The delay to the first flight of Sikorsky-Boeing’s SB-1 Defiant may not impact the timeline for the US military's Future Vertical Lift programme, a Pentagon official says.

The rigid-rotor, coaxial compound helicopter is months behind schedule for its first flight in the US Army’s Joint Multi-Role Technology Demonstration (JMR-TD), but the delay to the flight vehicle test may not affect the larger FVL programme, says Col Robert Freeland, from the office of the undersecretary of defense (OSD).

The army’s JMR-TD activity serves as the precursor to its FVL competition, which will replace the Boeing AH-64 Apache and CH-47 Chinook and Sikorsky UH-60 Black Hawk. The demonstration phase was designed to inform the service on the limits and possibilities of high-speed rotorcraft technology.

“I wouldn’t focus too much on when we start flying and are we missing something,” Freeland said at the Center for Strategic and International Studies in Washington DC. Instead, he emphasises the designs and capabilities industry has accomplished.

“That should tell us what can we accomplish during a technology maturation risk-reduction [TMRR] phase and when we prepare a JMR-TD for the mission architecture demonstration that tells us the level of risk going forward,” he says.

Freeland will not commit to an acquisition timeline, but says the OSD is well positioned to make the necessary risk-reduction adjustments in the TMRR phase to enter into the engineering, manufacturing and development stage sometime in the mid-2020s, with rapid production following.

JMR-TD was intended to accelerate development by skipping a TMRR phase, but the Department of Defense has not indicated that the demonstration will allow the army to omit such an activity.