19990615007109A

Accident · Destroyed

FAA accident report · Hughes OH-6A · Tucson, AZ · June 15, 1999

Date
June 15, 1999 · 13:35 local
Place
Tucson, AZ
Airport
Tucson International
Phase of flight
Pwr On Vertical Ldng/Rtrcrft
Operating rules
General operating rules (Part 91)
Damage
Destroyed
Aircraft
N6187C
NTSB investigation
NTSBLAX99GA216
Reported as
Hughes OH6A
Reported engine
Allison 250C20B
Fatal injuries
0
Pilot’s flight hours
5,500 total1,500 in this make and model

From the FAA’s Accident/Incident Data System (AIDS), through its Aviation Safety Information Portal, as reported. The NTSB investigates accidents separately, and its record of an accident is the fuller one. The aircraft is matched to the registry 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.

What happened

The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.

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.

As the FAA filed it

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.

NTSB investigation

The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.