Almost everything that gets onto a commercial plane — fuel, checked-in baggage, cargo and meals — is weighed. For passengers and their cabin bags, most airlines use average data.

But Finland’s national carrier Finnair said Friday that it started asking passengers this week voluntarily and anonymously hop onto a scale with their hand luggage at the country’s main airport in Helsinki, the airline said Friday. The aim is to get their own figures.

“We will need data for both winter season and for summer season — in winter season people typically have heavier clothing, which impacts weights,” Finnair spokeswoman Päivyt Tallqvist told The Associated Press, adding that the survey would last until May.

Passengers boarding onto European and long-haul flights won’t be “penalized for their weight,” and “the numbers are kept discreet, away from prying eyes,” she added.