Overview
- A preliminary NTSB report found that Marine One’s required three-minute departure calls were not received by Ronald Reagan National controllers on Aug. 4, producing a momentary loss of separation with an Envoy Air jet.
- Preliminary federal estimates place the closest gap at about 0.82 nautical miles laterally and roughly 700 feet vertically, a distance that met the vertical standard but fell short of the lateral separation rule.
- Investigators traced the problem in part to Marine One’s temporary move to the Ellipse during White House helipad construction, which created inadequate radio line-of-sight between the helicopter and the airport receiver.
- HMX-1 pilots and Reagan tower staff agreed on July 30 to use backup relays if direct radio contact failed, but those relays did not work on Aug. 4 and related ATC audio shows a similar relay was needed again in late August.
- The FAA moved the transmitter to the top of the Reagan tower and reported successful follow-up tests, the NTSB and FAA continue active investigations, and officials warn the episode raises wider safety questions for Washington’s mixed military and civilian airspace.