Airlines don't dump waste mid-air, say experts

Modern aircraft have vacuum toilets and suction pumps drain the waste from toilets

After the National Green Tribunal's (NGT's) directive to Directorate General of Civil Aviation (DGCA), aviation experts clarified that Airlines do not dump waste from aircraft mid-air and poop falling from mid-air could be due to a leak.  Aircraft cockpits do not have switches to drain toilet tanks and such leaks are highly unlikely in modern aircraft, they added.

Yet regulators around the world have been receiving complaints of mid-air dumping and the NGT on Tuesday directed the DGCA to ask all the airlines to not dispose waste mid-air. A bench headed by NGT Chairperson Swatanter Kumar also asked the DGCA to impose a fine of Rs 50,000 on the airline, if any flight is found violating directions.

"In a  Boeing 737NG or A320, for about 160 to 180 passengers there is between three and four toilets and the waste accumulated in the aircraft waste management system is disposed off after landing into a lavatory service truck that connects directly into the aircraft. It is technically unfathomable to dump ‘raw-aircraft-sewage’ mid-air in flight," said aviation consultant Mark Martin.

Modern aircraft have vacuum toilets and suction pumps drain the waste from the toilet to the toilet tank inside the plane.

In older aircraft (like older Boeing 737s, Airbus A300s or A310s) airlines used a blue coloured liquid to flush toilet waste to the tanks. This system was prone to leakage and the leaked substance came to be described as blue ice.

Now modern aircraft toilets do not have the blue liquid and drainage is controlled through an electrical system which activates only when an aircraft is on ground. A leak is unlikely, even if the toilet service panel on an aircraft fuselage gives away for the same reason, a retired aircraft maintenance engineer said.

"In Boeing 787 and the Airbus A350 planes there is a  waste treatment system that ensures that the aircraft at least ‘partially’ treats its sewage prior to release as most aircraft sewage includes paper and other non-biodegradable material," Martin said.

Questions are also being raised on how the order will be enforced. "Dumping of waste from mid-air is not possible.  But, the question is how will the DGCA enforce the order. How will it ascertain if an aircraft dumped waste mid-air," said Shakti Lumba, retired operations head of IndiGo.

In 2011, the Civil Aviation Authority (CAA) of New Zealand released a report after probing complaints of countryside homes being splattered with frozen waste. The samples were taken to check if there were traces of any chemical used to clean airline toilets. The report found that the splattering waste was not related to aircraft.