New Zealand airline is asking passengers to weigh in before their flights

Air New Zealand says it wants to weigh 10,000 passengers during a month long survey

New Zealand's national airline is asking passengers to step on the scales before they board international flights.

Air New Zealand says it wants to weigh 10,000 passengers during a month long survey so pilots can better know the weight and balance of their planes before takeoff.

But the numbers from the scales won't be flashing up for all to see.

There will be no visible display anywhere, the airline promised, and the weigh-in data will remain anonymous even to airline staff.

“We weigh everything that goes on the aircraft — from the cargo to the meals onboard, to the luggage in the hold," said Alastair James, a load control improvement specialist for the airline, in a statement.

"For customers, crew and cabin bags, we use average weights, which we get from doing this survey.” Indeed the numbers are required by the nation's industry watchdog, the Civil Aviation Authority.

Under the authority's rules, airlines have various options to estimate passenger weight. One option is to periodically carry out surveys like Air New Zealand is doing to establish an average weight.