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Runway overrun

Print edition : Jun 18, 2010 T+T-
in Mangalore

Within hours of the May 22 crash of the Air India Express Flight IX 812 near Mangalore's Bajpe airport, Minister for Civil Aviation Praful Patel confidently announced that the pilots of the ill-fated aircraft had touched down late, well beyond the touchdown zone (the first 3,000 feet of the runway), realised the error and braked hard but could not stop the aircraft in the available distance.

The investigations may very well prove him right. But Praful Patel was probably following the old aviation dictum: after an air accident, if the pilots are alive nail them, if they are dead blame them. (A section of the airline's pilots have demanded the resignation of the Minister and that of Air India's Chairman and Managing Director Arvind Jadhav.)

He also discounted theories that the Mangalore airport, perched atop a hill with a gorge at the end of its table-top runway, was unsafe. Why did Flight IX 812 not slow down if the airport has, as per International Civil Aviation Organisation (ICAO) standards, a sanded runway end safety area (RESA) of 90 metres (295 feet) to arrest a speeding aircraft.

Says Capt. A. Ranganathan, an experienced airline instructor pilot and consultant in the field of air accident prevention, The ICAO stipulates a RESA of 120 metres and in airfields such as Mangalore, where the terrain is not conducive to a recovery, it recommends a RESA of 240 metres. This is just not there at Mangalore.

Questions about what made the Boeing 737 aircraft overshoot the runway and plummet down a cliff on a day when visibility was good, the winds were calm and the weather was fine demand answers.

Some aviation consultants, media talking heads and environmentalists see flaws in the location of the airport and its runway as the primary reason for the crash. They point to the fact that the 8,037-foot runway, its stop-way (which is the last 300 ft of a runway, and though not fit to take the weight of an aircraft during take-offs and landings is designed as a soft surface to allow a sinking down of the aircraft's tyres) and the RESA rest on hardly a length of 9,000 ft, after which there is a drop into a gorge. This, they say, gives a pilot very little room for error during an emergency.

Other experts are of the view that a runway length of 8,000 ft is robust enough not to cause alarm and feel that there was ample room for a Boeing 737 to land comfortably under almost all conditions. Nevertheless, they agree that a table-top runway with a small RESA and, worse, a gorge at the end of it does make it less forgiving should the pilot end up making a serious misjudgment during a touchdown.

Pilots who have operated from Mangalore airport opine that by no stretch of imagination can it be said that the experienced commander of Flight IX 812, Capt. Zlatko Glusica, who was familiar with the airport, would have been unprepared to pull off a table-top runway landing. But, was it too late when he tried to take control? Was there a lack of implementation of standard procedures? Was there a lack of communication between the pilots at a crucial juncture? According to aviation experts, an accident is the end result of a series of events, a systemic failure.

One of the foremost points of the investigation would be to find out who was at the controls during the approach and again during the final moments? Was it Capt. Glusica, who was known to be confident enough to allow many of his first officers to undertake a landing, especially in challenging conditions, or the first officer, Capt. H.S. Ahluwalia? And equally critically, was there a delay in Capt. Glusica assuming that he was the PNF (pilot not flying), taking over controls in the event of an emergency?

A senior Air India flying instructor said that there was always the question of pilot fatigue since it was a QTA (quick turnaround) flight and they had flown all night and through pre-monsoon weather over the Arabian Sea. This, the pilot explained, could have slowed down their reaction time. Global studies have shown that 14 per cent of air accidents take place in the early morning hours due to fatigue. Also, statistically, the hours between 2 a.m. and 6 a.m. are the most dangerous to fly in. And most Air India Express flights are scheduled at night.

Initial reports had indicated that the pilots of Flight IX 812 had tried to initiate a go around procedure (abort the landing and take off again), but did they suddenly realise that there was not enough runway length to do so and so attempted a full stop landing?

Aviation experts said that while attempting a go around there could have been a partial failure of brakes, thrust reversers (which decelerate the engine) and/or spoilers (devices on the wings that destroy the air flow/lift on the wings and, therefore, help transfer the weight of the aircraft on to the wheels, helping it to stop). Any such failure would greatly increase the landing distance required. Even a partial failure could lead to asymmetric control problems. With both engines at full power during a go around, a failure of one of them could also send the aircraft swinging to one side. Further, did the pilots, after touching down, deploy the spoilers (any failure can extend the landing distance). Attempting a go around would have required the reversers to be stored by pushing them down and then pulling the throttle forward.

Aviation expert Patrick Smith, writing on the Mangalore crash in his column Ask the Pilot for the website, wonders whether the pilots found themselves in a position where, having neglected to break off the landing when it was still perfectly safe to do so, suddenly found that there was neither room enough to accelerate to climb speed nor room enough to stop.

Other questions include a possible miscommunication between the expatriate and Indian pilots and the possibility of the light drizzle resulting in the runway, already coated with rubber deposits from aircraft tyres, experiencing the highly dangerous situation of reverted rubber aqua-planing, wherein aircraft can skid on the thin film of slippery rubber and steam.

Also, did the presence of storm clouds in the vicinity cause a severe and sudden change in wind direction and did the wind shear/microburst lead to a sudden tailwind causing the aircraft to float? There have also been questions whether the aircraft was overloaded. Air India Express pilots said that this was often the case in Gulf stations where ground staff often do not show the extra baggage weight to the pilots. This makes speed calculations go awry.

Again, were the pilots trying to make a soft touchdown instead of a firm touchdown as recommended in the books on short/critical runways? Air India pilots claimed that the management had been pressuring pilots to make softer landings as the company had lower landing G load tolerances than what Boeing recommended. Explained a pilot: The pilot of the ill-fated aircraft could have floated the aircraft as a result of this, and then touched down late, well beyond the aiming point.

According to experts, India has had a fairly good civil aviation safety record, but poor regulatory implementation, substandard hiring, inadequate training and a general attitude of complacency could spoil the copybook. India also does not have an independent regulatory body like the National Transportation Safety Board the independent agency in the United States responsible for the investigation of transportation accidents.

Ironically, while the Commission of Railway Safety, which deals with matters pertaining to safety in rail travel and train operations, works under the administrative control of the Ministry of Civil Aviation, giving it a degree of independence, investigation into air accidents is the sole prerogative of the Directorate General of Civil Aviation (DGCA). Patrick Smith writes:

The Mangalore incident highlights a particular and growingly common kind of accident: the runway overrun. A plane is landing or taking off in what seem to be manageable conditions, yet for one reason or another it careens off the runway and crashes. We've seen this several times in the past few years in Toronto, Sao Paula, Chicago, Lexington. This can be looked at in a couple of ways, one more positive than the other. On the bright side, we're seeing more runway accidents because, through vastly improved crew training and technology, we've all but eliminated most of the other kinds. What's left over are those causes that are the toughest to engineer away. There is a certain, inexorable precariousness of fate any time a jetliner is hurtling down a runway at 160 mph, and this will always be the most inherently dangerous portion of any flight...

In retrospect, a majority of these accidents turn out to have been easily avoidable, the fault of human error compounded by airport infrastructures (short runways, lack of stop-way zones, etc.) that maybe aren't as top-notch as they could be. It could be we still have some work to do when it comes to that training and technology.