Boeing faces a further battle in getting the 737 Max aircraft type back into service after the US Federal Aviation Administration (FAA) identified an additional software flaw.
The FAA found the “potential risk”, which it did not reveal details of, during a review of the 737 Max software update and recent simulator sessions, and has asked Boeing to address it through the software changes it has been developing for the past eight months.
The FAA said in a statement: “The FAA is following a thorough process, not a prescribed timeline, for returning the Boeing 737 Max to passenger service. The FAA will lift the aircraft’s prohibition order when we deem it is safe to do so.
“We continue to evaluate Boeing’s software modification to the MCAS and we are still developing necessary training requirements. We also are responding to recommendations received from the Technical Advisory Board (TAB). The TAB is an independent review panel we have asked to review our work regarding 737 Max return to service.”
“On the most recent issue, the FAA’s process is designed to discover and highlight potential risks. The FAA recently found a potential risk that Boeing must mitigate.”
The 737 Max was taken out of service by regulators across the globe after two fatal crashes that killed all on board a Lion Air flight in October and an Ethiopian Airlines flight in March.
Boeing is upgrading the aircraft’s flight control system, which is the focus of crash investigators. The system can help prevent a plane from stalling.
Last month, the FAA indicated approval of Boeing’s changes to the 737 Max could come in late June which would have allowed test flights in early July, but this latest issue seems certain to push it back until later in the year.
Boeing said: “The FAA review and process for returning the 737 Max to passenger service are designed to result in a thorough and comprehensive assessment. Boeing agrees with the FAA’s decision and request, and is working on the required software.
“Addressing this condition will reduce pilot workload by accounting for a potential source of uncommanded stabiliser motion.
“Boeing will not offer the 737 Max for certification by the FAA until we have satisfied all requirements for certification of the Max and its safe return to service.”