With autumn’s annual bird migrations underway, on October 3, the FAA issued a 4-page Special Airworthiness Information Bulletin 21-17 addressing Rotorcraft Bird Strike Protection and Mitigation. It also introduces the voluntary Rotorcraft Safety Promotion Concept (RSPC) that encourages the...
With autumn’s annual bird migrations underway, on October 3, the FAA issued a 4-page Special Airworthiness Information Bulletin 21-17 addressing Rotorcraft Bird Strike Protection and Mitigation. It also introduces the voluntary Rotorcraft Safety Promotion Concept (RSPC) that encourages the installation of safety enhancing designs, using specific safety equipment, and implementing operational procedures to mitigate the risks of helos having runs-ins with our feathered friends. Unlike fixed-wing aircraft that zip through densely populated avian territory, helos face increased bird strikes because they cruise in the lower reaches of the atmosphere, 3,500 feet and below, where 90% of snarge is created.
The RSPC webpage links to a list of bird-strike compliant helos. There are nine of them: the Airbus H225, MBB-BK 117 C2, D2, and D3; the Leonardo AB139, AW139, AW169, and AW189; and the Sikorsky S-92A.
It is followed by the Illustration of Voluntary Bird Strike Options that take normal category Part 27 helos toward the bird strike requirements of Part 29 transport category rotorcraft. These enhancements include bird resistant polycarbonate windshields, bird deterring lights, audio, and high visibility main rotor blades, and flight manual limits that limit the indicated airspeed to 80 knots.
Other operational risk mitigation options include flight planning and in-flight decisions that avoid bird-rich environments, mindful that these areas and the avion populations wax and wane with the season. If encountering birds in flight, slowing down, if practical, should be the pilot’s first reaction. More than three-quarters of all helo bird strikes happen when flying faster than 80 knots.
Gaining altitude, if possible, is another operational mitigation option. The SAIB says the likelihood of a bird strike decreases 32% for every 1,000 feet gained from 500 feet above the ground. And helo pilots should know and remember that birds fly at higher altitudes at night than they do during daylight.
Rotary wing aviators should also know and remember that their last line of bird strike defense is wearing a good helmet with the visor firmly in place. And if you fly in a birch world, you might consider the face guard many military helo crews use. Collecting snarge for a wildlife strike is never a good time, especially if you are scraping it from the facial folds of any member of the helo’s crew. –Scott Spangler, Editor