Aerospatiale ATR-42-300 incident near San Juan, Puerto Rico, November 6, 1990
On November 6, 1990 at about 7:16 pm local time, a Aerospatiale ATR-42-300, registered N972NA, was involved in an incident near San Juan, Puerto Rico. 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 IMPROPER USE OF AILERON TRIM AND THE IMPROPER PREPARATION FOR AUTO PILOT DISCONNECT BY THE FLIGHT CREW COMBINED WITH EXCESSIVE FORCES APPLIED BY THE AILERON TRIM SYSTEM RESULTING IN A DEPARTURE FROM CONTROLLED FLIGHT. CONTRIBUTING FACTORS TO THE INCIDENT WERE INADEQUATE AND MISLEADING AUTOPILOT WARNINGS, LACK OF CONSPICUITY OF THE AILERON TRIM INDICATOR, LACK OF FAA REGULATION GOVERNING CONTROL AUTHORITY IN MISTRIM CONDITIONS, AUTOPILOT SYSTEM MASKING OF MISTRIM CONDITIONS, AND THE LACK OF FAA REQUIREMENT FOR RECURRENT PILOT TRAINING IN AUTOPILOT USE.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 6, 1990 · about 7:16 pm local time
- Place
- San Juan, Puerto Rico
- Type
- Incident
- Injuries
- No one was hurt; 44 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Aerospatiale ATR-42-300 ATR 42-300
- Registration
- N972NA · no longer on the register · serial 023
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
PLT STATED AUTOPILOT ENGAGED AT 1,000 FEET AFTER T/O. AILERON TRIM WAS USED AFTER AUTOPILOT ENGAGEMENT. FLT WAS GIVEN HEADING CHANGE TO RT. AUTOPILOT HDG BUG DID NOT TURN A CFT. HE DISCONNECTED THE AUTOPILOT AT 2,200 FT AND THE ACFT IMMEDIATELY ROLLED INTO A LEFT 60 DEGREE BANK AND BEGAN DESCENDING. HE THEN ACTIVATED AILERON TRIM TO THE RT AND ALONG WITH THE COPILOT ON THE CONTROLS THEY RECOVERED. POST CRASH EXAMINATION OF THE ACFT STRUCTURE, FLT CONTROLS, AND AUTOPILOT SYSTEM REVEALED NO EVIDENCE TO INDICATE PREINCIDENT FAILURE OR MALFUNCTION OF THESE. THE DFDR AND RADAR DATA INDICATED THE EVENT OCCURRED AT 3,300 FEET AND THAT FOR 45 SECONDS BEFORE THE EVENT OCCURRED THE AILERONS WERE DEFLECTED TO THE RT 2 TO 5 DEGREES. AFTER THE DESCENDING LEFT TURN BEGAN PLTS DID NOT REDUCE POWER FOR 60 SECONDS AND ACFT SPEED EXCEEDED 250 KNOT VNE SPEED. AFTER THE INCIDENT THE ACFT MFG RESTRICTED USE OF THE AILERON TRIM TO 1 DOT WITH AUTOPILOT ENGAGED, NOT THREE DOTS AS HAD BEEN PREVIOUSLY ALLOWED.
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
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 19,813 hours in all; 1,641 in this make and model; 73 in the last 30 days
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Last inspection: approved inspection programme; 0 hours since
- Maximum gross weight: 36,825 lb
- Seats: 47
- Landing gear: retractable
- Engine: P&W PW-120 (turboprop); 0 hours total
- Operator: Executive Air Charter, INC.
The flight
- Destination: STX St. Croix
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 100° at 8 knots
- Visibility: 15 statute miles
- Sky: broken clouds at 25,000 ft; scat at 2,500 ft
- Temperature: 90°F (32°C), dew point 73°F (23°C)
- Altimeter: 29.00 inHg
- Observation at 6:50 pm from SJU, 5 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 3 | |||
| Passengers | 41 |
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.