In a move designed to stem a spike in helicopter accidents that occurred over the past couple of decades, FAA on Feb. 20 released a comprehensive final rule that imposes a series of equipment, training and operational requirements on helicopters flown in Part 135 generally and in air ambulance missions specifically.

FAA’s rule, proposed in 2010, comes just days before the Helicopter Association International’s Heli-Expo in Anaheim, Calif., and also coincided with the release of a series of measures that the U.K. Civil Aviation Authority released Feb. 20 to address offshore helicopter safety.

For Part 135 operators, the new FAA rule calls for radio altimeters, includes over-water equipment requirements, revises alternate airport weather minimums, and strengthens pilot testing for handling in difficult conditions such as whiteout or brownout circumstances.

After concerns raised in comments on the original proposal, the agency is permitting deviations to the radio altimeter requirements, noting that some of the older helicopters cannot accommodate them. The agency also removed requirements included in the proposal for life rafts and for all airplanes and helicopters operated under Part 135 to complete a load manifest in duplicate and carry one aboard the aircraft. FAA believes the costs outweighed the safety benefit in each case. But instead of rafts, FAA is requiring 406 MHz emergency locator transmitters.

Air ambulance operators face nearly a dozen new requirements, including a mandate that they meet the requirements of Part 135, rather than Part 91. Larger operators will need to meet drug and alcohol testing requirements, and all air ambulance operators are required to develop an FAA approved preflight risk program, provide safety briefings to medical personnel, follow certain procedures for transitioning between instrument flight rules (IFR) and visual flight rules (VFR) and ensure pilots in command hold an instrument rating. The rule further permits IFR operations at airports without weather reporting and establishes VFR weather minimums. In addition to the new Part 135 requirements, air ambulances must be equipped with Helicopter Terrain Awareness and Warning Systems (Htaws) and a flight data monitoring system.

While not directed at Part 91 helicopter operations, the rule does add Class G airspace weather minimums for those operators to reduce the likelihood of encountering instrument meteorological conditions (IMC). When proposed, the Experimental Aircraft Association and other operators objected to such a requirement, questioning a lack of data and stating pilots “are the best judge of what speed and visibility are acceptable for safety operation in those circumstances.” FAA says it recognizes that the change would prohibit both civil and public operations currently conducted in low visibility conditions, but that the increase in safety justifies those prohibitions. The agency does say it would consider waivers and proposed changes that would provide a little more flexibility.

FAA estimates that the final rule will cost the air ambulance industry $224 million, and commercial operators in general another $19 million. But the agency says the rule “represents the most significant improvements to helicopter safety in decades and responds to government’s and industry’s concern over continued risk in helicopter operations.”

Helicopter safety came under the spotlight after the number of air ambulance accidents reached “historic levels” between 2003 and 2008, with 2008 being the deadliest. In that year, five crashes resulted in 21 deaths. At the same time, accidents involving other commercial helicopters increased, FAA says.

FAA looked at the causes of 62 air ambulance accidents between 1991-2010 and found most involved inadvertent flight into IMC, loss of control, controlled flight into terrain and night conditions. FAA also looked into 49 accidents from 1991-2010 involving helicopters operating under basic VFR weather minimums.

“The FAA has determined that these accidents may have been prevented if pilots and helicopters were better equipped for [inadvertent flight into IMC], flight-light, whiteout and brownout conditions and for flights over water,” the agency says.

In addition to FAA scrutiny, the accidents led to numerous recommendations from the National Transportation Safety Board and caught the attention of Congress, which in the most recent FAA reauthorization bill called on the agency to issue a rulemaking to address the issue. Along with the congressional directives and NTSB recommendations, the rulemaking further incorporates recommendations of a Part 125/135 Aviation Rulemaking Committee.