It was early morning on the 17th anniversary of 9/11—a grim reminder to the horrors of terrorism. As most New Yorkers were getting ready to start their daily chores on 11 September this year, a long-range Boeing 777-300 with 370 passengers was approaching John F. Kennedy International Airport (JFK). The Air India plane—the world’s largest twin-engine jet—was in the final leg of a 15-hour non-stop flight using the Polar route over Pakistan, Afghanistan, Russia, Finland, Greenland and Canada.

On the controls were two pilots along with two co-pilots. It included a seasoned Air India pilot who had to draw on all his skills to thwart what would have been another catastrophe on 9/11. As the Boeing aircraft neared about 14 miles to JFK in what so far was a normal flight, the cockpit suddenly erupted with sounds and lights of varied colours. The pilots soon discovered Air India 101 was in the midst of multiple system failure.

The next 38 minutes were one of the tensest moments for Indian aviation as human skills came into play to overcome failure of machines. Eventually, the plane landed safely, but after being diverted to another airport, Newark (Newark Liberty International Airport) in New Jersey. “This kind of failure is very rare. But, when it happened, it’s good that Air India had an experienced captain to handle this. A raw hand wouldn’t be able to handle this," said captain Mohan Ranganathan, former airline instructor pilot and a safety expert.

Air India is conducting an internal investigation into the incident. The report of the investigation, which will not be made available publically, should be out shortly, said an airline spokesperson.

A senior Air India official, who spoke to Mint on condition of anonymity, said engineers had deemed the 777-300 fit to fly to New York. “We can only speculate the reasons that could have led to this kind of multi-instrument failure. We are investigating the issue and will take action," the official said.

National Transportation Safety Board (NTSB), an independent US government accident investigation agency, is likely to investigate the incident as well. NTSB did not respond to an email seeking comments.

Four minutes from JFK

The skies over New York were overcast and the cloud ceiling was just about 200 feet. For any other aircraft, whose systems were running perfectly, it wouldn’t have been a problem. Inside the cockpit were commander Rustom Palia, and first officer captain Vikas, as well as captain Sushant Singh and captain D.S. Bhatti, the second set of pilots. The protocol required the four pilots, incidentally all from Mumbai, to be present in the cockpit during landing.

Captain Palia and his team, while doing an approach for the airport, realized that the Boeing’s Instrument Landing system (ILS) had gone kaput, while it was about three to four minutes from the airport. The TCAS (Traffic collision avoidance system), a system designed to reduce mid-air collisions, had also failed.

ILS helps guide pilots while landing a plane especially when they are unable to establish visual contact with the runway especially during a cloudy or foggy day.

ILS consists of two parts. While the ‘localizer’ helps guide to the centerline of the runway once the plane is locked on to it, the ‘glide slope’ brings it down on a descent profile. As the Air Traffic Controller (ATC) at the JFK cleared AI 101 to go on to the localizer for the landing approach, captain Palia and his crew realized that the localizer was not captured on the aircraft’s systems.

“We were basically going blind," said captain Palia.

While approaching JFK, the pilots realized that the Boeing’s landing system had gone kaput—just three to four minutes from the airport -

As the cloud base was close to 200 feet, captain Palia and crew couldn’t use a non-precision approach, or a landing that doesn’t utilize electronic glide path guidance. A non-precision approach using Lateral Navigation (LNAV) and Vertical Navigation (VNAV), which takes data from GPS (global positioning system) to know the location of the aircraft, was not an option since it required a much higher cloud base of 650-700 feet.

The crew also noticed flash warnings about some problem with the landing gear, which fortunately turned out to be a false alarm.

As AI 101 continued and stabilized on its approach, the crew decided to do a ‘go around’ of JFK as it was too risky to land with a non-functioning ILS with a cloud ceiling of 200 feet. “The ATC asked us to do an auto landing (using ILS), which we said was not an option," captain Palia said, adding, “In the meantime, we were trying to figure out alternate airports with a better cloud base for landing."

A problem with fuel

The pilots were now faced with another serious issue: fast depleting fuel. After its non-stop flight from New Delhi, the plane was left with about 7.3 tonnes of fuel, or one hour of fuel, after executing a ‘go around’, which burnt as much as two tonnes of fuel. An aircraft flying at lower altitude consumes more fuel than one flying at a higher altitude.

The pilots were constantly seeking latest weather updates from the ATC at JFK to decide on an alternate airport nearby for landing. Suggestions were offered for a few alternate airports, with a higher cloud base, which, however, had to be left out with fuel stocks running low. “After such a long flight, we just had fuel to reach our primary alternate, Newark, and the secondary alternate, Stewart (New York Stewart International Airport), and half an hour of holding fuel," captain Palia said.

Meanwhile, AI 101 was separated from other traffic, while the pilots started to urgently work on the issue. “We needed an airport with cloud base of over 600 feet to do an approach using LNAV and VNAV. At that point, when we were deciding what to do, ATC told us that there is nothing in the vicinity with cloud base over 600 feet," captain Palia said.

While the pilots worked upon the best course of action, captain Palia did consider other options like using RNAV (utilizing GPS that enables a pilot to guide his aircraft to a landing in low visibility situations) but the pilots didn’t have any time to go through the charts with low fuel and fatigue also setting in. “Options of doing other approaches played in my mind, but it didn’t come up in our discussions since the stress was too much and we were already under fatigue after flying for 15 hours," said captain Palia.

Head to Newark

The pilots continued to seek the ‘latest’ weather report from ATC who informed them that the cloud ceiling at Newark airport, which is about 51.5 km away from JFK airport, had risen to 400 feet from 200 feet earlier. The pilots decided to take the option. “Ideally we would have liked the cloud ceiling to be at 700 feet. But, then 400 feet was better than 200 feet, and at least we could see something and align our aircraft (to the runway)," said captain Vikas. They, however, faced the challenge of aligning the aircraft to the centre of the runway at Newark. The 777-300 weighs more than 158 tonnes (when empty), and therefore needs to be adjusted precisely or can overshoot the runway.

The pilots had earlier, during AI 101’s second approach to JFK, realized that the three radar altimeters had stopped functioning.

“It is quite unheard of, the failure of three radar altimeters at the same time," captain Palia said. A radar altimeter measures altitude above the terrain presently beneath an aircraft by timing how long it takes a beam of radio waves to reflect from the ground and return to the plane. These instruments kick in when an aircraft is below 2,500 feet.

“It was an out of box situation. We needed some guidance, so we decided on the LNAV and VNAV approach, which we hadn’t done before," captain Palia said. Though the aircraft’s LNAV was working fine, which the pilots figured from their previous approach for landing, they were happy to see the aircraft’s systems were able to lock on to the VNAV path. “Now, we knew, we were safe height wise. We were about 2,000-3,000 feet high when we locked in from VNAV," captain Palia added.

However, at about 1,000 feet, while making the approach for Newark, the pilots lost the aircraft’s VNAV path. “This thing was happening very fast, when we made about three miles arch across our final approach," captain Palia said. “Now we were not following the path, and we were going too high. So, we used something called vertical speed which would increase our rate or speed of descent, from 800 feet per minute to 1,200 feet per minute," he said.

Meanwhile, the passengers and cabin crew were blissfully unaware of the crisis unraveling in the cockpit. They were only informed that the plane was being diverted to Newark due to some technical issue.

The final descent

“As we started descending faster, our speed started going up. This speed had to be brought down, as the aircraft put its nose down," captain Palia added. This is when the commander decided to switch from auto-pilot to manual mode, to bring down the speed of descent and land the plane. “But, when you can’t see anything you can’t just put the nose of the aircraft down. You got to gently come on the path and the aircraft got to slow down so to use the flaps, which is basically what happened," captain Palia said.

While making the descent, the pilots had the cloud base at Newark at 400 feet overcast and 200 feet broken, which meant that pilots could see through the cloud at 200 feet. The cloud situation was clearing but it wasn’t fully clear. The aircraft’s precision approach indicator, which shows two white lights and two red lights if aircraft is on correct path, showed all white lights, which meant that the aircraft was still too high on the path. The pilots had to quickly align the aircraft while it was on a descent with its nose down.

The passengers and cabin crew were unaware of the crisis unraveling in the cockpit. They were only told that the plane was being diverted -

“While the radio altimeter was not functional, the aircraft system had auto-callouts, which told us the distance from the ground—100 feet, 50 feet, 40 feet, 30 feet, 20 feet, 10 feet—till the time we touched down," captain Vikas said. The pilots were sitting in the cockpit which is about two storied high. “I could see the runway, so used my judgment and landed the plane," captain Palia said. “Once we saw the runway, we took control of the aircraft and did a safe landing. We were aligned to the centre while landing," captain Vikas added.

About 15-20 minutes after the 777-300’s engine was switched off, it started pouring at Newark. “We had a very small window (to make the landing). Had it rained 20 minutes earlier, the outcome could have been different," captain Palia added.

Both pilots attributed the successful landing of the massive jetliner to teamwork with pilot eye-balling any critical move of the other. “The teamwork built up a lot of confidence. At least, I know if I did some sort of mistake, it was immediately pointed out," said captain Palia. He said failure of multiple instruments as seen on 11 September is rare. “It’s an extremely safe machine. And, if the weather was fine, there would have been no problem as the aircraft engines were perfectly fine," said captain Palia.

“We do a lot of manual landing, but not in such weather conditions, and not with this combination, failure of radio altimeter, ILS and TCAS along with the low cloud cover," he added.

“The four Air India pilots did a terrific job to land the plane amidst such a challenging situation," says an aviation analyst who did not want to be identified. “But, we are still in the dark about the reasons that led to multiple instrument failure. If Air India wants to be prudent, it needs to investigate this case thoroughly," he added.

As the four pilots trudged their way to the hotel, they began to realize how they had just averted a big disaster. None of the pilots onboard AI 101 had faced such a situation—even in training simulators. “We are taught to act and not think in situations like this," said captain Palia.

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