Aviation regulator DGCA Friday said that in cases of adverse weather or airport limitation, airlines must factor in the alternative destination during the flight planning stage itself.
The DGCA in a circular said in the past there have been a number of incidents, either during adverse weather conditions or due to airport limitations, wherein the operating crew has declared 'mayday fuel' for seeking priority in landing.
In a few cases after landing, the fuel available was less than the planned final reserve, it said.
Investigation of these incidents have revealed deficiencies in fuel planning, pilots' decision-making and support provided by the Air Traffic Control (ATC), the regulator said.
Therefore, it said, "During adverse weather conditions or aerodrome limitations conditions, second destination alternate should also be factored during the flight planning stage."
During its probe, the DGCA found that pilots, while deciding for an alternate destination for diversion, did not consider the "nearest landing airport".
Therefore, the regulator said that the flight dispatch must update the pilots - during transit halts - regarding weather conditions at destination airport as well as the alternate airport.
"Use of electronic briefing folder may also be considered for providing data to the (cockpit) crew," the DGCA said in the circular.
The electronic briefing folder allows pilots to access their briefing package - which consists of flight plans, weather details, maps, among others - from either the aircraft or any place outside through an internet connection.
The regulator also found that during aforesaid incidents, the pilots did not declare 'minimum fuel' call to ATC.
If pilots give a 'minimum fuel' call to an airport's ATC, it means the fuel quantity is so low that the plane has to land at that airport and no additional delay can be accepted.
The regulator's probe found that there were times when even after the pilots issued 'minimum fuel' call, the ATC did not allow immediate landing and gave "additional clearances resulting in further depletion of fuel".
Therefore, the regulator said if the pilots have given the call for 'minimum fuel', the ATC of that airport must "facilitate the early landing for the aircraft".
The DGCA said all the instructions are given in the circular "are for strict compliance by all the aircraft operators and ATC".