Finland's Finnair is hoping to get at least 150 passengers on every flight to volunteer to be weighed along with their luggage.

While it may sound unusual, there's logic behind the move: The airline wants a more accurate metric for determining aircraft weight and balance, which can in turn make operations more efficient.

Previously, Finnair has had to rely on 2009 estimates made by the European Aviation Safety Agency, according to YLE News.

“We want to make sure we have the best possible data at our disposal also in this respect,” Suokas told the newspaper Helsingin Sanomat. “That’s why we’re collecting data from our own network.”

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Passengers' weights can also change by season, especially in a country with such extreme temperatures as Finland.

“Loads are different in the summer, for example, when people don't have their winter jackets and shoes and other paraphernalia,” Finnair's media relations director, Päivyt Tallqvist, told YLE News. “There is also a considerable seasonal difference in hand luggage weight for business and leisure travelers.”

In addition to weight, the airline will gather information about the customer's age, gender, travel purpose, passenger class and checked-in luggage. About 1,000 to 1,500 volunteers total will be needed in order to have sufficient data.

Although it may sound unusual, this isn't the first time an airline has tried to gauge the weight of its passengers. Uzbekistan Airways weighed passengers back in 2015, and Samoa Air — in a more controversial move — became the world’s first airline to charge passengers by their weight rather than per seat in 2013.