He spent a day and night in the wild, with temperatures plummeting to -35 deg C, using diapers to cover his head to prevent heat from escaping.
"The diapers were unused, of course," quipped Mr Chong Chow Wah, director of the Transport Safety Investigation Bureau (TSIB).
The gruelling training in Finland was part of an exercise to simulate an air crash in an extreme cold environment, said Mr Chong, 50, who has been an air accident investigator for more than 12 years.
Trekking under the desert sun or surviving in the Arctic is part of training for investigators to learn to deal with harsh and extreme weather conditions because air accident sites can be anywhere.
Mr Chong said: "In the wild, we were taught to make our own shelters using whatever was available including aircraft equipment, blankets, seat cushions and newspapers."
In China during a desert trek , investigators were taught how to protect themselves and their equipment against heat and fine sand. Another test they undergo is high-altitude training to experience the difficulty of trekking on high ground, and high altitude sickness which includes nausea, lack of appetite and lethargy.
The key is to travel light and carry only equipment that is necessary for investigation, noted Mr Chong.
Where possible, helicopters should also be deployed to take investigators as near to the crash site as possible to reduce the trekking distance. Otherwise, investigators would be exhausted by the time they reach the site.
After being put through such training, Mr Chong said: "I remember sitting around the fire, freezing and telling myself that I will never complain about the hot weather in Singapore ever again."