The first Boeing 737 Max recertification flight just landed, marking a new milestone for the troubled jet

Boeing 737 Max
Boeing 737 Max

REUTERS/Jason Redmond

After 15 months on the ground, the Boeing 737 Max on Monday took a major step toward returning to passenger service as the troubled jet completed its first recertification test flight.

A Boeing 737 Max 7, registration N7201S, departed from Seattle's Boeing Field just before 10 a.m. local time for the milestone flight. Boeing and FAA test pilots and certification officials were on board.

The flight was the first of three, all expected to occur this week, which the FAA will use to determine whether Boeing has fixed the problems with the plane, and whether it can return to normal service.

At publication time, the plane was back in the air following its landing at Grant County International Airport, in Moses Lake, Washington. According to a flight plan, it was set to head back to Boeing Field. It appeared to be undergoing additional tests on the way.

The 737 Max has been grounded since March 2019, following the second of two fatal crashes that killed a combined 346 people. The first crash, Lion Air Flight 610, crashed into the Java Sea off Indonesia in October 2018 after 12 minutes, during which the pilots struggled to control the plane. The crash killed 189 people.

Although questions immediately emerged about a new flight-control system on the 737 Max — the latest iteration of Boeing's 55-year-old workhorse — the plane largely remained in service, with an emergency Airworthiness Directive issued by Boeing and the FAA warning pilots about possible control issues.

In March 2019, Ethiopian Airlines Flight 302 crashed six minutes after taking off from Addis Ababa, Ethiopia, killing all 157 on board. Within days, the plane type was grounded worldwide. On March 13, 2019, the US became one of the last countries to ground the jet.

Investigators found that both crashes were linked to the automated system, called the maneuvering characteristics augmentation system, or MCAS.

MCAS was designed to compensate for the 737 Max having larger engines than previous 737 generations. The larger engines could cause the plane's nose to tip upward, leading to a stall — in that situation, MCAS could automatically point the nose down to negate the effect of the engine size.

But the system could be activated by a faulty reading from a single angle-of-attack sensor, without any redundancies or backups. In both crashes the sensors are thought to have failed, sending erroneous data to the flight computer and, without a redundant check in place, triggering the automated system.

Although the grounding was initially expected to last only weeks, Boeing and the FAA found additional safety hazards — eventually requiring Boeing to redesign the jet's entire flight computer rather than just the MCAS software.

The certification flights, which are expected to take three days, "will include a wide array of flight maneuvers and emergency procedures to assess whether the changes meet FAA certification standards," according to a statement from the FAA.

Although the flights are among the biggest steps remaining before the planes receive a recertification, there are still several steps remaining.

"While the certification flights are an important milestone, a number of key tasks remain," the FAA said. "The FAA is following a deliberate process and will take the time it needs to thoroughly review Boeing's work. We will lift the grounding order only after we are satisfied that the aircraft meets certification standards."

Numerous federal investigations are underway into the design of the jet, part of an effort to determine how it was allowed to be certified in the first place and whether there was criminal negligence behind the design.

Questions remain over whether other countries will accept the FAA's decision on the plane, an industry norm, or choose to conduct their own recertification flights, which would represent a loss of standing for the American agency.

In a statement to Business Insider, a Boeing spokesperson said that the company was working with authorities.

"We continue to work diligently on safely returning the 737 MAX to commercial service," Boeing said. "We defer to the FAA and global regulators on the process."

Boeing previously said it expected the jet to return to service in the second half of this year. Although airlines have eagerly awaited the jet's return, the collapse of travel demand because of the coronavirus crisis has complicated the need for more capacity from the fleet's return.

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