In 1981 I was dispatched to Hatfield to do a report evaluating the BAe146 for European/North African operations, mainly ACMI, using De Havilland's predicted performance figures.
I made a lot of the claim, as did BAe, that a complete spare engine could be carried in the hold, enabling fast return to service if a change were needed away from base (SEN).
The Chairman read the report, looked at me and in his inimitable fashion said "You stupid prat, why the f**k do you think it's important to carry a spare?" I muttered about lower costs of recovery, blah, blah.
"It's because those f*****g Lycoming engines are designed for helicopters and are f*****g unreliable".
That was the last we heard of the BAe 146.