The problem

A Boeing 777-300ER was losing nitrogen pressure in the nose landing gear over successive flights. The leak rate was slow enough to be invisible to visual and soap-bubble inspection but fast enough that a complete pressure loss — and a potential hard-landing scenario — was on the horizon. Traditional troubleshooting would have required a specialist technician dispatch and an extended AOG.

How the UL101 solved it

The line mechanic used the UL101 with an airborne cone accessory to scan the manifold and fittings on the nose gear. A defective manifold assembly produced a clear, localized ultrasonic hiss that the operator could pinpoint within a few feet of scanning. The failing manifold was replaced in place without dispatching a specialist and without waiting for an off-site diagnostic team.

The outcome

The nose gear was restored to full nitrogen pressure. The airline avoided both the AOG cost and the safety exposure of continued dispatch with a leaking gear. Because the diagnosis and repair were performed by the on-site line team, no specialist dispatch was required.