A spilled cup of coffee on the flight deck of an Airbus A330 knocked out the flight crew’s audio control panels (ACPs) and touched off a chain of events that led the crew to divert their planned trans-Atlantic flight to Shannon, Ireland.
The U.K. Air Accidents Investigation Branch (AAIB) said, in its final report on the Feb. 6, 2019, serious incident, that after the flight left Frankfurt, Germany, bound for Cancun, Mexico, the flight crewmembers were served coffee in cups without lids, as was typical for the operator’s aircraft on this route.
The commander placed the coffee on his tray table while he completed some required tasks, and the cup was knocked over, spilling coffee onto the commander’s lap and onto his ACP. Although the spill on the center console was quickly wiped up, it “resulted in immediate malfunction of [the commander’s ACP] that affected VHF transmissions and public address announcements from this unit,” according to the report, issued Thursday.
The ACP then became hot and failed, filling the flight deck with the odor of electrical burning. A small amount of smoke also was observed, the report said.
Soon afterward, the first officer’s ACP also failed, and the commander decided to divert to Shannon, with the pilots alternately using supplemental oxygen.
The ACP failures resulted in communication problems, including the commander’s inability to receive or transmit on ACP1; he could hear transmissions through the copilot’s speaker, however. The report said the landing at Shannon was otherwise uneventful, and no one was injured as a result of the coffee spill or the subsequent events. Airplane damage was confined to the VHF radio unit, the report added.
The AAIB’s analysis blamed “liquid contamination” for the failure of the commander’s ACP and said that the electrical shorting led to the smoke and fumes. The report did not discuss reasons for the failure of the first officer’s ACP.
The report noted that Airbus recommends using cup holders on the flight deck. Nevertheless, “the size of cups used by this operator on this route made it more difficult to take cups in and out of the cup holder than larger cups that have a bigger area at the top of the cup holder to grasp,” the report said. “This incompatibility generally discouraged use of the cup holder, despite the policy.”
As a result of the incident, the operator changed its procedures and now ensures that cup lids are provided on all flights, the report said. The operator also reminded cabin crewmembers that the lids must be used, issued a flight crew notice “reminding pilots to be careful with liquids” and sought a supply of cups that would fit the airplane’s cup holders.