# Accident 19990615007109A: Hughes OH6A, Tucson, AZ, June 15, 1999 - Type: FAA accident report (Accident/Incident Data System), as reported - Date: June 15, 1999, 13:35 local time - Place: Tucson, AZ - Airport: Tucson International - Damage: Destroyed - Phase of flight: Pwr On Vertical Ldng/Rtrcrft - Operating rules: General operating rules (Part 91) - Location: 32.1503° N, 110.9290° W: From the FAA, an estimate near the named town, within about 3 miles - Nearby events: https://openairdocs.org/map.md?lat=32.1503&lon=-110.9290&mi=10 - Aircraft: N6187C, a cancelled registration (https://openairdocs.org/deregistered/N6187C-2008-07-08) (OpenAirDocs) - Registry model: Hughes OH-6A (registry code 4470905, https://openairdocs.org/model/hughes-oh-6a) (OpenAirDocs) - Reported make and model: HUGHES OH6A - Reported engine: ALLSN 250C20B - Fatal injuries: 0 - Pilot flight hours: 5,500 total, 1,500 in this make and model - NTSB investigation: [NTSB LAX99GA216](https://openairdocs.org/ntsb/LAX99GA216) (OpenAirDocs) - FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/) - Page: https://openairdocs.org/incident/19990615007109A ## Narrative As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^. U.S. BORDER PATROL AIR OPERATIONS HUGHES OH-6A HELICOPTER WAS ON SHORT FINAL TO RWY 03 WHEN THE PILOT STATED THAT THE ENGINE HAD QUIT, AND THE ACFT CRASHED SHORT OF THE RWY, OTHER CIRCUMSTANCES ARE UNKNOWN. (-23) A/C LOST POWER WHILE APPROACHING TUCSON INTL. AIRPORT. THE PILOT AUTOROTATED THE SHIP TO AN AREA OFF THE AIRPORT RESULTING IN SUBSTANTIAL DAMAGE AND INJURIES TO THE PILOT. PRELIMINARY INVESTIGATION REVEALED THE A/C WAS LOW ON FUEL. THE ENGINE WILL BE FURTHER INVESTIGATED FOR MALFUNCTIONS. THE A/C IS OPERATED AS PUBLIC USE AND IS OWNED BY THE US BORDER PATROL. (.4)THE PILOT WAS ON SHORT FINAL APPROACH TO LAND WHEN HE REPORTED AN ENGINE FAILURE. HE ATTEMPTED TO STRETCH HIS GLIDE TO AVOID BUILDINGS AND CARS ON THE GROUND; HOWEVER, THE HELICOPTER STRUCK RAILROAD TRACKS NEXT TO THE FIELD BOUNDARY. DAMAGE TO THE MAIN ROTOR BLADES WAS CONSISTENT WITH A LOW ROTOR RPM AT IMPACT. THE PILOT DID NOT RECALL HOW MUCH TIME HAD ELAPSED SINCE HIS LAST REFUELING. EXAMINATION OF THE NAVIGATION AND FUEL ENDURANCE LOG FROM THE HELICOPTER COCKPIT (REQUIRED BY THE OPERATOR) SHOWED THE PILOT HAD NOT COMPLETED THE FUEL ENDURANCE CALCULATIONS AT THE TIME OF LAST FUELING. TH E HELICOPTER WAS EQUIPPED WITH A MAIN FUEL SYSTEM AND AN AUXILIARY FUEL SYSTEM. A DEFERRED MAINTENANCE ITEM, 'MAIN FUEL GAUGE UNRELIABLE IN FORWARD FLIGHT,' WAS STILL OPEN. THE SAME DISCREPANCY HAD ALSO BEEN ENTERED PREVIOUSLY AND IT, TOO, HAD NOT BEEN CLEARED. THE AUXILIARY FUEL GAUGE WAS ENTERED AS INOPERATIVE ON THE DEFERRED MAINTENANCE LOG WITH 'PARTS ON ORDER' BUT HAD NOT BEEN CLEARED AT THE TIME OF THE ACCIDENT. THE PILOT LAST RECALLED READING APPROXIMATELY 78 POUNDS ON THE MAIN FUEL GAUGE. HE DID NOT RECALL SEEING THE 20-MINUTE LIGHT ILLUMINATE BEFORE THE ACCIDENT. A CHECK OF THE LOW FUEL WARNING SYSTEM FOUND THAT FLOAT ARM CONTACT IN THE FUEL CELL OCCURRED AT 34 POUNDS, WHICH APPROXIMATES 20 MINUTES OF USABLE FUEL; NO DISCREPANCIES WERE FOUND IN THE OPERATION OF THE SYSTEM. NO EVIDENCE OF A FUEL SPILL WAS FOUND AROUND OR UNDER THE WRECKAGE. THE CRASHWORTHY MAIN FUEL CELL WAS UNCOMPROMISED AND ABOUT 12 OUNCES OF TRAPPED FUEL WAS FOUND. NO FUEL WAS FOUND IN THE AUXILIARY FUEL TANK. THE LIGHT BULBS FOR THE 'ENGINE OUT, FUEL LOW, AND MASTER CAUTION' WERE REMOVED FOR EXAMINATION. ONE 'MASTER CAUTION' BULB SHOWED A SMALL AMOUNT OF FILAMENT STRETCHING, CONSISTENT WITH HOT STRETCHING FROM A LIGHT TO MODERATE IMPACT FORCE. THE FILAMENTS OF BOTH 'FUEL LOW' BULBS WERE INTACT AND UNSTRETCHED, CONSISTENT WITH BULBS NOT BEING ILLUMINATED DURING A LIGHT TO MODERATE IMPACT. THE FILAMENTS FROM BOTH 'ENGINE OUT' BULBS SHOWED A SMALL AMOUNT OF STRETCHING, AGAIN CONSISTENT WITH HOT STRETCHING FROM LIGHT TO MODERATE IMPACT. THERE WERE NO OTHER DISCREPANCIES FOUND WITH THE ENGINE OR ENGINE-RELATED SYSTEMS. ## The NTSB's investigation of this event (1) 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. - [NTSB LAX99GA216](https://openairdocs.org/ntsb/LAX99GA216), Jun 15, 1999: Hughes OH-6A (N6187C), Tucson, AZ, destroyed. Probable cause: Fuel exhaustion resulting from pilot's failure to perform adequate fuel consumption calculations. The unreliable and inoperative fuel level indicating system components and the operator's operation… From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record. --- 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.