# NTSB LAX93LA126: Cessna Soloy TU206G, N9987M, Cochise, AZ, February 19, 1993 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: February 19, 1993, 15:45 local (22:45 UTC) - Place: Cochise, AZ - Coordinates: 32.059848, -109.910171 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.0598&lon=-109.9102&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 3 minor - Status: Completed, report March 25, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 27928 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX93LA126 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27928/pdf - Page: https://openairdocs.org/ntsb/LAX93LA126 ## Probable cause 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. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - nonmechanical, cruise - normal - weather condition - icing conditions (contributing factor) - flight into known adverse weather - continued, pilot in command (cause) - powerplant - ice (cause) - powerplant - water (cause) - Forced landing, descent - bleed air system,fittings - loose (cause) - maintenance,installation - inadequate, other maintenance personnel (cause) - anti-ice/deice system - inadequate (contributing factor) - acft/equip,inadequate design, manufacturer (contributing factor) - acft/equip,inadequate compliance determination, manufacturer (contributing factor) - In flight collision with terrain/water, descent - terrain condition - none suitable (contributing factor) - terrain condition - mountainous/hilly (contributing factor) ## Analysis 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. ## Aircraft - Registration: [N9987M](https://openairdocs.org/deregistered/N9987M-1993-07-20), registration cancelled 1993-07-20, S/N U20604636 (OpenAirDocs) - Reported make and model: Cessna Soloy TU206G - Registry model: [Cessna TU206G](https://openairdocs.org/model/cessna-tu206g) (registry code 2073357) (OpenAirDocs) - Category: Airplane - Serial number: U20604636 - Airframe hours: 1304 - Engines: ALLISON 250-C20S 420 horsepower turbo prop - Damage: Substantial damage - Flight: Ferry, Part 91 - Operator: Hammonds Air Service - Registered owner: Daedalus Aviation, Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, February 3, 1993, 32 hours before - Departed: MYF, SAN DIEGO, CA - Destination: ELP, EL PASO, TX - Flight plan: IFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 42; commercial; airplane ratings: single-engine land, single-engine sea; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 6,042 total, 28 in this make and model, 5,933 as pilot in command, 103 in the last 90 days, 45 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 5 statute miles - Lowest ceiling: 1,200 ft overcast - Temperature: 61 °F ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 19930219002939A](https://openairdocs.org/incident/19930219002939A), Feb 19, 1993: Cessna STC206CESSNA, Cochise, AZ, Substantial damage. En route in icing conditions engine flamed out. Unable restart in bypass mode. Bleed air b nut loose. Ice placard. From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.