Through July 2, Air New Zealand—which was named the world’s best carrier by aviation rating agency AirlineRatings this week—will be asking more than 10,000 fliers to step onto the scales as part of its “passenger weight survey.”

According to the airline, the weighing of passengers is “is essential to the safe and efficient operation of the aircraft,” and is required by New Zealand’s Civil Aviation Authority.

The airline said it will use the results to calculate an average passenger weight, which will help its pilots determine the weight and balance of loaded aircraft.

Alastair James, load control improvement specialist at Air New Zealand, said in a statement on Monday that pilots needed to be aware of this information before taking off.

“We weigh everything that goes on the aircraft—from the cargo to the meals on board, to the luggage in the hold,” he explained. “For customers, crew, and cabin bags, we use average weights, which we get from doing this survey.”

People traveling overseas on certain Air New Zealand flights from Auckland International Airport will be asked to weigh themselves before they fly, with participation being completely voluntary. Air New Zealand carried out a separate weight survey for domestic travelers in 2021.

The airline acknowledged in its announcement that some customers would feel daunted by weighing themselves in public—but James insisted that no one in the vicinity would be able to see the reading.

“There is no visible display anywhere,” he said. “No one can see your weight—not even us. It’s completely anonymous.”

Air New Zealand isn’t the first airline to weigh its passengers.

Between 2017 and 2018, Finland’s Finnair asked people flying from Helsinki Airport to step on the scales before boarding, so it could collect data on the weights of passengers and their carry-on luggage during the summer and winter months.

Meanwhile, the preflight weighing of passengers was carried out by Uzbekistan Airways in 2015 as part of the airline’s safety measures.

In 2021, the U.S. Federal Aviation Administration (FAA) reportedly contemplated requiring airlines to weigh plus-size passengers or ask that they provide their weight before boarding aircraft.

The move was proposed as the FAA said existing data on average passenger weights did not reflect modern obesity rates in America, with the organization noting new statistics would help planes—particularly smaller ones—ensure they did not exceed their maximum weight limits.