NTSB Calls for Changes in Air Ambulance Flight Rules

The U.S. National Transportation Safety Board (NTSB) is calling on the FAA to impose stricter requirements on all emergency medical services (EMS) flights, including new flight visibility and crew rest rules, dispatching procedures, and the use of TAWS (terrain alerting and warning systems).

The NTSB is making its request after investigating fifty-five EMS accidents between January 2002 and January 2005.

EMS flights, which are often preformed with helicopters, are required to operate in accordance with 14 CFR (Code of Federal Regulations) Part 135 when carrying patients or organs, but when flying without patients on board, they are permitted to operate under the less stringent provisions of Part 91.  The Board noted that thirty-five of the fifty-five accidents occurred on positioning flights operating under Part 91 rules.

The problem, according to the Board, is that Part 135 and Part 91 requirements differ significantly (Part 91 is less stringent) on weather minimums and crew rest requirements – two key factors found in the EMS accidents it investigated.

Risk Program

The Board also found that none of the operators involved in these accidents had an established aviation risk-evaluation program, which would include procedures for evaluating the potential risks of a flight, such as weather, darkness, pilot training and experience, and even how to respond to mission pressures.

Besides a lack of risk evaluation, the Board said its investigation revealed that many EMS operators lack a consistent, comprehensive flight dispatch procedure to assist pilots in determining the safety of a mission.  Because of this, the Board is asking the FAA to require EMS operators to use formalized dispatch and flight following procedures that include a dispatcher with aviation experience, along with up-to-date weather information.

Typically these programs would require pilots to fill out a form before departing on a mission, and annotate the weather conditions, visibility and other factors that might affect the safety of the proposed flight.  If the mission is rated moderate- to high-risk, the pilot must receive approval and contact dispatch before taking off.

Use of Modern Safety Technologies

Finally, the report reviewed several technologies that can assist in flight operations, including TAWS (terrain awareness warning systems) and NVIS (night vision imaging systems).  The report said that controlled flight into terrain is a common factor in helicopter EMS accidents, and noted that these could be "alleviated" by the use of TAWS.  Seventeen of the fifty-five accidents it investigated might have been avoided if TAWS had been available, the Board said, so it recommended that the FAA require the installation of TAWS on all EMS aircraft.

The Board also found that some EMS operators were using NVIS to enhance a pilot's ability to see and avoid terrain and other obstructions.  If used properly, NVIS could help EMS pilots identify and avoid hazards during nighttime operations, the Board stated.  However, because the use of NVIS isn't feasible in some situations such as populated areas with ambient light or numerous streetlights, in the Board's opinion, it didn't make a recommendation on this subject.  Nor did the Board mention the use of EVS (enhanced vision systems) or SVS (synthetic vision systems) in its synopsis of the investigation report or its conclusions and recommendations.  (As an aside, Canadian Helicopters recently said it would install EVS on their aircraft, partly for safety reasons.)

More information, along with the Board's briefs of the individual accidents, and their probable causes, in its investigation, can be found on the Board's Website at www.ntsb.gov.  01-29-2006.

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