US Military Sikorsky VH3D incident

On August 4, 2026, about 1434 eastern daylight time (EDT), Marine One (VM1) a Sikorsky VH-3D, and Envoy Air flight 3742 (ENY3742), an Embraer E-170, were involved in a loss of separation about 2 miles north of Ronald Reagan Washington National Airport (DCA), Arlington, Virginia. There were no injuries reported to the passengers or crewmembers on board either aircraft. VM1 was a military Presidential transport local flight operating under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91 from The Ellipse Park, Washington, D.C. ENY3742 was a scheduled domestic passenger flight operating under the provisions of Title 14 CFR Part 121 from DCA to Pensacola International Airport (PNS), Pensacola, Florida. At the time of the loss of separation, VM1 had departed The Ellipse when ENY3742 was departing runway 1 and beginning their initial climb. After the loss of separation, VM1 completed their local flight without incident while ENY3742 completed their flight to PNS without incident. Figure 1 below shows key locations and estimated position of both aircraft at FAA’s estimated closest proximity.

Figure 1. Key locations and estimated position of both aircraft at FAA's estimated closest proximity overlaid onto a street map in Google Earth. As part of the investigative process, the NTSB invited qualified parties to participate in the investigation. Parties to the investigation include the Federal Aviation Administration (FAA), Department of the Navy (DON), and Envoy Air Inc. In accordance with the International Civil Aviation Organization (ICAO) Annex 13, Centro de Investigação e Prevenção de Acidentes Aeronáuticos (CENIPA) of Brazil, representing the State of Design of the Embraer 170 airplane, was notified of the investigation. Certified air traffic control (ATC) audio recordings and Standard Terminal Automation Replacement System (STARS) radar data were provided by the FAA. Table 1 provides a summary of key communications between the DCA Airport Traffic Control Tower (ATCT) Helicopter Control (HC) and Local Control (LC) controllers and the flight crews of VM1 and ENY3742. The two transmissions in red italics were sourced from a third-party application: ATC – Live Air Traffic Radio. According to the disclaimer in their application, ATC audio in their application is sourced from Enhanced Radar (a company that builds Artificial Intelligence (AI)-driven systems to transcribe, analyze, and optimize ATC communications and airspace operations) and processed with their Y4-small AI model. These transmissions were not received by FAA ATC radio receivers and were unable to be heard by the DCA ATCT HC or LC controllers. Note: The HC and LC positions operate on different frequencies and therefore, flightcrews and controllers can only hear what is being transmitted on the frequency they are using – in this case, VM1 was on the HC frequency and ENY3742 was on the LC frequency. Table 1. Summary of key communications between DCA ATCT (both HC and LC control), and flight crews of VM1 and ENY3742. All times are approximate and in EDT. (Communications in red italics were not able to be heard on FAA ATC frequencies.)

A preliminary FAA estimate of the closest proximity between VM1 and ENY3742 determined they were about .82 miles apart laterally and about 700 feet vertically, as shown in figure 2.

Figure 2. Radar flight tracks of both VM1 and ENY3742 overlaid onto satellite imagery with the FAA estimated closest proximity illustrated (.82 nautical miles (nm) lateral and 700 feet vertical). Envoy Air Flight 3742 Flightcrew Statements Postincident statements provided by ENY3742 flightcrew revealed the first officer (FO) was the pilot flying and the captain was the pilot monitoring. Both crewmembers recalled that after takeoff from runway 1, as the aircraft climbed and accelerated, the Terminal Collision Avoidance System (TCAS) announced a traffic advisory (TA) with “Traffic, Traffic.” At no time was the TCAS TA target acquired visually by either crewmember. The TCAS TA target symbol remained to the right and below their own-ship symbol the entire time. Both recalled seeing 600 feet of vertical separation being displayed on TCAS as the TA target passed behind their right wing of the own-ship symbol on the display. The captain added that at no time was the TCAS resolution advisory (RA) displayed, announced, or commanded. DCA Helicopter Frequency Communications Certified ATC audio recordings revealed that the first attempt to contact DCA ATCT was not received at all, and the second attempt was broken and completely unreadable (to which the controller advised on frequency). The frequency had been working normally and there were no known outages or reports of degradation of this frequency on the day of the event, nor was there a history of problems with this frequency according to FAA. As a result of the missed transmissions with VM1 on the day of the incident, FAA technicians from Spectrum Engineering conducted a coverage analysis and determined that there was not adequate line-of-sight to ensure communications between the radio transmitter/receiver sight and The Ellipse, where VM1 was temporarily operating from while construction was ongoing at the White House. FAA Technical Operations Personnel Interviews Postincident interviews were conducted with personnel from FAA’s technical operations responsible for the ATC radios used at DCA ATCT. Both technicians stated that there had been no documented history of reported problems with the HC frequency and had been no report on the day of the incident until after the incident had occurred. After finding the line-of-sight deficiencies in their coverage analysis done immediately after becoming aware of the problem, the FAA relocated the radios for the HC frequency from their location in a nearby residential neighborhood, to the top of the DCA ATCT. DCA ATCT Air Traffic Manager Interview The postincident interview with the air traffic manager (ATM) also revealed that there was no known history of problems with the HC frequency from ATC. The ATM also reported that once the technicians had relocated the radios to the tower, ATC conducted radio checks with two separate Marine Helicopter Squadron One (HMX-1) aircraft located at The Ellipse and in the local vicinity and reported no deficiencies. Additionally, there were no deficiencies noted in communication with other helicopters in communication with DCA ATCT either. Meeting Between DCA ATCT and HMX-1 DCA ATCT and HMX-1 staff met the week preceding the incident on July 30, 2026. According to the ATM, this was not a regularly scheduled meeting, but rather a meeting that had been requested by HMX-1 to discuss local operations and to express the need for more training flights within the DCA Class B airspace, and ATC wanted to discuss concern with recent reports of their not receiving the required 3 minute to liftoff call from HMX-1 flight crews. At that time, HMX-1 advised that communications “had been spotty,” and felt that may have been the reason. It was agreed that they would attempt other means of reaching the tower in situations where they were unable to reach them to provide the 3-minute call (for example, relaying through another aircraft), and on the day of the incident evidence showed they did. After not reaching them on their initial attempt, they had attempted to relay the 3-minute call through the helicopter facility at Joint Base Anacostia-Bolling, which was also unsuccessful. Loss of Standard Separation The FAA reported the preliminary estimated closest proximity between VM1 and ENY3742 as about .82 nm laterally and 700 feet vertically. This would meet the required minimum radar separation as set forth in FAA Order JO 7110.65BB, Air Traffic Control, paragraph 7-9-4, which required 1.5 nm lateral or 500 feet vertical separation within Class B airspace, between a VFR aircraft and any aircraft weighing more than 19,000 pounds or any turbojet aircraft. The NTSB is still reviewing all sources of surveillance data to calculate and confirm closest proximity. Additionally, in accordance with the letter of agreement (LOA) between HMX-1 and Washington, DC area ATC facilities, aircraft operations with the President on board require flightcrews to contact DCA ATCT on 134.35 (HC frequency) 3 minutes prior to departure, and according to the LOA between DCA ATCT and PCT TRACON, DCA would stop all departures once the 3-minute call was received. In this incident, after attempting to contact DCA ATCT at least twice, they ultimately departed and were then able to reach DCA ATCT when the helicopter reached an altitude that provided adequate line-of sight communications. Having received no 3-minute call, the LC controller had cleared ENY3742 for takeoff and the airplane was becoming airborne simultaneously as VM1 established communications with the tower. The current altimeter setting and traffic advisory were provided to VM1, to which the crew immediately reported visual contact with the traffic. The NTSB’s incident investigation is ongoing.

Verbatim NTSB factual narrative from the NTSB dataset