he refused to sign off on flight. The decision was taken out of his hands and authorisation signed by a non-engineering manager above him?
I have refused to sign a Certificate of Compliance (as it was, but now a Release to Service) several times. On one occasion my decision to delay for 12 hours until spares arrived was overruled by the Chief Inspector. I discussed this with the Captain who packed up his nav-bag and went home. I was dragged before the Big Boss who after interrogating me on the matter said "You'd better be right - otherwise you're on the plane home". Fortunately I was right (on that occasion) but I'd have been happy to accept the sack rather than give in.