On 9 April 2021, Boeing announced it was recommending operators of specific 737 MAX address a potential electrical issue prior to flying the aircraft again. Airlines like Southwest, United, Alaska, and Copa have grounded portions of their MAX fleets awaiting a fix from Boeing. On 22 April, the Federal Aviation Administration issued a Continued Airworthiness Notification to the International Community (CANIC) detailing the problem and promising an airworthiness directive would soon follow. We tracked down where airlines have parked their affected 737 MAX in the meantime. On 12 May, Boeing issued the requisite service bulletins so that airlines can begin the process of correcting the defect and putting the affected aircraft back into service.

What’s the problem?

Boeing’s initial message to operators said that actions were needed to ‘allow for verification that a sufficient ground path exists for a component of the electrical power system.’ The FAA’s CANIC elaborates to say an ‘electrical bonding and grounding issue’ was discovered during testing of a newly manufactured 737-8. Boeing’s investigation ‘identified potential degradation of bonds associated with electrical grounding of equipment that could affect the operation of certain systems.’

[Update 13 May] — We now have a definitive answer for what went wrong thanks to reporting from the Seattle Times and the problem is related to a manufacturing change where electronic bay racks were switched to being drilled first, then painted. This switch lessened the grounding effectiveness of the racks.

Which airplanes are affected?

The potential electrical grounding issue only affects certain individual aircraft manufactured after Boeing implemented design changes in early 2019.  The affected aircraft are a mix of 737-8 MAX and 737-9 MAX between line numbers 7399 and 8082. The FAA’s CANIC lists 106 total aircraft and and 71 US operated aircraft. We were able to find 105 total and 70 US operated aircraft so far. Some undelivered aircraft within the line number range are also believed to be affected.

Most affected is Southwest Airlines with 32 aircraft, followed by American at 18, and United with 16. Multiple airlines have just one affected aircraft, like Belavia, which took delivery of its first 737-8 MAX just a day before Boeing announced it had found this issue.

Where are the parked planes?

The affected aircraft are currently parked in 54 different locations, with Denver hosting the most at 7 aircraft.

Featured image © Ricky Teteris