Aircraft weight

[rlsbutler]

self-weighing

As to one potential error in self-weighing, frequently mentioned here, surely the surface wind is a non-problem. Presumably any aircraft that requires a significant rotation (almost any big airliner I would have thought – perhaps any tricycle aircraft) to lift off is generating little lift on the taxi-way. Indeed, this is the posture of the aircraft when it rolls on the runway, a posture designed to give minimum drag and therefore little or no lift.

Anyway, what lift an aircraft might get from any particular wind can be calculated by the aircraft manufacturer to subtract from the observed weight readings.

Actually an offset wind will generate different elements of lift as between each mainwheel set, giving the crew a clue to the value of the total readings. Perhaps in that case a good reading might be adduced by applying the reading of the out-of-wind mainwheel set to both sides.

In the Bogota prospectus the configuration includes a laser printer but no anemometer. Enough experience of that installation must have accrued to show whether surface wind has been any problem at all.

A quick look at Wikipedia tells us that most of the 747 hull losses over the last twenty years are freighters. At least two of the freighters were disastrously badly loaded. I suggest that the industry knows there is a risk of misloading, but that resulting losses have proved bearable so far. The cure we are discussing is expensive. I assume that the calculation for the airline companies is that freighter losses cost them little – perhaps no more than increased insurance premiums. Misloading of passenger aircraft is relatively difficult to get wrong. So while the litigation and reputational cost of a passenger aircraft loss is very great, airlines have little reason to fear misloading as a cause of such a loss.

So, how much do we care that our freight-dog friends are not being looked after properly by their employers ? (Don’t anybody mention Lithium-ion batteries – OK?)