The only privately owned Sea Harrier vertical/short take-off and landing fighter suffered a gear collapse when making an emergency landing at the US Navy's Patuxent River test centre after experiencing a hydraulic problem.

This video footage posted by Nalls Aviation, the US owner of the ex-Royal Navy BAE Systems Sea Harrier F/A-2, shows the 11 November emergency vertical landing on the hover grid at Pax River in Maryland.

According to the Sea Harrier's owner Art Nalls, the hydraulic problem occurred on only the second flight since the ex-Royal Navy aircraft was made airworthy following its arrival in the USA.

The first flight was the day earlier, on 10 October from St Mary's airport in Maryland, and the landing gear remained down throughout that flight. On the second flight the gear was cycled soon after take-off.

"Approximately 12 minutes into the flight , I got a 'hydraulic 1' warning light," says Nall. He lowered the gear, but "all landing gear indications remained unsafe".

The decision was taken to divert to nearby Pax River for an emergency vertical landing. Nall executed a series of positive- and negative-G manoeuvres in a bid to use gravity to lock the gear down, but did not get a positive indication.

The Sea Harrier arrived in the hover over the V/STOL grating at Pax "looking like it had all gear hanging down...but still unsafe indications in the cockpit," he says. "We thought we had the main gear and nose gear down. The landing light illuminated, which is an indication the nose gear is down and locked - but it's not a reliable indication, I have since been told."

Nall, a former US Marine Corps AV-8 Harrier pilot, had not flown a vertical landing in 16 years, "but it was like putting on an old pair of shoes", he says, praising the Sea Harrier's flight controls. After a gentle touchdown, the nose gear and starboard outrigger abruptly collapsed.

"It was the most violent 4ft fall I have ever had," he says. "By the grace of God the ejection seat didn't fire."

Damage to the Sea Harrier appears to be minor. "There is no evident engine damage, only cosmetic nose abrasions and some minor skin wrinkling," he says. The aircraft is on its wheels and will be towed back to St Mary's by road for repairs.

A replacement radome, nose-gear doors, starboard pitot-static probe and VHF aerial are already on their way from the UK, he says.

The incident occurred during "Phase 1" flight testing to gain FAA approval to put the civil-registered Sea Harrier on the US air show circuit. Phase 1 requires 4h of flight testing to demonstrate safe handling. Nall expects the aircraft to make its East Coast display debut in the spring.

A Washington, DC real-estate developer, Nall acquired the freshly overhauled aircraft via a broker from the UK Ministry of Defence after the Sea Harriers were retired from service. He believes it is the only flyable privately owned Harrier in existence and is looking for sponsors to keep the aircraft on the show circuit.