The FAA Requires both Positive Safety Controls and Risk Caps

When a launch operator seeks a waiver from the FAA for a requirement governing the flight termination system (FTS) on its launch vehicle, the operator should not look to satisfaction of the FAA’s risk requirements as a justification for the FTS waiver it requests. Instead, the operator should address how its proposed design or test change provides an equivalent level of safety or will not otherwise jeopardize public health and safety.

Background: The safety requirements of part 417 of Title 14 of the Code of Federal Regulations apply to the launch of expendable launch vehicles.  The requirements consist of, among other things, positive safety controls and caps on acceptable risk.

The positive safety controls provide design and test requirements for the vehicle’s flight safety system, which is usually an FTS. If an expendable launch vehicle starts going off course, launch safety personnel destroy the rocket by transmitting a signal to the on-board flight termination system. In the U.S. launches generally take place from the coasts so the debris from a destroyed launch vehicle stage falls in an ocean. Because of the destructive power of a launch vehicle, especially early in flight when fully fueled, both segments of the flight safety system must work. Accordingly, the FAA’s requirements govern the ground-based command control system as well as the destruct—or termination—system on board the rocket.

The FAA’s risk requirements limit the collective, public risk attributable to a launch to 1 x 10-4 for debris, toxic releases and far field blast overpressure under 14 C.F.R. § 417.107(b). Individual risk may not exceed 1 x 10-6 for each hazard.

The requirements are not interchangeable. The risk caps and the positive controls are separate requirements, and, as is evident in section 417.107, both requirements apply. Historically, as discussed here at 63938, satisfaction of the risk requirements may have been used by the federal launch ranges to justify waiving a particular requirement governing a flight termination system’s design or testing. In the early days of FAA regulation of commercial space transportation, prior to codification of part 417, the FAA relied greatly on the U.S. Air Force, Army, and NASA federal launch ranges for safety oversight. When the time came , the FAA codified a large part of the ranges’ safety requirements as part 417 of its own rules, and the FAA and the Air Force strove to achieve common requirements for consistency, as discussed here at pages 63925-26. However, the FAA made the decision to require both positive safety controls, including in the design and test requirements for a flight termination system, and risk caps. Accordingly, just as I may not get out of paying my federal taxes on the grounds that I paid my state taxes, a launch operator may not avoid satisfying a flight termination system requirement merely because its launch satisfies the FAA’s risk requirements. If it needs to request a waiver from the FAA it must justify the waiver by addressing the requirement it seeks waived, not by relying on risk analysis.