The recommendation by Singapore's civil aviation authority that all local carriers must have at least two people in the cockpit at all times is being reviewed, The Straits Times has learnt.
It follows feedback from airlines and industry studies that have found few benefits in the practice.
The Civil Aviation Authority of Singapore (CAAS) is working with Singapore carriers to review the recommendation it made last year.
Though not compulsory, it has been adopted by all carriers here, including Singapore Airlines (SIA).
Singapore was one of several countries to introduce the policy last year after a Germanwings co-pilot - later discovered to have suffered from severe depression - locked his captain out of the cockpit and crashed an Airbus 320.
The two-person policy aims to enhance safety by ensuring that a pilot is never left alone, for example, if the other pilot has to step out.
But because short-haul flights typically have just two pilots on board, and on longer flights the third pilot is usually taking a break when the other two are flying, it is usually a cabin crew member who ends up in the cockpit when one pilot walks out.
With no, or perhaps little, knowledge of flight operations, there is not much the cabin crew member can do if the pilot has malicious intentions, some observers say.
The European Aviation Safety Agency (EASA) has suggested that there are better ways to prevent a repeat of the crash in the French Alps in March last year. The key is for airlines to focus on pilots' mental health, and to have in place processes and procedures to ensure troubled pilots are detected early and given the necessary support.
The European safety authority has made some recommendations, which it hopes will be implemented globally, to the International Civil Aviation Organisation (ICAO) - the United Nations' civil aviation arm.
These will be discussed at the ICAO's assembly, which kicked off on Tuesday and will end on Oct 7, in Montreal, Canada.
Among the recommendations, the EASA is pushing for mandatory drug and alcohol testing for all new pilots. It also wants countries to ensure that pilots undergo compulsory aptitude and psychological tests.
Peer support groups for pilots should also be compulsory, it says.
Singapore is aware of the recommendations, and a CAAS spokesman said that while there are currently no regulations for mandatory drug and alcohol testing, aptitude and psychological testing, and peer support groups, the CAAS will take into consideration the recommendations.
All Singapore carriers already have "strict policies and procedures for alcohol consumption and zero- tolerance policies for drug abuse".
They also have aptitude and psychological testing as part of their selection process for pilots.
"Most of our airlines have peer support groups," she said.
SIA spokesman Nicholas Ionides said the airline has a "comprehensive psychological support framework" which involves trained peer counsellors, an aviation psychiatrist and psychologist, and the Civil Aviation Medical Board. This is to ensure flight safety and the mental well-being of pilots, he said. "This support structure has been in place for the last 10 years and, in that time, pilots have been helped."
Budget carriers Scoot-Tigerair and Jetstar Asia say they also provide similar support for their pilots.
