FAA proposes Airworthiness Directive for Boeing 787 Equipment Water Leaks
by Jonathan E.Hendry Dec 2022 Simple Flying
IFA’s CEO reflects: Water plus avionics – bad mix. This takes me back to a serious incident of more than 30-years ago. It was on a classic UK registered Boeing 737. The aircraft was equipped with a forward chemical toilet. That leaked its unpleasant blue fluid. The avionics compartment on those Boeing 737 aircraft is located under the floor. Under the position taken by the retracted air-stair door. To keep rain water from spilling from a wet retracted air-stair there’s a drip tray above the avionic equipment bay but that only works for the one purpose. The chemical toilet leak trickled onto a cable form and then ran into the back of an avionics box connector. The in-flight impact of this was an unexpected kick of the aircraft rudder. Not nice. The lesson here is that lessons need to be remembered. Safety promotion is part of most SMS rules but there are few good examples of it in practice.
The Federal Aviation Administration proposes adopting a new airworthiness directive(AD) for Boeing 787 Dreamliners. The proposal, which was published this week, was prompted by reports of a loss of water pressure during flight and water leaks that affected sensitive electronic equipment.
The mandate applies to Boeing’s 787-8, 787-9, and 787-10 model airplanes, of which there are 134 on the US registry. This proposed directive would require a detailed visual inspection of lavatory doors and galley potable water systems for any missing or incorrectly installed clamshell couplings following reports of water leaking into the avionics compartment.
Interested parties have until January 27th, 2023, to comment on the proposal before it goes into effect.
Background of the proposal
The FAA confirmed this week it had received reports of a loss of water pressure during flight and water leaks that affected multiple pieces of electronic equipment. One operator of the Boeing 787 Dreamliner reported a significant water leak due to a loose drinking water system hose caused by a clamshell coupling within the lavatory that had been installed incorrectly.
A second operator also reported a water leak due to a loose clamshell coupling. The leak occurred below the forward center galley countertop, adjacent to the gray water interface valve maintenance access compartment. The incident resulted in include a loss of water pressure during flight. Upon landing, the ground crew discovered the potable water system leak had caused water to migrate into the forward electronic equipment bay, which affected several pieces of electronic equipment.
Boeing initially notified operators in August 2022 about this condition and has been working closely with the FAA in diagnosing potential issues and suggesting remedies for operators of its aircraft. Both parties agreed that incorrectly installed or missing lavatory and galley clamshell couplings could result in water leaks and potential damage to critical flight equipment if not addressed, compromising the airplane’s continued safe flight and landing. When reached by Simple Flying on Saturday, a spokesperson for Boing confirmed that the manufacturer backs the proposed measure:
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“We previously issued guidance to our operators and fully support the FAA’s proposal to make that guidance mandatory.”
What comes next?
The Notice of Proposed Rulemaking (NPRM) calls for a visual inspection of the affected areas to be undertaken. Representatives for each of the airlines that operate the affected aircraft will have to conduct a detailed visual inspection of all door 1 and door 3 lavatory and galley potable water systems for any missing or incorrectly installed clamshell couplings.
Further actions include installing clamshell couplings, doing a leak test, and performing corrective actions until the leak test passes inspection. The checks are estimated to take one hour per lavatory or galley at a rate of $85 per hour, costing operators a total of $11,390.
The aircraft is no stranger to receiving notices. A previous airworthiness directive was issued last year for decompression panel issues. The 2021 directive called for a visual inspection of the forward and aft cargo compartments to find any disengaged or damaged decompression panels. Any affected panels were then reinstalled or replaced.
All three of the major US carriers fly the Boeing 787. The largest operator is United Airlines, which recently placed the largest-ever order for the type.
