Friday, September 21, 2018

Mumbai flight scare puzzles Kolkata pilots

Kolkata: Seasoned pilots of commercial airlines are unable to comprehend how the crew of Jet Airways flight 9W 697 from Mumbai to Jaipur forgot to switch on the cabin pressurization system when their ears would have clogged and aircraft would have falshed a warning in the cockpit.
“I don’t know how the pilots could have ignored the error. As soon as the climb begins, the pilots will themselves feel the effect with the ear drums beginning to hurt and the ears getting clogged due to the pressure surge. They will also begin to feel the heat as the pressurization and airconditioning system are integrated. After a while, they will be breathless. All this will happen in the cockpit before it does in the cabin. In addition, a caution will flash 120 seconds after takeoff. A louder warning will sound when it climbs 10,000 ft. I don’t see how two pilots can ignore them. I suspect a pressurization failure in the aircraft,” a veteran pilot said.
The pressurisation system as well as the AC in the aircraft works on bleed air or compressed air from the engines. This hot air is cooled and fed to aircraft’s environment control unit that controls the cabin’s temperature as well as pressure. When the bleed switch is off, the AC also stops functioning.
A pilot of a private airline said it wasn’t uncommon for pilots to forget switching on the AC pack immediately after takeoff, occuring in 2 out of 100 takeoffs. But in nearly all the cases, the pilot switches on the first AC pack when the ear gets clogged or the flight system sounds a caution.
21/09/18 Subhro Niyogi/Times of India