Cabin pressure in Jet flight drops as pilots fail to switch on

As many as 111 passengers onboard a Jet Airways flight from Leh to Delhi had to face breathing problem momentarily as the pilots allegedly failed to switch on the auxiliary power unit (APU) which led to drop in cabin pressure.
The airline had grounded the commander and the first officer, who were operating the flight, till a probe by the Directorate General of Civil Aviation (DGCA) was over, sources said, adding that acting tough, the civil aviation regulator had withdrawn the trainership of the commander.
The incident took place on July 7, when Jet Airways flight 9W-2369 from Leh was getting ready to depart for Delhi.

The pilots allegedly forgot to switch on the APU, which is mandatory for flights operating from Leh, resulting in sudden drop in cabin air pressure which led to deployment of oxygen masks for the passengers, they said.
When contacted, a Jet Airways spokesperson confirmed the grounding of the two pilots but did not comment on the DGCA action against the commander.
"The matter is currently under DGCA investigation. As per standard procedure, the crew (does not undertake flying duties) to facilitate the investigation," the spokesperson said in a statement.

Sources also said all passengers had be deboarded as the oxygen masks were deployed and another aircraft was dispatched from Delhi to Leh to fly them back.

An APU is used to run accessories while the planes engines are shut down. It allows the cabin to remain comfortable while the passengers are boarding before engines of the aircraft are started.
APUs fitted in an extended-range twin-engine operations (ETOPS) aircraft are a critical safety device, as they supply backup electricity and compressed air in place of the dead engine or failed main engine generator.
It is regulatory requirement for an aircraft to have a functional APU while operating flight to Leh, and it has to be kept on while on ground and taking off from this high altitude airport, a pilot said.