What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Narrative: on March 11, 1998, about 1145 Alaska standard time, a Boeing 737-205 airplane, N733AR, had an uncommanded rudder movement while parking at the gate at Anchorage International Airport, Anchorage, Alaska. The airplane was operated by arco Alaska, inc., under 14 CFR part 91, between prudhoe bay, Alaska, and Anchorage. There were no injuries to the two pilots, three flight attendants, or the 76 passengers on board. During a telephone conversation with the NTSB investigator on March 11, the captain indicated that while on the ground in prudhoe bay, the crew felt a momentary airframe vibration. The airplane then departed prudhoe bay en-route to Anchorage. On arrival in Anchorage, while completing the shut down check list, the crew again felt a moderate vibration. Ground personnel outside the airplane noted the 76 passengers on board. During maintenance troubleshooting, while on ground power, application of rudder resulted in a severe airframe vibration. Ground personnel reported the rudder was moving at a very high rate of speed. Further tests involving NTSB, FAA, Boeing and arco Alaska personnel, determined that the yaw damper coupler was producing oscillatory inputs to the rudder actuator. The coupler has been removed for further testing.
As the FAA filed it
NARRATIVE: ON MARCH 11, 1998, ABOUT 1145 ALASKA STANDARD TIME, A BOEING 737-205 AIRPLANE, N733AR, HAD AN UNCOMMANDED RUDDER MOVEMENT WHILE PARKING AT THE GATE AT ANCHORAGE INTERNATIONAL AIRPORT, ANCHORAGE, ALASKA. THE AIRPLANE WAS OPERATED BY ARCO ALASKA, INC., UNDER 14 CFR PART 91, BETWEEN PRUDHOE BAY, ALASKA, AND ANCHORAGE. THERE WERE NO INJURIES TO THE TWO PILOTS, THREE FLIGHT ATTENDANTS, OR THE 76 PASSENGERS ON BOARD. DURING A TELEPHONE CONVERSATION WITH THE NTSB INVESTIGATOR ON MARCH 11, THE CAPTAIN INDICATED THAT WHILE ON THE GROUND IN PRUDHOE BAY, THE CREW FELT A MOMENTARY AIRFRAME VIBRATION. THE AIRPLANE THEN DEPARTED PRUDHOE BAY EN-ROUTE TO ANCHORAGE. ON ARRIVAL IN ANCHORAGE, WHILE COMPLETING THE SHUT DOWN CHECK LIST, THE CREW AGAIN FELT A MODERATE VIBRATION. GROUND PERSONNEL OUTSIDE THE AIRPLANE NOTED THE 76 PASSENGERS ON BOARD. DURING MAINTENANCE TROUBLESHOOTING, WHILE ON GROUND POWER, APPLICATION OF RUDDER RESULTED IN A SEVERE AIRFRAME VIBRATION. GROUND PERSONNEL REPORTED THE RUDDER WAS MOVING AT A VERY HIGH RATE OF SPEED. FURTHER TESTS INVOLVING NTSB, FAA, BOEING AND ARCO ALASKA PERSONNEL, DETERMINED THAT THE YAW DAMPER COUPLER WAS PRODUCING OSCILLATORY INPUTS TO THE RUDDER ACTUATOR. THE COUPLER HAS BEEN REMOVED FOR FURTHER TESTING.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.