On Sunday, Ethiopian Airlines flight 302 crashed minutes after takeoff killing all 157 passengers and crew on board.
On October 29, 2018, Lion Air flight 610 crashed minutes after takeoff into the Java Sea off the coast of Indonesia, killing all 189 on board.
Both crashes involved the same aircraft: a Boeing 737 MAX 8, both crashes showed similar flight patterns prior to impact.
Both crashes are under investigation.
The flight data recorder and the cockpit voice recorder have both been recovered in the Ethiopian Airlines flight, and will give investigators vital information regarding the cause of the crash.
Boeing’s newest jet is under scrutiny after concerns over a new computer system arose following the the Lion Air crash.
Worldwide 25 airlines have grounded the Boeing planes as they wait for more information. For now, the US continues to use the aircraft.
So far, the investigation of Lion Air crash shows that prior to the crash, a system called Maneuvering Characteristics Augmentation System (MCAS) had engaged, and the pilots might not have known it.
The MCAS lowers the nose automatically to prevent a stall if it detects that the angle of the plane’s nose is too high compared to the ground.
A sensor is used to detect how high the nose is compared to the ground.
But, this sensor was probably not working correctly.
With information from the faulty sensor, the MCAS was engaged and the nose was lowered (and shouldn’t have been). Pilots corrected by manually lifting the nose (not realizing that the faulty sensors would send the nose down again). Again, the MCAS engaged, again the nose was lowered, and again the pilots manually lifted the nose. The flight pattern shows this raising and lowering of the nose until the fateful final plunge into the sea.
Interestingly, when the system lowered the nose (and shouldn’t have), the pilots should have gone through a series of checks, one of which is to disengage the automatic system. It appears that the pilots didn’t do this.
Also interesting, the same Boeing aircraft was flown just prior to the fatal crash by a different pilot. This (different) pilot experienced the nose-diving, and went through the protocols, and disengaged the system, and landed the plane safely.
Want to go a little deeper on the mechanics of the plane crash and the MCAS system? Geek out here.
Were the Boeing crashes related to pilot error or mechanical failure or a combination of the two? Investigative reports will go a long way to answering this question, but background information could currently lend insight into this question.