On Monday, Representatives Rick Larsen (D, WA-02) & Bennie Thompson (D, MS) wrote a letter to Department of Homeland Security (DHS) Secretary Kristi Noem and Transportation Secretary Sean Duffy alleging the misuse of C-UAS equipment by the United States Secret Service (USSS).

In the letter, Larsen and Thompson state that USSS personnel used C-UAS systems within the vicinity of Ronald Reagan Washington National Airport (DCA) in violation of operating parameters and Federal Aviation Administration (FAA) notification requirements.

This, the lawmakers allege, led to erroneous notifications on the Traffic Collision Avoidance System (TCAS) which led to 10 resolution advisories and three aircraft go-arounds. These alerts impacted both commercial and U.S. Coast Guard aircraft, causing confusion and potentially jeopardizing the safety of hundreds of passengers.

FAA spectrum analysis found that the USSS C-UAS system had interfered with the TCAS system’s detection software, causing the false advisories. This, the lawmakers allege, was caused by the USSS’ use of C-UAS equipment outside of the initially agreed frequency parameters which resulted in interference in adjacent spectrum bands.

Larsen and Thompson go on to state that the USSS also violated DHS Concept of Operations by failing to notify the FAA at all that the C-UAS equipment was being activated at all, exacerbating the confusion.

Although inherently serious, the impact of this incident is further magnified by the recent tragedy at DCA whereby an airborne collision between an Army helicopter and commercial liner cost the lives of 67 crew and passengers.

Fortunately, on this occasion no damage was done it is not hard to imagine a scenario where the TCAS malfunctions and erroneous alerts could have had serious consequences.

As state and local officials lobby for the easing of restrictions on C-UAS tech to protect citizens from the emerging drone threat, this incident brings to the fore the debate on how to effectively mitigate that threat without causing additional unintentional harm.

Larsen and Thompson have demanded answers to 7 written questions by no later than next Monday and we will be sure to monitor this story closely.