The term 'Sir' should never be used in an aircraft - it only serves to promote 'cross-cockpit gradient' which is the antithesis of CRM.
Never ever had a CRM problem when using the term 'sir'. Even when I'm the trapper and aircraft captain. The gradient always goes in the right direction.....
It's maybe an 'Army thing' but it certainly doesn't break down the team side of life if 'sir' is used. It's not as if we sit to attention or doff our helmet when applying it.
