Boeing 737-400 incident near Portland, Oregon, November 11, 1999
On November 11, 1999 at about 11:20 pm local time, a Boeing 737-400, registered N772AS, suffered minor damage in an incident near Portland, Oregon. It was a flight of an unrecorded kind under scheduled airline rules (Part 121). No one was hurt; 145 people were on board or involved. The weather was conditions the NTSB did not record.
The NTSB's probable cause their words, unchanged
Arcing in the electrical system wiring for undetermined reasons.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 11, 1999 · about 11:20 pm local time
- Place
- Portland, Oregon · map
- Type
- Incident
- Injuries
- No one was hurt; 145 people were on board or involved.
- Weather
- conditions the NTSB did not record
- Aircraft
- Boeing 737-400 · all 737-400s on the register
- Registration
- N772AS · no longer on the register · serial 25105
- Damage
- Minor damage
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
The flight returned to its departure point after encountering apparent electrical problems, including circuit breakers open for the center tank right pump and the right tank forward pump. After landing, the crew performed a normal shutdown. During taxi in, they noted an electrical smell, which they originally attributed to use of the galley ovens. When they elected to disembark the passengers, passengers leaving the airplane who had been seated mid-cabin noted that they had smelled electrical smoke. The airplane was repowered by maintenance personnel after shut-down and disembarking of passengers. During the trouble-shooting process, additional systems and indicators were affected, including right wing anti-ice and right wing overheat. Technicians isolated an electrical short to the forward cargo compartment. When they touched the panel around station 410, they saw some sparks. Power was removed from the aircraft once the damage was found. The technicians opened the ceiling panel to gain access to the area. When they touched the bottom of the raceway clamp, it fell apart. FAA and NTSB investigators documented the damaged wiring bundles at station 420 above the forward cargo compartment ceiling on the right side of the airplane, and had them sectioned for further inspection and testing. The wire bundle channel and clamp were also removed for inspection and analysis. A total of 113 conductors were reported to have been subjected to the electrical arcing event. Investigators were unable to determine the cause of electrical arcing that burned numerous wires of the subject bundles in two. One of the nine Teflon insulated wires, W336-003-10, exhibited evidence that it might have been damaged prior to the electrical arcing. W336-003-10, and two other 10 gauge wires in the bundles, were conductors for the three-phase 115VAC system A electric hydraulic pump. Electrical arcing had damaged approximately twelve inches of insulation on wire W336-003-10. The exposed conductors at one end of the wire had sustained arc damage at two locations. The arcing burned several wire strands in two, which became unraveled from the rest of the strands. There was approximately one third of the insulation left in this area of the wire. A small area of the edge of the insulation appeared to have been cut prior to the occurrence of the electrical arcing. The wire bundle channel (bracket) and clamp were also analyzed. Evidence indicated that an unidentified wire that was involved in the arcing/burning event had been out of place, along the side of the bracket between the cushioning foam and the plastic (nylon) frame before or during the event. Analysis of these two parts could not determine what type of wire had caused the damage to the side of the cushion clamp or the nylon channel.
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; instrument: airplane
- Flight time: 7,334 hours in all; 3,409 in this make and model; 27 in the last 90 days
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 22,732 hours
- Last inspection: continuous airworthiness programme, November 5, 1999; 57 hours since
- Maximum gross weight: 143,500 lb
- Seats: 148
- Landing gear: retractable
- Engine: Cfm CFM56-3C-1 (turbofan); 0 hours total
- Operator: Alaska Airlines
The flight
- Departed from: KPDX at 11:20 pm
- Destination: KSFF San Francisco CA
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: not reported
- Sky: not recorded; not recorded
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 5 | |||
| Passengers | 140 |
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.