Domestic airlines have denied dumping human excreta mid-air. Days after the National Green Tribunal (NGT) ordered a fine of Rs. 50,000 on airlines emptying toilet tanks in the air, they said modern aircraft are not designed to do so.
They said the lavatory waste is stored in a tank inside the aircraft. It is cleaned by the ground crew only after the plane lands.
Dumping of waste during the flight may happen rarely due to leakage. Some aviation experts said it was not possible for a pilot to dump a tank while in flight, as there were no controls inside the aircraft for doing this.
“After every flight, when the aircraft is parked at the parking bay, the lavatory waste is drained and the waste tank is pressure cleaned via documented process using equipment specific for this purpose,” Kamal Hingorani, senior vice-president and head, In-Flight Services and Customer Experience at SpiceJet, told The Hindu in an e-mailed response.
He said it took about eight minutes for the entire procedure, adding the water tank is pressure sealed in flight and “there is no possibility of any leak or inadvertent release of water in flight.”
AirAsia India said its Airbus A320, by design, cannot dump lavatory waste while landing or during the flight.
“Our lavatory waste draining and disposal is outsourced to Globe Ground India (GGI). It collects the waste from the aircraft and dumps it in the airport’s designated waste dumping location,” an airline spokesperson said.
A Vistara spokesperson said the airline follows the Aircraft Maintenance Manual, according to which waste is to be emptied into specialised carts.
“All necessary health, environment and safety procedure are taken while carrying out these activities,” the spokesperson said, adding that emptying toilet tanks is not possible mid-air in modern pressurised aircraft.
Jet Airways said ‘blue ice’, a term used for frozen sewage material leaked mid-air, as a “rare occurrence” which signifies “a leaking toilet system, leading to the formation of ice in high altitude.”
The airline conducts standard checks that include removing the waste from the aircraft and taking it to the designated place after every flight, a spokesperson said.
In its order, the NGT had asked the Directorate General of Civil Aviation (DGCA) to issue a circular to all airlines using the Delhi airport to ensure that they do not release any waste while landing or taking off at the airport or near it.
It also asked the aviation regulator to impose an environmental compensation of Rs. 50,000 per violation of the circular and submit a quarterly report to the tribunal.
The petitioner had told the court that excreta fall on houses near the airport due to “evacuation of the aircraft toilet canisters while flying.”
“There is one exterior lever outside the aircraft and only the ground crew can operate the valve that opens the tank while the plane is on the ground,” said Bimal K. Srivastava, retired General Manager at Airports Authority of India, who has done extensive research on ‘blue ice.’ He added that “under no circumstances” can a pilot empty the storage tank during the flight.
