By Gene Trainor, FAA Compliance & Airworthiness Division
The FAA is issuing new Special Airworthiness Information Bulletins (SAIBs) outlining how the rotorcraft community can voluntarily improve safety through FAA recommended actions and technology.
The SAIBs are part of the Rotorcraft Safety Promotion Concept (RSPC), an initiative that seeks to promote safety through voluntary compliance by highlighting rotorcraft safety features and designs. The first SAIB was issued Sept. 13, 2021, and covered preventing and mitigating the effects of bird strikes. The FAA’s Strategic Policy for Rotorcraft section plans to issue additional SAIBs through 2023, with the next focused on crash resistant fuel systems.
For those unfamiliar with SAIBs, these bulletins serve to alert, educate, and make recommendations typically regarding safety. They are published in the FAA’s Dynamic Regulatory System, more commonly known as DRS. It’s the FAA’s depository for regulatory guidance material (drs.faa.gov).
The RSPC SAIBs focus on the continuous improvement of helicopter safety and allow for safety recommendations to be shared as information and technology become available.
The bird strike SAIB in part recommended:
- Learning about the local bird population and using that knowledge to safely plan and fly a route. Key considerations include seasonal migratory times and concentration patterns within an operating area.
- Reducing airspeed when practical. Three out of four bird strikes (77%) occur during operations with airspeeds greater than 80 knots. When operating rotorcraft in areas of high bird concentrations, the likelihood of a damaging bird strike increases with airspeed. Fly at 80 knots or less, particularly at lower altitudes.
- Increasing altitude as quickly as practical. The likelihood of a bird strike drops 32% for every 1,000 feet gained above 500 feet above ground level. Also, birds fly higher at night, so increase your altitude even more than during the day to try to avoid them.
- Wear personal protective equipment (PPE). A helmet and visor, at least for the crew, should be worn when practical.
With regard to crashworthy fuel tanks, the FAA Reauthorization Act of 2018 requires any rotorcraft manufactured on or after April 5, 2020, to be equipped with crash-resistant fuel systems. This will require updates to a significant number of helicopters now in service.
The forthcoming crash-resistant fuel system SAIB highlights a three-level continuum for crashworthy fuel systems. Ultimately, the FAA recommends a multitude of steps to prevent fuel tanks from rupturing after a crash. The continuum of options include:
- Using crash resistant fuel bladders in the fuel tanks. Designs incorporating fuel bladders made from crash resistant materials, even if no certification credit was received by the installer, have been shown to reduce fuel leaks after an accident.
- Fuel systems that comply with the subset of regulations in the congressional mandate codified in Title 49 USC section 44737 (helicopter fuel system safety) are very effective in preventing post-crash fires.
- Full compliance to latest amendment of Title 14 part 27 or 29 for fuel systems (sections 27.952, 27.963, 27.967, 27.973, and 27.975) assures the highest level of protection from post-crash fires in helicopters.
These fuel system regulations include a broad set of requirements, and are intended to accomplish the following:
- Minimizing crash-induced fuel leaks, typically through installation of crash-resistant bladders and reduction of puncture hazards to these bladders.
- Minimizing fuel contact with potential fuel ignition sources during and after a crash.
- Increasing the time occupants have to get out of the helicopter before a post-crash fire.
Gene Trainor is a technical writer/communications specialist for the FAA Compliance & Airworthiness Division.