Runway incursions and major aviation disasters: causes and prevention

Runway Incursions That Lead to Accidents

The objective of this study is to examine runway incursions that lead to accidents such as the Tenerife airport disaster, U.S. airways Flight 149, Madrid Runway Disaster and Madrid Runway disaster as well as Linate Airport disaster. Toward this end, this study will examine the literature in this area of inquiry which includes such as the 'Runway Incursion Joint Safety Analysis Team' (JSAT) report; the International Civil Aviation Organization 'Manual on the Prevention of Runway Incursions', as well as other pertinent and relevant studies. This study will attempt to disseminate the available information on prevention of runway incursion and to report on the same in the findings of this study.

Introduction

Runway incursion accidents that involve general aviation aircraft and air carriers are reported to be a rare occurrence. Landsberg (1998) reports that in 1994 "A Cessna Conquest II taxied onto the wrong runway in St. Louis and was flattened by a TWA airliner on a night takeoff. A Beech King Air was not clear of a runway in Atlanta when it was struck by a Boeing 727 in the early 1990s. The granddaddy of all runway incursion accidents was in Tenerife when two loaded Boeing 747s collided in the fog" (p.1) Landsberg additionally reports that the FAA "…has become very interested in runway incursions recently because GA pilot deviations are on the rise and have been for several years. The most recent numbers show an increase of almost 19% from 1995 to 1996; deviations are up almost 30% from the prior eight-year average. It would be comforting to report that GA flight operations are also up, but according to the FAA, they have not increased significantly. According to the inspector general of the Department of Transportation, GA is responsible for roughly 71% of the aircraft incursions, yet accounts for only 59% of the flight operations at towered airports." (1998, p.1) General Aviation aircraft are reported to be responsible for more runway incursions than are other aircraft, however historically air carriers have had more runway incursion related accidents." (Landsberg, 1998, p.1) Landsberg reports that the primary cause of the General Aviation pilot incursions was "inadequate knowledge or experience with ATC procedures and language. The second most identified problem was inadequate knowledge or experience with the airport. (1998, p.1) According to Landsberg, the reason that runway incursions must be addressed during both initial and recurrent training includes: (1) Taxi operations and radio procedures are also spelled out for testing in the Private Pilot Practical Test Standards; (2. There will probably be a higher level of enforcement action directed toward runway incursions; and (3) Additionally, in the very unfortunate event of a GA-airline collision where GA is at fault, there could easily be severe restrictions placed on our flight activities." (Landsberg, 1998, p.1)

International Civil Aviation Organization Report

Reported as common scenarios in which runway incursions are known to occur are the following: (1) crossing landing aircraft path by aircraft or vehicle; (2) aircraft/vehicle crossing path of aircraft taking off; (3) runway-holding position marketing crossed by aircraft or vehicle; (4) inadvertent enter into active runway by aircraft or vehicle unsure of its position; and (5) communications breakdown resulting in failure to follow air-traffic control instruction. (International Civil Aviation Organization, 2007) Communication factors resulting in runway incursions include the use of phraseology that is nonstandard; failure of readback of instruction accuracy on the part of pilot or driver of vehicle; (3) controller's failure to ensure that the readback given conforms with issues clearance; misunderstanding of instructions of controller by pilot or vehicle operator; transmissions blocked fully or in part; and complex and lengthy transmissions. (International Civil Aviation Organization, 2007) Reported as common scenarios in which runway incursions are known to occur are the following: (1) crossing landing aircraft path by aircraft or vehicle; (2) aircraft/vehicle crossing path of aircraft taking off; (3) runway-holding position marketing crossed by aircraft or vehicle; (4) inadvertent enter into active runway by aircraft or vehicle unsure of its position; and (5) communications breakdown resulting in failure to follow air-traffic control instruction. (International Civil Aviation Organization, 2007) Pilot related airway incursion factors are inclusive of signage and markings being inadequate, instructions issued by controllers as the aircraft is rolling out following landing during a time when cockpit noise is extremely high and pilot workload very heavy; head down tasks performed by pilots which are mandatory but which reduce awareness of the situation; capacity enhancement procedures resulting in pilots being pressed and rushing; complex airport designs requiring runways to be crossed; information that is incomplete and non-standard on taxi routing; and finally, last minute changes by ATC in taxi and departure routings. (International Civil Aviation Organization, 2007) Cited as air traffic control factors are: aircraft, runway closure, vehicle on the runway, clearance that had been issued failing to anticipate the required "separation or miscalculation of the impending separation or inadequate coordination between controllers, a cross clearance issued by ground instead of air/tower controller, aircraft misidentification on location, controller failure to give correct readback on another controller's instructions; controller failure to ensure that the pilot readback conforms with issued clearance and finally, communication errors, too lengthy instructions, use of non-standard terms and reaction time reduced due to on-the-job-training. (International Civil Aviation Organization, 2007) Cited as other common factors that can be attributed to air traffic control factors are those of distraction, workload, experience level, inadequate training, lack of clear sight lie from control tower, human-machine interface, and handover between controllers being incorrect or inadequate. (International Civil Aviation Organization, 2007) Cited as well are airside vehicle driver factors such as failure to obtain runway clearance and comply with ATC instructions and aerodrome design factors including airport layout complexity, insufficient spacing between parallel runways; departure taxiways that fail to intersect active runways at right angles; and no end-loop perimeter taxiways to avoid runway crossings." (International Civil Aviation Organization, 2007) Briefing checklists are cited in the International Civil Aviation Organization report that include the need to conduct a briefing for flight crew members and to become familiarized with the aerodrome as well as plan timing and execution of checklists, review NOTAMs, ensure that the flight crew fully understand all departure briefing items, ensure that the briefing on the assigned taxi route is as thorough as that of the instrument approach, and ensure that the aerodrome diagram is readily available to all flight crew members." International Civil Aviation Organization, 2007)

Williams (2008)

Williams (2008) investigates such accidents and states that there are findings that show the following specific factors to blame for runway incursions:

(1) multiple entry points used increasing the risk of runway incursions since more points for possible conflict of traffic result as well as workload increases for aerodrome controllers;

(2) Risks are increased further by use of angled taxiways for entry into runway, which limits the view of the pilot on the threshold of the runway and other aircraft;

(3) radio transmissions that are crossed are a contributory factor to runway incursions;

(4) Line-up and take-off that are delivered rapidly as well as clearances for take-off by controller and rapid pilot compliance in addition to pressure applied toward minimizing occupancy times of runway;

(4) Failing to transfer control of an aircraft departing from ground to aerodrome controller until the aircraft is near the runway holding point which resulted in a reduction in situational awareness of controllers since less time was available for review of details of aircraft and of pilots who had a reduced time available to listen to the frequency of the Tower prior to entering the runway;

(5) Conditional clearance in the absence of a confirmation that the pilot acknowledged the conflicting traffic as a great risk in use of angled taxiways for runway entry; and (6) Failure to know rate of runway incursions due to inaccurate data being kept and analyzed resulting in no standard definition for runway incursion. (Williams, 2008)

The International Civil Aviation Organization published its Manual on the Prevention of Runway Incursions" in 2007 and states that several U.S. states along with international organizations have developed extensive programs geared toward the reduction of runway incursion risks. There are several recurring scenarios cited in the manual for incidents involving runway incursions including: (1) when an aircraft or vehicle is crossing on front of an aircraft that is landing; (2) when an aircraft or vehicle crosses in front of an aircraft that is taking off; (3) when an aircraft or vehicle is crossing the runway-holding position marking; (4) when an aircraft or vehicle is unsure of its position and accidentally enters a runway that is active; (5) when a breakdown in communications occurs resulting in a failure to follow the instructions of air traffic control; and (6) when an aircraft passes being an aircraft or vehicle that has not left the runway. Runway incursions can be avoided through use of technology applications including technology that serves to raise situational awareness. Heads-up guidance systems (HGS) can also be useful. HGS is a graphic cockpit display that includes taxi route and clearance limit in addition to a device that alerts and warns about deviations. Traffic situation displays including air/ground conflict information should be developed and installed by airlines, manufactures, and operators as well as should anti-blocking technology for voice communication. (Runway Incursion Joint Safety Analysis Team, 2000, paraphrased) It is advised that regulators and operat5ors install lighting that better marks the runway exist and taxi route and that visual aids that are not ambiguous should be installed to provide a signal of clearance for entering a runway that is active. The FAA is advised to require that SMGCS be implemented at airports during operations in conditions of low visibility and that runway-vacated guidance be installed at airports. (Runway Incursion Joint Safety Analysis Team, 2000) Included among interventions focused on reduction of runway incursions are such as airlines and operators ensuring that "command oversight training is provided for captains" and that they "encourage a culture that emphasizes safe arrivals over timely arrivals." (Runway Incursion Joint Safety Analysis Team, 2000 ) Suggested as well is that a system be implemented that will provide automatic transmission of instructions and information between the aircraft and the ground controller. Airlines operators and service providers should "implement transmission of instructions and information between the aircraft and the ground via a computer rather than through voice communications

Findings and Conclusion

This study has examined the occurrences of runway incursions and how these accidents occur and has found that many of the accidents could be avoided quite easily and are due to lack of communication, failure to understand communications, condition clearance confusion, angled taxi lanes, failure to transfer aircraft control from ground to tower quickly enough, and predominant in the studies reviewed is the factor of 'haste'. The variations in the design of aerodromes also results in confusion leading to runway incursions. There have been a great many recommendations made by various committees that would assist in the prevention of runway incursions. This study has been too brief to report on all the problems that result in runway incursions or to report on all the solutions and interventions that have been cited to prevent the problem of runway incursions. However, it has been noted in this study that poor communication between the ground and tower are one cause of runway incursions and in fact incidents on the ground are the primary cause of runway incursions which can be avoided through use of technology and communication applications and which should be implemented at all airline locations.