An international panel of safety technicians will take additional time in its review of how the US Federal Aviation Administration certified Boeing 737 Max aircraft that have been grounded since March, including how the agency allowed the airframer to oversee parts of its own certification.
The Joint Authorities Technical Review panel "expects to submit its observations, findings and recommendations in the coming weeks", the FAA says in a statement on 30 August.
"The JATR’s focus on the certification of the aircraft is separate from the ongoing efforts to safely return the aircraft to flight," the FAA says.
The panel's recommendations could affect both the future of how the FAA conducts safety certification and could influence how soon regulators from other nations return the aircraft to service. The FAA's certification of the Max does not require the panel to first finish its review, and Boeing still aims for the agency to clear the aircraft to fly in the fourth quarter.
Boeing is coordinating with the FAA on software modifications and safety training for pilots related to the automated flight controls unique from the earlier-generation 737NG, known as the manoeuvring characteristics augmentation system (MCAS). FAA safety technicians in June discovered a data processing issue with the aircraft separate from MCAS.
The airframer says in a statement that "work is progressing on software to address the additional requirement identified by the FAA on June 26, which will be submitted for certification with the main MCAS software package that is already complete".
The consistent message from the FAA during the review since March is that the agency "is following a thorough process, not a prescribed timeline, for returning the Boeing 737 Max to passenger service".
Most operators have extended cancellations of flights on their grounded 737 Max fleets until the end of 2019. United Airlines on 30 August, prior to the FAA announcement, pushed the scheduled return of Boeing 737 Max flights out another six weeks until 19 December.
The panel, formed after two fatal crashes of Max aircraft spurred a worldwide grounding, includes safety technicians from nine nations, along with representatives from FAA and NASA. Its chairman is Christopher Hart, the former chair of the US National Transportation Safety Board.
Safety research by the panel has included discussions about the 737 Max design, certification, regulations, compliance, training and activities of the FAA's Organisation Designation Authorisation certification process. Lawmakers and families of the 346 Max crash victims have questioned that FAA process that gave Boeing authority to oversee part of its own safety certification for the Max.
"While the agency’s certification processes are well-established and have consistently produced safe aircraft designs, we welcome the scrutiny from these experts and look forward to their findings," the FAA says.
Investigations into the Max crashes of Ethiopian Airlines flight 302 and Lion Air flight 610 remain ongoing, but evidence indicates that MCAS software automatically trimmed the aircraft into dives, killing 346 passengers and crew.