To chase away the Birds so the Airports are Safe to land at will

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Looks way too fast & I see no airbrakes/spoilers, flaps or landing gear.

Bird strike took out hydraulics?
Even then the plane should have backup gravity deployment on the gear I believe.

Pilots did have it nice and straight though but ran out of runway and why a embankment at the end instead of runoff room?

If engines went out, power to hydraulic pumps goes too. There is gravity release for landing gear, but it takes time to lock.

The flight crew's attention was probably consumed with restarting the engines and lining up some kind of landing, and maybe didn't notice the landing gear wasn't fully deployed.

Pilot was given clearance to land backwards on that runway, probably because the plane was already nearly lined up with it and dropping like a stone.

Wonder why they fully retracted them, should only be a partial retraction for a go around I believe.
And how long to start the APU? That would power the flaps.

Hopefully the crew did all they could in the time they had but CVR/FDR should hopefully shed light on that, hopefully they did not shut down a good engine by mistake like in TransAsia Airways Flight 235

ala Eastern Air Lines Flight 401(although with a much more serious problem then a burnt out gear light) and not optimal CRM, but time will tell.

That clip is mind shattering. I couldn't imagine the people at the airport waiting for their loved ones and seeing them blown apart.
Hard to put yourself in that reality...even a little tear in my eye..

I was on a plane when I was 12 years old. Hit a flock of birds. Though we Lost landing gear. They diverted the plane and foamed the runway. Luckily, the landing gear was fine. But, I was terrified. Like you said, they must not have had time to prepare.

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Even if a bird strike somehow caused double engine failure, they should still be able to use the APU to lower the landing gear and adjust the flaps and slats, so total hydraulic failure too?

post from Airliners.net:
This is strange. A gear up, flaps up landing is not something that should occur. A bird strike shouldn’t be able to cause that to happen

Flaps can be lowered electrically if the lose hydraulics. It’s slow (takes 5 min) but can be done as long as there is electrical power.

Landing gear can be lowered manually by pulling the release cables that cause the gear to gravity drop. No electrical or hydraulic power is required. It takes seconds to do this.

Looking at the FR24 data the aircraft descended to about 500ft before climbing at +1500fpm before descending again. Prior to that the descent rate was around 700-900fpm which seems reasonable for a 3 degree approach. Ground speeds were also normal at around 150kts.

It's very early to speculate but I can't help wonder If a go around was initiated, the gear was retracted and then the birdstrike occurred and a hasty decision to try and land was made (forgetting that the gear had since been retracted).

If this was a landing gear issue, you would expect to see a go around followed by some holds/vectors whilst the QRH was run. Plus Jeju is very close with a much longer runway (a consideration for any gear issues)

Or possibly they were going to try a go around and lost all power (pilots have shut down the wrong engine before also) and had no time for a set up, just down we go.

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Looks to me like they concentrated too hard on making it smooth & eat up too much runway in the process, they set her down with around 4,000ft left (according to some calculations done over at Airliners.net), less then 1/2 when they needed it all at that speed.

Also a gear up/flaps up landing may have faired better on the grass when it comes to slowing the plane down,

Other speculations include past examples of poor CRM (Crew Resource Management) in past Korean pilot accidents due to cultural authority issues.

See:

https://en.wikipedia.org/wiki/Asiana_Airlines_Flight_214

https://en.wikipedia.org/wiki/Korean_Air_Flight_801

. . . I ain't going.

The Boeing 737-800 has a generally strong safety record, largely due to mature technology, rigorous maintenance, and extensive pilot training.

This was a no-gear/no-flaps landing. The only thing these two systems have in common is they run on electricity - the flaps and slats are extended with electric motors and extending the landing gear requires electricity to either run the hydraulics or release the locks so gravity can pull them down.

Doubtful a bird strike could knock out that many systems IMO

I am afraid crew mistakes may have played a part but hope not.

Last edited Sun Dec 29, 2024, 09:52 PM - Edit history (1)

Spectator video shows something happened to the right engine on approach, possibly a bird strike or a compressor stall following an earlier bird strike. At this point, flaps appear to be deployed but the landing gear is up.
A FlightRadar24 statement says no ADS-B data (altitude, speed, heading, etc.) was received after the bird strike, potentially indicating an electrical failure or damage to the transmitter.

There are unconfirmed reports of fume in the cockpit.
737NG oxygen masks normally mix oxygen with ambient air but an "emergency" mode can be used to supply 100% oxygen under positive pressure.
The cockpit windows can also be opened safely during flight, at least at low speed.

Despite media reports of bad weather, METARs in fact report nearly perfect flying conditions: winds were almost calm, visibility was good, there were a few clouds at 4,900 ft., no precipitation in the area, and temperatures were slightly above freezing.

Preliminary information indicates that after the bird strike, the aircraft flew for about 9 minutes as it circled back to the airport from the opposite direction (from the north) and attempted to land. This indicates it was controllable and had at least partial engine power. The flight path as currently understood is not consistent with a complete engine failure scenario as experienced in US Airways 1549 (the Hudson landing).

From the deeply distressing footage of the landing, the leading-edge and trailing-edge flaps appear to be fully retracted. This "clean wing" configuration would have required a very high approach speed, likely close to 200 knots, versus 140-150 knots for a typical landing.
Some video viewers see heat blur and/or hear engine power from at least one engine during the landing. Personally, I can't distinguish potential heat blur from compression artifacts in the video and from dust/smoke generated by contact with the ground. Similarly, it's hard to distinguish potential engine sound from aerodynamic noise and friction with the ground, so my own view is that the videos are not conclusive.

The 737NG has two independent main hydraulic systems: system A is powered by the left engine and system B is powered by the right engine. Aircraft services are divided between the two systems. An additional standby hydraulic system is driven by an electric motor and operates a small number of critical services, including the rudder, leading-edge flaps, and thrust reversers. If both engine-driven electrical generators are inoperative, electricity is provided by the auxiliary power unit (if running) or by a standby battery that provides about 30 minutes of electricity. Some 737s are equipped with two batteries providing 60 minutes of backup power, which is apparently an EASA requirement; the accident aircraft was initially delivered to Ryanair, so it may have had two.

Primary flight controls (ailerons, elevators, rudder) are actuated by both main hydraulic systems.
Leading-edge flaps/slats are directly actuated by system B and by the standby system. Additionally, in the event of a loss of pressure to system B, a power transfer unit automatically uses system A to pressurize system B for leading-edge flap/slat deployment.
Trailing-edge flaps are actuated by system B.
Landing gear is actuated by system A.

Flight crews train intensively for failure of an engine and the associated hydraulic system in every phase of flight (this is probably the single most trained scenario) and crews should be deeply familiar with how the aircraft behaves in this situation. In an actual emergency, the crew would immediately complete a small number of memory items and then refer to the appropriate checklist in the quick reference handbook for additional steps to troubleshoot and/or mitigate the issue.

On the 737, the nose gear doors are held closed by system A. In the event of a loss of hydraulic pressure, they will open under their own weight. Notably, the doors appear to be closed as the aircraft landed, which implies that system A was functioning. (The 737 does not have main gear doors; when the gear is retracted, the wheel rims sit flush with the fuselage and the struts are covered by attached panels.)
The above notwithstanding, in the event of complete loss of hydraulic pressure:
Ailerons and elevators are actuated via cable relays from the control columns, albeit with a significantly higher force requirement than typical.

Landing gear can be manually released via a set of handles located under an access cover on the cockpit floor next to the first officer. When the handles are pulled, the gear will deploy under its own weight.
Flaps can be deployed by backup systems via a switch located on the overhead panel. Trailing-edge flap deployment using the alternate electrical system is significantly slower than a hydraulic deployment
.
A landing gear warning horn will sound if any landing gear is not down and locked in the following conditions:
Flaps 0°-10°, thrust levers below 20° (or 34° with one engine inoperative), altitude below 800 ft radar altimeter (cannot be silenced below 200 feet)
Flaps 15°-25°, thrust levers below 20° (or 34° OEI) (cannot be silenced)
Flaps 30°-40°, regardless of altitude and thrust lever position (cannot be silenced)

The aircraft appears to have touched down about halfway down the runway and was still traveling at very high speed (calculated upthread as approximately 130 knots) when it departed the end of the runway.
A second video suggests the pilot "floated" the landing for a gentle touchdown and then may have maintained nose-up elevator to mitigate loads on the engines. This suggests the flight crew was aware they were making a gear-up landing and that gear deployment was not simply overlooked. However, holding the aircraft's weight off the engines would have reduced friction with the ground and thus deceleration.

There is no indication that spoilers deployed on touchdown. When 737NG auto spoilers are armed, deployment is triggered by either weight on the right main landing gear or by any two of the three landing gear wheels spinning up to more than 60 knots. Thus, spoilers would not automatically deploy in a gear-up landing scenario. Speed brakes (flight spoilers) can be manually commanded at any time via the cockpit spoiler handle.
Inboard and outboard flight/ground spoilers on each wing are powered by different hydraulic systems.
Ground-only spoilers on both wings are powered by system B.

Although a dark band appears around the right engine immediately after touchdown that is visually similar to thrust reverser deployment, Jon Ostrower believe this represents damage to the engine cowling upon contact with the ground, creating only the appearance of reverser deployment. There is no visual indication that the left reverser deployed.
On the 737NG, reverser deployment requires the thrust levers to be moved to the reverse position, as well as either a weight sensor in the right landing gear determining the aircraft is on the ground or the radio altimeter detecting below 10 feet to the ground. Thrust reversers are actuated by system A on the left engine and by system B on the right engine. Both reversers are also actuated by the standby system.

About 450 feet beyond the end of the runway, the aircraft struck a berm supporting the localizer antenna array and was completely destroyed on impact. The localizer is part of the instrument landing system that provides guidance to aircraft on approach and it must be positioned on the centerline near the runway threshold. Presumably the localizer was elevated to provide a better signal, but elevated terrain so close to a runway is not recommended; the International Civil Aviation Organization standard requires a 90 m / 300 ft runway end safety area and recommends an additional 240 m / 790 ft beyond that. At LAX, for example, one localizer is mounted on a metal frame that would be secured to the ground with breakaway connections to limit damage to an aircraft in a collision.
Many localizers are mounted directly on the ground, again with breakaway bolts. However, given the aircraft's extremely high speed when it departed the runway, it is speculation to assert what might have happened had the berm not been present.

Perhaps everyone. They were still traveling pretty fast at that point and would have gone much farther and possibly hit something else like the wall surrounding the airport, but would have dispersed more energy prior to that.

It’s just very poor airport design. You would never see that in the US.

..I will say the mound is 875 feet past the end of the 1.7+ mile runway.
But yes, they should be on frangible supports.

But I suspect we will find the pilots made several serious mistakes, one engine out is not a "we are going to crash!" problem unless you compound the issue by turning off the wrong engine etc.

I will retract that if it is found they had a second bird strike on the go around that took out the other engine but consider that pretty low probability.

But this would have been pretty much useless when the antennas are sitting on top of a concrete reinforced berm.

At this point it isn't worth speculating whether or not they made any mistakes. They may have lost both engines due to the bird strike and this would explain the situation.

.. with a double engine out I don't think there would have been any go around, it would have been straight in and cross your fingers gear down flaps down get her on the ground

But we will know more when the Black boxes get read, there's also some speculation there was smoke in the cabin that made them fear fire possibly, the bird ingestion can cause the ventilation system to smoke but again that's another reason to put her down on the first try IMO

There's evidence of a compressor stall on one engine, but not the other. Seems possible, if not likely the other engine sustained damage which is why they opted for an immediate return. What I think happened was the other engine had massive blade damage and was vibrating so badly they didn't know how long it was going to hang in there. In that situation I would have done exactly as they did which was to initiate an immediate return and if you think the other engine is going to fail on short final you don't put the flaps or gear down. I think it's entirely possible, if not likely they did everything right. Regardless what doomed them was the very stupid airport design.

...but once the runway is ahead some gear/flaps/slats/spoilers would have helped here, they obviously had some hydraulics based on the way they made corrections on final, some of those systems should have been available, I think CRM wasn't optimized here, even the manual gear release brings the gear down in seconds, not minutes.

The CoPilot only had 1,600 hrs and this was a redeye so they may not have been at their best.
But the CVR has been downloaded and they are working on the FDR now, it has a busted plug so more info should be available soon.

It started with the crash of a Japanese commercial jet with a Japanese SDF plane, and ends with the crashes of an Azerbaijani and a Korean plane.. I feel so sorry for the victims of these crashes, as well as their friends and loved ones