Jeju Air Crash

[Tlcooper44]

https://www.forbes.com/sites/conorm...-in-south-korea-as-investigators-probe-cause/

I didn’t see another thread about this, but delete if there is.

Some pretty astounding decisions here leading up to the crash. Truly a horrific disaster possibly avoided.

Combined with Azerbaijan, a pretty bad week for aviation.

 

[BlackDiamond]

There is a lot we still don't know, as to why the plane had not deployed landing gear or flaps, whether one or both engines were functional or shut down, etc. We will have to wait for the reports from the Korean equivalent of the NTSB.

A contributing factor seems to be the concrete embankment near the runway overrun, which is there to raise the ILS localizer antenna to compensate for a slope in the runway (about 6m from the threshold). In the US or Canada such an embankment would not be allowed and instead a breakaway mounting for the ILS would be required, but Korean standards are different. No doubt such an installation would have reduced the casualties.

 

[jiml]

A contributing factor seems to be the concrete embankment near the runway overrun, which is there to raise the ILS localizer antenna to compensate for a slope in the runway (about 6m from the threshold). In the US or Canada such an embankment would not be allowed and instead a breakaway mounting for the ILS would be required, but Korean standards are different. No doubt such an installation would have reduced the casualties.

Indeed. The crash itself looked survivable if extremely frightening, but the sudden collision with the wall is what destroyed the plane. I would expect any investigation to recommend its removal, no matter the actual cause of the accident.

 

[jis]

I agree that the concrete wall needs to go and they need to update their airport design rules to disallow such. As for the rest, I’d wait for the investigation report as quite a few things don’t quite add up. Unfortunately South Korea has a bit of a bad history in being not as open and transparent as desirable about accident investigation, but one can hope it will be different this time.

 

[alpha3]

The big question is why they tried landing with no landing gear or flaps deployed. Landing gear is easily 'gravity dropped' on the 737, which would then enable spoilers and thrust reversers for braking power. The TE flaps can be deployed electrically if the hydraulics fail.

Some speculation is that the aircraft had both engines taken out by birds in the area, ala US1549. There's a video that clearly shows a compressor stall on #2 engine, shooting out flames, apparently the bird strike as the plane climbs out for go-around. Thoughts are that the pilots may have shut down the 'good' engine instead of the bird strike engine, by mistake.

The FDR and the CVR should have very interesting tales to tell on this one. SKorea will probably move fast on this, with the crash so spectacularly documented on video for all the world to see. Indeed, I just heard on the news that they have already downloaded the CVR data. Now we wait for the reveal as to what it shows. RIP to the victims

 

[alanh]

The only thing that makes sense is a double engine failure, either directly or by shutting the wrong one down. It would have been easy to do a normal go-around on one engine.

Assuming a double engine failure, they made a 180 turn and came in for landing. I don't know how hard it is to activate the gear gravity drop, but if it's more than a second or two they probably didn't have time. The 737 still has manual reversion on the controls so it can be steered without hydraulics. But it's probably pretty difficult. It may have taken both pilots to wrestle with the controls, leaving no one to work on the gear.

I'm also not sure how fast the hydraulic pressure drops after both engines stop. They didn't have time to start the APU.

 

[Tlcooper44]

A plane landing with the wind (rather than against it), with no flaps, and no gear, 2/3 down a 9,000 ft runway indicates a seriously desperate situation - if there wasn’t an engine failure, that would just be poor judgement on the part of the pilots.

I’ve been looking to get ahold of an ATIS report for that date to see winds.

 

[jis]

A plane landing with the wind (rather than against it), with no flaps, and no gear, 2/3 down a 9,000 ft runway indicates a seriously desperate situation - if there wasn’t an engine failure, that would just be poor judgement on the part of the pilots.

I’ve been looking to get ahold of an ATIS report for that date to see winds.

I heard in a nice presentation by a 737-800 pilot that the wind was calm that day so it was not a factor.

 

[Tlcooper44]

I heard in a nice presentation by a 737-800 pilot that the wind was calm that day so it was not a factor.

Good to know.
Link to presentation possible?

 

[jis]

Good to know.
Link to presentation possible?

I’ll look for it. Unfortunately I did not save it.

 

[Asher]

I think the pilot was attempting a go around after a attempted landing and for whatever reasons didn’t get lift.

 

[jis]

I think the pilot was attempting a go around after a attempted landing and for whatever reasons didn’t get lift.

That is a possibility that has been raised by several people who observed that the plane was not slowing down at all while scraping along the ground. I have no opinion this way or that since I have not studied it sufficiently myself.

 

[Devil's Advocate]

The root cause of the Korean emergency is anyone's guess, but the main cause of death seems to be the reinforced concrete wall that obliterated the entire plane in an instant. Watching a fast moving but fully intact aircraft suddenly turn into a fireball of tiny fragments was quite disturbing. Without that wall the plane would have likely dug into the overrun dirt and slowed very abruptly. You'd likely have lots of serious injuries but also lots more survivors. As for the Azerbaijani jet it would appear that Putin has given a vague between the lines apology for shooting it down or otherwise causing it to crash.

 

[Asher]

The root cause of the Korean emergency is anyone's guess, but the main cause of death seems to be the reinforced concrete wall that obliterated the entire plane in an instant. Watching a fast moving but fully intact aircraft suddenly turn into a fireball of tiny fragments was quite disturbing. Without that wall the plane would have likely dug into the overrun dirt and slowed very abruptly. You'd likely have lots of serious injuries but also lots more survivors. As for the Azerbaijani jet it would appear that Putin has given a vague between the lines apology for shooting it down or otherwise causing it to crash.

I think the barrier the plane hit was part of the ATC Equipment some distance from the end of the runway.

 

[jis]

I think the barrier the plane hit was part of the ATC Equipment some distance from the end of the runway.

ILS antenna.

 

[Devil's Advocate]

I think the barrier the plane hit was part of the ATC Equipment some distance from the end of the runway.

As Jis stated above the functional hardware is part of an ILS antenna array, which is normally designed to break away in an overrun impact. It's the earthen mound and reinforced concrete platform that are highly unusual (and extremely destructive to an overrun aircraft).

 

[Asher]

ILS antenna.

ILS, My bad.

 

[Stevenz]

It might pay to listen to the latest Flight Radar 24 podcast on the subject.

 

[basketmaker]

I think the pilot was attempting a go around after a attempted landing and for whatever reasons didn’t get lift.

You could be right. Sounded like the engine(s) were actually spooled up as it slid down the runway. But it also appears the reverser(s) were open. Not sure.

 

[Asher]

You could be right. Sounded like the engine(s) were actually spooled up as it slid down the runway. But it also appears the reverser(s) were open. Not sure.

Yeah, a lot went wrong, it sounded like full power to me.