WASHINGTON – Investigators at the crash site of the convicted Ethiopian Airlines flight have found new evidence pointing to another link to the previous disaster involving the same Boeing jet.
The proof, part of the Boeing 737 Max 8 jet crashing in Ethiopia last weekend, killed 157 people, suggesting that the planet's stabilizers were tilted upwards, according to two people familiar with the recovery operations. At that angle, the stabilizers would have forced the nose off the beam, similar to the Lion Air crash in October.
The reasons for both crashes are still being investigated, but the new evidence potentially indicates that the two planes both had problems with a newly installed 737 Max jet automated system designed to prevent a stall.
The new evidence found at the crash site in Ethiopia, a tool called a jack screw, controls the angle of the horizontal stabilizers. The stabilizers can be triggered by the automated system called MCAS.
The stabilizers may have been tilted upwards for other reasons. The survey is in early stages, and the authorities in France are analyzing the black boxes in the Ethiopian Airlines plane for more information.
The Indonesian and US authorities also focus on whether MCAS contributed to the Lion Air crash that killed 189 people in October. In this crash, the automated system, possibly based on erroneous sensor readings, may have repeatedly pushed down the Lion Air plane, creating a battle between the new flight control system and the pilots.
After the Lion Air crash Boeing claimed that its plan was safe, and the 737 Max aircraft continued to cross the plane. But in the background, the company had been working on a software update for the plan that would address some of the problems that arose in the accident in October.
The current automatic system is activated if one of two sensors mounted on an aircraft exterior says the nose is too high. This means that a fault with one of the sensors can force the plane in the wrong direction. Boeing's software update would require data from both sensors for the MCAS to kick in, according to pilots of several major airlines and two lawmakers who informed themselves of the issue.
Such a single point in the failure of a modern jet "is very rare," and more risky than having a backup system, says Michael Michaelis, security chief of the American Airlines pilot union and a captain in 737.
Pilots on United and American Airlines said they still felt comfortable flying the 737 Max jet, in part because they were now aware of the new automated system. Boeing did not fully disclose the pilot system until after the Lion Air crash.
Boeing said the software would "make an already safe aircraft even safer". F.Å.A. has said it expects to ask the airlines by April to incorporate the software.