US probing certification of Boeing 737 MAX

Boeing and US aviation regulators are coming under intense scrutiny over the certification of the 737 MAX aircraft after news that two recent crashes of share similarities.

On March 11, just a day after the Ethiopia crash left 157 dead, a grand jury in Washington issued a subpoena to at least one person involved in the plane's certification, according to a Wall Street Journal article citing people close to the matter.

The subpoena, which came from a prosecutor in the Justice Department's criminal division, seeks documents and correspondence related to the plane, according to the report.

A criminal inquiry is "an entirely new twist," said Scott Hamilton, managing director of the Leeham Company, who recalled a probe of a 1996 ValuJet crash as the only other aviation probe that was not a civil investigation.

"Unlike France, where criminal investigations into aviation accidents seems common, it is very, very rare in the US," Hamilton added.

The Transportation Department also is probing the approval of the 737 MAX by the Federal Aviation Administration (FAA), the Wall Street Journal reported. Neither department responded to requests for comment from AFP.

The probe is focusing on the Maneuvering Characteristics Augmentation System or MCAS, implicated in the Lion Air crash, which authorities have said shared similarities with the latest accident.

The Ethiopian Airlines crash on March 10 came less than five months after a 737 MAX 8 of Lion Air crashed in Indonesia, killing 189.

While it may take months for definitive conclusions, Ethiopian officials said Sunday that there were "clear similarities" between the two catastrophes based on information from the flight data recorder.

The two incidents have prompted air transport regulators to ground the planes worldwide, a surprising setback for a plane that has been flying for less than two years and is Boeing's top seller.

An investigation by the Seattle Times newspaper -- in the town where Boeing is located -- showed numerous problems with the MCAS, including that it would repeatedly override a pilot's actions based on one faulty sensor. The paper asked for response from Boeing and the FAA at least a week prior to the latest crash.

Shares of Boeing dropped another 2.5 per cent on Monday to USD 369.70. The company has fallen more than 12 per cent since the Friday before the crash.

FAA officials had no comment Monday on the investigations, but reaffirmed that the certification for the plane followed standard process.

Boeing said it followed the rules in bringing the plane to the market.

"The 737 MAX was certified in accordance with the identical FAA requirements and processes that have governed certification of all previous new airplanes and derivatives," Boeing said.

"The FAA considered the final configuration and operating parameters of MCAS during MAX certification, and concluded that it met all certification and regulatory requirements."