United flight 1996 from Chicago O’Hare to San Juan was delayed three hours when the captain spilled coffee in the cockpit. The Airbus A321neo was already taxiing out when this happened, and had to return to the gate. That delayed the return flight from San Juan back to Chicago O’Hare by nearly three hours as well. Spilling much more than a little bit in the cockpit would certainly have cancelled the flight. Not only does the spill need to be cleaned, but whatever was spilled on needs to be inspected as well. Coffee is especially bad because it’s hot, acidic,...