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Flight Deck question.

Looking at some flight deck videos, on the central windscreen pillar of some aircraft is a fixture that has horizontal fixture of a central white ball, with a red ball either side.
Can anyone tell me what it is please?. Thanks in advance.

Alignment for eye positioning. It becomes very important in Cat II ILS situations...

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It becomes very important in Cat II ILS situations...

Not sure I agree, it's there to help the pilot find the ideal eye height but I can safely say I seldom reference it and its never spoken about in any LVO training I've witnessed.

Intruder is correct. The idea is to align the balls to ensure correct seating height. This becomes important in LVO as sitting lower than ideal increases the cut off angle (you will see less runway/approach lights.

I thought it was probably to do with eye level. Many thanks for the replies. Regards, John.

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Not sure I agree, it's there to help the pilot find the ideal eye height but I can safely say I seldom reference it and its never spoken about in any LVO training I've witnessed.

Maybe your training has been deficient. From the Cat II section of our All Weather Ops manual:

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Effects of Pilot Eye Position/Seat Height on Cockpit Cutoff Angle

Down vision angle is formed by the airplane axis and a line connecting the pilot’s eyes with the glare shield in the cockpit and may be referred to as cockpit cutoff angle. Assuring that the pilot's eyes are located in the optimum design eye position is an important factor in preventing hard or short landings in any conditions, but especially during reduced visibility.

Pilot eye position is directly controlled by pilot seat adjustment.

Many pilots become accustomed to sitting in positions that produce other than the designed Eye Reference Position. These pilots may not realize the significance of eye position during low visibility approaches and landings. Seat adjustment that produces lower than design eye positions greatly reduces the amount of visual ground segment (the portion of ground features and approach lighting visible to the pilot. See Effect of Pilot’s Seat Position on page xxx).