"Let he who is without sin cast the first stone". I can only assume that the critical posters above are all experienced authors who have never missed an error when proof reading their own or someone else's work; I wish I was good enough to join you.
Oh dear. What a mistake from an author who “has established himself as one of the pre-eminent British historians and writers specialising in RAF history.”
I have learned that he was a navigator so perhaps that explains the error.
India Four Two, for your information Graham was my squadron commander and my navigator at one time. Please explain to me (and him - I will pass on your explanation) the justification for your last sentence? I suspect (hope) that it was an attempt at humour.. Remind me of the books that you have written ....