Mcdonnell Douglas DC-9-82 (MD-82) accident near Seattle, Washington, September 2, 1997
On September 2, 1997 at about 4:10 am local time, a Mcdonnell Douglas DC-9-82 (MD-82), registered N951AS, was substantially damaged in an accident near Seattle, Washington (Seattle-Tacoma Intl airport). It was a flight of an unrecorded kind under scheduled airline rules (Part 121). 19 people had minor injuries; 97 others were unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
fatigue failure of the nose landing gear upper lock link, due in part to reduced strength after the manufacturing process was changed from forged to machined plate stock; and inadequate non-destructive inspection process for testing the link.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 2, 1997 · about 4:10 am local time
- Place
- Seattle, Washington · Seattle-Tacoma Intl · map
- Type
- Accident
- Injuries
- 19 people had minor injuries; 97 others were unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Mcdonnell Douglas DC-9-82 (MD-82) DC-9-82 (M · all DC-9-82 (MD-82)s on the register
- Registration
- N951AS · no longer on the register · serial 49111
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
During the landing roll-out, the nose landing gear collapsed. Examination of the nose landing gear revealed the nose gear upper lock link, PN 3914464-503, had failed, and had separated into two pieces. The link, which was subject to recurring non-destructive testing every 5000 cycles (per AD 97-02-10), had an eddy current inspection by the operator, 1075 cycles before the accident. The link was one of a series manufactured from plate stock, rather than being forged. Due to this changed process, the lack of draft angle allowances on the machined parts reduced the load-carrying cross sectional area of the machined links to less than that of the forged links, resulting in a decrease in the overall strength. Metallurgical analysis revealed that about 10,000 major fatigue progression cycles had occurred within about .6 inches of the crack progression. Based on two major stress cycles per gear retraction/extension cycle, the crack length at 1075 cycles before the accident would have been greater than .25 inches. The inspection procedure and process provided by the airframe manufacturer did not specify removal of the upper lock link from the aircraft before recurring non-destructive tests (NDT). During the investigation, NTSB investigators and FAA inspectors observed that access to the upper lock link for NDT was limited when the part remained installed on the airplane.
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
- Ratings: multi-engine land; single-engine land; instructor: instrument airplane; instrument: airplane
- Flight time: 27,388 hours in all; 1,491 in this make and model; 222 in the last 90 days; 69 in the last 30 days; 18,068 as pilot in command
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 45,378 hours
- Last inspection: approved inspection programme, August 30, 1997
- Maximum gross weight: 149,500 lb
- Seats: 138
- Landing gear: retractable
- Engine: P&W JT8D-217 (turbofan); 0 hours total
- Operator: Alaska Airlines
The flight
- Departed from: KLAX Los Angeles CA at 1:21 am
- Destination: KSEA
- Flight plan: IFR
- Runway 16L, 11,900 ft by 150 ft
- A second pilot was aboard
Weather at the time
- Light: night, dark
- Wind: from 220° at 6 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 3,800 ft; clear
- Temperature: 66°F (19°C), dew point 55°F (13°C)
- Altimeter: 30.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 5 | |||
| Passengers | 19 | 92 |
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.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.