B737 max in-flight restart
 

Have you ever experienced or heard about MAX succesfull in-flight restart? Because I found a lot of engine failure incident reports on avherald but I didn't find any in flight restart attempt.

Engines rarely flame out nowadays, so it's very likely that a restart attempt would not be a good idea in most of those engine failure situations you have found.

I just did a search on AvHerald myself, and it was quite basic, just "B38M". There were about 4 pages and of all the entries, 22 directly described some form of engine event (i.e., fire, failure, vibrations, etc.) There could be a few more with the bird strike entries, but I didn't want to spend that much time going through those.

There was not a single case that I came across that described an engine flameout. Each even described a situation where either the engine shut itself down through an internal mechanism, the crew proactively shut the engine down due to fire, vibration or other indications, or the crew was directed to shut the engine down in the non-normal checklist, for example the oil pressure issues you will have read about. FlyingStone hit the nail on the head: none of the events were good candidates for an in-flight restart attempt.

Condition: An engine start is needed and all of the following are true:

Condition statements are underrated.

Not max. I have had a few engine issues, all turbine. Low oil pressure on downwind, engine was still running, so landed, but would not have tried a restart. Bearing/seal failure with smoke in the cockpit (twice), would not have tried a restart for either. Engine flame out during idle descend from FL450, restart worked at FL250. "it depends"

I agree but in case of fuel nozzle coking it should be possible and in some situations it can be useful to have a both engines. But honestly I asked this question due to some rumor that its impossible due to fan aeroelastcs properties. IHMO its bull s**t but I used to thing the same way in the past and was wrong :-)

The manual has instructions for doing it and it's surely been done during certification flights.

Lower engine failure rates and improvements in control systems mean it's probably increasingly rare to have an engine get damaged enough that the control system can't keep it running, but not so damaged it can be relit.

I know manuals but I'm looking for a real example.

The only time I’ve attempted an in flight restart it failed and we ended up doing an OEI approach and landing. It was an air test on a 737 but a much older model.

As others have noted, "restartable" shutdowns are rare - and reasons to attempt a restart are even rarer. Since commercial aircraft are certified to fly just fine with one engine shutdown, the primary reason to attempt a restart would be that the remaining engine has an issue as well. As a general rule, 'restartable' shutdowns are due to precautionary measures - e.g. low oil pressure or quantity, so as long as the other engine is fine, the reason you shut it down is still there -you're trying to protect it.

As for the LEAP engine not being restartable in-flight - yes, complete and total BS. There are very specific and demanding cert requirements for the ability to restart an engine in-flight, and if the LEAP couldn't meet them, it never would have been certified.

BTW, I doubt many people realize how many hours/cycles the 737 MAX fleet has already accumulated - it's in the millions of flights and increasing rapidly (as is the size of the in-service fleet). So even a very good shutdown rate (1 per 100,000 hours required for 180 ETOPS) means a quite a few shutdowns.
In fact - in spite of the two MCAS crashes - the MAX has racked up enough cycles that the fatal loss rate as of the end of 2024 was already semi-respectable at 0.41/million departures (in comparison, it's about the same as the A330 at 0.38).

than you for a lecuture but its nothing about topic ;-)

Thank you for letting me know not to ever bother to respond to a query by you again...

sorry to be a bit unkind but I believe 95% of people here know roughly know how certification process looks like. I'm looking for inservice example. Maybe some company still doing in flight restart during the technical check flight?

I could answer that.




But I won't...