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I think this resolves YES. TL;DR: FOD ingestion is operating the engines outside their intended operating regime, it is not an engine problem when they then proceed to fail.

Things that seem uncontroversial to me:

• All engines worked on the first stage ascent burn

• All second stage engines worked when commanded (the on-orbit burn was skipped for non-engine reasons, and the ship exploded during re-entry before landing burns)

The complexity comes, obviously, in the boostback and landing burns of the first stage, where several engines shut down. I see two primary points to consider:

• The problems discussed in the report are listed as the "most likely root cause"; this is not a completely certain finding. We may or may not get more certainty later.

• The problems are mostly attributable to FOD ingestion and filter blockages, likely in the form of ice (not mentioned in the report, but widely rumored).

So the major question is whether ice in the prop system counts as an "engine problem". My view is that it is much closer to "tank problems, propellant slosh, tank depressurization, or other related problems" than it is "engine problems". I expect that, if there is a defined amount of allowed FOD, ice, solids, or similar in the engine spec, it was exceeded in this flight. Which is to say, the engines failed because they were operated outside of their intended parameters, causing "loss of inlet pressure in engine oxygen turbopumps". That's not quite the same wording as something like "loss of inlet pressure to the engine" would be; I gather that the filters that clogged may be part of the engine rather than the stage. So this isn't quite "the stage failed to supply propellant to the engine" but rather the closely related case of "the stage supplied contaminated propellant to the engine".

If the engines had ingested a rag or tool that was left in the tank and failed as a result of that, it would be a prop system problem (or, more broadly viewed, an operational and procedures problem), not an engine problem. The only way this is an engine problem is if the engine spec had an allowable FOD limit that this was within, and the engine (and engine filters) failed to tolerate it. As best I can tell, that's not what happened.

This turned out to be a bit more of a mess than I was hoping for, and I think the fault their lies with question writing that did not adequately anticipate the full range of failure scenarios; that's entirely my fault. I think I could have written this much more clearly, concisely, and more closely matching my goals had I included phrasing like "while operated within their intended design envelope".

@EvanDaniel the cause of the early boostback shutdown being "most likely" filter blockage I'm totally happy to take to as "not an engine problem". I think if there's ambiguity, it's about the engines that failed to relight during the landing burn - the ones that weren't locked out due to their early shutdown during the boostback burn. The cause of their failure isn't mentioned, and the closest we get to them saying something about it is the quote on what changes they'll make to improve things:

And utilizing data gathered from Super Heavy’s first ever landing burn attempt, additional hardware and software changes are being implemented to increase startup reliability of the Raptor engines in landing conditions.

@EvanDaniel SpaceX has posted some info

https://www.spacex.com/updates/#flight-3-report

They say that some engines shutdown early during boostback due to filter blockage. These engines were disabled for the landing burn, but there were also additional failed relights during the landing burn. Unclear if these failed relights can be blamed on "engine problems".

The most likely root cause for the early boostback burn shutdown was determined to be continued filter blockage where liquid oxygen is supplied to the engines, leading to a loss of inlet pressure in engine oxygen turbopumps. SpaceX implemented hardware changes ahead of Flight 3 to mitigate this issue, which resulted in the booster progressing to its first ever landing burn attempt. Super Heavy boosters for Flight 4 and beyond will get additional hardware inside oxygen tanks to further improve propellant filtration capabilities. And utilizing data gathered from Super Heavy’s first ever landing burn attempt, additional hardware and software changes are being implemented to increase startup reliability of the Raptor engines in landing conditions.

SpaceX

SpaceX designs, manufactures and launches advanced rockets and spacecraft. The company was founded in 2002 to revolutionize space technology, with the ultimate goal of enabling people to live on other planets.

@chrisjbillington thanks! I'll give it a read.

There were failed relights in the booster landing burn, but since there were so many of them, I would guess it was not an engine problem. We'll see.

@chrisjbillington imo it seemed like an engine problem? It's that or what, slosh? 97% seems high.

Ehh don't feel like betting on hard-to-resolve markets today tho

https://youtu.be/Gq7wd6QHS38?t=2194
At about 8km altitude Booster seems to lose stability. Probably a grid fin software thing. Wobbles getting bigger and bigger.

Could imagine that messed with the propellant slosh, there wasn't much left in the tank and they were trying to light 13 engines.

@Mqrius slosh was what did them in last time, so that's what I was thinking, yeah. Or anything about propellant feed in rather than the engines themselves.

Comments from Scott Manley (forget where he mentioned this, maybe his latest video) suggest something going wrong during boostback burn shutdown may be responsible for the subsequent failed landing burn relights. Hopefully he says more about this, Scott has a pretty impressive track record on figuring out things like this.

@chrisjbillington Fuel filters blocked reported to be the problem with second flight. Perhaps slosh was at least part of the cause of that. This is fuel feed in? Upgrading the filters is a fuel feed in system not an engine upgrade?

@ChristopherRandles I think that's right, since the question description here does suggest that the failed boostback relights in IFT-2 would not have counted as engine problems.

@chrisjbillington
>forget where he mentioned this, maybe his latest video

yes. but 2 possibilities mentioned, It is here
https://www.youtube.com/watch?v=8htMpR7mnaM
4m 40s to 8min 20sec has the relevant parts

Possibility 1. Asymmetric engine shutdown at end of boostback burn looked odd - just a telemetry issue mentioned as a possible alternative explanation, but perhaps this indicates some problem.
Possibility 2. Grid fin control possibly being tested high up but maybe this control was off leading to the unstable roll movement and this could cause fuel slosh or some other issue preventing engines from being relit.

@chrisjbillington Yes, the intent is that stuff like "ice in the feed lines because of water / humidity in the tank" is not a "Raptor reliability" problem.

I'm reopening the question while we await the FAA report.

Starship is planned to engine relight in space (simulating a deorbit burn but will reenter regardless of success). If the engines fail to relight does this resolve no immediately? or do we wait possibly a lot longer to hear whether it is fuel flow to engines or something like that?

@ChristopherRandles it mentions failed relights explicitly as counting the same, where it must be engine problems specifically.

Related market:

Uncommanded shutdowns, engine explosions, and failed relights will all result in this resolving No, with the major caveat that this must be attributed to engine problems.

Registering that I think Starship failed during IFT-2 because of "engine problems", interestingly the video you linked also attributes it to what I would call "engine problems" so I'm kind of curious how this is going to resolve. The first "puff" almost certainly can't be from a tank failure, I agree that it's most likely an engine failure of some sort followed by increased LOX flow. I'm not sure what else could fail, but not fail catastrophically and not otherwise lead to any other problems for a few minutes.

I think the Super Heavy explosion was probably feed system / tank problems, not Raptor.

I think the Starship failures might have been similar, I've heard rumors of premature propellant depletion. Unclear whether that was caused by an engine failure or something else; I think we need to wait for mishap reports and such.

Right now I'm not sure how this market would resolve if it had been about IFT-2.