Boeing 737-205 incident near Anchorage, Alaska, March 11, 1998
On March 11, 1998 at about 3:45 pm local time, a Boeing 737-205, registered N733AR, was involved in an incident near Anchorage, Alaska (Anchorage Int'L Airport). It was a business flight under general aviation rules (Part 91). No one was hurt; 81 people were on board or involved. The weather was conditions the NTSB did not record.
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The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 11, 1998 · about 3:45 pm local time
- Place
- Anchorage, Alaska · Anchorage Int'L Airport · map
- Type
- Incident
- Injuries
- No one was hurt; 81 people were on board or involved.
- Weather
- conditions the NTSB did not record
- Aircraft
- Boeing 737-205 · all 737-205s on the register
- Registration
- N733AR · registry record · serial 1256
- Damage
- Not recorded
- Flight
- Business flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane; rotorcraft: helicopter
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 24,850 hours
- Last inspection: continuous airworthiness programme, March 10, 1998; 3 hours since
- Maximum gross weight: 124,500 lb
- Seats: 119
- Landing gear: retractable
- Engine: P&W JT-8D (turbofan); 0 hours total
- Operator: Arco Alaska, INC.
The flight
- Departed from: PUO Prudhoe Bay AK
- Destination: ANC AK
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Sky: not recorded; not recorded
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 5 | |||
| Passengers | 76 |
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number ANC98IA026.