (revenue generating) practices.

I would very much like inconel downpipes, too. The owner produced parts concession is an interesting one.

Shoreham EGKA, United Kingdom

I used to think that owner-produced parts for N-reg had to be of the same material and design as original.

However, on reading FAR 43.13, the requirement seems to be that the new part is “at least equal” to the old one “with regard to aerodynamic function, structural strength, resistance to vibration and deterioration, and other qualities affecting airworthiness”.

Which seems characteristically sensible for a private aircraft.

Glenswinton, SW Scotland, United Kingdom

Yes this is a very good concession.

It needs to be suitably documented though.

Owner produced parts.

Shoreham EGKA, United Kingdom
Sign in to add your message

Back to Top