Get it fixed and get it back in the air – but get it fixed right.
That seems to be the advice of legendary Captain Chesley “Sully” Sullenberger, the man who safely landed a commercial airliner in the Hudson River after a devastating bird strike.
In an exclusive interview, the celebrated pilot said that even if the FAA ungrounds the jet next month as expected, additional modifications are needed as soon as possible to improve the plane’s crew alerting system and add a third check on the jet’s angle of attack data.
“I’m not going to say, ‘We’re done, good enough, move on,'” said Sullenberger.
“People are going to fly on it and I will probably be one of them,” he added. “The updated MAX will probably be as safe as the (previous model) 737 NG when they are done with it. But it’s not as good as it should be.”
Dennis Tajer, spokesman for the Allied Pilots Association, the union representing American Airlines pilots, said he’s with Sullenberger, Seattle Times reported.
Though the specific flight control software — the Maneuvering Characteristics Augmentation System (MCAS) — that brought down the jets in two fatal crashes is now fixed, Tajer said, the investigations into the crashes “have exposed other areas we can do better on that airplane” and also on the 737 NG.
“We cannot lose this opportunity to address something that needs to be enhanced,” Tajer said.
With Boeing financially strapped, the cost of what they propose could be a major barrier — not least because the safety issues raised apply not just to the MAX but equally to older versions of the 737 currently flying, like the 737 NG, Seattle Times reported.
But Sullenberger says these improvements will make 737s safer — both the MAX and the older models — and shouldn’t be shelved due to cost.
“Is that really something we are comfortable saying out loud to everybody who boards an airplane?” he said. “I just don’t think that’s defensible. In safety-critical domains, ‘just good enough’ isn’t.”
In 2009, when a flock of geese took out both engines of his US Airways jet soon after takeoff, Sullenberger guided the Airbus A320 to an emergency landing in New York City’s Hudson River, saving all 155 people on board, Seattle Times reported.
The “Miracle on the Hudson” made Sullenberger an emblem of piloting skill and aviation safety.
In June 2019, testifying at a 737 MAX investigation hearing before the US House Transportation Committee, he severely criticized both Boeing’s design failures and the FAA’s oversight.
With the ungrounding of the MAX now imminent, he weighed in on what still needs to be done.
His first concern echoes that of the European Aviation Safety Agency (EASA) and many of the public comments submitted on the FAA proposal: MCAS will take input from the jet’s two angle-of-attack sensors, but Sullenberger believes a third check is necessary, Seattle Times reported.
If one of two sensors is faulty, the computers won’t know which is correct.
The likely solution is not a third angle of attack vane on the jet’s exterior, but an indirect, “synthetic” software calculation of the angle of attack based on parameters such as the aircraft’s weight, speed, inertial position and GPS signal.
Boeing’s newest jet, the 787, has such a check on the reliability of its air data sensors called Synthetic Airspeed, a system Boeing rejected for the MAX on cost grounds, Seattle Times reported.
“It’s really important that a third angle of attack input, or synthetic airspeed, be available on this airplane,” Sullenberger said.
EASA has said Boeing has agreed to develop a third angle of attack input after the MAX returns to service and to retrofit it — in one or two years.
Sullenberger’s other main concern is that Boeing do something about the cacophony of false alerts that were triggered erroneously on the crash flights by one failed sensor.
In June 2019, at the invitation of Dave Calhoun, now Boeing CEO, Sullenberger tried out both the original and the updated MCAS software in one of Boeing’s flight simulators in Miami, replicating what happened on the crashed flights, Seattle Times reported.
There, he experienced “the multiple, compounded alerts and the ambiguity of the events and the physical workload and the distraction.”
“It was clear to me how the accident crews could have run out of time and altitude,” he said. “It’s likely the crew never fully comprehended what was killing them, especially since they had never heard of MCAS.”
Sullenberger said there should be some way to shut off erroneous alerts, especially the highly distracting “stick shaker” stall warning.
If triggered inadvertently, this loud steady shaking of the pilot control column will nevertheless continue for the remainder of the flight, Seattle Times reported. Fixing this is something Transport Canada has demanded, and again Boeing has agreed to find a solution.
While Sullenberger accepts that aviation is safer now than it ever has been — “We have made huge strides” — he believes the MAX crashes could have happened in the US and the flaws revealed have ripped away the prior sense of security.
“For most of Boeing’s history, it had a stellar record for designing and building excellent airplanes,” he said. “On the MAX, the flight-control system design was flawed … They had inadvertently created a deathtrap. It was a matter of time until it claimed lives.”