As was the norm in the mid 1960's, when young RAF airmen like me conversed with Flight Sergeants we respectfully called them 'Flight'. This was OK until I had to share an office at Khormaksar with an ex NCO pilot named Flight Sergeant Flight! - a tricky situation for a 20 year old!. However, to avoid embarrasment he kindly agreed to be known as 'Chief''. A nice man. Regards....Paul