What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
The pilot departed the company hangar facility located at the mesquite, TX airport. While enroute to the planned 133 work location west of denton, TX. At low altitude and approximately 12 minutes into the flight, the pilot experienced electrical smoke in the cockpit coming from the battery compartment below the floorboards in a location aft of the left side anti torque pedals and forward of the left pilot’s station, where he was seated. The pilot immediately declared an emergency to the addison ATCT and executed an immediate emergeny landing at a vacant field across the street from a school in Richardson TX. Upon touchdown, the pilot immediatly shut down and exited the helicopter with the hand held fire extinguisher. The pilot accessed the extent of the fire to be minimum and proceeded to open the battery compartment floor cover and discharge the fire extinguisher into the battery compartment successfully and briefly experienced a flash fire during this process. First responders arrived on scene quickly. The pilot was not injured.
The iic arrived upon the secured scene and determined damages were limited to thermal damages to the following components:
The battery case, electrical wiring, electrical componets and painted surfaces in and above the battery compartment. An arcing hole was noted on the top of the gcu box, and arcing damamges on the side of the metallic battery case, as well as arcing damages to the positive terminal on the battery contactor solenoid, all in the same alignment. No damages to any adjacent structural members was noted. The NTSB was consulted and declined to issue a NTSB id to this incedent. The operator diasembled the aircraft and ground transported it to their maintenance facility in beaumont TX for further dissembly and inspection by the operator, per the faa's iic instruction.
Maintenance records comfirmed a servicable battery RG-624 a lead acid battery part #41387736 was installed on 12/6/2024 total time 2411.3. All inspections and maintenance records were complete and current.
Following the operators additional disassembly and assessments, the dom advised that the object that had caused the short circuit of high current directly to ground and the resulting fire, was determined a result of a metallic can of marking paint carried by pilots (for the purpose of marking landing zones) that had bridged from the metallic battery case, across the top of the metallic case of the gcu, to the positive terminal of the battery contactor solenoid, thus rupturing and igniting the contents of the paint can within the battery compartment located below the left pilot station floorboards.
As the FAA filed it
THE PILOT DEPARTED THE COMPANY HANGAR FACILITY LOCATED AT THE MESQUITE, TX AIRPORT. WHILE ENROUTE TO THE PLANNED 133 WORK LOCATION WEST OF DENTON, TX. AT LOW ALTITUDE AND APPROXIMATELY 12 MINUTES INTO THE FLIGHT, THE PILOT EXPERIENCED ELECTRICAL SMOKE IN THE COCKPIT COMING FROM THE BATTERY COMPARTMENT BELOW THE FLOORBOARDS IN A LOCATION AFT OF THE LEFT SIDE ANTI TORQUE PEDALS AND FORWARD OF THE LEFT PILOT’S STATION, WHERE HE WAS SEATED. THE PILOT IMMEDIATELY DECLARED AN EMERGENCY TO THE ADDISON ATCT AND EXECUTED AN IMMEDIATE EMERGENY LANDING AT A VACANT FIELD ACROSS THE STREET FROM A SCHOOL IN RICHARDSON TX. UPON TOUCHDOWN, THE PILOT IMMEDIATLY SHUT DOWN AND EXITED THE HELICOPTER WITH THE HAND HELD FIRE EXTINGUISHER. THE PILOT ACCESSED THE EXTENT OF THE FIRE TO BE MINIMUM AND PROCEEDED TO OPEN THE BATTERY COMPARTMENT FLOOR COVER AND DISCHARGE THE FIRE EXTINGUISHER INTO THE BATTERY COMPARTMENT SUCCESSFULLY AND BRIEFLY EXPERIENCED A FLASH FIRE DURING THIS PROCESS. FIRST RESPONDERS ARRIVED ON SCENE QUICKLY. THE PILOT WAS NOT INJURED.
THE IIC ARRIVED UPON THE SECURED SCENE AND DETERMINED DAMAGES WERE LIMITED TO THERMAL DAMAGES TO THE FOLLOWING COMPONENTS:
THE BATTERY CASE, ELECTRICAL WIRING, ELECTRICAL COMPONETS AND PAINTED SURFACES IN AND ABOVE THE BATTERY COMPARTMENT. AN ARCING HOLE WAS NOTED ON THE TOP OF THE GCU BOX, AND ARCING DAMAMGES ON THE SIDE OF THE METALLIC BATTERY CASE, AS WELL AS ARCING DAMAGES TO THE POSITIVE TERMINAL ON THE BATTERY CONTACTOR SOLENOID, ALL IN THE SAME ALIGNMENT. NO DAMAGES TO ANY ADJACENT STRUCTURAL MEMBERS WAS NOTED. THE NTSB WAS CONSULTED AND DECLINED TO ISSUE A NTSB ID TO THIS INCEDENT. THE OPERATOR DIASEMBLED THE AIRCRAFT AND GROUND TRANSPORTED IT TO THEIR MAINTENANCE FACILITY IN BEAUMONT TX FOR FURTHER DISSEMBLY AND INSPECTION BY THE OPERATOR, PER THE FAA'S IIC INSTRUCTION.
MAINTENANCE RECORDS COMFIRMED A SERVICABLE BATTERY RG-624 A LEAD ACID BATTERY PART #41387736 WAS INSTALLED ON 12/6/2024 TOTAL TIME 2411.3. ALL INSPECTIONS AND MAINTENANCE RECORDS WERE COMPLETE AND CURRENT.
FOLLOWING THE OPERATORS ADDITIONAL DISASSEMBLY AND ASSESSMENTS, THE DOM ADVISED THAT THE OBJECT THAT HAD CAUSED THE SHORT CIRCUIT OF HIGH CURRENT DIRECTLY TO GROUND AND THE RESULTING FIRE, WAS DETERMINED A RESULT OF A METALLIC CAN OF MARKING PAINT CARRIED BY PILOTS (FOR THE PURPOSE OF MARKING LANDING ZONES) THAT HAD BRIDGED FROM THE METALLIC BATTERY CASE, ACROSS THE TOP OF THE METALLIC CASE OF THE GCU, TO THE POSITIVE TERMINAL OF THE BATTERY CONTACTOR SOLENOID, THUS RUPTURING AND IGNITING THE CONTENTS OF THE PAINT CAN WITHIN THE BATTERY COMPARTMENT LOCATED BELOW THE LEFT PILOT STATION FLOORBOARDS.
Other reports on N812LH · 1
Matched to the same aircraft by N-number and date.