Douglas DC-8-73 incident near Seattle, Washington, June 17, 2000
On June 17, 2000 at about 1:12 pm local time, a Douglas DC-8-73, registered N831AL, was involved in an incident near Seattle, Washington. It was a flight of an unrecorded kind under scheduled airline rules (Part 121). No one was hurt; 5 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Auxiliary hydraulic pump leak resulting in a failure of the hydraulic system.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 17, 2000 · about 1:12 pm local time
- Place
- Seattle, Washington · map
- Type
- Incident
- Injuries
- No one was hurt; 5 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Douglas DC-8-73 · all DC-8-73s on the register
- Registration
- N831AL · registry record · serial 46149
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
The flight crew reported that while in cruise flight at flight level 310 (31,000 feet) they noted a loss of hydraulic fluid quantity in the aircraft's main hydraulic system reservoir. Shortly after powering the auxiliary rudder pump, the crew felt a '...chattering and feedback with the rudder pedals'. The crew also reported that the rudder momentarily deflected to the left. Post flight inspection of the aircraft's hydraulic system indicated that the auxiliary hydraulic pump was leaking fluid and that the hydraulic fluid quantity was at 'standpipe level'. Examination of the auxiliary hydraulic pump assembly revealed that the gasket located between the hydraulic pump mainframe and the AC electric drive motor, had failed. Further examination of the hydraulic pump subassembly revealed that the rate piston (part number 56909) was 'frozen' in the extended position. A frozen rate piston (in the extended position) could result in high internal case pressures capable of exceeding the manufactures specifications and the specifications of the gasket. Heavy scoring on the piston and the piston housing, with evidence of contamination were also noted.
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, commercial pilot, flight engineer
- Ratings: multi-engine land; single-engine land; instrument: airplane; rotorcraft: helicopter
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 52,823 hours
- Last inspection: continuous airworthiness programme, June 4, 2000; 60 hours since
- Maximum gross weight: 355,000 lb
- Seats: 7
- Landing gear: retractable
- Engine: Ge CFM 56 (turbofan); 0 hours total
The flight
- Departed from: DAY Dayton OH
- Destination: SEA
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: dawn
- Visibility: 10 statute miles
- Sky: broken clouds at 20,000 ft; scat at 16,000 ft
- Temperature: 54°F (12°C), dew point 48°F (9°C)
- Altimeter: 30.00 inHg
- Observation at 12:56 pm from SEA
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 5 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
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 documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text 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 SEA00IA108.