Air carrier flight crew reported that during takeoff roll the aircraft veered to the left. When the pilot flying applied right rudder to correct; the aircraft continued turning left. Post-flight it was determined that a nose wheel steering component had been incorrectly installed causing inverse steering commands.
Synopsis
Air carrier flight crew reported that during takeoff roll the aircraft veered to the left. When the pilot flying applied right rudder to correct; the aircraft continued turning left. Post-flight it was determined that a nose wheel steering component had been incorrectly installed causing inverse steering commands.
Narrative
The purpose of this flight was a FCF (Functional Check Flight) due to a heavy check. All flight controls were disconnected and reconnected to replace a beam under the cockpit. After about 30-45 minutes of normal FCF tests of hydraulics and flight controls; we taxied out and completed the reverser test and engine runup. It was after sunset and dark out now. We're cleared for takeoff on Runway XX with no delay due to a flight on the visual approach. We lined up slightly nose left. The Captain; PF; added full power for a standing takeoff with bleeds closed; per FCF procedure. He released the brakes and used the right rudder pedal to steer right; but the aircraft went more left. So he hit the right pedal harder and we went left harder. He aborted the takeoff not too far past the numbers and nose about 45 degrees to the left. The speed appeared to be less than 40 knots and the brakes were in the green. I notified tower and we exited the runway for the arriving plane. We ran the aborted takeoff checklist and continued. We remained on the runway surface at all times but got relatively close to exiting the prepared surface. We hadn't noticed the problem because the tiller had been used up until then. We taxied off and returned to the runway; in agreement with both pilots and Maintenance on board to test the steering while we were out there. I tested my pedals and noticed the commands were reversed. So when I hit the right pedal; the aircraft goes left. We returned to parking without further incident. I don't recall the tail number exactly; but believe this is it.We found out the cause is the component that controls steering through the rudder pedals was installed backwards. I would like to see the FCF checklist modified and updated to include this item since it can easily be installed backwards.
Second reporter narrative
During a Functional Check Flight; after a maintenance-heavy check; the initial take-off was aborted after rudder pedal nose wheel steering was found to be malfunctioning. The aircraft was lined up on the runway power was set to take-off power with full brakes; once the brakes were released and the takeoff roll began; the aircraft started to drift left of the centerline. I (PF) started to apply right rudder to correct to the centerline; but the aircraft continued to go left of the centerline. After achieving full-scale deflection on the right rudder without corrective action from the aircraft; I aborted the take-off and came to a complete stop on the runway. The speed at the time of the abort was less than 40 knots. We ran the QRH and were able to taxi the plane off the runway using the tiller. Before taxing back to the ramp; we lined up on the runway again; this time only intending to test the rudder pedal nose wheel steering. Both the CA and FO side pedals were tested; and it was discovered that both sets of pedals were giving inverse steering commands. Right rudder was giving a left steering command and left rudder was giving a right steering command. The aircraft returned to the ramp and the discrepancy was entered into the logbook.The cause of inverse steering commands was traced back to one of the electrical components that activates nose wheel steering was installed 180 degrees out of normal position. Updating Functional Check Flight Checklist to include more detailed pre-flight checks. To include the testing of rudder pedal steering during taxi out.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.