Korean airplane crash

[LittleInch]

All but two presumed dead after Jeju Air plane crash in South Korea – video

The Boeing 737-800 skid along the runway before hitting what appears to be a concrete barrier and bursting into flames at Muan airport in South Korea.

www.theguardian.com

Looks like a near text book landing wheels up until they hit a rather oddly placed concrete wall.

Only two survivors.

 

[RedSnake]

Maybe don't build a runway inside a place crowded with birds.

Of course preventing bird strikes is good, but as LittleInch says a plane should be able to withstand this.
Our airport is next to one of the largest resting places for emigrating birds in the north of Scandinavia.
We have cranes, swans, gees and sea eagle but they just pass by up and down the river, I won't mention all smaller birds than that.
We had a seagull incident a some years back only thing happening was the poor seagull died.
Of course this larger birds can be seen on radar so they just tell the planes to wait before landing and takeoff.

And in Asia they also have birds that can fly 7000 meter over sea level so preventing bird strikes at airports want be enough.

And as LittleInch says you you cant see any birds in the video long distance though, but still how would a hit in one engine as it looks like, make the hydraulics fail.

 

[TugboatEng]

A go around due to loss of an engine requires the airplane be cleaned aerodynamically. That means gear up flaps up ASAP to allow the plane to gain air speed with the reduced power. The second attempt at landing was very shortly after the first. The crew did not give themselves much time to figure things out. It's quite possible they forgot to reconfigure the plane for landing. This happened to PIA 8303. Coincidentally, there were two survivors on that flight as well.

 

[Cool_Controls]

Another airline casualty this week.
https://www.aviation24.be/airlines/...-member-dies-after-emergency-landing-in-graz/

 

[Alistair_Heaton]

There was a hydraulic failure yesterday as well in Oslo with klm which resulted in a runway excursion.

They haven't released any details about the A220 fumes.

Huge condolences to the swiss crew family.

Dreading walking into the swiss crew centre and seeing the addition to the memorial at the entrance.

 

[Jordonlaw]

RedSnake - Aircraft carriers use tailhooks, not crash nets, to stop airplanes.

The main cause of this was ineffective bird management at an airport surrounded by bird habitat. Maybe don't build a runway inside a place crowded with birds.

Bird management is a well-practiced operation but birds still appear when not expected - the Hudson airbus was an example. I used to work with a team who 'designed' bird management for airports around the world and the main guy said that basic things (like having a nice large pond in front of the terminal block) were often part of the initial design, but that with care you could reduce birds hanging around significantly.

2nd aspect is moving the birds away. The best method I learnt about was using sheepdogs to chase birds off - better than falcons in fact - and the guy who started the company who did it used rescue dogs; a perfect combination of need and availability. The US and Israel were major customers I recall.

Despite all of this birds do get through and the regulations reflect this. If as we suspect the aircraft's engine did hit a bird then it's designed to run on at a given power level for a given time (and it's tested) whish should have covered the scenario here. Same with the airframe, windows, etc.

So yes, best not to build airfields where there are birds, but that would mean, practically, no airfields.

Background: I was the lead birdstrike research engineer for a major UK aerospace company for ~10 years.

CHE

 

[DirteJoe]

Curious what the actual transcripts will show. A few days ago it was about 6 minutes, but this morning with what the South Korean govt. has released, it looks like only 3 minutes occured beteeen the bordstrike, mayday call, go around, 180* turn, and crash.

How much time does it typically take to go over the checklists for a bird strike and go around?

 

[Alistair_Heaton]

RedSnake - Aircraft carriers use tailhooks, not crash nets, to stop airplanes.

The main cause of this was ineffective bird management at an airport surrounded by bird habitat. Maybe don't build a runway inside a place crowded with birds.

they use arrestor cables and hooks for normal landings.

They also have a "last hope" net system. But you don't often see them deployed.

Military airfields sometime have both an arrestor cable for hook at the landing end then a net system at the other end just past the tarmac area. Its something to do with accelerated stop area and performance and risk of overshoot into populated area. If they can have a deceleration pit full of gravel they will use that instead so they are not common.

There are major differences between different countries around the world and normal practise. In relation to runways. You can ask Jordon about Barra and the Western Isles bridstrikes. I must have murdered hundreds of them there with a Jetstream in BEB and SYY only 1 in Barra with a C172

Checklist is very related to what stage it happens at and what it causes.

It may not even result in a go around if landing.

300ft gear out, flaps configured. birdstrike and fire warning triggers. We wouldn't go around unless there was something physically blocking the runway. Land and then fire checklist. It a very common end of sim session scenario as the end item is turn the power off after evacuation which needs 10 mins to get everything up again for reset.

Between 2000ft and 1000ft it becomes normal to go around. 4 items in the go-around checklist. Depends what's broken for the rest. Say surging engine due compressor damage 10 items 2 mins, then another 2 mins and 8 items to shut the engine down and secure it and do the house keeping for other systems to make sure everything is configured.

In my experience in simulators (never done it in real life and 12000 hours flying). It doesn't generate issues on turbo props or jets apart from an occasional brain fart shutting the wrong engine down error which this may turn out to be. Which happens in real life as well unfortunately.

 

[LittleInch]

Well from what I gather the protocol for a wheels up landing is full flaps, go as slowly as possible then stick it on the tarmac or was this concrete? to give you as much length of runway as you can then just brace for impact.

They seems to come in really fast, no or little flap and a mixture of floating/ got it wrong and got it down about halfway down the runway.

Not enough friction and it's not clear if the engines powered down or not.

Still no idea why this was a wheels up landing. Pilot error or on purpose? Alarm overload quite likely if an engine or both died.

But the runway overshoot protection issue seems to be cropping up a lot and it seems no one wants to start installing gravel traps, catch netting or similar to stop aircraft before they run out of airport land. Don't know what the official requirement is, but I think it's pretty low and not mandatory.

 

[Alistair_Heaton]

"Well from what I gather the protocol for a wheels up landing is full flaps, go as slowly as possible then stick it on the tarmac or was this concrete? to give you as much length of runway as you can then just brace for impact."

yep.

And the fire services will give you a foam mattress if time permits.

"Still no idea why this was a wheels up landing. Pilot error or on purpose? Alarm overload quite likely if an engine or both died."

That's the major issue which will I suspect be answered by the cockpit voice recorder. I have hinted what my gut instinct is in the previous post. Human error.

"But the runway overshoot protection issue seems to be cropping up a lot and it seems no one wants to start installing gravel traps, catch netting or similar to stop aircraft before they run out of airport land. Don't know what the official requirement is, but I think it's pretty low and not mandatory"

They have been rolled out progressively in EASA for over 10 years. It is an issue at some airports.

I might add those concrete berm mounts for the localiser arrays are also banned in EASA but are permitted in ICAO

 

[TugboatEng]

The 737 is allowed to be flown without a APU, correct? If the pilots shut down the wrong engine and the airplane was operating without a functioning APU, that may explain the urgency to attempt to land again and a loss of hydraulics?

 

[Alistair_Heaton]

yes it can be dispatched without a working APU.

Normally the APU is not running after engine start for the flight until after landing and before parking or shutting down one engine for taxi.

Some equipment deficiencies may require it to be on eg an engine generator broken etc.

It takes approximately 90 seconds to start and provide electric and bleed air. The backup hydraulic pumps won't come on line until the APU electrics is good.

There is a backup called a RAM air turbine (RAT) which provides limited hydraulics and electric. It pops out when there is both generators failed. But... it can take a reasonable time before the system registers there is a twin engine failure due to the inertia of the engine spinning down and generators producing a voltage.

 

[TugboatEng]

Also, I believe I saw that the 737 gear doesn't require hydraulics to drop but the brakes require hydraulics to stop. This is pure speculation but maybe the pilots thought the plane would stop faster on a belly landing vs wheel landing with no hydraulics and no reversers (assuming they shut down the wrong engine).

 

[3DDave]

From http://www.b737.org.uk/landinggear.htm#Brakes

The brake pressure gauge merely shows the pressure of the air side of the accumulator and should normally indicate 3000psi. The normal brake system and autobrakes are powered by hydraulic system B. If brake pressure drops below 1500psi, hydraulic system A automatically provides alternate brakes which are manual only (ie no autobrake) and the brake pressure returns to 3000psi. Antiskid is available with alternate brakes, but not touchdown or locked wheel protection on series before the NG's.

If both system A and B lose pressure, the accumulator isolation valve closes at 1900psi and you are just left with residual hydraulic pressure and the pre-charge. The gauge will indicate approx 3000psi and should provide 6 full applications of brake power through the normal brake lines (so full antiskid is available) As the brakes are applied the residual pressure reduces until it reaches 1000psi at which point you will have no more braking available.

If the brake pressure gauge ever shows zero, this merely indicates that the pre-charge has leaked out, normal and alternate braking are unaffected if you still have the hydraulic systems (see QRH). The accumulator also provides pressure for the parking brake.​

For gear deployment, if the hydraulics are unavailable:

 

[RedSnake]

Was actually looking for something on the KLM Boeing 737-800 that made a emergency landing in Norway when I came across this...

South Korea orders nationwide inspection of navigation facilities and all of country's Boeing 737-800s after Jeju Air crash

Following the Jeju Air crash at Muan International Airport on December 29, which claimed 179 lives, the South Korean government has mandated inspections

www.aviation24.be

Following the Jeju Air crash at Muan International Airport on December 29, which claimed 179 lives, the South Korean government has mandated inspections of all 101 Boeing 737-800 aircraft operating in the country. South Korea’s Ministry of Land, Infrastructure and Transport will also inspect navigation facilities at all domestic airports. The focus will be on compliance with domestic and international safety standards, particularly the materials and placement of localiser structures, which guide aircraft during landings.

Preliminary findings indicate that bird strikes during the approach may have compromised the engines, and the landing gear and reverse thrust system appeared to malfunction during landing.

The crashed aircraft, in service since 2009 and purchased from Ryanair in 2016, was considered relatively modern by aviation standards. Black box data, which records flight parameters and cockpit audio, is expected to clarify the exact sequence of events. International cooperation, including support from France’s Bureau of Investigations and Analyses, may assist in analysing the engines manufactured by CFM International.

These inspections aim to ensure the safety of the Boeing 737-800 fleet and address concerns following South Korea’s deadliest air disaster.

The crash highlighted concerns about the use of concrete for supporting localisers, a design decision from over 20 years ago. Initial ministry claims that such structures meet international standards have faced scrutiny, with doubts raised about their presence at other airports like Los Angeles and Tenerife. A thorough review of international regulations and standards is underway.

Meanwhile, the flight data recorder from the crash will be sent to the U.S. for analysis, as local extraction proved impossible. All victims have been identified, and the government is providing support to their families. Acting President Choi Sang-mok has called for a transparent and thorough investigation to address public concerns and prevent future tragedies.

 

[TugboatEng]

Inspection of what? This sounds like a press release to appease the public until real information comes out. I doubt they have any suspicions beyond our own.

 

[Alistair_Heaton]

I read it as they were inspecting the airports for compliance with modern best practices.

 

[TugboatEng]

Mandated inspections of 101 B737-800 aircraft is specifically not airports. The airport inspections is more of a side note.

 

[Alistair_Heaton]

It could be a counterfeit part issue.

 

[RedSnake]

Well at least the KLM emergency landing in Norway have been explained.

According to Halvorsen, one of the wheels on the plane's main landing gear punctured when it took off from Gardermoen.

– They had a puncture during takeoff and hydraulic problems as a result. They then chose to land as a precaution.

In a press release on Monday evening, the Accident Investigation Board Norway wrote that parts of the wheel came loose and damaged the aircraft's hydraulic system.

Halvorsen of the Accident Investigation Board says the discovery at Gardermoen involves rubber fragments from one of the wheels.

 

[LionelHutz]

@TugboatEng - I think you called it. They trimmed for the go around and really rushed the next attempt because they thought they had a fire and forgot to drop the gear which caused them to float above the runway waiting for the wheels to touch down.