FAA Publishes New Special Class Airworthiness Criteria for UAS

Today, the DOT’s Federal Aviation Administration (FAA) published a notice of proposed airworthiness criteria in the Federal Register (87 FR 60338-60344) for “Special Class Airworthiness Criteria for the Insitu Inc. ScanEagle3 Unmanned Aircraft”. The criteria outlined in this notice are very similar to those set out last month for MissionGO MGV100 Unmanned Aircraft. The differences are due to the larger size (80-lb GTW) of the ScanEagle3 as well as its use of a JP5/JP8 powered piston engine.

Fire Protection Requirements

This latest Special Class Airworthiness Criteria adds a new section D&R.140, Reciprocating Engine and Fuel Carriage. This section outlines the requirements for “fire prevention and protection, fuel venting and draining, prevention of fuel contamination, and fuel system crashworthiness.”

In addition to preventing fires in the aircraft, the SCAC addresses the potential for fires in the event of an aircraft crash. The SCAC notes that:

“When assessing risk posed by UA, the presence of flammable fluids provides an additional source of potential hazard in the event of an accident due to the possibility of fire, which could spread beyond the immediate impact site of the aircraft. While traditional aircraft considerations with fuel system crashworthiness focuses on occupant protection, the intent of the fuel system crashworthiness for this UA is to ensure crash site containment and prevent the risk of injury or fatality to persons outside the immediate crash site.”

These considerations could prove to be especially important if the ScanEagle3 were used in an attack on critical infrastructure facilities, either deliberately by the operator, or by an attacker that gained control of the aircraft from the owner.

Commentary

While UAS of this size are not nearly in as widespread use as the much smaller quadcopter used by hobbyists, they do pose a much larger potential hazard if used in an attack on a critical infrastructure facility such as a chemical manufacturing plant or an electric transmission substation. The use of JP5 fuel to sustain the 18-hour mission endurance capability and the 19-lb payload capacity of the aircraft provide for a potentially effective weapon in a critical infrastructure attack.

The FAA certification requirements outline in this SCAC do address some cybersecurity concerns; they do not, however, address cybersecurity provisions for the remote aircraft controller. This is the same concern that I voiced about the earlier SCAC.