A coffee spillage in the cockpit of a plane flying over the Atlantic forced the aircraft to be diverted to Ireland.
The hot liquid damaged an audio control panel, creating “significant communication difficulty” for the pilots flying the Condor aircraft, according to an accident report.
The spilt also produced an electrical burning smell and smoke, the Air Accidents Investigation Branch (AAIB) said.
No injuries were reported among any of the 326 passengers and 11 crew members on board.
The incident took place on 6 February and forced the Airbus A330 flight from Frankfurt, Germany to Cancun, Mexico to turn back and land in Shannon.
The report said that the 49-year-old captain had placed his coffee cup on a tray table, where objects are “vulnerable to being knocked over”, despite Airbus recommending pilots use the cup holders provided.
The AAIB noted that, because the cups are small, holders make it difficult for somebody to grasp them. However, putting a lid on the cup may have reduced the amount of coffee spilled.
Following the accident, Condor is ensuring cup lids are provided on all flights and has reminded pilots to be careful with liquids and supplying cups that are an appropriate size for cup holders.
The Civil Aviation Authority estimates the cost of a diversion at between £10,000 and £80,000 depending on the size of the aircraft and where it diverts to.