Posted on 01/11/2025 3:01:06 AM PST by Libloather
The flight data and cockpit voice recorders on the Jeju Air jet that crashed on Dec. 29 stopped recording about four minutes before the airliner hit a concrete structure at South Korea’s Muan airport, the transport ministry said on Saturday.
Authorities investigating the disaster that killed 179 people, the worst on South Korean soil, plan to analyze what caused the “black boxes” to stop recording, the ministry said in a statement.
The voice recorder was initially analyzed in South Korea, and, when data was found to be missing, sent to a US National Transportation Safety Board laboratory, the ministry said.
The damaged flight data recorder was taken to the United States for analysis in cooperation with the US safety regulator, the ministry said.
Jeju Air 7C2216, which departed the Thai capital Bangkok for Muan in southwestern South Korea, belly-landed and overshot the regional airport’s runway, exploding into flames after hitting an embankment.
The pilots told air traffic control the aircraft had suffered a bird strike and declared an emergency about four minutes before it crashed into the embankment exploding in flames.
Two injured crew members, sitting in the tail section, were rescued.
Two minutes before the Mayday emergency call, air traffic control gave caution for “bird activity.”
(Excerpt) Read more at nypost.com ...
In past accidents the reasons it stops recording is:
1) loss of electrical power which is generated by the engines
2) disconnection of the wires that lead to the recorder.
So damage to the fuselage or to the power system are prime suspects.
Just wondering …..Did they send it to FBI for analysis????
Seemed to me the ac was at dang near full power skidding down the runway right up to the impact with the structure.
They landed long and fast, with no flaps or spoilers. Also, they hung in “ground effect” way too long. All of those made it damn near unstoppable once it reached the runout.
CC
I'll lean towards the Bird Strike option causing damage to the wiring.
Pages 4 & 5 on the .PDF Page Count are simple Schematics.
Looks like both engines have Generators and also the Aircraft has an APU (Auxiliary Power Unit) Generator as well. Automatic Power switching will switch to any of these systems if the needs arise.
No battery backup?
Seriously?!
If the last 4 minutes was missing and the aircraft came in very very hot, that could suggest that the black box stopped recording 10-15 miles from the airport.
Reports say no flaps, no spoilers for landing. The pilots had it pointed at the runway and it sounds like the aircraft went totally dead 10-15 miles from the airport.
Catastrophic failure in every system at the same time seems impossible.
Box has its own power source.
Most do have backup. Maybe not this model.
large jets use the ram air turbine for power. It drops from the belly of the plane and the airflow turns the turbine.
Batteries are heavy and a plane demands a lot of power. Yes there are batteries but not enough to run all systems.
The easy explanation is the pilots messed up. They had a bird strike that killed engine #1 the First Oofficer who should have been running the bird strike check list messes up twice. First he doesn’t immediately start the APU which would have provided not only 400HZ 115V power for every system but also the third independent hydraulic pressure system AND most importantly high pressure bleed air that is required to start either one of the main engines. So no APU is first critical screwup then he in the panic shuts down the wrong engine 2# this with #1 bein killed by the bird strike and no APU running means they just lost all hydraulics, electrical expect for critical battery back up instruments and also the ability to restart either engine since no high pressure bleed air either. They lacked the speed or altitude to attempt a windmill restart on 2# so they are dead stick at this point flying on back up instruments and manual flight controls. They didn’t drop the RAT the ram air turbine which would have spun up and given basic hydraulics and emergency electric power which they could have then used to start the APU with , and with its high pressure bleed air restart #2 engine. I say the FO panicked and shut down the wrong engine as the first responsibility of the Captain is to fly the aircraft so the FO would have been running the checklist and attempting restarts. Lack of power and hydraulics also explains the lack of flaps they had zero hydraulic pressure to drop them. The gear has gravity drop down back up they missed that in the check list as well. With no RAT and time dead and one inoperative engine plus no APU they were dead stick and yes the black boxes would be dead as well. So the FO killed the good engine by mistake at least 4 min from touch down.
I checked the 737 doesn’t have a RAT as standard equipment at all, it’s a custom order so that could explain the lack of RAT deployment clearly in the videos there is no turbine hanging down from the fuselage. Boeing expects the APU to be running should both engines fail or be unavailable. The APU is the backup third redundant system in the 737 series. So if the FO killed the good engine by mistake and didn’t have the APU already running they were in deep kimchi at that point.
This is a 800 series it has three hydraulic circuits A,B and stand by <<< this is the APU driven one. the manual says that either engine’s hydraulic pump can still be driven by ram air via windmilling at speed. It doesn’t specify what the minimum airspeed is for windmill operation it looks like under 200 knots is below the minimum windmill speed. Without that APU they would’ve been running on manual reversion controls without hydraulics at all. Plus too slow for a windmill restart on the good engine ,since no APU means no high pressure bleed air either. Boeing says there are two electrical driven pumps one each for A&B systems with batteries for 60 min of basic instruments and also basic hydraulics this was their justification for not being required to have a RAT by the FAA. Someone would have forgotten to link the battery bus to one of the electrical driven pumps on the hydraulic circuit of the good engine. Those batteries also supply DC voltage to the APU starting motor/generator bus so they could have spun up the APU and then had full electrical and hydraulics plus HP starting air. Someone messed up and messed up badly this aircraft has triple redundant back ups plus manual reversion flight controls and a full 60 min battery for flight instruments no way those were depleted in 4 min driving the hydraulics ou the A or B system. The FO didn’t tie the emergency DC bus to either the hydraulics nor the APU nor the bus with the black bdoes which would have been primary flight instrumentation bus as well.
No RAT on a 737.
I heard a report (don’t know if it’s accurate, of course) that the APU was out of service on that flight. If true, one more hole in the Swiss cheese that came into alignment.
Only if the breakers were pulled.
You might be close on some of that. Like you, I think someone shutdown the wrong engine. That would explain the gear up, no flap approach. Keeping best L/D to extend the glide.
My 40 years in the flying profession has seen all variations of emergency checklist philosophy. The one that seemed the most workable was FO flies and CA works the checklist. But, of course, we hired experienced and capable FOs that could fly a plane and work the radios.
The lower tier airlines don’t have the luxury of a deep hiring pool, so they may use a Captain flies and FO runs the checklist philosophy.
The things you mention that could have been done immediately are farther down in the checklist. There could have also been confusion on which checklist was needed first. Of all the aircraft I have flown, the 737 was the most difficult to select the proper checklist. A simple generator failure at the wrong time could present itself as an electrical problem, a hydraulic problem, a fuel pump problem, an AC problem, a lighting problem, or a radio problem. Diagnosis took a fairly deep knowledge of the systems.
What happened may forever be a mystery with the missing CVR and FDR data.
As a side note, the B777 electronic checklist was IMO one of the greatest advances in aviation safety in a long time. It presented the most critical checklist first, then by priority the next checklist. You could not move on unless the item was already automatically done or the item was manually checked.
EC
My BIL is a engineer in the triple 7, they live in Everett, he is also a flight engineer, test pilot , and flight instructor. Love that aircraft.
I just assumed most second and third tier always flew CA flies FO runs the check lists. Some one up thread said the APU was out of service and they were allowed to fly anyways. Well then it only takes the FO hitting the wrong fire suppression system for that bird strike to put them in deep kimchi. Low slow and no APU means you are not having a good day. I don’t know what minimum airspeed or altitude you would need for a 737/800 windmill start but I would think it’s much higher and faster than a typical go around missed approach.
Windmill start is in the 230 knot range. Best L/D glide speed is just under 210 depending on weight.
EC
Certainly there could be one to run the black box??
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