FAA Warns Boeing 747s Face Electrical Risks From Leaks
Published Date: 6/30/2026
Proposed Rule
Summary
The FAA wants Boeing 747-400 planes checked regularly for water leaks that could mess with important electrical parts. This means inspecting water and waste lines on the upper and main decks and fixing any problems found. Owners need to act soon, with comments due by August 14, 2026, and should expect some inspection costs to keep flights safe and sound.
Analyzed Economic Effects
3 provisions identified: 0 benefits, 3 costs, 0 mixed.
On-condition fixes must be done before flight
If an inspection finds a leak or clog, the AD requires using normal operator procedures to resolve the issue and perform any applicable on-condition actions before further flight, as specified in step 27 of the Water Leak Check Work Instructions. The AD makes those on-condition actions mandatory before the airplane may continue flying.
Required repetitive water-leak inspections
If you operate a Boeing Model 747-400 identified in Boeing Message TBC-TBC-25-6694-01B (dated November 7, 2025), you must perform repetitive inspections of potential water sources on the upper and main decks, including potable water and waste water lines, for leaks and clogs. The Boeing message calls for inspections within 1,000 flight hours of the message date and at recurring intervals not to exceed 1,000 flight hours.
FAA cost and fleet impact estimate
The FAA estimates this proposed AD would affect 4 U.S.-registered Model 747-400 airplanes. The agency estimates a per-airplane inspection labor cost of $425 (5 work-hours × $85/hour) and totals $1,700 across the 4 U.S. airplanes per inspection cycle; on-condition actions are estimated up to $510 per airplane when needed.
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Key Dates
Department and Agencies
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