Tough question to answer is wholly correct, John, because I made a mistake. I have checked my notes and the registration of this Beech 18 which I saw at Harlingen,Texas in October 1978 is, in fact, XB-POB.
I apologise to all those who have viewed the original message and it goes to prove how easyily miistakes can occur and why input should be previewed before submission. Sorry, everybody.
If any-one can still assist in telling me the type of Beech 18 and the c/n for this aircraft I would be very grateful.
Peter