The US Air Force's Shadowy Surveillance Test Plane

U.S. Air Force says that a specialized Dornier Do-328 twin-engine turboprop was not snooping on ongoing protests in Portland, Oregon during a series of flights earlier this week. Online flight tracking software had shown the aircraft, which belongs to a secretive special projects office called Big Safari and conducts research and development and test and evaluation activities in support of U.S. Special Operations Command, flying circular orbits often associated with intelligence, surveillance, and reconnaissance missions in the area.

The aircraft, which carries the U.S. civil registration code N645HM and is also known by the nickname Cougar, had first arrived at Hillsboro Airport outside Portland on July 19, 2020. The plane flew patterns for three days straight, but was never actually over downtown Portland, where protests are occurring, for any protracted period of time. It left the area today for Denver, Colorado, another area where it had been observed flying similar orbits last week. 


A similar orbit that N645HM flew near Boulder, Colorado outside of Denver on July 17.

"The Dornier Do 328 aircraft, assigned to Air Force Materiel Command's 645th Aeronautical Engineering [Systems] Group, was not gathering intelligence or conducting operations related to civil unrest in Portland, Oregon," Ann Stefanek, an Air Force spokesperson, said in a statement to The War Zone, using the formal unit designation for the Big Safari program office. "This week the Air Force conducted previously planned test flights in the Northwest United States that required the environmental conditions typical of the region. This location was chosen several months ago due to the high likelihood of cloud cover desired for this equipment test."


Portland has seen persistent protests since May, when they first began in response to the police killing of George Floyd in Minneapolis, Minnesota. President Donald Trump's Administration sent Federal law enforcement officers from various agencies, including Customs and Border Protection and the U.S. Marshals Service, to the city earlier this month where they have been engaged in a controversial crackdown on the demonstrators using at best murky legal authority.


The appearance of N645HM nearby drew the attention of activists, journalists, and politicians, who were concerned that this reflected a further militarization of the Federal Government's response. There are strict laws for when the President may order military elements operating in a Federal capacity to respond to any crisis or contingency within the United States, which you can read about in more detail in this past War Zone piece.

"It would be totally unacceptable for U.S. armed forces to take part in surveillance of protests in an American city," Senator Ron Wyden, a Democrat from Oregon, had told The Intercept. "I've asked the Air Force to explain these flights, including why this plane is circling Portland, what data it is collecting and who approved the mission."


That's not to say there hasn't been actual aerial surveillance going on of the Portland protests in recent weeks. These flights have included a number of aircraft, including those flown by local and federal law enforcement agencies. At least one of Customs and Border Protection's Multi-Role Enforcement Aircraft, which are twin-engine Beechcraft King Air turboprops configured for intelligence, surveillance, and reconnaissance missions, has arrived in the Portland area just this evening..


So what was Cougar actually doing?

"We do not discuss specific capabilities or testing conducted by Big Safari," Stefanek, the Air Force spokesperson, said in a separate statement to The War Zone, using the official nickname for the 645th Aeronautical Engineering Systems Group (AESG). "For all research, development, test and evaluation missions, as well as system modernization missions, Air Force Materiel Command units routinely fly in dedicated military operating areas, restricted airspace and the broader national airspace system. Each mission profile is logistically unique depending on the nature of the system being tested."


However, as I was first to report back in 2015 for War Is Boring, Cougar is set up to be a modular, plug-and-play testbed for sensors, communications systems, defensive countermeasures, and even weapons. Inside, the aircraft has readily reconfigurable work stations and equipment racks, as well as adaptable fuselage bays, to support all kinds of related testing. The plane also has two external sponsons, one on each side of the rear fuselage, that can carry stores or other equipment externally.


Aviation photographer Paul Carter was kind enough to share pictures of N645HM that he took during the plane's recent visit to Hillsboro that show it is fitted with one large sensor turret on the sponson on its left side. These kinds of turrets typically hold full-motion electro-optical, infrared, or multispectral video cameras. They can also support persistent wide-area aerial surveillance systems. 

The right-side sponson appears to have a small pod of some kind fitted. It's hard to say what might be inside, but possible options might include a communications or data link system, a miniature electro-optical system, some sort of lidar or laser mapping scanner, or even a countermeasures system. There are increasingly tiny radar systems, as well, although that is quite small for that type of application. 


The aircraft also has a large dome on top, typically associated with high-bandwidth satellite communications systems able to send video feeds and other data beyond-line-of-sight in near-real-time. It also has a bat-wing ultra-high-frequency satellite communications antenna on top of the forward fuselage. Both the dome and the platter antenna have been seen fitted to the aircraft regularly in the past. 


Without being able to see inside, its not clear what other systems it might have been carrying during its flights over Oregon this week. Still, we do know that those sorties took it over both rural and some urbanized areas, which could have provided a good opportunity to test any systems in very different environments. This would be especially valuable for evaluating the ability of payloads to collect useful imagery or other data about objects of interest. It's just important to test all types of systems under different atmospheric conditions, too. Oregon definitely provides a dynamic weather environment. 

As to who ordered up these tests, it's unclear. Big Safari traces its history back to the Cold War and today it is responsible for managing a wide variety of specialized and often classified aircraft programs. These include the Air Force's RC-135 fleets, Area 51's unique HH-60U Ghost Hawk helicopters, and what are often described as "non-standard" aircraft. It supports secretive aviation projects for other U.S. military services, U.S. government agencies, and even foreign allies and partners, too. N645HM is known to actively support U.S. Special Operations Command (SOCOM) projects, specifically, though it is not related in any direct way to the Air Force Special Operations Command's (AFSOC) fleet of C-146A Wolfhounds, which are militarized Dornier Do 328s configured primarily as light airlifters.


Not much is known about N645HM, which the Sierra Nevada Corporation (SNC) sold to the Air Force in 2014, or its specific activities, in general. The fact that it is known that it belongs to Big Safari at all is something of a clerical error. SNC listed the 645th AESG the buyer in the official bill of sale that it sent to the Federal Aviation Administration (FAA). In 2018, officials at Wright-Patterson Air Force Base in Ohio, where the group is headquartered, tried to get it changed to simply "United States Air Force," but the FAA said they would need to submit a revised bill of sale, according to documents the author obtained via the Freedom of Information Act (FOIA). The Air Force appears to have dropped the issue and renewed the plane's registration just this year without making any changes to the information about who actually owns the plane. 

In many ways, Cougar's appearance in the Portland area seems very similar to the activities of an even more top-secret Air Force CASA CN-235 aircraft near Seattle, Washington in 2017. That aircraft, which is also configured for intelligence, surveillance, and reconnaissance missions and affiliated with the secretive Joint Special Operations Command (JSOC), flew circles over that city for days as part of what could have been a test or exercise.

Whatever N645HM was or wasn't doing near Portland this week, the Air Force has now unequivocally said it was not related to the protests in that city.