The Federal Aviation Administration has issued a new airworthiness directive for certain Boeing 747-400, 747-400F, 747-8F, and 747-8i aircraft. The directive, which goes into effect on March 21, 2025, requires the installation of additional safeguards to prevent water leaks from damaging critical electronics.
The AD was prompted by an incident in which multiple engine indicating and crew alerting system messages occurred during potable water servicing of a 747. Investigators later determined the cause was a separated fitting and water supply tube above an electronics cooling air filter.
To address this safety issue, the FAA is mandating several modifications depending on the specific aircraft configuration, including shrouds and shields over various water lines.
These changes aim to prevent water from leaking into the main electronics bay, which could impact multiple systems essential for safe flight. The FAA estimates the modifications will cost U.S. operators up to $1.2 million to implement across the affected fleet of 178 U.S.-registered aircraft.
Past Incident
In 2008, a Boeing 747-400 experienced widespread failures on approach to Bangkok after a galley leak allowed water to flood electronic components. Though the aircraft landed safely, several systems became inoperable, including the autopilot and the first officer’s instruments.
No scheduled U.S. airline operates the 747. However, the jet still remains in service with various charter and cargo operators.
