Jeju plane crash: How the plane actually landed, and what might have gone wrong | Explaining the News

Could it have gone wrong?

Stomach arrival

Belly landing is dangerous and only done in an emergency. With the landing gear up, the wings are very close to the ground when the plane touches down. Therefore, the wings must be held completely ‘level’ (relative to the ground). Even if a small bank to the left or right of the pilot or a strong gust, the wing can hit the ground, turn the plane, send the carriage or separate it.

Even if the plane goes well and everyone gets out alive, a belly landing causes significant damage to the plane, its engines and wings as the plane dives to a stop and can leave those on board injured. Friction caused by an aircraft skidding on a runway can also create sparks or cause a fire.

The team worked on the private land and decided to land the plane under the following conditions:

1. Landing gear fails to deploy.
2. The stricken plane cannot reach the airport and remains in the area. The pilot considers gliding the plane to a landing position safer than touching down on the wheels.
3. Ditching: when the plane makes an emergency landing on the water.
4. In any other situation the pilot considers a belly landing to be safer than a wheel landing.

That said, there have been incidents where pilots, overworked or distracted during the busiest landing phase, have simply forgotten to deploy the landing gear and belly planes. Pilots are also human and fallible.

Landing gear fails to deploy

The pilots of Jeju Air flight 7C2216 were warned by the air traffic controller (ATC) on duty in Muan about the presence of birds in the airport area and the possibility of bird strikes (birds colliding with the plane). A few minutes later, the pilots declared Mayday and were allowed to land in the opposite direction, a BBC said the report.

“Cleared to land on the other side” may mean that ATC cleared flight 7C2216 to land in the opposite direction to what the crew had planned.

The runway has two ends. Let’s say a plane is moved to land at the end of the runway but later, ATC asks the crew to land on the other side. ATC can make such a request for several reasons. In the Jeju Air crash, the crew had declared an emergency and needed to arrive early.

Why the pilots declared an emergency is not yet known. It is thought that the Boeing 737 failed to deploy the landing gear. Experts have questioned this theory. That’s right.

Bird ingestion can disable aircraft engines, puncture the aircraft skin, damage navigation / communication antennas installed around the aircraft or break the windshield / window glasses in rare cases. But a bird strike that damages the plane’s retracted landing gear – which retracts into bays locked by the electrically operated doors in flight – is unlikely.

In addition, if the team decides to land the belly at the airport, there is its own procedure. Fire and emergency trucks must be ready to deal with a potential fire or to evacuate passengers and crew after the plane stops. Spraying the runway with chemicals before landing to suppress sparks and fire, which existed decades ago, is no longer necessary.

In the Jeju Air crash, it is unlikely that the landing gear malfunctioned and failed to operate.

What is more likely is that the Jeju Air crew decided to sit on their stomachs because they consider it safer than going down the gear. Why?

Long and fast arrival

‘Long and fast landing’ is an aviation term that means an aircraft touches down far beyond the designated touchdown area on the runway, leaving the crew with little runway to land the aircraft, and at a speed well in excess of the recommended landing speed.

In crash videos, the Boeing 737 appears to remain ‘long and fast’. Experts and officials quoted by news reports also said.

It is possible that at some point during the approach, the Captain noticed this: That the plane was coming ‘long and fast’ and they were going to ‘shoot’, which is beyond the touchdown zone. To go around – to stop the way – was probably impossible. The Captain must have decided that sitting on the stomach was safer, giving better chances of landing the aircraft inside the runway than sitting on the wheels. It is just speculation but what actually went wrong will be known only in the official investigation report.

Why did the plane come in so fast?

A passenger on flight 7C2216 texted a relative that there was a bird stuck in the wing, according to Reuters and BBC reports, a clear indication that the plane was struck by a bird or flock of birds. How many birds and what kind of bird, small or big, we do not know yet. Was a bird stuck on a wing, or multiple birds, and what part of the wings were they stuck on?

On landing, the pilot uses slats and flaps, the retractable areas on the front and back of the wings. You can see them in the passenger window, in the extended area before landing. The plane needs to be lowered slightly before landing but, at low speeds, the wings cannot generate enough ‘lift’ – the upward, upward force produced by the wings that keeps the plane aloft. At low speed, the wings need help to create more ‘lift’. This extra ‘lift’ comes from the slats and flaps.

Another possibility is that investigators will look into whether birds stuck in critical wing areas prevented the Jeju Air crew from deploying the flaps before landing. If the crew could not extend the flaps, then landing at the slow and recommended speed was probably impossible. And the crew had no choice but to retreat at full speed.

Here is the reason.

But first the row about the ‘shop’. A ‘stall’ is a situation where an aircraft stops flying forward and begins to fall like a stone from the sky. An aircraft can ‘stall’ if its nose is raised too high, which disrupts the smooth flow of air around the wings causing ‘lift’ generation. The aircraft also ‘stalls’ at low speed, which again spoils the production of ‘lift’.

Flaps & stall speed

With flaps, the ‘surface’ speed of the aircraft is low. Without flaps, the plane’s ‘surface’ speed is high. For example, let’s say the ‘local’ speed of an airplane with flaps is 80 knots. In the same aircraft, without flaps, the ‘shop’ speed would be 120 knots. Therefore, with the flaps extended, the aircraft will not ‘stall’ at speeds above 80 knots. But without flaps, crews need to fly the plane above 120 knots to prevent a ‘stall’.

This probably explains why Jeju Air Boeing came in so quickly.

Braking

Modern jets are slowed down in three broad ways: Using thrust reversers, spoilers and wheel brakes.
* Thrust Reversers: When the plane touches the ground, the thrust from the engines is transferred in the reverse direction, making the plane go slower.
* Spoilers or speed brakes: Mounted on the wing and sliding in mid-flight, the moving panels act after the aircraft lands, slowing it down with aerodynamic ‘drag’.
* Wheel brakes: Common (used by pilots) and car brakes.

Modern jets operate automatically. For example, the aircraft’s automation / computer may prevent the auto brakes from being applied unless it ‘senses’ that the aircraft is in a stall, flaps extended and wheels down.

In the Jeju Air crash, investigators will look at what type of brake was available to the crew as the landing gear was retracted.

Last chance?

Realizing that the Boeing 737 was not going to stop on the runway, did the crew try to divert the plane to a large, open area near the runway and attempt a 180-degree turn using the rudder? Perhaps, it was their last chance to survive. In the video, one can see flat, empty land on both sides of the road.