Navy Releases Timeline For Mysterious 2019 “UAS Swarm” Involving Warships Off California

An official unredacted presentation shows how an encounter with the swarm went down, as well as an infrared image supposedly showing the vehicles.

byAdam Kehoe and Marc Cecotti| UPDATED Feb 10, 2022 9:23 PM
Navy Releases Timeline For Mysterious 2019 “UAS Swarm” Involving Warships Off California
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In a previous update on our investigation into a series of drone swarm incidents in 2019, The War Zone published an intriguing, but heavily redacted briefing slide. Strangely, before our appeal could be fully processed, we and other FOIA filers received completely unredacted versions of the same slide attached to separate requests. The unredacted version of the slide provides several new details, namely a timeline of interactions between the U.S. Navy's Arleigh Burke class destroyer USS Paul Hamilton and several objects denoted as “UAS” or unmanned aerial systems. To our knowledge, this is the first publicly available document to use the term “swarm” in relation to the incident.

Additionally, the newly released material includes an infrared image of three of the objects. It is too low in quality to show any identifying features of the objects.

You can view the now unredacted timeline and briefing slide here:

The briefing slide regarding the USS Paul Hamilton interactions with several unidentified aerial objects on July 17, 2019., US Navy

The incidents, which we now know continued on throughout the second half of July, have been the subject of considerable interest since 2020, when documentary filmmaker Dave Beaty first brought them to light. 

As for this new timeline, it shows that the incident began around 2:56 AM Zulu Time, also known as Greenwich Mean Time, on July 17th, or 7:56 PM local time July 16th. U.S. Coast Guard data separately indicates that the USS Paul Hamilton stopped broadcasting its location via the Automatic Identification System (AIS) approximately 10 minutes earlier at 7:47 PM local time. U.S. Navy vessels are not required to broadcast via AIS, and sometimes disable their transponder to lower their overall electronic signature in situations of heightened security. 

Though deck logs do not indicate why the USS Paul Hamilton disabled its AIS, other ships in similar circumstances that month noted that they disabled AIS transponders specifically due to possible UAS activity. Additionally, logs indicate that the event began just after navigation lights were turned on.

At the start of the incident, the timeline indicates that a UAS was spotted at a distance of about one nautical mile. Twenty minutes later, the timeline indicates two UASs were seen with one of them falling in the water. By 8:26 PM local time, multiple UAS were spotted. The timeline also indicates that the bridge was able to see flashing red lights. 

At 8:50 PM local time, the timeline notes a “UAS swarm.” By 9:11 PM the timeline notes that one of the objects was directly overhead at 2,000 feet. Just a minute later, all of the objects appeared to change course and head away from the ship at 60 knots, or 69 miles per hour. However, eight minutes later, UASs were again seen behind the ship. The last event noted in the slide is when one of the UAS crossed the ship at approximately 2,000 feet. In total, the event appeared to last from 7:56 PM local time until 10:39 PM, or a total of two hours and 49 minutes.

USS Paul Hamilton underway at night., USN

Due to the highly abbreviated notation in the briefing slide, it is difficult to discern exactly how many contacts in total were spotted, or how many were observed for a sustained period. The embedded image in the briefing slide, which was taken using an unspecified forward-looking infrared (FLIR) system, is of extremely low resolution. Three blurry dots are discernible, but there are no other visible details. 

Given that the slide and image appear to be a part of a larger presentation, we requested the full document it came from. In response to this request, we were told that the USS Paul Hamilton and the offices of the Commander of Naval Surface Force Pacific and Strike Group Nine conducted a search and determined "that no responsive records exist." We were also told that “the record previously provided to you in a separate request was titled 'UAP Brief' by the Command FOIA Coordinator for his own use to distinguish it as a PowerPoint slide. It is not part of a larger brief.” Although according to the Navy, this slide is not part of a larger presentation, we know that at least one classified briefing document was prepared regarding the pattern of incidents. That document consists of six pages, and its release to us was denied on the grounds of national security.

FOIA Response Letter, The War Zone

Importantly, the unredacted version of the slide and photo were released to us in the context of a request for any video footage or photos produced in connection with these incidents. Given the reference to possible videos in the map caption, we sought clarification from the Navy FOIA coordinator responsible for this request about whether the FLIR image was the only media that had been located with respect to this incident. At the time of writing, the Navy claims that this the only releasable photo or video it has of this event:

The USS Paul Hamilton FLIR image from July 17, 2019, US Navy

It is unknown exactly what system produced the image, or if local conditions could have impacted the clarity of the image. It bears noting that the region saw some fog at the time of this incident. Given that the USS Paul Hamilton was some distance from any established weather observation station it is impossible to know the exact local conditions. However, fog may have played a role in visually identifying and photographing the objects. Still, the destroyer has multiple infrared sensors, including one that is extremely powerful. Fog has varying levels of impact on infrared imaging equipment depending on the band it is built to operate on.

The description of red flashing lights matches descriptions in other ship logs. After appealing redactions, we recently obtained this log from the USS John Finn from the evening of July 14th, during a separate swarming incident:

Deck log of the USS John Finn, US Navy

The log contains a similar description of a possible UAS with red flashing lights crossing the ship from port to starboard, this time at an estimated elevation of 1,000 feet. Complete alignment with all of the other ships in the area has proven to be challenging. Not all ships submitted deck logs for the relevant time period, notably the Independence class Littoral Combat Ship USS Omaha. In the case of Littoral Combat Ships, digital records are also maintained in a voyage management system (VMS). However, these VMS records are now beyond the retention period. No explanation has been offered as to why the logs were never created.

Watchstanders keep an eye on the action while USS Paul Hamilton navigates the Strait of Hormuz., USN

Several characteristics stand out from this timeline. First, to our knowledge, this is the only publicly available Navy document to directly describe the event as a “UAS swarm.” As has been noted in other incidents from this general timeframe, the overall duration of the event was fairly long. However, it remains unclear exactly how many contacts were detected and if they were observed continuously, or if it was possible that some of the objects came in waves. The timeline also does note at least one object falling into the water, making it possible that some of them did run out of power or malfunctioned during the incident.

The timeline makes no indication of the use of countermeasures, which we now know were the subject of drills in later weeks. Other records indicate that portable counter-drone devices were likely introduced to at least one ship plagued by drone sightings in subsequent weeks.

Strangely, the corresponding deck logs from this time period show nothing out of the ordinary. The complete log records for the evening of July 16th from the USS Paul Hamilton are available below:

US Navy
US Navy

Cumulatively, these new records continue to paint a highly concerning picture. The incident described in the briefing slide was one among several others that occurred throughout the back half of July. Our previous coverage showed that the Navy investigation into this matter did not appear to have much success, and posed similar unanswered questions as to the intent of the UAS operators.

When asked about these incidents in a press briefing in April 2021, Chief of Naval Operations Admiral Michael Gilday said that the Navy has still not determined what these aircraft were or who they belonged to. The Department of Defense and Navy have declined to answer subsequent questions about this matter. As such, it remains uncertain as to the exact extent of the security breaches, or the efficacy of counter-UAS technology fielded later in the month.

In addition to being concerning, taken cumulatively, the documents are also puzzling. It remains unclear why the Navy released a heavily redacted version of the timeline document, only to release it again without any redactions whatsoever. Furthermore, it is strange that an event described as a "UAS Swarm" would result in a detailed timeline and presentation slide, but no obvious references to the events in the underlying deck logs.

The Independence class Littoral Combat Ship USS Omaha. , USN

With respect to deck logs more broadly, records from other vessels, such as the USS Omaha, are incomplete, apparently because they were never created in the first place. For such a major event that resulted in an investigation and the Chief Of Naval Operations being briefed, the fact that the deck logs were never even retained or retrieved from one of the ships involved is puzzling.

While the latest release provides a picture supposedly of the objects, it is so unclear that it adds virtually nothing to our understanding. It remains unknown to what extent the Navy itself understands these incidents, despite the seriousness of being repeatedly swarmed by unknown aircraft in close proximity to home waters. Considering the vast array of sensors deployed aboard a fleet of their most advanced warships that were involved in these events, there is likely a tremendous amount of data they are not releasing to the public and not even commenting on anecdotally. 

We will continue to investigate and to keep readers updated on what we learn about these strange events and the Navy's response to them.

Contact the authors: Adam@thewarzone.com and Marc@thewarzone.com

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