Runway Mishaps

There are lurking hazards to aircraft manoeuvring on the ground at airports and near misses are frequent. However, passengers generally remain oblivious to these. Worldwide data indicates that in the last five years, there have been reports of about three incidents every day, involving inadvertent intrusion into an active runway by a plane or a vehicle.

On February 9, 2009, at about 0900 hours, one of the helicopters from among three of the Indian President’s entourage, landed at Mumbai’s Chhatrapati Shivaji International Airport, on a runway from which Air India flight IC-866 with 150 passengers onboard was taking off for Delhi. The Commander of IC-866 aborted take-off at an advanced stage with speed nearing 200 kilometres per hour and applied emergency brakes. While the passengers onboard were safe, the tyres of the aircraft had to be changed.

In October 2012, there was a ground incident at Chennai when Air India flight AI-5184 to Jeddah was being towed towards the taxiway. Neither the driver of the towing vehicle nor the pilot noticed a ground trolley that lay on the path. The aircraft impacted the trolley, resulting in severe damage to the airframe. The flight, which was to carry 400 passengers, had to be cancelled.

There are lurking hazards to aircraft manoeuvring on the ground at airports and near misses are frequent. However, passengers generally remain oblivious to these. Worldwide data indicates that in the last five years, there have been reports of about three incidents every day involving inadvertent intrusion into an active runway by a plane or a vehicle. As per International Air Transport Association (IATA), for every 1,000 departures there is one ground incident injuring about nine people costing the industry $10 billion ( Rs. 65,000 crore) annually.

Statistics from the insurance industry indicate that when measured in terms of passenger-distance, air travel is the safest. ‘Fatality-per-mile’ basis, air travel is six times safer than road travel and twice as safe as travel by rail. However, when calculating risk-per-journey over a billion journeys, air travel is three times more dangerous than travel by car and 30 times more risky than travel by bus. In aircraft accidents between 1983 and 2000 in the United States, the survival rate for passengers was over 95 per cent. The notion that seats in the rear of the aircraft are safer has been discounted by the US Federal Aviation Administration (FAA). Safety in air travel has been achieved through strict regulation and continuous upgrade of safety equipment.

A Typical Airport

The Indira Gandhi International Airport (IGIA) at New Delhi has a passenger handling capability of 46 million per year, while it handled 35 million in 2011. Spread over 2,100 hectres, it has three runways with a complex network of taxiways connecting these to aprons. A large number of vehicular movements is undertaken to transport passengers. Safety is as relevant, if not more, for movement on aircraft operating surfaces as it is in the air. The types of vehicles plying are for transportation of crew, passengers and baggage, airport security, fire safety, in-flight catering, aircraft maintenance, towing of aircraft, alighting ladders, fuel bowsers and works services. The movements of these vehicles as also personnel on foot, frequently conflict with aircraft operating on taxiways.

Aircraft operating from various aprons have to adhere to complex ground routing, often funneling towards a common aircraft departure holding point and sometimes in near zero visibility conditions. Often, there is reciprocal traffic in close proximity to each other. Movement on the ground is thus a high-risk exercise with scope for error. Although there is close control of movement of aircraft and vehicles on an airfield, statistics indicate frequent conflict in traffic with high incidence of near miss and sometimes collision.

Another factor in the game especially at Indian airports is the nuisance caused by stray animals such as dogs, cattle, deer, wild boars, snakes, jackals and monkeys, posing a threat to air safety. Hyenas have often forced closure of IGIA. In 2008, an Air India flight narrowly escaped an accident when it hit a blue-bull while landing at Kanpur airport. Birds also affect ground/air movement especially during take-off and landing. At any given time, there is at least some construction work going on in some part of every major airport. Often, parts of the runway are under resurfacing at times entailing displacement of the landing threshold. Construction means additional vehicular traffic, labour and foreign objects. Weather such as rain, snow and sleet also affect landings and could lead to aircraft skidding off the runway. There is thus the need for overrun areas and clear runway shoulders. The Coir Board of India has proposed innovative carpeting of runway shoulders and overruns with coir pith to slow down the aircraft, should it go off the runway.

Increased Frequency

Increasing traffic density exerts its own pressures. Gap between landing aircraft has reduced from six to two nautical miles at some modern airports which are now able to handle 100 flights an hour. While this enhances risk, it also results in higher rate of aborted landings. While systems have been designed for safety in operations in the air, the same level of attention has not been devoted to ground operations. Ground incidents are often due to a combination of factors such as heavy traffic, limited visibility and human error by aircrew and air traffic controllers.

As per a FAA study, the main reasons for runway incursions are lack of clear communication between controllers and cockpit crew and unfamiliarity with airport layout; 44 per cent are due to lack of positional awareness. There have been incidents of takeoff from the wrong or reciprocal runway. Firms such as Honeywell have come out with new air traffic management technologies which help maintain separation at crucial time of taxi, takeoff and landing. Enhanced ground proximity warning systems (EGPWS) used on approach to landing gives audio and visual warnings in the event of deviation from glide path. Electronic display of airport layout in the cockpit helps ground navigation. Several airports have now installed radars to monitor movements on the ground. Airfields now have warning lights to prevent inadvertent incursion into the active runway.

While new technologies have helped reduce the number of serious ground incidents, clearly more needs to be done. Generally, airplanes are responsible for runway incursions. However, ground vehicles also contribute to this problem. James M. Burin of Flight Safety Foundation says that congestion will keep increasing the risk of collision. One pilot landed on a taxiway mistaking it as the runway. Who can forget the deadliest accident of 1977, when two Boeing 747s of Pan Am and KLM collided on the runway at Tenerife airport, killing 583 passengers? On May 22, 2010, Air India Express Flight 812 while landing at Mangalore, overshot the runway, fell off the cliff and crashed into the valley below. This third-most deadly aviation disaster of India resulted in 158 fatalities.

As per an Australian study, the period 1998-2007, had 141 runway excursion accidents resulting in 550 fatalities. Of these, 120 occurred during the landing phase—71 per cent cases were attributable to flawed decision-making by the flight crew, faulty technique and weather. Unsteady approach, landing at too high a speed, insufficient braking, not opting for missed-approach, fatigue, task saturation, wet runway, excessive tailwinds or crosswinds have been some of the reasons for such episodes.

Safety First

In 2007, due to the concerns of Air Line Pilots Association, FAA revisited the entire runway safety programme. Runway/taxiway markings and signage are being reviewed, additional ground radars are being installed and mandatory permissions before crossing any runway have been introduced. A new runway status lights system is under development which is to be operational by 2016 and the incident reporting system is being revised. The Atlanta airport built a taxiway that goes around the runway thus reducing 600 runway crossings a day.

Airports the world over are trying to identify high-risk hotspots and cautioning pilots and vehicle operators. Pilots are expected to act as safety backups to controllers. Many countries have introduced the local runway safety action teams (LRSAT). Standardisation of radio phraseology at runway entry points has also reduced ambiguity. Checklists for pilots for airfield procedures have been revised. Taxi speeds are being monitored and warnings instituted. Runway holding points have been moved farther back. All aircraft cleared to take-off are required to switch on landing lights to indicate their status to other aircraft.

Similarly, best practices have been introduced for controllers. Their awareness about the aircraft is being increased; they are asked to must have a plan ‘B’ for every situation; must keep runway crossings to the minimum; must be very conversant with the weather; listen attentively and speak clearly. Training packages to foster teamwork between pilots and controllers have been evolved. Training and education packages for vehicle operators have also been put in place. They are expected to have manoeuvring area charts in vehicles. Use of roads in place of taxi tracks is encouraged wherever available. Speed restrictions, vehicle lights and monitoring ground radio channel are covered during daily briefings.

The Indira Gandhi International Airport at New Delhi is gearing up for 100 million passengers a year. Air is going to be the popular medium of travel in the future. Runway and ground accidents are highly avoidable. It is time to act and exercise greater control. This calls for greater situational awareness for anyone on an aircraft operating surface.