The Problem With "Probable Cause"
The National Transportation Safety Board (NTSB) is the primary agency in the United States charged with the authority to investigate incidents and mishaps related to civil aircraft. The agency's primary role is to perform an independent investigation of the facts and conditions that give rise to an accident/incident in effort to reach a determination as to the "probable cause" of an accident/incident. The purpose of determining the probable cause of an accident/incident is permit the NTSB an opportunity to provide industry recommendations that are ultimately designed to prevent future mishaps in furtherance of air safety promotion.
The problems with charging the NTSB with finding only the probable cause of an incident are two fold. First, often times the root (actual) cause of an incident is not determined. Thus, the agency's purpose to propose future recommendations intended to prevent other future incidents may be frustrated. Second, the very determination of the "probable cause" of an incident ultimately is only as accurate as the essential "facts" relied upon in making such a determination. In many instances the essential facts relied upon may be conveyed to the NTSB from other sources and may be biased. As such, the future impact of agency "recommendations" intended to promote overall air safety, without more, may be of limited social utility or value. This can be further troubling when one looks at the vast percentages of incidents that the probable cause is declared to be pilot or human error thus providing little or limited guidance to prevent future similar incidents.
On May 5, 2008, the Honorable Cooper, sitting on the United States District Court, Central District of in California, rendered a decision wherein the Court determined that the actual or root cause of a 2003 mid-air collision involving two helicopters was in direct opposition to the NTSB's determination of the "probable cause" of the incident. On November 6, 2003, two helicopters crashed in front of a control tower at Torrance Municipal Airport. The two helicopters were operating within the jurisdiction and control of the air traffic control tower (FAA). Following the crash, statements were provided by the air traffic controllers. The NTSB relying largely upon the statements of the controllers determined that the junior pilot failed to comply with tower instructions and determined that the probable cause of the incident was attributed to pilot/human error.
Following a seven day bench trial the Court fully exonerated the junior pilot finding that the pilot did comply with all tower instructions and that the proximate cause of the accident was a collection of numerous errors committed by the air traffic controllers. This case illustrates the conflicts presented by one--charging the agency with determining only the probable cause of an incident 2--while relying upon "facts" from other sources in forming a conclusion 3--for the purpose of providing future recommendations to avoid other similar incidents without more. Left alone, in this instant analysis the NTSB report would provide little to no intrinsic value. First, human error will, unfortunately, play a substantial factor in many if not most aviation incidents in at least some fashion, however, "future recommendations" to avoid repetition of the same is such instances due to the very specific nature of the alleged human error are or may be of limited value. Second, charging the agency to go only as far as probable cause relaxes the standard of ultimate accountability by relieving the agency of the duty to conduct a full inquiry or challenge information/facts provided in furtherance of an investigation. Finally, as the instant case study reveals, the primary purpose of the agency, i.e., prevention of future incidents becomes frustrated.
To the contrary, a determination of the root cause, in this instant, collective failures of the tower giving rise to the unfortunate incident, does provide valuable assistance in furtherance of avoidance of future similar mishaps. The ability to learn from the mistakes that actually give rise to incidents and mishaps will ensure the continued development and improvement of the industry and the future of air travel and commerce.