Douglas DC-9-34 incident near St. Louis, Missouri, April 30, 1998
On April 30, 1998 at about 3:40 pm local time, a Douglas DC-9-34, registered N928L, was involved in an incident near St. Louis, Missouri. It was a flight of an unrecorded kind under scheduled airline rules (Part 121). No one was hurt; 44 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
the yaw rate gyro of the Stab Aug Computer had been installed in a reverse position that was 180 degrees opposite from the correct position.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 30, 1998 · about 3:40 pm local time
- Place
- St. Louis, Missouri · map
- Type
- Incident
- Injuries
- No one was hurt; 44 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Douglas DC-9-34 · all DC-9-34s on the register
- Registration
- N928L · no longer on the register · serial 48124
- 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 experienced a flight control malfunction after takeoff. The flight declared an emergency and returned to the airport safely with no damage to the aircraft or injuries to the crew or passengers. The Captain stated: 'After takeoff the aircraft began to yaw and roll in a cyclic fashion left and right. I switched the yaw damper off and on to ensure that the yaw damper was on. Yaw and roll continued and appeared to increase in its yaw amplitude as the airspeed increased... I declared an 'Emergency' and requested an immediate return for a landing with the emergency equipment standing by... The landing was made in a normal fashion without damage to the aircraft or injury to anyone on board. Total air time was 6 minutes.' The Stability Augmentation Computer, Part 2587826-3, S/N 0270890 was inspected at the TWA Maintenance Facility. The inspection determined that the yaw rate gyro of the Stab Aug Computer had been installed in a reverse position that was 180 degrees opposite from the correct position.
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
- Medical certificate: Unknown
- Seat: unk
The aircraft
- Last inspection: inspection type not recorded
- Landing gear: fixed
- Engine: (type not recorded); 0 hours total
- Not recorded
- Operator: Trans World Airlines
The flight
- Departed from: STL
- Destination: YYZ Toronto
- Flight plan: IFR
- Runway 0
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 | 39 |
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.