Boeing 737 airplanes, including one for Ethiopian Airlines, fourth from left, are pictured at the Boeing Renton Factory in Renton, Washington on March 12, 2019. The US said there is "no basis" to ground Boeing 737 MAX airplanes, after a second deadly crash involving the model in less than five months prompted governments worldwide to ban the aircraft. "Thus far, our review shows no systemic performance issues and provides no basis to order grounding the aircraft," Federal Aviation Administration (FAA) chief Daniel Elwell said in a statement.
AFP/Jason Redmond
Ethiopian Airlines crash: What is the MCAS system on the Boeing 737 Max 8?
Chris Lefkow (Agence France-Presse) - March 13, 2019 - 8:33am

WASHINGTON, United States — Similarities between the Lion Air and Ethiopian Airlines crashes have focused attention on an anti-stalling system used in the new Boeing 737 Max 8 aircraft.

The Maneuvering Characteristics Augmentation System (MCAS) is an automated safety feature on the 737 Max 8 designed to prevent the plane from entering into a stall, or losing lift.

Both the Lion Air jet, which crashed in October, killing 189 people, and the Ethiopian Airlines aircraft, which went down on Sunday, leaving 157 people dead, were fitted with the system.

Both planes experienced similarly erratic steep climbs and descents and fluctuating airspeeds before crashing shortly after takeoff.

The US Federal Aviation Administration (FAA), while noting the similarities between the Lion Air and Ethiopian Airlines accidents, stressed that it was too early to draw any conclusions.

MCAS was introduced by Boeing on the 737 Max 8 because its heavier, more fuel-efficient engines changed the aerodynamic qualities of the workhorse aircraft and can cause the plane's nose to pitch up in certain conditions during manual flight.

Angle of attack sensors on the aircraft tell the MCAS to automatically point the nose of the plane down if it is in danger of going into a stall.

This is done through horizontal stabilizers on the plane's tail which are activated by the aircraft's flight control computer.

According to Boeing, MCAS does not control the plane during normal flight but "improves the behavior of the airplane" during "non-normal" situations.

These could be steep turns or after takeoff when a plane is climbing with flaps up at speeds that are close to stall speed.

According to the flight data recorder, the pilots of Lion Air Flight 610 struggled to control the aircraft as the automated MCAS system repeatedly pushed the plane's nose down following takeoff.

The pilots of the Ethiopian Airlines plane reported similar difficulty before the aircraft plunged into the ground shortly after takeoff.

Software updates

A preliminary report on the Lion Air Flight 610 accident blamed it in part on a faulty angle of attack sensor that triggered the MCAS system and automatically forced the plane's nose down.

Pilots flying the same Lion Air plane the previous day had managed to override the automated flight control system.

Boeing came in for some criticism after the Lion Air crash for allegedly failing to adequately inform 737 pilots about the functioning of MCAS or provide training about the system.

Following the Lion Air crash, Boeing issued a bulletin to airlines operating the 737 Max 8 advising pilots how to override the MCAS system.

The US aircraft manufacturer issued a statement on Monday saying it was too early to understand the cause of the Ethiopian Airlines accident.

Boeing also said it was working on software updates to the MCAS system which would be deployed across the 737 Max fleet.

It said procedures already exist to "safely handle the unlikely event of erroneous data coming from an angle of attack (AOA) sensor," the suspected cause of the Lion Air crash.

"The pilot will always be able to override the flight control law (MCAS) using electric trim or manual trim," the aircraft manufacturer said.

A growing list of countries have grounded their 737 Max aircraft after the two deadly crashes in just five months.

Boeing has described the Max series as its fastest-selling family of planes, with more than 5,000 orders placed to date from about 100 customers.

But not since the 1970s -- when the McDonnell Douglas DC-10 suffered successive fatal incidents -- has a new model been involved in two deadly accidents in such a short period.

BOEING 737-8 MAX ETHIOPIAN AIRLINES PLANE CRASH
As It Happens
LATEST UPDATE: March 14, 2019 - 9:34pm

Ethiopia's parliament has declared Monday a day of national mourning after a Nairobi-bound Ethiopian Airlines plane crashed, killing all 157 people onboard.

"The House of People's Representatives have declared March 11, 2019, a national day of mourning for citizens of all countries that have passed in this tragic accident," the office of Ethiopia's Prime Minister Abiy Ahmed said on Twitter on Sunday. — AFP

March 14, 2019 - 9:34pm

French investigators have received the black boxes from the Boeing 737 MAX that crashed east of Addis Ababa in Ethiopia, killing all 157 people on board, France's BEA airline safety agency says.

Ethiopian authorities had requested French help to analyze the content of the flight data recorder and cockpit voice recorder to discover what caused the Ethiopian Airlines flight to plunge to the ground just minutes after takeoff on Sunday.

March 14, 2019 - 5:30pm

US authorities say that new evidence showed similarities between Sunday's deadly crash of an Ethiopian Airlines Boeing 737 MAX 8 and a fatal accident in Indonesia in October. The weekend crash killed all 157 people aboard. 

The ban on the Boeing 737 MAX aircraft became worldwide after US President Donald Trump joined Canada and other countries in grounding the aircraft, and the black box flight recorders from the doomed plane were flown to France for analysis. — AFP

March 14, 2019 - 4:14pm

Ethiopian Airlines says that the black box flight recorders from the Boeing 737 MAX 8 that crashed with 157 people on board have been flown to Paris for analysis.

Urgency is mounting to determine the causes of Sunday's crash as Boeing finds its entire fleet of the model grounded after it emerged the plane experienced similar difficulties to an Indonesian Lion Air flight in October, which also crashed minutes after takeoff. — AFP

March 13, 2019 - 7:03pm

Ethiopia does not have the equipment to analyze the black boxes from Sunday's deadly Ethiopian Airlines plane crash, and is considering sending them abroad, a spokesman for the airline says.

"It could be sent abroad because there is no equipment to read it here," says spokesman Biniyam Demssie. — AFP

March 13, 2019 - 4:26pm

The United States says there is "no basis" to ground Boeing 737 MAX airliners, after a second deadly crash involving the model in less than five months prompted governments worldwide to ban the plane.

Despite the aviation giant's assurances that the plane is safe and reliable, the European Union, Britain and India joined China and other countries grounding the plane or banning it from their airspace as they await the results of the investigation into the crash.

But the US has so far refused to take similar action against the American aerospace giant's best-selling workhorse aircraft.

A new Ethiopian Airlines 737 MAX 8 went down minutes into a flight from Addis Ababa to Nairobi on Sunday, killing all 157 people on board.

That followed the October crash of a new Lion Air jet of the same model in Indonesia, which killed 189 people shortly after takeoff from Jakarta. — AFP

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