Ethiopian Airlines accident: New details on the Boeing 737 MAX 7 accident causing 157 dead

When the Ethiopian Airlines flight crashed three weeks ago, it claimed the lives of 157 people and left behind many uncertainties, doubts and a great mystery: why did he fall?

All Boeing MAX 7 and 8 models still do not fly and, apparently, those who suspected a technical failure of the aircraft were correct.

The maneuvering feature augmentation system (MCAS), an anti-stasis system in the aircraft, has been at the center of the controversy.

Shortly after takeoff, only 137 meters above the ground, the nose of the aircraft of Ethiopian Airlines began to point down. According to the American newspaper The Wall Street Journal, one driver told the other, "Get up, get it up!" before the death of the radio. The plane crashed only six minutes after takeoff.

"A catastrophic failure"

The Wall Street Journal, which claims to have spoken to people close to the ongoing investigation, says it "portrays the chart of a catastrophic failure that quickly swamped the flight crew ".

Leaks this week of the accident investigation in Ethiopia and the United States. suggest that the Maneuverability Enhancement System (MCAS), an automatic anti-lock system, was activated at the time of the incident.

The MCAS was also involved in the deadly crash of a Lion Air Boeing 737 MAX flight in Indonesia last October, which claimed 189 lives.

The mechanism, which is new to the 737 MAX family, prevents the aircraft from heading too high during take-off, which could cause it to lose lift.

Flightradar24, an air traffic control service, estimated that both aircraft had speed and altitude problems.

Documents reveal that the captain of the Indonesian airline has indicated that the autopilot has been activated to facilitate the tilting of the aircraft, which has alerted the warning system to the aircraft. a possible fall.

An investigation into the flight of Lion Air revealed a malfunction of the anti-stasis system and forced the nose of the plane to descend more than 20 times before hitting the seabed.

The Ethiopian authorities have already indicated that there were "obvious similarities" between the Lion Air incident and the crash of Ethiopian Airlines. But the failures were not reported only on the aircraft of Lion Air and Ethiopian Airlines.

Two other US pilots They reported incidents related to the "angle of attack" of this sensor (which causes the tilt of the nose of the aircraft to increase speed) and to the MCAS .

In these latter cases, which could be solved without major incident, the pilots were obliged to intervene to prevent the aircraft from falling.

According to the documents presented in the US Aviation Safety Reporting System, the system would apparently fail and require an accelerated descent.

The mechanism is automatic. Several drivers therefore ensured that it was difficult to suspend it to take manual control of the aircraft.

System update

Boeing announced that it redesigned the software to disable the MCAS if it received conflicting data from its sensors.

As part of this process, Boeing will install an additional warning system on all 737 MAX aircraft, which was previously an optional security feature.

Neither of the two aircraft involved in the fatal accidents carried these additional warning systems, designed to alert pilots when sensors produce conflicting readings.

The aircraft update is designed to ensure that the MCAS will no longer make repetitive corrections when a pilot tries to regain control.

Boeing is also reviewing pilot training to provide "a better understanding of the 737 MAX flight system" and crew procedures.

But earlier this week, the company claimed that the updates were not an admission that the system had caused the locks.

The researchers have not yet determined the cause of these accidents, but a preliminary report from the Ethiopian authorities is expected in a few days.