B737 Crashes on landing in South Korea

[savas]

If I had to place a bet and choose one scenario:
Pilots work overload too high to start off with due to initial bird strike leading to CRM going out the window

[propstrap]

https://edition.cnn.com/2024/12/30/busi ... index.html

All in the link above just speculation of course like much else, but there are some interesting tidbits in there... as with all media, to be taken salty. But there are some great minds in aviation offering an opinion. Yet no-one was there and could say for certain the whats and whys... A preliminary report should be out within 30 days and the final report in a year.

“This accident is very, very sad with the loss of life that we have seen,” Shahidi [Hassan Shahidi, president and CEO of the Flight Safety Foundation] said. “It’s a complicated accident that involves many, many different factors that the investigators will be looking into to really understand the confluence of those factors that led to this disaster.”

The tragic even has so many layers, and everything at the moment is speculation, said Erika Armstrong, a pilot and former contract worker at Boeing. Armstrong is the director of marketing and vice president of business development at Advanced Aircrew Academy, an aviation e-learning firm that trains pilots, flight attendants and crew.

Shahidi said if there was a bird strike, investigators will be looking if it destroyed one or both engines, which will be critical.

“From the time that the crew declared ‘May Day’ emergency, it was only about five minutes before the aircraft landed and crashed, so there was little time in that to for the pilots to be able to do what they needed to do,” Shahidi said.

Although, Armstrong said, even if her theory is true, it doesn’t explain why the landing gear didn’t deploy.

A bit of duff gen from the article...

Boeing data from 1959 to 2023 shows the 737-800 recorded just 10 fatal accidents that damaged aircraft beyond repair, one of lowest rates in the industry when compared to the number of flights they’ve flown.

About the concrete emplacement of the localiser antenna...

The FAA defines the surface surrounding runways as “runway safety areas,” which are typically 500 feet wide and extend 1,000 feet beyond each runway end.

Shahidi said investigators will take a further look at the barrier to determine whether it was in compliance with international standards for runway construction.

Of course reading the whole article is better than just the few tidbits above. Many factors were at play, most of which we do not know. Speculation that the wrong engine was shut down could be the case, as many other theories, in the end the concrete barrier sealed the fate for all but two on board. Very sad indeed...

[Volo]

The accident investigation team have probably had their first meeting and have already run the tapes .
The data has already indicated the sequence of engine shutdowns and or management .
They listened to the tapes and know what was said in the cockpit .
By and large they pretty much know what happened by now but it will be year before the report comes out.
What a waste of resources - bone idle bunch .
They will probably claim that they need the maintenance records of the engines for the last 5 years to determine whether a screw came loose and fell in to the turbine at the precise same time as a goose went through there.

[propstrap]

The accident investigation team have probably had their first meeting and have already run the tapes .
The data has already indicated the sequence of engine shutdowns and or management .
They listened to the tapes and know what was said in the cockpit .
By and large they pretty much know what happened by now but it will be year before the report comes out.
What a waste of resources - bone idle bunch .
They will probably claim that they need the maintenance records of the engines for the last 5 years to determine whether a screw came loose and fell in to the turbine at the precise same time as a goose went through there.

Hi Volo, that may seem like an open and shut case, but we simply do not know. The first rule of aircraft accident investigation (one of many 1st rules ) is not to assume anything. The investigation team is mandated to leave no stone unturned to unravel the relationship among the many factors that contributed to the accident and fatalities. Why the accident? Why the fatalities? That may be some questions I guess the team is asking. Not as simple as looking for a screw so much as why the many layers of safety failed. And as a consequence, what can be done to ensure a different outcome?

Granted, willful or gross negligence or incompetence is one thing, but that is not necessarily the case here, which is important to understand. Vaguely parallel may be the Tenerife disaster, and the positive impact the investigation had on Human Resource training amongst others. The Challenger disaster and effect it had on high level decision making. The Titanic is always a classic case study. It hit an iceberg, but there were so many attributing factors and there were many positive changes arising from the investigation. The point is, the investigation must be thorough for those positives to surface.

So the investigation team must do as mandated, and yes, sometimes it can be boring, but without it aviation would have been much more a haphazard affair...

[Volo]

The accident investigation team have probably had their first meeting and have already run the tapes .
The data has already indicated the sequence of engine shutdowns and or management .
They listened to the tapes and know what was said in the cockpit .
By and large they pretty much know what happened by now but it will be year before the report comes out.
What a waste of resources - bone idle bunch .
They will probably claim that they need the maintenance records of the engines for the last 5 years to determine whether a screw came loose and fell in to the turbine at the precise same time as a goose went through there.

Hi Volo, that may seem like an open and shut case, but we simply do not know. The first rule of aircraft accident investigation (one of many 1st rules ) is not to assume anything. The investigation team is mandated to leave no stone unturned to unravel the relationship among the many factors that contributed to the accident and fatalities. Why the accident? Why the fatalities? That may be some questions I guess the team is asking. Not as simple as looking for a screw so much as why the many layers of safety failed. And as a consequence, what can be done to ensure a different outcome?

Granted, willful or gross negligence or incompetence is one thing, but that is not necessarily the case here, which is important to understand. Vaguely parallel may be the Tenerife disaster, and the positive impact the investigation had on Human Resource training amongst others. The Challenger disaster and effect it had on high level decision making. The Titanic is always a classic case study. It hit an iceberg, but there were so many attributing factors and there were many positive changes arising from the investigation. The point is, the investigation must be thorough for those positives to surface.

So the investigation team must do as mandated, and yes, sometimes it can be boring, but without it aviation would have been much more a haphazard affair...

...................
I here you Sir - but I simply can't go with the " Time frame " that appears to be typical of some of these investigations .

[GrahamW]

[MadMacs]

[Volo]

Its unthinkable that Boeings electrical systems are so inadequate that they can't provide power to the Flight recorders for the last 4 minutes .
They might as well not have had any recorders for all they were worth.

[propstrap]

Its unthinkable that Boeings electrical systems are so inadequate that they can't provide power to the Flight recorders for the last 4 minutes .
They might as well not have had any recorders for all they were worth.

That is quite so, but if it had, the investigation goes up a whole new level. Fortunately the two survivors should collaborate whether there was power or not, but even so. Did the recorders stop recording, or recorded but stopping receiving data? At the same time or not? Who knows what the crew was facing in their final minutes...

[Volo]

According to the graphic a total of 4 minutes elapsed between the mayday call and the crash .

There is no way he did a 180 turn without power from at least one engine and if so electric power must have been delivered during the turn unless electric power is only delivered by one of the engines, which to.my mind should be unthinkable , however Boeing keep surprising us with dumb design features.

[Hexapilot]

If they had no electrical systems operating, why is the reverse thruster on the RH engine deployed?

[Volo]

Its unthinkable that Boeings electrical systems are so inadequate that they can't provide power to the Flight recorders for the last 4 minutes .
They might as well not have had any recorders for all they were worth.

................................................................................................................................
Why are Boeing not being taken to task for this missing 4 minutes of Data - Even the simplest form of a Battery and capacitor back- up would have guaranteed the feed of Data, however it appears that was not built into the system .

I think they have got a lot to answer for . They might just as well not have the Data Loggers .

The investigators are now standing around with nothing to do - just standing staring at one another !!!

I am guessing the voice tapes have not been helpful - probably just loud exclamations and grunts - sorry I am being a bit unkind but classically they never seem to get much out of these - or did they also suffer a power failure .

My mickey mouse Logger in my glider keeps Logging until I switch it off even after I have taken it out of the cockpit and stood on it in the Mud ( Well I dont do that every time but you get what I mean ).

[Scrapyard Dog]

The B737-800 FDR starts recording when the first engine start goes through 50% N1 and stops when both engines are shut down.

This leans credence to the theory that the pilots shut down the incorrect engine after the bird strike, effectively dead sticking the aircraft.

The battery and aux battery will give 60mins of standby power to the aircraft, however I cannot remember if they power the FDR and I seem to have misplaced my -800 FCOM.

The -800 has 2 dedicated batteries to give the standby instruments as well as main and APU fuel shut off valves power (150mins worth)

[propstrap]

From AvHerald:

On Jan 13th 2025 South Korea's Ministry of Transport further detailed, that the CVR stopped recording at 08:58:49L before the crew declared emergency at 08:59L. The ministry further reported that structures endangering flight safety like concrete mounds for ILS antenna will be replaced or removed. Three more airports in South Korea with such structures have been identified.

As the crew transmitted a mayday after the recorders stopped working, there would still have been some electrical power... Not knowing the B738 (or any Boeing) I don't believe the CVR and FDR will stop recording when both engines spool down, maybe with aircraft stationary and park brake set. Refer below in the extract of Far 25.

Big questions are what did the crew face exactly (one cannot say assuredly wrong engine shut down, although possible, training hammers on that, but it has happened in the past once that I know with a B73 and other types), which systems failed and why.

It is clear whatever happened should not occur to a flagship airliner. Given that there are more than 4400 of the model in service (Google so sprinkle salt) the answers are imperative to be found.

FAR 25 (Large aeroplanes airworthiness standards)

Look at https://www.ecfr.gov/current/title-14/c ... on-25.1457 and also for Data Recorders, not included below.

(d) Each cockpit voice recorder must be installed so that—

(1)

(i) It receives its electrical power from the bus that provides the maximum reliability for operation of the cockpit voice recorder without jeopardizing service to essential or emergency loads.

(ii) It remains powered for as long as possible without jeopardizing emergency operation of the airplane.

(2) There is an automatic means to simultaneously stop the recorder and prevent each erasure feature from functioning, within 10 minutes after crash impact;

(3) There is an aural or visual means for preflight checking of the recorder for proper operation;

(4) Any single electrical failure external to the recorder does not disable both the cockpit voice recorder and the flight data recorder;

(5) It has an independent power source—

(i) That provides 10 ±1 minutes of electrical power to operate both the cockpit voice recorder and cockpit-mounted area microphone;

(ii) That is located as close as practicable to the cockpit voice recorder; and

(iii) To which the cockpit voice recorder and cockpit-mounted area microphone are switched automatically in the event that all other power to the cockpit voice recorder is interrupted either by normal shutdown or by any other loss of power to the electrical power bus; and

(6) It is in a separate container from the flight data recorder when both are required. If used to comply with only the cockpit voice recorder requirements, a combination unit may be installed.

(e) The recorder container must be located and mounted to minimize the probability of rupture of the container as a result of crash impact and consequent heat damage to the recorder from fire.

(1) Except as provided in paragraph (e)(2) of this section, the recorder container must be located as far aft as practicable, but need not be outside of the pressurized compartment, and may not be located where aft-mounted engines may crush the container during impact.

(2) If two separate combination digital flight data recorder and cockpit voice recorder units are installed instead of one cockpit voice recorder and one digital flight data recorder, the combination unit that is installed to comply with the cockpit voice recorder requirements may be located near the cockpit.

[Vogoff]

FAR 25 (Large aeroplanes airworthiness standards)

Look at https://www.ecfr.gov/current/title-14/c ... on-25.1457 and also for Data Recorders, not included below.

If I heard correctly... blancalirio stated that the requirement for a backup CVR battery is relatively new and this aircraft was just old enough for it not to be fitted with a backup battery.