What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
According to pilot and observer's statements, they were taxiing out for departure when the left main wheel came off its axle. As the strut grounded on the taxiway, the left rear wing spar was fractured and fuselage crown skin wrinkled. Examination of the aircraft revealed that the left wheel was separated into its two halves and the tire had come off the wheel. All ten nuts were stripped off the bolts that hold the wheel halves together. The air pressure in the right tire was measured with a gage that only goes to 125 PSI; the pressure in the tire pegged the gage at that value. According to the aircraft's flight manual, the maximum main landing gear tire pressure should be 60 PSI. (-23) on July 29, 1998 at approximately 1500 hrs local time, N349AC was taxiing south on the parallel taxiway enroute to runway 36 for takeoff at Ely, NV. About 3/4 of the way to the taxiway, the left main wheel separated causing the outer half of the wheel to be propelled about 50 yards to the left of the aircraft. Shortly thereafter the tire came off and went into the airport infield. The aircraft came to a stop in about 20 feet riding on the inner wheel half and brake assembly. Inspection revealed damage to the wheel, brake assembly, top of the left engine cowl and damage to the left wing rear spar. No an 364-624 nuts, 8 total, could be found at the scene. These are the nuts that connect to the bolts (an 6-40A), 8 total, that hold the main wheel halves together. The threads on all the an 6-40A bolts appear to have been bent over, as if the nuts were forced off without turning.
As the FAA filed it
ACCORDING TO PILOT AND OBSERVER'S STATEMENTS, THEY WERE TAXIING OUT FOR DEPARTURE WHEN THE LEFT MAIN WHEEL CAME OFF ITS AXLE. AS THE STRUT GROUNDED ON THE TAXIWAY, THE LEFT REAR WING SPAR WAS FRACTURED AND FUSELAGE CROWN SKIN WRINKLED. EXAMINATION OF THE AIRCRAFT REVEALED THAT THE LEFT WHEEL WAS SEPARATED INTO ITS TWO HALVES AND THE TIRE HAD COME OFF THE WHEEL. ALL TEN NUTS WERE STRIPPED OFF THE BOLTS THAT HOLD THE WHEEL HALVES TOGETHER. THE AIR PRESSURE IN THE RIGHT TIRE WAS MEASURED WITH A GAGE THAT ONLY GOES TO 125 PSI; THE PRESSURE IN THE TIRE PEGGED THE GAGE AT THAT VALUE. ACCORDING TO THE AIRCRAFT'S FLIGHT MANUAL, THE MAXIMUM MAIN LANDING GEAR TIRE PRESSURE SHOULD BE 60 PSI. (-23) ON JULY 29, 1998 AT APPROXIMATELY 1500 HRS LOCAL TIME, N349AC WAS TAXIING SOUTH ON THE PARALLEL TAXIWAY ENROUTE TO RUNWAY 36 FOR TAKEOFF AT ELY, NV. ABOUT 3/4 OF THE WAY TO THE TAXIWAY, THE LEFT MAIN WHEEL SEPARATED CAUSING THE OUTER HALF OF THE WHEEL TO BE PROPELLED ABOUT 50 YARDS TO THE LEFT OF THE AIRCRAFT. SHORTLY THEREAFTER THE TIRE CAME OFF AND WENT INTO THE AIRPORT INFIELD. THE AIRCRAFT CAME TO A STOP IN ABOUT 20 FEET RIDING ON THE INNER WHEEL HALF AND BRAKE ASSEMBLY. INSPECTION REVEALED DAMAGE TO THE WHEEL, BRAKE ASSEMBLY, TOP OF THE LEFT ENGINE COWL AND DAMAGE TO THE LEFT WING REAR SPAR. NO AN 364-624 NUTS, 8 TOTAL, COULD BE FOUND AT THE SCENE. THESE ARE THE NUTS THAT CONNECT TO THE BOLTS (AN 6-40A), 8 TOTAL, THAT HOLD THE MAIN WHEEL HALVES TOGETHER. THE THREADS ON ALL THE AN 6-40A BOLTS APPEAR TO HAVE BEEN BENT OVER, AS IF THE NUTS WERE FORCED OFF WITHOUT TURNING.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.