Amateur-built TU206G accident near Cochise, Arizona, February 19, 1993
On February 19, 1993 at about 10:45 pm local time, a amateur-built TU206G, registered N9987M, was substantially damaged in an accident near Cochise, Arizona. It was a ferry flight under general aviation rules (Part 91). 3 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE PILOT'S CONTINUED FLIGHT INTO KNOWN FORECASTED ICING CONDITIONS, IN AN AIRPLANE NOT CERTIFICATED FOR SUCH FLIGHT, WHICH RESULTED IN AN ENGINE FLAMEOUT DUE TO ENGINE ICE/WATER INJESTION, AND THE PILOT'S INABILITY TO RESTART THE ENGINE DUE TO INADEQUATE INSTALLATION OF THE PNEUMATIC AIR LINES ON THE COWL DOOR SEQUENCING VALVES WHICH PREVENTED THE ALTERNATE AIR DOORS TO COMPLETELY CYCLE OPEN. THE INADEQUATE SYSTEM DESIGN LED TO A BLOCKED COMPRESSOR INLET. FACTORS IN THE ACCIDENT WERE: ICING CONDITIONS, INADEQUATE ENGINE AND INDUCTION ANTI-ICING SYSTEM DESIGN, FAILURE OF THE MANUFACTURER TO PERFORM ADEQUATE SYSTEM TESTING TO ENSURE ADEQUATE OPERATION, AND MOUNTAINOUS TERRAIN.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 19, 1993 · about 10:45 pm local time
- Place
- Cochise, Arizona · map
- Type
- Accident
- Injuries
- 3 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built TU206G
- Registration
- N9987M · no longer on the register · serial U20604636
- Damage
- Substantial damage
- Flight
- Ferry flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE ENGINE FLAMED OUT AFTER ENCOUNTERING FORECASTED ICING. (THE PILOT HAD EARLIER USED ALTERNATE AIR, BUT WAS UNABLE TO MAINTAIN ALTITUDE DUE TO THE POWER LOSS). DURING AIR RESTART, TOT ROSE TO ABOUT 520 DEG, THE ENGINE WOULD NOT ACCELERATE, AND QUICKLY DIED AWAY. A FORCED LANDING WAS MADE IN MOUNTAINOUS TERRAIN. THE INDUCTION SYSTEM HAS NORMAL AND ALTERNATE AIR PATHS. NORMAL PATH HAS TWO RAM AIR SCOOPS DIRECTING AIR TO AN AIR BOX, THEN DOWN TO THE ENG INLET. SELECTION OF ALT AIR PATH DIRECTS ENGINE BLEED AIR TO CLOSE THE RAM AIR SCOOP DOORS, AND OPEN ALT AIR DOOR ON BOTTOM OF COWL. AIR THEN CIRCULATES AROUND ENGINE AND THROUGH A SPRING LOADED DOOR ON REAR OF AIR BOX. ON SITE EXAM FOUND RAM AIR DOORS CLOSED AND COCKPIT LEVER ON ALT AIR. ALT AIR DOOR OPEN AIR LINE WAS FOUND TO HAVE A LOOSE B-NUT FITTING AT THE VALVE. CHECKLIST CALLS FOR ALT AIR DURING AIR START. STC HOLDER COULD NOT PRODUCE ANY ENGINEERING OR FLIGHT TEST DATA TO VALIDATE THAT ENGINE WOULD PRODUCE SUFFICIENT VACUUM TO OPEN AIR BOX SPRING LOADED DOOR DURING AIR START.
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: commercial pilot
- Ratings: single-engine land; single-engine sea; instrument: airplane
- Flight time: 6,042 hours in all; 28 in this make and model; 103 in the last 90 days; 45 in the last 30 days; 5,933 as pilot in command
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 1,304 hours
- Last inspection: annual inspection, February 3, 1993; 32 hours since
- Maximum gross weight: 3,800 lb
- Seats: 6
- Landing gear: fixed
- Engine: Allison 250-C20S (turboprop); 0 hours total
- Operator: Hammonds Air Service
The flight
- Departed from: MYF San Diego CA at 9:00 pm
- Destination: ELP El Paso TX
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 5 statute miles
- Sky: overcast at 1,200 ft; not recorded at 1,200 ft
- Temperature: 61°F (16°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 2 |
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.