Inside the NTSB’s General Aviation Investigative Process

By Member Earl F. Weener

This is the first in a new series of posts about the NTSB’s general aviation investigative process. This series, written by NTSB staff, will explore how medical, mechanical, and general safety issues are examined in our investigations. I hope you take time to read these posts and, in doing so, come away with a greater understanding of the NTSB, our processes, and our people.

It has been my ongoing honor and privilege to serve as a Member of the NTSB over the past seven years, and I’ve been impressed by the diverse professionals who make up the NTSB staff. They work in different modes—rail, highway, pipeline, marine, and aviation—and specialize in engineering, human factors, medicine, safety outreach, and recorders, to name a few, but they all share a common goal: to protect the traveling public through recommendations aimed at improving transportation safety.

The NTSB is made up of approximately 430 dedicated employees who have a wide range of educational backgrounds and relevant experience. Our ranks include MDs, JDs, and Ph.Ds. Among our investigators, we count former members of law enforcement, industry professionals, and technical experts. When we investigate an accident, a multidisciplinary team is selected to fit the needs of the investigation.

Member Weener and investigators at the scene of the July 2013, crash of a de Havilland Otter Air Taxi, in Soldotna, Alaska

I’m often asked how the NTSB—particularly our crash investigation process—works. The NTSB is required by law to investigate every aviation incident in the United States, and our aviation safety staff investigate more than 1,200 aviation events each year. Our investigative process looks at three factors—human, machine, and environment—to determine the probable cause of accidents and incidents. This process has evolved during our 50 years, leveraging the skills, talents, and professionalism of our people, who use the latest investigative techniques and tools to find facts, analyze those facts, and determine why and how an accident happened.

Investigators consider what may have caused or contributed to the events of every accident. They look for issues in areas such as mechanical failures, operations, and weather conditions. They doggedly work to recover all onboard recorders and other sources of data, even when those recorders may be severely damaged. They also consider pilot performance, collecting evidence regarding possible fatigue, medical fitness, prior training opportunities, and specific aircraft experience.

Evidence is gathered through cooperation with pilots, witnesses, law enforcement officials, the FAA, airport officials, industry, and other stakeholders; in extreme cases, our staff can also issue subpoenas to obtain needed evidence. Investigations cannot and do not try to answer every question of why and how, but focus on questions of what caused the accident, or made it worse. Probable cause is the factor—or factors—that, based on all available evidence, the Board concludes most likely resulted in the accident. It generally takes around a year to produce a final report, which includes a probable cause and contributing factors.

Based on our investigations and special studies, we issue safety recommendations to regulatory agencies, industry, and other parties to an investigation who are positioned to implement our suggestions and improve transportation safety. The NTSB isn’t a regulatory agency, so we cannot compel compliance with our recommendations; however, of the more than 14,500 safety recommendations issued in our 50-year history, more than 80 percent are acted upon favorably. This is testimony to the NTSB’s diligence, investigative acumen, and commitment to transportation safety.

Looking back over the years and contemplating the NTSB’s contributions, I am proud to see that transportation safety has, in fact, improved greatly—especially in commercial aviation. We have seen significant improvements in aircraft crashworthiness; the introduction of life-saving technologies, such as collision avoidance and ground proximity warning systems; implementation of safety policies and regulations aimed at preventing pilot impairment, distraction, and fatigue; and emphasis on safety management systems and enhanced flight crew procedures. NTSB investigations identified the need for these advancements and helped incentivize remarkable safety improvements. Modern commercial aviation is safer now than ever before.

I often quote author Douglas Adams, who tells us that people are almost unique in their ability to learn from others, but remarkable for their resistance to doing just that. You may have heard the old saying, “knowledge is power.” We believe “knowledge is safety.” I hope you take a moment to learn about the NTSB’s investigative process in the next several blog posts, and that you come away with a greater understanding of how we at the NTSB strive to turn our knowledge into safer transportation.

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