NTSB Links White House Construction to Marine One Radio Failure
A preliminary federal investigation says construction at the White House contributed to a radio coverage problem before an August 4 loss of separation involving Marine One and a commercial airliner near Ronald Reagan Washington National Airport.
The National Transportation Safety Board report, updated August 27, says Marine One, a Sikorsky VH-3D, and Envoy Air Flight 3742, an Embraer E-170 flying from Reagan National to Pensacola, came within a preliminary Federal Aviation Administration estimate of 0.82 nautical miles laterally and 700 feet vertically.
No injuries or aircraft damage were reported. Both aircraft completed their flights, but the NTSB emphasized that its report is preliminary and subject to change.
What happened near Reagan National
The incident occurred at about 2:34 p.m. EDT on August 4, roughly two miles north of Reagan National in Arlington, Virginia. Marine One was operating from the Ellipse because construction was underway at the White House. Envoy Air Flight 3742 was departing runway 1 and beginning its initial climb.
Marine One’s crew attempted to contact the airport’s helicopter-control frequency before departure. The first transmission was not received by the tower, and the second was broken and completely unreadable, according to certified air traffic control recordings reviewed by the NTSB.
Because controllers did not receive the required three-minute warning call, the local-control position cleared Envoy 3742 for takeoff. Marine One established communication with the tower once it reached an altitude that provided adequate line of sight. The crew was given a traffic advisory, reported visual contact with the airplane and briefly delayed its movement.
Investigators found a line-of-sight gap
FAA technicians conducted a coverage analysis after the missed transmissions. They determined that the temporary Marine One location at the Ellipse did not have adequate line of sight to the existing radio transmitter and receiver used for helicopter control.
The finding connects the communication problem to the relocation of Marine One’s operating site during White House construction. It does not assign fault to individual pilots or controllers, and it is not a final determination of the event’s cause.
The NTSB report also says Marine Helicopter Squadron One and Reagan National controllers had met on July 30 to discuss reports that crews were not receiving or completing the required three-minute calls. They agreed to try alternate relay methods when direct contact failed. On August 4, an attempted relay through the helicopter facility at Joint Base Anacostia-Bolling was unsuccessful.
FAA moved the helicopter-control radios
After the incident, FAA technicians moved the helicopter-control radios from a nearby residential neighborhood to the top of the Reagan National tower. Radio checks with two Marine Helicopter Squadron One aircraft operating from the Ellipse and the surrounding area found no communication deficiencies, the NTSB said.
The change addressed the specific coverage deficiency identified after the August 4 event. It does not resolve every operational question while the investigation remains open.
Why the preliminary distance matters
The NTSB reported a preliminary FAA estimate of about 0.82 nautical miles of lateral separation and 700 feet of vertical separation. Investigators are still reviewing surveillance data to calculate and confirm the closest point.
The report cites an FAA rule requiring 1.5 nautical miles of lateral separation or 500 feet of vertical separation in the relevant Class B airspace. The preliminary estimate did not meet the lateral minimum but did exceed the vertical minimum. That is why the NTSB is treating the event as a loss of separation while continuing to examine the exact flight paths and applicable procedures.
What remains unresolved
The NTSB investigation is ongoing, and the preliminary report may change as investigators review surveillance data, recordings and other evidence. The agency has not issued a final cause determination.
Associated Press reporting also described a separate, brief Marine One communication problem on August 27. The cause of that episode was not established in the available reporting, so it should not be treated as proof that the FAA’s radio relocation failed.
The next developments to watch are additional NTSB findings, any FAA or military procedural changes and evidence about whether further equipment or coordination changes are needed for presidential helicopter operations near Reagan National. Commercial flights can be subject to special coordination or departure holds when those operations are active.
Sources
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