The National Transportation Safety Board (NTSB) is “an independent federal agency charged by Congress with investigating every civil aviation accident in the U.S. and significant accidents in other modes of transportation–railroad, highway, marine and pipeline. The NTSB determines the probable cause of each accident investigated and issues safety recommendations aimed at preventing future accidents.”
NTSB Accident Reports
The NTSB website states: “Accident Reports are one of the main products of an NTSB investigation. Reports provide details about the accident, analysis of the factual data, conclusions and the probable cause of the accident, and the related safety recommendations. Most reports focus on a single accident, though the NTSB also produces reports addressing issues common to a set of similar accidents.”
Preliminary – Within a few days of an accident, the NTSB issues a “Preliminary” report which is based on the preliminary accident report and includes a synopsis of the data that is known at the time of the crash and which is subject to change.
Factual – A “Factual” report is a final description of the accident, following months of investigation, and replaces the Preliminary report. The Factual report contains a final and full narrative description of the accident and its probable cause.
Probable Cause – This is the part of the final report that contains the NTSB’s official determination of the probable cause(s) of the accident.
In a commercial airline accident, the NTSB will immediately send out a “Go Team” which is a team that rotates a duty roster to be on call to go at a moment’s notice wherever they are needed. The investigators carry the tools of their trade with them: “carefully selected wrenches, screwdrivers and devices peculiar to their specialty. They all carry flashlights, tape recorders, cameras,” etc.
Each member of the Go Team has a specialty which may include: Operations (flight history and crew); Structures (wreckage and scene); Powerplants (engines and propellers); Systems (aircraft components, hydraulic, electrical, etc.); Air Traffic Control; Weather; Human Performance; and Survival Factors.
Each part of the team gathers data and collects evidence on every factor involved in the crash. They will investigate the crash at the site, looking at the functioning of the aircraft as the accident occurred. They interview the crew and survivors and any witnesses. They will also collect any documentation from the airport towers, other entities in radio contact prior to the crash, and will gather any photographic or video of the incident, before or after, whether from airport cameras or witnesses’ cell phones.
After the onsite documentation and investigation is complete, the NTSB will collect every component piece from the crash scene. Parts of the airplane may be taken to various labs or facilities to further tear down and analyze the functioning of components such as the engines. In some instances, they will reconstruct the aircraft in a warehouse location to further analyze the performance and destruction of the various parts of the vehicle.
A vital part of the data collection procedure is to secure the “black boxes” (actually orange in color) and send them to a lab to retrieve the data from them. In an aircraft crash such as the Asiana 214 Boeing 777 SFO crash, there were three such recorders.
- A Cockpit Voice Recorder records the sounds inside the cockpit. Any conversations, orders, radio transmissions and any ambient noises such as system alarms are all recorded. The tapes of the Flight Voice Recorder are privileged and confidential by law and will not be released to the public.
- The Flight Data Recorder records electronically all computerized systems within the airplane. The Boeing 777’s flight recorder captured data from “1400 different parameters that are measured by the recorder.” A “parameter” is a factor that can have a variable value such as the speed of an engine, the pressure in a hydraulic system, etc. These measurements are taken and recorded at specific time intervals such as every 3 seconds. It captures switch positions, warning alarms, and many other types of data.
- The 777 also has another recorder called a Quick Access Recorder, which provides quick and easy access to in-flight data.
The Party System
The NTSB investigates an average of about 2,000 aviation incidents, per year, plus other types of transportation accidents such as railroads, highway, marine and pipeline. To handle the vast amount of work these investigations entail, the NTSB uses a “Party System” to delegate its responsibilities. This means that the NTSB designates other organizations or corporations as “parties” to the investigation. The parties so designated must be experts in their fields. The Federal Aviation Administration (FAA) is automatically a party to the investigation. These parties function as aids to the NTSB with their technical or special expertise. No legal firm or person is allowed to be designated as a party. All parties report directly to the NTSB which verifies the accuracy of the reports. Each NTSB investigative group chairman prepares a factual report which is placed into the record of the investigation.
Other NTSB Functions
The NTSB also serves, under the Aviation Disaster Family Assistance Act (or other such legislation for railroad accidents, etc.), to give help and aid to the survivors or the families of the decedents of a crash. They coordinate with local agencies such as the Red Cross, the Coroner’s Office and the airline carrier to see that the survivors and families are taken care of in the aftermath of an accident.
The analysis of a crash is a slow and painstaking process of reconstructing what occurred that caused the incident. It involves many experts in many fields and many man hours of investigation. The process can take many months and sometimes years, to complete. But in the end, the data will emerge to give the Probable Cause of the crash: whether mechanical or human error; whether design flaws or structural failures; whether environmental or atmospheric interference. The data learned from these crashes and safety studies are then published as NTSB Safety Recommendations and sent to the organizations best able to address the safety issue. The data learned may also be used to design better aircraft or aircraft support systems. The goal is safer flying for us all.