FAA proposes four key Boeing 737 MAX design changes through airworthiness directive

The US Federal Aviation Administration (FAA) has announced that it intends to issue an airworthiness directive for the troubled Boeing 737 MAX, which involves the updating of flight-control software, revised display-processing software to generate alerts, revising a number of flight-crew operating procedures, and changing the routing of certain wiring bundles.

While significant, the announcement does not include the finalizing of flight-training procedures which are critical to the 737 MAX once again taking to the air. Boeing has confirmed that it is: “continuing to make steady progress towards the safe return to service, working closely with the FAA and other global regulators. While we still have a lot of work in front of us, this is an important milestone.”

The FAA said in a separate 96-page report released at the beginning of this week, the FAA stated that it: “has preliminarily determined that Boeing’s proposed changes to the 737 MAX design, flight crew procedures and maintenance procedures effectively mitigate the airplane-related safety issues” in the two fatal crashes.

The grounding of the 737 MAX has so far cost Boeing approximately US$19 billion, while the FAA’s comprehensive review has lasted over 18 months, involving in excess of 40 full-time engineers, inspectors, pilots, and technical support staff who have been involved in 60,000-plus hours of review, certification testing, and document evaluation. Much of the focus has been on the MCAS system and the FAA has recommended that Boeing carry out an Angle of Attack (AOA) sensor system test to check that the amendments to the system will ensure that if two AOA sensors receive conflicting data, the flight crew will be able to recognise this and act accordingly, with particular respect to stabilizer movements.

The FAA said the changes minimize “dependence on pilot action and the effect of any potential single failure.”