A plane carrying 337 people to Mexico had to be diverted after a pilot spilled coffee on the controls, causing equipment failure, a report revealed.
The 49-year-old pilot, who had more than 13,000 hours of experience, was flying from Frankfurt Airport to Cancun, Mexico on February 6 when they were routinely served a cup of coffee without a lid, according to the Air Accidents Investigation Branch (AAIB).
The pilot reportedly put the coffee on a tray table while completing tasks, as it was too small to easily get in and out of the cup holder.
At around 4.20pm, the cup was knocked over, spilling liquid onto the pilot's lap and onto the plane's audio control panel.
The liquid was quickly dried, but the spill resulted in the immediate malfunction of the control panel, impairing the pilot's ability to receive or transmit audio and converse with their co-pilot, the report said.
Roughly 20 minutes later the audio control panel became very hot and failed - releasing an electrical burning smell into the cockpit.
Around 5.20pm, the co-pilot's audio control panel also failed, after reaching a temperature hot enough to melt one of the device's buttons.
Smoke began emitting into the cockpit, prompting the pilot to divert the plane to Shannon, Ireland.
According to the report, supplementary oxygen was provided to the pilot and shared between cabin crew during the diversion.
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Nobody on board the flight was injured.
An analysis of the equipment after landing revealed that the smoke and fumes from the primary audio control panel were the result of an electrical short caused by the spilled liquid.
As a result of the incident, the AAIB said the flight operator has changed their policy to require lids and reminded cabin crew of the requirement to use them.
