Boeing 767-233 incident near Kansas City, Missouri, April 10, 1993
On April 10, 1993 at about 4:12 pm local time, a Boeing 767-233, registered CGAUP, was involved in an incident near Kansas City, Missouri. It was a flight of an unrecorded kind under foreign airline rules (Part 129). No one was hurt; 101 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A FROZEN AILERON CONTROL BEARING AFTER IT HAD BECOME WORN, CORRODED AND EXPOSED TO WATER, AND THE MANUFACTURER'S INADEQUATE MAINTENANCE/INSPECTION REQUIRMENT OF THE BEARING(S).
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 10, 1993 · about 4:12 pm local time
- Place
- Kansas City, Missouri · map
- Type
- Incident
- Injuries
- No one was hurt; 101 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 767-233 · all 767-233s on the register
- Registration
- CGAUP · no longer on the register · serial 22521
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · foreign airline rules (Part 129)
The NTSB's narrative final · quoted from the NTSB record
THE FLIGHT CREW NOTED A LOSS OF AILERON CONTROL (FELT FROZEN), WHILE CRUISING AT FL 370. THEY WERE ABLE TO MAKE HEADING CHANGES BY USING THE RUDDER & ELECTED TO DIVERT TO KANSAS CITY (MCI). THE AIRPLANE HAD BEEN EXPOSED TO RAIN & STANDING WATER BEFORE THE FLIGHT. THE CREW FELT THE LOSS OF AILERON CONTROL MAY HAVE BEEN DUE TO FROZEN WATER IN THE CONTROL SYSTEM. DURING DESCENT TO MCI, ABOVE FREEZING AIR TEMPERATURES WERE ENCOUNTERED, & CONTROL OF THE AILERONS GRADUALLY RETURNED UNTIL FULL CONTROL WAS REGAINED. AN UNEVENTFUL LANDING WAS MADE AT MCI. INVESTIGATION REVEALED WORN AILERON CONTROL BEARINGS IN THE LATERAL CONTROL ACTUATOR SYSTEM. THE WORN BEARINGS WERE TESTED BY SOAKING IN WATER & FREEZING. WATER PENETRATED A BEARING HOUSING & FROZE INSIDE THE BEARING RACE, DISABLING THE BEARING. SUBSEQUENT DISASSEMBLY OF THE BEARING DISCLOSED CORRODED & WORN BALL BEARINGS. BOEING SERVICE LETTER (767-S-27-094) & SEVICE BULLETIN 767-27-0128 WERE ISSUED TO ADDRESS INSPECTION/REPLACEMENT CRITERIA OF THE BEARINGS.
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
- Medical certificate: Unknown
- Seat: left
The aircraft
- Airframe total time: 32,301 hours
- Last inspection: continuous airworthiness programme, January 2, 2000
- Maximum gross weight: 330,000 lb
- Seats: 255
- Landing gear: retractable
- Engine: P&W JT9D-7R4D (turbofan); 0 hours total
- Operator: Air Canada
The flight
- Departed from: SFO San Francisco CA at 2:47 pm
- Destination: YYZ Toronto
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 50 statute miles
- Sky: clear
- Temperature: -69°F (-56°C), dew point 0°F (-18°C)
- Altimeter: 29.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 8 | |||
| Passengers | 93 |
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.