...they also worked very well in Trinidad when a certain gifted Greenie understood how to pair up the computers, matching their outputs so hard duplex faults would not occur.
It was amazing what a bit of cyclic friction did to the SFENA - just as it said in the manual.
I personally preferred the SFENA to the cheapskate basterdised (by BHL chief accountant) Sperry. If the Sperry had all the stuff it was supposed to have, then I would agree, SFENA was not as good. If BHL had refrained from their "It's not in the contract, they haven't paid for it, take it out attitude" maybe things would have been different.
SFENA managed to get Concorde to fly pretty well....