Tyre pressure indicators
Paul Wilson,
You quote about four quid for low pressure indicators for car tyres. By the time it has been approved, certified and anything else that can be thought of to bump the price, I think you would have to be thinking of at least ten times the cost for a car. (Even though it is identical).
World of Tweed,
I think you are referring to the inflation valves incorporating a pressure gauge, If so these are optional to the standard valve stem installed on wheels. I have worked on several operators B757s and never had them fitted to this aircraft. I have, however, seen them on other types, and not necessarily on every wheel. They are useful, as it saves carrying a tyre pressure gauge on a walk round and, are calibrated to within 10% accuracy,when new.