When pilots are tired or sleepy during a flight, they usually stretch, wash their face and drink lots of coffee.
However, global industry regulators said, in the interest of passenger safety, things should not be allowed to reach such a state.
It is crucial to find out what causes fatigue so airlines can better plan duty rosters, they added.
Singapore Airlines (SIA), which employs more than 2,000 pilots, has started the ball rolling, and is working with its pilots' union to collate data.
For a start, pilots will soon be asked to complete a survey form at the end of every flight.
This will seek to determine, among other things, how they ensure they get adequate rest before reporting for duty, and the periods during the flight when they feel tired or sleepy.
Like many other airlines, SIA's approach to managing crew fatigue has been to set limits on maximum daily, monthly and yearly flight and duty hours, and mandate minimum breaks within and between duty periods.
The general rule of thumb is a minimum 10 hours' rest after being on duty for under 10 hours.
For longer flights, the rest period must be at least as long as the duty time.
The United Nations' International Civil Aviation Organisation (ICAO) and the International Air Transport Association (Iata) have said in recent joint reports that setting arbitrary limits not founded on research and science is an ineffective way to manage crew.
The two associations, working with the International Federation of Airline Pilots' Associations (Ifalpa), are driving a global initiative to better understand and manage pilot fatigue. The ultimate aim is to boost safety levels.
"The traditional idea that one size fits all does not work in the real world," said Captain Amornvaj Mansumitchai, Ifalpa's Asia- Pacific executive vice-president.
Speaking to The Straits Times during a recent meeting in Singapore of the association's regional members, he added: "The current method does not take into account, for example, the time of flight departure and arrival and time-zone changes which can affect alertness levels."
SIA senior first officer Marcus Tan, an Ifalpa director and member of the Air Line Pilots Association-Singapore (Alpa-S), said: "There have been cases where guys have fallen asleep and overshot the runway. We need to learn from these incidents and find a new way to do things."
In a case of pilot fatigue in January last year, a co-pilot of an Air Canada night flight woke up from a scheduled nap and mistook the planet Venus for another aircraft.
He took the plane into a nosedive, which led to seven passengers being hospitalised for injuries. Investigations concluded that pilot fatigue was a factor that led to the incident.
Mr Tan said the aviation industry is growing very quickly, especially in the Asia-Pacific, and there will be a desire for airlines to get as much mileage as possible from their pilots. "If proper fatigue management systems are not in place, we run the risk of compromising safety levels."
Industry experts said Asia will need 185,600 new pilots over the next two decades - about 40 per cent of the global requirement.
SIA spokesman Nicholas Ionides said: "The global initiative driven by ICAO and Iata offers multilayered defensive strategies as opposed to a single layer, such as only flight-time limitations."
He added this should allow SIA to further enhance safety levels.