FAA Airworthiness Directive: Boeing 737 Operators Must Update Thermal Procedures

The Federal Aviation Administration issued an emergency airworthiness directive July 21, 2026, requiring Boeing 737-8, 737-9, and 737-8200 operators to adopt immediate procedural changes after crews reported uncontrolled high temperatures in the cabin and flight deck that existing checklists could not manage.

The FAA traced the root cause to a specific standby power control unit (SPCU) circuit breaker. Under the directive, operators must revise their airplane flight manuals to include non-normal procedures for instances where the breaker trips, giving crews a defined response path before conditions deteriorate. The agency stopped short of ordering fleet groundings, emphasizing targeted procedural and maintenance fixes over broad withdrawal from service.

The directive affects the entire 737 MAX family — the -8, -9, and -8200 variants — and applies to all operators regardless of route network. Although the FAA did not name specific carriers, the mandate requires prompt manual updates to maintain crew safety. The action is the latest in a series of heightened FAA oversight measures for the Boeing 737 aircraft family, which has faced sustained scrutiny over structural and systems integrity in recent years.