With many of the systems malfunctioning, the pilots showed a lot of skill to land the aircraft safely
Senior Commander Rustom Palia and second-in-command Captain Sushant Singh would have been looking forward to a hearty breakfast and a well-earned rest. They were preparing to land their Air India flight AI-101 at New York’s John F Kennedy International Airport on September 11, after a 15-hour journey from New Delhi, one of the world’s longest flights.
But what looked like a normal landing, turned out to be one of the worst nightmares for the two pilots.
To their dismay, the instrument landing system (ILS) of the Boeing 777-300 aircraft was malfunctioning. That's not all. “We have a Traffic Collision and Avoidance System failure,” Palia informed the Air Traffic Control in New York. TCAS prevents mid-air collisions between aircraft and was instrumental in preventing a collision between two IndiGo aircraft in July.
Other systems like auto-land, wind shear systems, auto speed brake and the auxiliary power unit were also 'unserviceable'.
The ILS plays a critical part in ensuring a safe and smooth landing. “One of the reasons ILS is important is because human beings respond faster to a visual than an oral instruction,” says Mohan Ranganathan, a former pilot turned aviation safety consultant.
Localiser and glidepath are two important parts of the ILS. While localiser gives the lateral part of the course, glidepath tells pilots if they are at a correct height. Both are included as an indicator in the cockpit. “As the needles move, the pilot can move left or right (localiser) or up and down (glidepath),” Ranganathan said.
The precision provided by the ILS is important to time the landing perfectly and safely. It comes in handy when the weather is not conducive and visibility below normal. In such conditions, ILS is important because even without normal visibility, pilots can know where to turn and adjust the height by looking at the ILS.
In the case of AI-101, besides the ILS indicators not working, visibility at the John F Kennedy airport was not good enough for 'non-precision landing'. Fuel supply was running out, putting in danger the safety of 370 passengers on board.
“This multiple system failure is a rare occurrence. There would be just 2 or 3 such instances in the last 25 years,” Ranganathan said, adding that the most probable culprit would be battery failure, rendering all these systems unusable.
Rustom and Singh though were up for the task. Experts said rarely are pilots trained for a non-precision landing, something that the two Air India pilots were now going to attempt. They received clearance to land at the Newark airport, where visibility was better.
Now, instead of banking on an automated system which uses ILS for landing, Palia had to use ground beacons and aircraft equipment. A lot of skill, including a correct judgment of height and movement, is required of a pilot undertaking a non-precision landing.Finally, after nearly 40 tension-filled minutes, AI-101 landed at Newark airport. “The experience and expertise of our cockpit crew came to the fore and they landed safely at an alternate airport at Newark,” Air India said in a statement.