Jeju plane crash: How precisely a airplane lands, and what may have gone flawed | Defined Information

What may have gone flawed?

Stomach-landing

Stomach-landings are dangerous and carried out solely in an emergency. With the touchdown gear up, the wings are very near the bottom when an plane touches down. Subsequently, the wings should be held completely ‘stage’ (parallel to the bottom). With even a slight left or proper financial institution both by the pilot or a robust gust of wind, a wing may hit the bottom, flip the jet, ship it cartwheeling or break it aside.

Even when the touchdown goes effectively and everybody walks out alive, a belly-landing ends in appreciable injury to the airplane, its engines and wings because the plane skids to a cease and might go away these onboard injured. The friction generated by the plane skidding on the runway also can create sparks or end in a hearth.

A cockpit crew decides to land an plane on its stomach within the following conditions:

1. Touchdown gear fails to deploy.
2. A stricken plane can’t make it to an airport and touchdown is completed in a area. The pilot considers skidding the plane to a cease safer than touching down on wheels.
3. Ditching: when an plane makes an emergency touchdown on water.
4. Another scenario a pilot considers a belly-landing safer than touchdown on wheels.

That mentioned, there have been incidents the place pilots, task-saturated or distracted through the extraordinarily busy section of touchdown, merely forgot to deploy the touchdown gear and landed plane on their stomach. Pilots are additionally people and fallible.

Touchdown gear fails to deploy

Jeju Air flight 7C2216’s pilots had been warned by the air visitors controller (ATC) on obligation at Muan of the presence of birds within the airport’s neighborhood and chance of a fowl strike (birds colliding with the plane). Minutes later, the pilots declared a Mayday and had been cleared to land from the wrong way, a BBC report mentioned.

“Cleared to land from the wrong way” probably means ATC cleared flight 7C2216 to land from a route reverse of what the crew deliberate.

A runway has two ends. Let’s say a flight is cleared to land from a particular finish of the runway however later, ATC requests the crew to land from the opposite finish. ATC could make such a request for a number of causes. Within the Jeju Air crash, the crew had declared an emergency and wanted to land on the earliest.

Why the pilots declared an emergency is just not identified but. It has been speculated that the Boeing 737’s touchdown gear didn’t deploy. Consultants have questioned the speculation. Rightly so.

Chicken ingestion can disable an plane’s engines, dent the plane’s pores and skin, injury navigation / communication antennas fitted across the plane or break the windshield / window glasses in uncommon circumstances. However a fowl strike damaging an plane’s retracted touchdown gear — retracting into bays locked by hydraulically operated doorways in flight — is unlikely.

Furthermore, if a crew decides to hold out a belly-landing at an airport, there’s a process for it. Fireplace vans and emergency companies should be prepared to answer a doable hearth or evacuate passengers and crew after the plane involves a cease. Foaming the runway with a chemical earlier than belly-landings to suppress sparks and hearth, which was in observe a long time in the past, is not required.

Within the Jeju Air crash, it’s unlikely the touchdown gear malfunctioned and didn’t deploy.

A extra seemingly chance is Jeju Air’s crew determined to hold out a belly-landing as a result of they thought of it safer than touchdown with the gear down. Why?

Touchdown lengthy and quick

‘Touchdown lengthy and quick’ is an aviation time period meaning an plane touches down far past the designated landing zone on the runway, leaving the crew with much less runway size to cease the plane, and at a pace far exceeding the really helpful touchdown pace.

From movies of the crash, the Boeing 737 seems to land ‘lengthy and quick’. Consultants and officers quoted by information studies too have mentioned so.

It’s doable that in some unspecified time in the future through the strategy, the Captain realised this: That the jet was coming in ‘lengthy and quick’ and that they had been going to ‘overshoot’, that’s land far past the landing zone. A go-around — calling off the strategy — was maybe not doable. The Captain should have determined that touchdown on the stomach was safer, providing higher possibilities to cease the plane throughout the runway than touchdown on wheels. It’s solely a conjecture however what really went flawed can be identified solely from the official investigation report.

Why did the jet are available quick?

A passenger on flight 7C2216 texted a relative {that a} fowl was caught within the wing, in keeping with Reuters and BBC studies, the clearest clue but that the plane was hit by a fowl or a flock of birds. Simply what number of birds and what sort of fowl, small or massive, we don’t know but. Did a fowl get caught within the wing, or was it many birds, and in what a part of the wings had been they caught?

For touchdown, a pilot makes use of slats and flaps, retractable surfaces on the back and front of wings. You’ll be able to see them from a passenger window, in prolonged place earlier than touchdown. An plane must be slowed earlier than touchdown however, at slower speeds, the wings can’t generate ample ‘carry’ — the upward, aerodynamic drive generated by the wings that retains a airplane aloft. At slower speeds, the wings need assistance to generate further ‘carry’. This further ‘carry’ comes from the slats and flaps.

One of many prospects investigators will study is whether or not birds caught in vital areas of the wings prevented the Jeju Air crew to deploy flaps earlier than touchdown. If the crew was unable to extends the flaps, then touchdown at a slower and really helpful pace was maybe not doable. And the crew had no selection however execute a high-speed touchdown.

Right here’s why.

However first a line about ‘stall’. A ‘stall’ is a situation when an plane stops flying ahead and begins dropping from the sky like a stone. An plane can ‘stall’ if its nostril is raised too excessive, which disturbs the sleek stream of air across the wings spoiling technology of ‘carry’. An plane additionally ‘stalls’ at sluggish speeds, which once more spoils technology of ‘carry’.

Flaps & stall pace

With flaps, an plane’s ‘stall’ pace is decrease. With out flaps, an plane’s ‘stall’ pace is greater. For instance, suppose an plane’s ‘stall’ pace with flaps is 80 knots. For a similar plane, with out flaps, the ‘stall’ pace might be 120 knots. So, with flaps prolonged, the airplane received’t ‘stall’ at speeds above 80 knots. However with out flaps, a crew must fly the plane above 120 knots to forestall a ‘stall’.

This maybe explains why the Jeju Air Boeing got here in quick.

Braking

Fashionable jets are slowed down in broadly 3 ways: Utilizing thrust reversers, spoilers and wheel brakes.
* Thrust reversers: As soon as an plane touches down, the thrust from the engines is redirected within the reverse route, slowing down the airplane.
* Spoilers or speedbrakes: Mounted on the wing’s floor and flushed throughout flight, the movable panels deploy after a airplane lands, slowing it down with aerodynamic ‘drag’.
* Wheel brakes: Standard (operated by pilots) and auto brakes.

Fashionable jets are extremely automated. For instance, an plane’s automation / pc may stop auto brakes from deploying until it ‘senses’ that the plane is in touchdown configuration, flaps are prolonged and the wheels are on the bottom.

Within the Jeju Air crash, investigators will take a look at what kind of braking was accessible to the crew with the touchdown gear retracted.

Final probability?

Once they realised the Boeing 737 was not going to cease on the runway, did the crew attempt to swerve the airplane into the large, open house beside the runway and try a 180-degree flip utilizing rudder? Maybe, it was their final probability at survival. Within the video, one can see flat, empty land on each side of the runway.