Boeing has been given the green light to begin test flights of its 737 MAX fleet, more than a year after the planes were grounded following two devastating crashes in the space of five months.
The aircraft have been banned from taking to the air since last March, when an Ethiopian Airlines flight crashed just moments after taking off from Addis Ababa – killing all 157 people on board.
Five months earlier, in October 2018, 189 people died when a 737 MAX used by Lion Air crashed into the Java Sea only 13 minutes after departing the Indonesian capital of Jakarta.
Both were blamed on a malfunctioning anti-stall device named Manoeuvring Characteristics Augmentation System, which Boeing has since been working to make less powerful in order to give pilots more manual control.
Now, after several delays, the Federal Aviation Administration (FAA) has said key certification test flights have been approved to begin as early as Monday.
In an email to Congress seen by the Reuters news agency, the US flight regulator said it had completed its review of the modified aircraft, “clearing the way for flight certification testing to begin”.
“Flights with FAA test pilots could begin as early as tomorrow (Monday), evaluating Boeing’s proposed changes to the automated flight control system on the 737 MAX,” the email added.
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The news will be a relief to Boeing, which had been forced to make what was seen as a humiliating admission that the fleet’s fate lied in the hands of regulators after its own timetable dragged by months.
Back in December, Boeing announced that it would temporarily halt production after being advised by the FAA that clearance in the US was still some way off.
Shares fell sharply in January when Boeing admitted it may be July before the 737 MAX was able to fly again, which saw the company lose a number of orders for the 737 MAX from major customers.
And while approval from the FAA for tests is significant, separate approval is needed from European regulators.
Pilots will also have to be re-trained before 737 MAX commercial operations could resume in European airspace.
In addition to making the software behind the malfunctioning anti-stall device less powerful, Boeing has also been working on changes to flight-control computers and pilot-training requirements.
The company had been desperate to have the planes up and running again for the usually busy summer season, however demand for air travel has taken a pounding from the coronavirus pandemic.
Airlines have seen demand plummet to unprecedentedly low levels as a result of COVID-19, which has compounded what was already Boeing’s worst-ever corporate crisis.
The FAA-approved tests are also by no means a foregone conclusion.
One person familiar with the plans told Reuters: “Based on how many problems have been uncovered, I would be
stunned if the flight tests are ‘one and done’.
“(The FAA will) make sure they find enough stuff wrong to demonstrate they are putting this jet through its paces.”
An industry source added: “This is new territory. There’s a lot more play between regulators, and certainly a lot more pressure and public attention.”
Reuters reports that the test flights will take off from a Boeing base near Seattle after a lengthy briefing, with crew to operate scripted mid-air scenarios such as steep-banking turns during a route over Washington state.
Other elements of the test flights could include touch-and-go landings at Washington’s Moses Lake airport, and a path over the Pacific Ocean coastline, with adjustments needed to accommodate for the weather and other factors.
Should the test flights go well and be signed off by the FAA, the regulator would then need to approve updated pilot training procedures.
September has been tipped as a possible target for when the planes could be given the all-clear in the US, meaning service could be resumed by the end of the year.