What aircraft was involved and where did it happen?

The accident on 2001-02-09 involved a Fokker B.V. Fokker F27, Mk050, at Saarbrücken, DE.

Rudder Balance Tab Misadjustment Causes Control Difficulty on Fokker F27

On February 9, 2001, a Fokker B.V. Fokker F27, Mk050 was involved in an aviation accident near Saarbrücken, DE. Investigators recorded the probable cause as: The disturbance occurred because the rudder balance tab deflections were outside the specified tolerance. This summary draws on records from the German Federal Bureau of Aircraft Accident Investigation (BFU).

During a ferry flight, a Fokker F27 experienced severe control issues due to a rudder balance tab misadjusted beyond tolerance. The crew aborted the flight and landed safely; no injuries or damage occurred.

Incident Overview

On 9 February 2001, a Fokker F27 Mk050 operated by an airline (holder) was conducting a ferry flight from Saarbrücken to Cologne-Bonn. The flight crew consisted of two pilots. During the takeoff run, large rudder inputs were required to keep the aircraft on the runway as it pulled strongly to the right. After lift-off and in the initial climb, full left aileron and full left rudder with maximum trim were needed to maintain direction, with deviations of up to ±30° and bank angles reaching 50°.

Actions by the Crew

The pilot flying (PF) was the second pilot. After retracting the landing gear and flaps, the pilot in command (PIC) took control. He reduced engine power and re-extended the flaps to 10°. With full left rudder trim and a speed of approximately 130 knots, the aircraft could be kept on the intended track. The crew decided to abort the flight and return to Saarbrücken. A visual check of the flaps and ailerons revealed no anomalies. During an ILS approach to runway 27, reducing speed to 106 knots (final approach speed) with 60–70% left rudder trim, slight left aileron input, and flaps set to 25° allowed the crew to complete the approach and land safely. Weather at landing: visibility 3 km, cloud base 400 ft, wind 230° at 12 knots.

Findings

Subsequent examination by the operator's maintenance personnel revealed that the rudder balance tab deflection was outside the specified tolerance. The pushrods to the balance tab were adjusted, and all rudder and trim travels were checked and found to be within limits. A post-incident ferry flight showed normal handling characteristics. No cockpit system warnings occurred during the critical situation. There was no checklist for this type of malfunction.

The aircraft had recently undergone a 250-hour maintenance check, during which a logbook entry ("rudder trim not centering in flight") was addressed. Significant play was found in the rudder trim tab bearing; the bearing was replaced and the rudder was reset.

Assessment

After rectifying a technical complaint related to the rudder trim, the maintenance personnel failed to verify that all rudder settings met tolerance requirements.

Conclusion

The disturbance occurred because the rudder balance tab deflections were outside the specified tolerance.

Probable cause