FAA issues directive to address Boeing 737 circuit breaker issue

By David Shepardson

WASHINGTON, Feb 25 (Reuters) – The Federal Aviation Administration said on Wednesday it has issued an airworthiness directive for all Boeing 737 MAX 8 and 8200 airplanes to address a circuit breaker issue that could lead to a malfunction causing excessively high temperatures in the cabin and flight deck. 

The directive requires revising the airplane flight manual within 30 days to provide the flight crew with operating procedures if a certain circuit breaker trips, causing an air conditioning malfunction. The FAA said the directive covers 2,119 airplanes worldwide, including 771 U.S.-registered airplanes.

Boeing said it supports the directive that mandates guidance it issued last month. “We are advancing an engineering solution to eliminate the possibility of this electrical fault,” Boeing said.

The FAA said two incidents in flight were recently reported in which temperatures increased sharply on board the airplane. Boeing said the root cause is a ground wire fault in the air conditioning system.

The FAA said the air conditioning system malfunction could cause an uncontrollable, excessively high temperature, which “could lead to injury or incapacitation of flightcrew and passengers, which could result in the inability to maintain safe flight and landing.”

Boeing said it expects the fix to be ready for the 737 MAX 7 and 10 before certification and does not anticipate this issue to affect the certification timeline.

Southwest Airlines, which had one of the reported incidents, said it is in close contact with the FAA and Boeing about the issue and has notified its flight crews about the steps that should be taken to respond to the specific electrical fault.

(Reporting by David Shepardson; Editing by Chris Reese, Rod Nickel)