Concorde - Eye Datum device
I've noticed on G-BOAC's flight deck an 'Eye Datum' device. It's a flat metal arm with a spectacle-shaped end with two eye-holes in it. It's stowed in a pocket on the LH side of the flight deck, but can be mounted into the side of the overhead panel so that it's poitioned in front of either pilot.
I presume it was for positioning the seat to the optimum position for the pilot, so that his eyes were in the correct place relative to the instruments and the view out the front.
Does anyone know if it was actually used in practice? I've never heard of such a device in any other aeroplane (has anyone else?). And interestingly, when it's in position, the eye holes are not in line - the 'outside' eye hole (left eye for the LHS, right eye for the RHS) is lower than the 'inside' eye hole. Why's this?
SSD