Boeing 737-205 N733AR

Summary

On 11 March 1998 at about 15:45 local time, a Boeing 737-205 registered N733AR, operated by Arco Alaska, Inc., was involved in an incident near Anchorage, Alaska, United States. 81 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

11 March 1998 at 15:45

Classification

Incident

Location

Anchorage, Alaska, United States

Nearest airport

Anchorage Int'l Airport (ANC)

Coordinates

61.1602, -149.9900

Aircraft

Boeing 737-205

Registration

N733AR

Category

Airplane

Engines

2

Operator

Arco Alaska, Inc.

Operating rule

Part 91: General Aviation

Purpose of flight

Business

Phase of flight

Not recorded

Route

Prudhoe Bay → Unknown

Aircraft damage

Not recorded

Weather

Unk

Light

Day

NTSB number

ANC98IA026

Nobody was injured.

The dynamic imbalance in the yaw rate gyro, which provided input to the yaw damper and rudder. A factor was the deteriorated grease in the gyro bearings.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

During parking at the gate, the airplane's rudder began a rapid rudder oscillation which shook the entire airplane. Postincident testing determined that the rudder was oscillating approximately 1.5 degrees either side of centerline, solely within the authority of the yaw damper. No corresponding cockpit rudder pedal movement occurred. Further testing revealed a loss of grease to the yaw rate gyro spin bearings, and corresponding damage to the spin and gimbal bearings. The yaw damp coupler and gyro had accumulated 24,850 hours in service.

Quoted verbatim from the NTSB record.