WHBM

Yes, on Jet Day BOAC were using all four of these types on London to New York. That day, incidentally, was also the last day (elsewhere) of another BOAC type, the Lockheed L749 Constellation.

BOAC had not had a lot of luck with their types in the 1950s. There was the Comet 1 disaster, the abandonment of the Comet 2 and 3 which they had placed substantial orders for, the appalling Handley Page Hermes, the Bristol Britannia which took years beyond plan to get into service, and the "emergency" purchase of 10 DC-7C to try and stay competitive, along with secondhand Strats and Constellations they picked up. Only the stalwart Canadair 4 Argonaut rolled along through all this for the whole decade.

Then a whole lot of new types all turned up at once, the two sizes of Britannia, the Comet 4, and the first Boeing 707s. The DC-7Cs had been bought on the understanding that as soon as the other types came along they would be sold to finance the new arrivals. Of course, just a couple of years after delivery the bottom had completely fallen out of the large piston market and they were faced with a huge loss.

Oh, and through all this they had all sorts of engine failures downroute (those four types used to New York had four different engine manufacturers), for which they retained a dedicated fleet of 1940s Avro York freighters at Heathrow just to ferry engines and engineers out.