Faulty Comms Preceded Marine One/Envoy Close Call

The NTSB is focusing on communication issues involving Marine One—VM1, a Sikorsky VH-3D—which lifted off from a temporary location while construction was ongoing at the White House in the August 4 close call with an Envoy Air Embraer ERJ 170-200 LR (E175) departing Ronald Reagan Washington National Airport (KDCA).

According to the NTSB preliminary report, the aircraft came within 0.82 nm laterally and 700 feet vertically—which was still within guidance of either 1.5 nm laterally or 500 feet vertically—at about 2:34 p.m. local time, roughly two miles north of KDCA. Both flights continued without further incident.

Flying under Part 91, the VM1 crew had departed from the Ellipse behind the White House as the Embraer regional jet had taken off from Runway 1 and begun initial climb for its Part 121 scheduled flight to Pensacola.

VM1 was on the helicopter control (HC) frequency, while Envoy Flight 3742 was on the local control frequency. The VM1 crew twice tried to advise HC of their intended departure, but neither transmission came through. The first was not received at all, while the second was broken and unreadable. The controller advised that, but later told investigators that the frequency had been working normally up to that point and there were no known outages.

Once the aircraft neared each other, the Envoy crew noted a traffic advisory alert from the traffic alert and collision avoidance system (TCAS) but did not spot the helicopter. The target appeared to the right and below the Embraer on the TCAS the entire time. The Envoy crew said they saw 600 feet of vertical separation displayed on TCAS, but at no time was a resolution advisory commanded.

After the incident, FAA technicians from Spectrum Engineering conducted a coverage analysis and found that there was “not adequate line-of-sight to ensure communications between the radio transmitter/receiver site and the Ellipse, where VM1 was temporarily operating from while construction was ongoing at the White House.”

After finding the line-of-sight deficiencies, the FAA relocated radios for the HC frequency from a nearby residential neighborhood to the top of an air traffic control tower. The air traffic manager 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.

Leading up to the incident, HMX-1 met with KDCA air traffic control staff to discuss their need for more training flights within the KDCA Class B airspace. Air traffic control relayed concerns that staff was not receiving the required three-minute-to-liftoff call from HMX-1 flight crews. HMX-1 noted that communications “had been spotty” and agreed to try other means of reaching the tower when they could not reach them through traditional channels.

On the day of the incident, the crew was unsuccessful in its first attempt and then tried through the helicopter facility at Joint Base Anacostia-Bolling, which was also unsuccessful, according to the NTSB. After attempting to contact KDCA ATC, the crew ultimately departed and was able to reach the tower once the helicopter reached an altitude of adequate line-of-sight communications. However, having received no three-minute call, the local controller cleared Envoy for takeoff.