US Federal Aviation Administration chief Steve Dickson has set out the milestones that must be passed before the Boeing 737 Max can be returned to service.

“The certification flight test, and then the evaluation of the certification flight, is really the next major milestone,” said Dickson during a briefing at the Singapore air show. “That’s FAA pilots evaluating the compliance of the final software to FAA Transport Category aircraft regulations.”

Steve Dickson Federal Aviation Administration FAA

Source: BillyPix

Dickson spoke at a briefing during the Singapore air show

However, the flight test has not yet been scheduled. “We still have a few issues to resolve, but we are continuing to narrow the issues,” he says. “We are waiting for proposals from Boeing on a few items to be able to clear the way to that flight.”

Elaborating on matters to be resolved, Dickson mentions an issue with the “stab out of trim” light, noting: “It’s not a problem with the software per se, but this light that’s been on the airplane forever tends to flicker when the trim is running very quickly… It’s coming on at inappropriate times – it’s essentially getting overloaded with data we think. They’ll have to buffer that a little bit.”

He adds: “We’ll be addressing that, evaluating that. That’s a matter of a few days.”

In reference to a separate issue with wire bundles on the Max, Dickson says: “Boeing has not yet given us a proposal on that. We’ll see to what extent those issues are common with the 737NG.”

Once the certification flight has been completed and the data analysed “within a few days”, operational validation will proceed. Boeing has made a pilot-training proposal, which the FAA will evaluate, says Dickson – himself a pilot.

“My deputy Dan Elwell is going to complete the training in conjunction with this. I’m also going to complete it subsequently before I fly the airplane,” says Dickson. “So we will be taking our own look at that.”

But he adds: “We don’t want to have our thumb on the scale. We’ve got international crews and US crews coming in to evaluate those proposals.” Thus will it be determined whether any modifications are required.

“It’s not a matter of us at this point accepting the Boeing proposal or not,” Dickson stresses. “We have a process to run that will give us the answer.”

That process will take nine to 10 days, says Dickson. An amendment will then be made to the Flight Standardization Board (FSB) report – which will take “a few days” – and this will then be put out for public comment for 15 days.

“From beginning to end, the JOEB [Joint Operations Evaluation Board] and FSB report process is roughly probably 30 days, and that can’t happen until the certification flight.”

737 Max FIA16

Subsequent processes include the final design documentation and the technical advisory board report. The FAA must also consider public responses to the master minimum equipment list that has been out for comment since 5 December, before it gets to the stage of issuing a continued airworthiness notification to the international community – providing notice of pending significant safety actions – and an airworthiness directive advising operators of the required corrective action.

“We’ll rescind the grounding order within a day or two after that,” says Dickson.

After the issuance of certificates of airworthiness, US airlines will need to get their training programmes approved by the FAA.

For now, though, the focus is on reaching the certification flight test. “If you look at it as a stream of work, it starts to break into some parallel streams once you get to that,” notes Dickson.

The FAA is “following a very diligent process”, he says, adding: “It’s important that we stay focused on the process and not on a timeline.”

He vows that the Max will upon its return to service be “the most scrutinised aircraft in history”. The FAA will also impose a requirement that every Max operator around the world conduct a validation flight without passengers.

Dickson also sketches how the whole process might affect future regulation: “The lessons learned will ideally lead to a more holistic rather than transactional item-by-item approach to aircraft certification – not only in the US, but around the world, where we will more effectively integrate human factors considerations throughout the design process as aircraft become more automated and systems more complex.”