airplanes hours

[tali122]

why is airplane mileage calculated in hours- surely they travel miles -why does hours give a better reference point?

[heathfield]

Because the winds move from west to east around the globe, a plane flying from London to Singapore has the wind behind it, but travelling in the opposite direction it has a head wind. Although the distance is identical in each case, the flying time is greater on the Singapore to London sector. This just might be of some importance in calculating fuel requirements!! It's time in the air on a route that counts, not the distance.

[steve208]

Further more another reason planes (also ships and submarines I believe) have milage calculated in hours is that this is useful in knowing when maintainance should be planned....ie say after 5,000 hours flying etc

[peanut]

Nearly all construction eqipment is counted in hours also.

[Skids]

Nearly everything on any aircraft has a lifespan rated in flying hours. How can a mile be measured in the air? It can be measure on the ground by the aircraft but the higher you get the longer that mile becomes. The question is; why are road vehicle lives measured in miles and not hours? If a car is sat stationary with its engine running, the engine is still wearing away but the car's mileage isn't increasing.

[Space]

when a car is stationary, the engine runs at a very low speed, so it doesn't wear much that way. It mostly wears when the car is moving.
Unlike a helicopter, for example.