Yeah definitely more to the story, be that a failure of equipment or crew. I lean towards crew panic but you never know..
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South Korea Jeju air plane crash
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As has been made very public, the recorders are powered by AC systems only and on this age of aircraft have no battery backup. This has been addressed since then and it is now an optional extra for exactly these sorts of situations, but generally the chances of complete AC system failure is generally considered extremely remote.
In this case (for whatever reason) they’ve lost both engines but also did not have the APU generator available, didn’t start it or just didn’t see the point as they were now a glider. Given the aircraft can be flown by hand without hydraulic assistance, and the screens would still be providing basic information using the main battery for emergency systems, they may simply have gone for ‘eyeballing it’ as they were so close to the ground. No checklists, no point starting the APU, just glide it to the runway maintaining as much energy as possible.
Yes you can pull the CB’s for the recorders at any point, but really that would be the last thing on anyone’s mind when you’re in a glider that size which has just lost both engines at such a low altitude.
I’d say they did that part almost too well as they got to the runway with TOO much speed and couldn’t get the aircraft on the ground early enough. The barrier just sealed their fate unfortunately, from what could have been a survivable accident.
In this case (for whatever reason) they’ve lost both engines but also did not have the APU generator available, didn’t start it or just didn’t see the point as they were now a glider. Given the aircraft can be flown by hand without hydraulic assistance, and the screens would still be providing basic information using the main battery for emergency systems, they may simply have gone for ‘eyeballing it’ as they were so close to the ground. No checklists, no point starting the APU, just glide it to the runway maintaining as much energy as possible.
Yes you can pull the CB’s for the recorders at any point, but really that would be the last thing on anyone’s mind when you’re in a glider that size which has just lost both engines at such a low altitude.
I’d say they did that part almost too well as they got to the runway with TOO much speed and couldn’t get the aircraft on the ground early enough. The barrier just sealed their fate unfortunately, from what could have been a survivable accident.
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Operating and having the generator online are two different things - a low idle speed, electrical problems or any number of things COULD stop the generator outputting anything even if the engine is still spinning. It could also have taken a bird and been ok at approach power till they tried to go into high power for go-around and that’s just been too much for it to handle.
I thought the video you linked to said it was on a single circuit no stand-by, and the pilot had to cut it over?
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It has a single power supply from one Bus Bar, but that Bus can be powered from multiple sources (Eng 1, Eng 2 or APU)
Ah gotcha. So the bus should have failed over to the other engine automatically?
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I’m not sure on the 737 architecture, as to whether they fly around with them connected together or keep them separate - there may also be company policy differences. I’d like to think it would do it automatically, but if both engines failed at roughly the same time and they didn’t/couldn’t start the APU then there’s no AC power to use.
There is a static inverter which converts the battery DC to Emergency AC, but the FDR wasn’t connected to the emergency bus. I definitely feel it SHOULD have power to help accident investigators, and that may be something that comes out of all this, or at the least give the FDR a mandatory battery backup.
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Reading the latest news it would seem that the investigators found bird remains in both engines - it would explain one engine being trashed and the other reduced to idle or lower and not being able to keep the generator online. Much like Sully, if you lose them both at such a low level there really isn’t much you can do, especially if they’d already started a go-around to try and avoid the birds in the first place.
You could commit to the landing as per the guidance, though. He did a go around which is against what he was meant to do.
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At the risk of sitting on the fence, it depends.
They may have chosen to go around and throttled up just prior to the bird strikes after being informed by ATC of the risk a few minutes earlier. By pulling out of the approach and throttling up at the moment BEFORE they took the birds, it may have thrown them off enough that they then couldn’t reconfigure for a landing straight ahead. The engines would take a while to wind down on taking the birds, and much like in Sully you have a time it takes the human brain to realise what’s happened and make decisions based on it. The radio call stating the bird strike and go around may have been ten seconds or so AFTER the go around decision. They then found themselves too high and close to the runway to make the landing again so elected to carry on and come round in the other direction.
If they did make the decision to go around after the bird strike then that would have been an error.
Nothing here is black and white but hopefully the exact timeline can be found from the FDR and CVR.
What about not dropping the landing gear manually or was there really no time?
I read this would only be 2 minutes to do on this aircraft.
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I'm far from an expert on these matters but some of the news articles I've read suggested that although a little far down the runway the landing was good. But it was utterly undone by the concrete topped berm. Is there really significant blame beyond this unchangeable aspect of the landing?
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I would hazard a guess that the checklists required for that might take a while to run while they were dealing with a gliding aircraft, no hydraulics or main electrics, cockpit warnings going off all over the place and simply trying to keep it airborne for as long as possible. The fact the gear was up and flaps retracted suggest they got part way through the go-around procedure before the engines gave out, or they adopted this configuration for the best glide speed early on before all hydraulic pressure was disapated.
It’s also possible they simply forgot about it in the chaos of the emergency, or maybe tried to lower it normally but didn’t realise until it was too late that they didn’t have any hydraulics - it may be this is one of the things we never know unfortunately.
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I think that yes, it was a lot more survivable. The concrete wall at the edge of the airfield is another obstacle but much thinner than the antenna base and whilst it would have damaged the aircraft, wouldn’t have stopped it. Once it got to the sea then it would have come to a halt fairly rapidly - just look at the footage of Sully to see how good a brake water can be if you hit it at the right angle.
There are a lot of aspects of this which we don’t understand yet, including decisions the crew made which may or may not have been the right ones, but which we also may never know the answer to. Ive changed my mind on many parts of this as more evidence has come out, and now knowing that both engines may have taken birds puts it in a whole new light.
If you want some evidence of what CAN be survivable, the DC10 crash in Sioux City of UA232 is a perfect example. They lost the centre engine and all the flying control hydraulics, so were flying it in purely using asymmetric thrust from the two remaining wing engines:
184 of the 296 passengers survived, 13 with no injuries.
As penfold says you go through the checklists for an engine out etc, and depending on the exact system to drop the landing gear it can take a fair bit of time after you start doing it for them to drop without power (and even then they may not lock).
IIRC the old manual pump/screw system for dropping landing gear on some aircraft took minutes and often required someone working fully on it, whilst the gravity drop takes time to let them fall into place and hopefully lock, and IIRC one of the powered backup systems that some aircraft have is much slower than the normal one as it uses something like a fairly small electric motor rather than the main hydrolic pumps.
There is an absolute catalogue of errors from the pilot --- for one, the berm was at the beginning of the runway. The pilot was landing "against the grain". He also started his decent half way down the usable runway. The berm was a considerable distance from the "usable" end of the runway.
Do we scold the pilot for creating a scenario that should have never existed? (he should have kept landing as per guidance on bird strike) or put total blame on a berm (and ignore the catalogue of pilot errors). Obviously there are 2 pages of debate about this though
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There is an absolute catalogue of errors from the pilot --- for one, the berm was at the beginning of the runway. The pilot was landing "against the grain". He also started his decent half way down the usable runway. The berm was a considerable distance from the "usable" end of the runway.
Do we scold the pilot for creating a scenario that should have never existed? (he should have kept landing as per guidance on bird strike) or put total blame on a berm (and ignore the catalogue of pilot errors). Obviously there are 2 pages of debate about this though
How to prove you know nothing about any of this and haven’t read anyone else’s posts in this thread in 2 short paragraphs.
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Errr
Yes, 69 posts (nice) of mostly nonsense where you have an unhealthy obsession with the infallible concrete antenna base and place all blame on the pilots without knowing anything about what actually happened and ignoring the information which has actually come out, or the decision making processes pilots have to go through.