Tensions and hazards came to a head shortly before the accident. On Thursday 15 June a captain complained that his inexperienced co-pilot "would be useless in an emergency". Upset, the co-pilot committed a serious error on departure from Heathrow, setting the flaps fully down instead of up.[4][5] The mistake was noted and remedied by the SFO, who related the event to colleagues as an example of avoidable danger. This became known among BEA pilots as the "Dublin Incident".[5]
An hour and a half before the departure of BE 548, its rostered captain, Stanley Key, was in a quarrel in the crew room at Heathrow's Queen's Building with a first officer named Flavell. The subject was the threatened strike, which Flavell supported and Key opposed. Both of Key's flight deck crew on BE 548 witnessed the altercation, and another bystander described Key's outburst as "the most violent argument he had ever heard".[6] Shortly afterwards Key apologised to Flavell, and the matter seemed closed.[7] Key's anti-strike views had won enemies and graffiti against him had appeared on the flight decks of BEA Tridents, including Papa India.[nb 1] The graffiti on Papa India's flight engineers' desk was analysed by a handwriting expert to determine who had written it, but this could not be determined. The public inquiry found that none of the graffiti had been written by crew members on BE 548 on the day of the accident