Boeing 737 Max’s autopilot has problem, reports EASA

Bloomberg

Europe’s aviation regulator has outlined five major requirements it wants Boeing Co to address before it will allow the planemaker’s 737 Max to return to service, according to a person familiar with the matter. One of them, about the jet’s autopilot function, hasn’t surfaced previously as an area of concern.
The European Union Aviation Safety Agency (EASA) has sent its list to both the US Federal Aviation Administration (FAA) and Boeing, the person said, asking not to be identified because the details aren’t yet public. The FAA hasn’t publicly discussed details about what changes it’s demanding on the Max, so it’s difficult to know whether the EASA demands differ dramatically — and whether they would significantly boost the cost and time to get the Max back in the air.
Regulators worldwide have grounded Boeing’s best-selling plane since March following two crashes in five months that killed a total of 346 people.
The issues being raised by EASA are consistent with the FAA’s own questions, said a person familiar with the US agency’s work who wasn’t authorised to speak about the matter. In a statement, the FAA declined to confirm the specific matters being raised by EASA but said: “The FAA continues to work closely with other validating civil aviation authorities
on our review of Boeing’s certification documentation for the 737 MAX. This process involves regular communications among all parties.”
Asked about the potential impact of EASA’s concerns, Boeing issued a statement saying company officials continue “to engage with regulators and are providing information as we work towards the safe return to service for the Max.”
EASA’s checklist includes a number of issues that have been disclosed: the potential difficulty pilots have in turning the jet’s manual trim wheel, the unreliability of the Max’s angle
of attack sensors, inadequate training procedures, and a software issue flagged just by the FAA pertaining to a lagging microprocessor. But the agency also listed a previously unreported concern: the autopilot failing to disengage in certain emergencies.
“Any of these could significantly affect the return to service, but we don’t know if they are actually going to become requirements or are they just items for discussion,’’ said John Cox, a former 737 pilot who is president of the aviation consulting company Safety Operating Systems.
Cox said that such questions between regulators are the norm during aircraft certification work and may not pose new risks for Boeing.
The one issue Cox said he hadn’t previously heard about involved the autopilot.
Having to alter a system as complex as the 737’s autopilot could have major ramifications, he said. However, he said he isn’t aware of any underlying safety issues with the autopilot that would justify such an action.
The European regulator has found that the autopilot doesn’t always properly disengage, which could mean that pilots wouldn’t have the time to intervene before the plane begins
to stall.
The EASA list excludes several other smaller issues that the agency hasn’t flagged as critical. The agency’s findings follow its broad, independent review of the 737 family’s entire flight control system that focused on the differences between the Max variant and the older “Next Generation” model, the person said. EASA opted to conduct its own assessment of the aircraft.
The review has become a critical focal point for the industry in gauging when the plane will be able to fly again, with regulators globally expected to lean on EASA’s findings. The FAA is facing multiple investigations over its handling of the original certification of the Max.