The FAA has issued Special Airworthiness Information Bulletin AIR-21-17R1 to advise owners, operators, crew, and passengers of techniques and equipment to avoid rotorcraft bird strikes as part of its new Rotorcraft Safety Promotion Concept (RSPC). According to the FAA, 90 percent of all bird strikes occur at altitudes of 3,500 feet agl and below.
Thus, the agency suggests several voluntary mitigation strategies for helicopter operators. They include installing equipment safety enhancements and flying helicopters with bird-resistant designs. Aircraft that fall into the latter category, according to the RSPC, include the Airbus H225 and BK 117 series; Leonardo AW139, AW169, and AW189; and the Sikorsky S-92A. Additionally, crews should wear helmets and visors when practical.
OEMs and MROs are encouraged to contact FAA ACOs for approval of design modifications that provide a higher level of bird strike protection. Pilots should make flight planning and in-flight decisions that keep rotorcraft away from bird-dense environments. It is also important to understand seasonal bird migrations.
The FAA suggests reducing airspeed and increasing altitude when practical because 77 percent of all bird strikes occur at speeds above 80 knots. Additionally, a bird strike is 32 percent less likely for every 1,000 feet above 500 agl.