AOPA Asks FAA To Weigh Supersonic Limits Below FL180

 - August 21, 2019, 9:46 AM
AOPA is particularly concerned that pilots operating under VFR above 10,000 msl might not have the ability to see and avoid supersonic aircraft, such as the Aerion AS2, flying at supersonic speeds. Thus, AOPA wants the FAA to study whether subsonic speeds below FL180 should be required. (Photo: Aerion)

Recognizing that supersonic flight represents “a new potential market in the aviation industry,” the Aircraft Owners and Pilots Association (AOPA) is cautioning the FAA to carefully consider issues such as see-and-avoid at lower altitudes to ensure supersonic flights are safely integrated into the National Airspace System alongside subsonic operations.

“We believe it is important that supersonic activity does not infringe on general aviation’s ability to access and transit the NAS,” AOPA senior director of airspace and air traffic Rune Duke said in comments to a notice of proposed rulemaking (NPRM) that the FAA released in June to facilitate special authorizations for supersonic flights primarily for flight-testing purposes. Deadline for comments to the NPRM (FAA-2019-0451) is August 27.

AOPA endorses the NPRM as an important step toward “adopting a regulatory posture that is accepting of these aircraft” and the modernization of flight that follows with supersonic development. But the association stressed the need to uphold safety standards. “This and future rules [should] in no way allow for the approval of operations which could decrease public safety or curtail an operator’s ability to efficiently traverse the NAS,” he added.

The FAA should consider how supersonic aircraft characteristics affect other aircraft; how see and avoid will take place; and the importance of the National Environmental Protection Act (NEPA) when adjudicating and approving applications, Duke said.

“It is critical that both the wake characteristics of airframes and the requisite air traffic separation standards are identified so that, in conjunction with the efficiency impact, the disruption or cost to other operators can be accurately determined,” he said. “It is crucial that the operation is both efficient and seamless.”

AOPA is particularly concerned that pilots operating under VFR above 10,000 msl might not have the ability to see and avoid supersonic aircraft flying at supersonic speeds. “Given that danger, we believe that the FAA should study whether subsonic speeds below Flight Level 180 (FL180) should be required,” the association said, adding that the FAA “should scrutinize any overland application for supersonic speeds below FL180 that do not include effective mitigations for see and avoid.”

AOPA pointed to higher VFR weather minimums above 10,000 feet msl put in place for Class E airspace because of the additional distance required to see and avoid aircraft with speeds above 250 knots. “These differences in basic VFR weather minimums highlight not only the important relationship between a pilot’s ability to conduct see and avoid but also illustrate why the 250-knot speed limit exists [below 10,000 feet in Class E airspace].”

Communication Concerns

AOPA’s membership survey revealed that 39 percent of pilots operate above 10,000 feet msl and 80 percent fly under VFR at least half of the time. “Given this, the FAA should consider that many general aviation aircraft are routinely flying above 10,000 feet msl, but outside of Class A airspace, VFR, and not necessarily in communication with air traffic control.” Many general aviation aircraft have no transponder or ADS-B requirement, he added.

“We are concerned that the existing mitigations for non-participating VFR traffic above 10,000 feet msl could be one-sided, as several strategies are predicated on the general aviation aircraft having a cooperative system and for controllers to de-conflict traffic that they may not be talking to," Duke said. "We are troubled that there could be situations in which pilots will be faced with having to completely relinquish their responsibility for themselves and their passengers’ safety to the pilot of another aircraft, especially one with whom they have no contact (visual or otherwise).”

The FAA should collaborate with industry groups and the Department of Defense and conduct a safety risk assessment and safety study on the issue, according to the association. AOPA further believes in the importance of environmental review through NEPA. This offers general aviation pilots the opportunity to provide feedback and the identification of unknown impacts, Duke said.

“Breaking the sound barrier not only exemplifies the essence of flight, but its imminent routine occurrence in commercial and non-commercial flying also represents a new potential market in the aviation industry,” Duke said. “As the interest in this flight regime increases, so does the need for policies and procedures that integrate these emergent operators with existing general aviation flights in a safe and efficient manner.”


This is starting to sound like a look at how the railroad industry coordinates their path/Time-of-Day/Route might make sense here. It seems to me supersonic flight should be left at higher cruising altitudes, at least above 25,000 ft considering regular slower traffic is still climbing to their ceiling.

But then again, I'm just a passenger :\