Boeing’s plan to return its 737 Max jet to the skies has hit a fresh obstacle, with regulators discovering a “potential risk” to the aircraft model.
The Federal Aviation Administration (FAA) said it discovered the issue during simulator tests, and warned Boeing must solve the potential problem before test flights can commence.
Boeing grounded its best-selling 737 Max aircraft in March following two crashes that led to airlines around the world banning the aircraft from their fleets.
The FAA said in a statement: “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.”
Boeing is currently improving the 737 Max’s anti-stall software.
The software is at the centre of crash investigators’ probes into a fatal crash of a Lion Air jet last October, and an Ethiopian Airlines crash that killed everybody on board in March.
Reports into both crashes suggest an anti-stall system triggered incorrectly based on a faulty sensor. In the Ethiopian crash, pilots could not regain control of the system.
The latest issue saw pilots take longer than expected to recover an aircraft in an FAA flight simulation in which the anti-stall software became active, according to Reuters.
Boeing said: “We are working closely with the FAA to safely return the Max to service” and that it believed a software fix would address the problem.”
If regulators are unhappy with the software fix, Boeing will have to replace a microprocessor unit, potentially delaying the upgrade process by months.
The FAA had previously estimated it could approve Boeing’s upgrades by late June, enabling test flights in early July.
However, even before the current setback Boeing’s 737 Max was not expected to return to service until late this year.
“The FAA is following a thorough process, not a prescribed timeline, for returning the Boeing 737 Max to passenger service,” the regulator said.
“The FAA will lift the aircraft’s prohibition order when we deem it is safe to do so.”