Runway excursions, when an aircraft departs the end or side of the runway surface, are the most common type of business aviation accidents. Information on how to mitigate the level of risk of runway excursions can be found in the NBAA Safety Resource, Reducing Business Aviation Runway Excursions.
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Runway Excursions Overview
Most business aviation accidents occur in the landing phase, according to IBAC’s 2013 Business Aviation Safety Brief. About one third are runway excursions, making this the most common business aviation accident. Despite efforts to improve it, the worldwide business aviation excursion accident rate has changed little over the last decade, hovering around 3.6 per million flights or some 60 percent higher than the corresponding commercial aviation rate (Source: NLR Air Transport Safety Institute briefing at BASS 2013). Runway excursions are often survivable, but that does not diminish this towering safety concern. The relentless frequency of excursions—by some estimates two per week worldwide—drives a staggering annual injury and damage toll estimated at $900 million industry-wide (Source: IBAC’s 2013 Business Aviation Safety Brief). About one third are runway excursions, making this the most common business aviation accident. Despite efforts to improve it, the worldwide business aviation excursion accident rate has changed little over the last decade, hovering around 3.6 per million flights or some 60 percent higher than the corresponding commercial aviation rate (Source: NLR Air Transport Safety Institute briefing at BASS 2013). Runway excursions are often survivable, but that does not diminish this towering safety concern. The relentless frequency of excursions—by some estimates two per week worldwide—drives a staggering annual injury and damage toll estimated at $900 million industry-wide (Source: G.W.H. van Es 2010). The sting is made more acute by the fact that most excursions are preventable, based on well-identified risk factors, aircraft performance considerations and recommended defenses. Shifting perceptions and behaviors to increase the procedural adoption of approach and landing best practices in business aviation represent hard challenges still ahead.
Deficiencies in runway alignment, aircraft configuration and energy state presage runway excursions, so stabilized approach criteria are established to help pilots precisely monitor and manage those parameters. Only about three percent of business jet approaches become unstable, but the vast majority of those are continued to a landing rather than aborted. Of concern are not just the factors making for unstable approaches, but also the tacit willingness of over 98 percent of crews experiencing them to, in the heat of the moment, accept the elevated risk and land anyway (Source: FORMS/C-FOQA 2013). Reinforcing a disciplined adherence to stabilized approach criteria remains important, but so does reducing real or perceived barriers to going around if an approach becomes unstable. Accidents caused by pilots attempting a balked landing or attempting a go-around too late in the landing sequence also underscore the importance of clearly pre-identifying (and then respecting) the point in the sequence after which the crew mentally and procedurally commits to the landing.
Arriving stabilized over the runway threshold sets the stage, but the landing technique also affects the outcome. Business aviators are more likely than commercial pilots to accept tailwind approaches to facilitate routing, operate from runways of differing lengths, and land at unfamiliar airports or ones with limited means to assess and manage runway surface conditions. Consistently touching down near the aim point (1,000 feet from the runway threshold) could help counter those challenges, but business aviation norms may impede this. Whether trying to minimize the “bump” felt by passengers or lulled by landing often on runways much longer than needed, business aviators tend to carry excess speed and float into long landings. The average business jet touch down point is about 1,600 feet from the threshold, and nearly 20 percent touch down beyond 2,000 feet, well past the aim point that is the basis for predicted aircraft landing performance (Source: FORMS/C-FOQA 2013). The stopping distance forfeited can significantly increase the risk of excursion, especially when the runway has limited excess length or braking action is compromised.
A fundamental mandate exists to address runway excursions in business aviation through a multifaceted approach. Conveying the problem’s scope, improving technical knowledge of aircraft landing and braking factors, shifting operational norms to ones that mitigate rather than enable excursion risks and reinforcing key skills in training will put the runway excursion accident trend on a long-overdue trajectory to real improvement.
International Business Aviation Council Ltd.