Nosewheel Steering Failure Leads To Runway Excursion

 - November 19, 2020, 12:13 PM

A Bombardier Global 6000 operated by VistaJet experienced a runway excursion following a nosewheel steering (NWS) failure and “inadvertent application of right braking” while landing at Liverpool Airport on Dec. 11, 2019, according to a UK Air Accidents Investigation Branch report issued today. As a result of a fault, the NWS went into free caster shortly after touchdown, the report notes. During the landing roll, directional control was lost and the aircraft—registered as 9H-VJM—departed the runway surface onto the grass, causing no damage.

“The commander, in applying left rudder to try to keep the aircraft straight, had inadvertently applied some right braking,” the AAIB said. “As the aircraft slowed, full left rudder was unable to counteract the effect of this braking.”

According to information from the flight data recorder, the aircraft was stabilized on approach and touched down on mainwheels, slightly right wing down and nose left, at about 115 knots and with the ground spoilers deployed. On rollout, the “small input on the commander’s right brake pedal” lasted about two seconds and “the nosewheel ‘bounced’ twice over a period of four seconds, during which a master caution occurred.”

Two seconds after the master caution illuminated, “the commander verbally announced a ‘nose steer fail’ just as the thrust levers were pulled back to max rev[erse]. A left rudder pedal input was made (copilot still applying right brake) with a corresponding right brake pedal input by the commander.”

The aircraft then started to veer to the right and increasing amounts of left rudder—and right brake by the pilot—were applied. At about 70 knots groundspeed, when full left rudder was reached, the aircraft started to veer more rapidly to the right onto the taxiway before veering further to the right over the edge of the taxiway 10 seconds after full left rudder was applied. According to the report, the aircraft then came to a stop 24 seconds after the master caution illuminated.