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Korean investigators have confirmed that evidence of bird-strike was found in both engines of the Jeju Air Boeing 737-800 involved in the fatal landing accident at Muan airport.
The inquiry has identified feathers and other debris as belonging to the Baikal teal, a species of east Asian duck which typically weighs 400g (just under 1 lb) .
It expects to release preliminary findings on 27 January but the transport ministry has disclosed initial details about the 29 December crash obtained by the investigation.
Three minutes after making contact with tower controllers – who subsequently granted landing clearance for runway 01 – the crew was warned of bird activity.
Shortly afterwards, the pilots remarked about the presence of birds below the aircraft, and some 40s later the cockpit-voice and flight-data recorders “simultaneously stopped”, the ministry says.
At this point the aircraft’s altitude was just under 500ft and it was travelling at 161kt.
The crew started executing a missed approach and declared an emergency, due to bird-strike, to the tower. After the bird-strike, the 737’s crew carried out a right turn in a bid to land on the opposite runway
During the go-around, the aircraft flew along the left side of the runway. Rather than rejoining the circuit, the crew carried out a right turn in a bid to land on the opposite-direction runway 19.
The aircraft approached the runway “squarely”, says the ministry, but landed without its landing-gear deployed. It overran after the touchdown and, 4min after the ‘Mayday’ call, collided with the localiser antenna mount. The impact destroyed the aircraft and left just two survivors from the 181 occupants.
Surveillance cameras at the airport captured the contact with birds and investigators discovered blood and feathers in both CFM International CFM56 engines, the ministry states. The remains underwent genetic analysis.
“It is not possible to determine the number of birds, or whether [the remains] include other types of birds,” the ministry says, adding that the engines will be disassembled for further inspection.
The inquiry will have to establish the cause of the crash without full information from the flight recorders, which ceased operating for the final 4min 7s of the accident sequence.
It will carry out a thorough examination of the wreckage – which has been transferred to a hangar at Muan – with detailed analysis of certain debris being conducted at Gimpo airport.
The data available from the flight recorders is being synchronised with air-ground communiations and other information in order to ascertain the operational status of the 737, and determine the extent of any external influence on, or abnormality with, the aircraft and its engines.
“It is expected that several months of detailed analysis and verification will be required,” the ministry says.
Investigators will need to explain several aspects of the accident, including the crucial the decision to attempt an opposite-direction landing.
Confirmation of bird debris in both engines could indicate a loss of thrust, and consequently limited inability to climb or even maintain height, leaving the crew with the choice between an urgent turnback or a possible ditching in the surrounding waters.
Although an opposite-direction landing potentially brings the risk of tailwind, and increased groundspeed, the ministry’s briefing states that Muan was experiencing crosswinds from the east at the time.
The ministry has not given details of the height and speed achieved by the aircraft during its go-around.
Simultaneous recorder cut-out points to a loss of electrical power generated by the engines, although this has yet to be confirmed, along with whether the aircraft also lost hydraulic power to any extent.
The jet should have had its flaps extended and landing-gear deployed for approach prior to the bird-strike. Normal go-around procedures would have involved establishing positive climb, raising the landing-gear and incrementally retracting the flaps.
But the aircraft did not have its landing-gear extended during the approach to runway 19, while its flaps also appear retracted. The inquiry has yet to establish the reasons for these observations, and whether they were the result of crew actions – intentional or otherwise – or system failures.
Muan’s runway 19 is about 2,800m in length. The precise distance along the runway, and the aircraft’s speed, at touchdown are among details yet to be confirmed.
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Comments
That’s an excellent summation. Still lots of unanswered questions. One possible reason for gear retracted and flaps not deployed is that would have significantly increased drag. Depending on AS they could also have induced stall. The non-operative recorder is the biggest mystery to me. Albeit, a complete loss of engine thrust (and so badly damaged they couldn’t rotate from air ingestion) could explain it. I don’t know whether APU would kick in automatically / if not, how long it would take to start it.
I’m still skeptical … Some things don’t add up. Didn’t a cockpit crew member survive? Able to talk?
@hank- No sir... both of the two survivors were cabin crew who had been seated in the tail section- about as far back as possible.
@hank- Yes sir, me too. One thing does occur to me though- I have no idea of the actual circuitry feeding the data to the two recorders, but it would seem probable that there would be "transmit modules" up in the cockpit area which would collate the data and transmit it back to the recorders.
The reason that I consider that possibility is just in thinking about how the flight recorder would be able to document all of the many different equipment operating conditions and positions. It doesn't seem likely that all of that different sensor information would be transmitted separately back to the recorder- it would make a lot of sense to collect, collate, and encode that information up front in or near the cockpit, and send one data stream back to the recorder.
Similarly, the voice recorder has inputs from a number of different microphones and radio communications in the cockpit, and may also be mixed and combined into one data stream- this is just speculation on my part, though.
If that's factual, then I have to wonder if the failure might have been in that equipment, rather than the actual recorders.
In defense of the crew, Sully I think had around 10,000 feet to work with. He didn’t have to do a climb out / go around. So the poor SOBs didn’t have much of a chance if both engines were completely out. Your point @Old_Joe about deficiencies at the airport make good sense. Certainly the causalities would have been far less. How many of us think about the airport we’re flying into?
(Text emphasis was added to the above report.)
Additional information from a CNN report:
The aircraft was at an altitude of 498 ft and flying at 185 mph at the moment the blackboxes stopped recording.
Pretty damned good piloting there folks... they deserved better... much better.
*** Unfortunately - If Bing’s AI robot is correct, the role of the NTSB in the investigation could be secondary to that of South Korean investigators. In that case I have serious doubts about the reliability of / accuracy of any report from a country that just arrested its President who himself had declared marshal law only days before the accident in December. SK sounds like as much of a banana republic as we are becoming. An early casualty of the chaos wrought is a lack of trust / confidence in the integrity of institutions. One hope is that Boeing will be able to do an independent analysis of the plane’s condition upon impact - especially condition of both engines.
Why does all that matter? Because lawyers have to be swarming all over this. Assessing ultimate blame for loss of life will have significant monetary implications for all involved.
Here’s the AI answer to my query about the role of the NTSB in this …
”If a U.S.-built plane flown by a foreign carrier crashes, the National Transportation Safety Board (NTSB) is not directly in charge of the investigation. According to the Chicago Convention of the International Civil Aviation Organization (ICAO), the country where the accident occurs is responsible for the investigation and controls the release of all information regarding the investigation.
“However, the NTSB may participate in the investigation under the Annex 13 process, which outlines the procedures for international cooperation in aviation accident investigations. The NTSB’s role in such cases is to provide assistance and support to the investigating country, and to represent U.S. interests in the investigation, particularly if the accident involves a U.S.-registered, U.S.-owned, or U.S.-manufactured aircraft.”
Gentlemen, do you guys just study & research the dickens out of planes and/or flying or are either of you licensed to fly? I merely ask because your inputs in these discussions go beyond the typical layman's and I am both impressed and appreciative of the color you add.
While tragic for all involved, accidents also provide insights into flight operations / equipment design / pilot and system capabilities for those of us with an interest in aviation.
Fascinating detail. What to make of it? The craft apparently stayed airborne 4 more minutes after the recordings cut out. From below 500 feet? With little if any propulsion? No flaps deployed? And a tail wind part of the way? Quite a feat.
A quick look at decent rates on final suggests perhaps 700 - 800 FPM under powered flight to be pretty common - less on touchdown.