A plane crash in Brazil, near Sao Paulo...

[JohnRBaker]

It appears that a a mid-sized passenger aircraft has crashed near Sao Paulo, Brazil:

https://www.dailymail.co.uk/news/article-13728665/brazil-plane-crash-sao-paulo-passenger.html

https://x.com/sentdefender/status/1821965394938327501

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[3DDave]

Says it's an ATR-72-500.

 

[Sym P. le]

How do you spin it at 17,000 ft., straight and level?

flightradar24

 

[3DDave]

I am leaning to a prop pitch reversal followed by total panic. Ice has also been implicated, but that doesn't look like the result of a stall transition to a spin. Those usually do a tightening spiral rather than sinking like a frisbee.

 

[Sym P. le]

Not tight enough for stall and too much nose down for flat.

 

[TugboatEng]

It's winter in Brazil. Icing conditions were present.

 

[btrueblood]

Juan has a video up on it as well.

https://www.youtube.com/watch?v=ozinSmylTmQ

He, like others above, also talks about icing as a high probability due to the plane's typical operating altitude, as well as how difficult it is to recover from a spin in a multi-engine turboprop aircraft.

 

[MintJulep]

ATR-42 and 72 have a long history of icing related crashes.

https://en.wikipedia.org/wiki/ATR_72#Accidents_and_incidents

Cargo hold in the back, so it's possible that the CG was out of limit aft.

 

[TugboatEng]

In the comments for Juan's video, someone stated that there was a severe weather or SIGMET bulletin.

 

[Sym P. le]

I'd say the granular data certainly implies icing.

This comment from the blancolirio (Juan) video must sum up the situation.

Ice played a role here, besides the SIGMET at the area showing severe icing between FL120 and FL210, there were several pilot reports of icing in the São Paulo approach area, including the accident aircraft apparently.

Some reported hearing them on frequency requesting to descend due to icing and the approach controller saying negative for some reason, then they just informed they were descending.

Also a friend of mine said that he’s seen ice in the leading edge of an A320 for the first time in his career today, when arriving in São Paulo.

Sad day to aviation, RIP passengers and crew.

Thank you, Juan, for always keeping us informed in such a clever and respectful manner.

 

[Alistair_Heaton]

Can I just check what people mean by prop reversal in this thread.

This side of the pond wouldn't use such a term.

And the atr hold is in the front just behind the cockpit. But CoG could still be an issue.

 

[MintJulep]

And the atr hold is in the front just behind the cockpit

Actually, it seems there's both fore and aft holds.

Serious Incident Report from 2015 about a loading error.

https://asn.flightsafety.org/wikibase/205940

 

[Alistair_Heaton]

The aft is more of a pod for hand carry that can't go under the seats.

The q400 has something similar at the front on the RHS.

The floor loading limits make them pretty restrictive in use.

I don't know much about the ATR.

I know the props are Hamilton Standard which are significantly different to the Macaulay props I have experience with. Hence the question about prop reversal.

 

[Andries]

Looks like the aircraft entered what is known as a deep stall; this occurs when the wings blank out the empennage, making the plane almost impossible to control.
This occurs with T -tail aircraft and the result is usually a flat spin.
The obvious question is why the aircraft went into a deep stall in the first place.

Andries

 

[hokie66]

Icing seems more and more the culprit. And as others have said, that type aircraft is particularly susceptible to icing problems.

https://edition.cnn.com/2024/08/13/americas/brazil-plane-crash-atr-ice-intl-latam/index.html

 

[Alistair_Heaton]

There were hot wing jets landing with 1" thick rime layers on the leading edges apparently in the area.

Pneumatic boots have no chance in those conditions.

I might add pilot error is involved. They should have got the hell out of it. And not pressed on.