sentences:  This necessitated the temporary lease of a Boeing 747-100 from Aer Lingus, and the use of BA flightdeck crews to operate the aircraft.The aircraft, which wore a slightly modified BCal livery, was operating the Gatwick—Houston schedule during the 1978/79 winter timetable period to cover for the late delivery of the airline's third DC-10.By 1978, BCal had fully recovered from the 1974 crisis year, which had threatened its very existence at that time.