History of Flight
On August 15, 2011, about 1130 mountain daylight time, a Piper PA-38-112, N2584N, sustained substantial damage when it impacted terrain near Silver Bow, Montana. The airplane was registered to and operated by JJ Aviation, Butte, Montana, under Part 91. The certified flight instructor (CFI) and student pilot sustained fatal injuries. Visual meteorological conditions prevailed; no flight plan was filed. The local flight originated from Bert Mooney Airport (BTM), Butte, Montana, about 1030.
Witnesses reported observing the airplane in a spin or spiral descent. One witness traveling east on I-90 saw the airplane flying clockwise horizontal circles with wings almost vertical, losing altitude slowly. During the second turn, it appeared to attempt to straighten and climb but then went straight down. Another witness saw it spinning to the right at about 3,000 feet, tried a loop, then descended spinning. A rated pilot observed a tight left spin from about 300 ft AGL and felt it was in spin recovery before disappearing behind a bluff. No witnesses saw the impact.
A company representative stated that before the flight, the CFI intended to conduct 4 or 5 touch and go landings at BTM then proceed to the west training area for steep turns, turns around a point, and level altitude practice. The representative observed 5 touch and go landings before departure to the west. The CFI typically used altitudes between 7,500 and 8,500 ft MSL for instruction.
Personnel Information
The CFI, age 61, held an airline transport pilot certificate with multi-engine land rating and a commercial pilot certificate with single-engine land rating. He had a second-class medical certificate issued June 3, 2011, with limitation "must hold glasses for near and intermediate vision." He reported 10,440 total flight hours on his medical application. His logbook as of August 9, 2011, showed 10,331.6 hours total and 34.4 hours in the previous 30 days. His most recent Part 135 checkride was May 6, 2011. He reported his weight as 180 lbs.
The student pilot, age 19, held a student pilot certificate and a third-class medical certificate issued January 5, 2011, with no limitations. His logbook as of July 24, 2011, showed 19.6 hours of flight time. He reported his weight as 174 lbs.
Aircraft Information
The two-seat, low-wing, fixed-gear Piper PA-38-112, serial number 38-79A-031, was manufactured in 1979. It was powered by a Lycoming O-235-L2C engine (serial L-19357-15) rated at 112 horsepower, but modified under Supplemental Type Certificate SE792NW to 125 hp at 2,800 rpm. It had a Sensenitch 71CK-0-56 fixed-pitch propeller. The most recent annual inspection was April 29, 2011, at 1,874.2 hours airframe time. Fuel: both tanks refueled to the tab/collar level (20 gallons) about a week prior.
Weight and balance: empty weight 1,216 lbs, useful load 454 lbs, max gross 1,670 lbs. Using reported weights of both occupants and 20 gallons fuel, CG was 76.62 inches. Total weight at departure was 1,690 lbs (above max gross). CG envelope: +73.5 (forward) to +78.5 (rear) inches for normal and utility category. Performance charts: fuel burn at 75% power about 6.5 gallons per hour.
Meteorological Information
Recorded data from Dillon Airport (44 miles south) at 1153: wind variable at 3 knots, visibility 10 statute miles, clear sky, temperature 26°C, dew point 7°C, altimeter 29.90 inHg. Calculated density altitude about 7,938 ft, pressure altitude 5,375 ft.
Wreckage and Impact Information
The airplane impacted terrain about 7 nautical miles west of BTM at elevation about 5,355 ft MSL. GPS coordinates: N46 00.102’, W 112 39.340’. Wreckage came to rest upright on magnetic heading 299°. Debris path was about 342 ft long, oriented on 082°.
First point of contact: a ground scar 10 inches wide, 24 ft long. Green lens fragments from right wing navigation light. Propeller and plexiglass debris in a 4x4 ft disturbed area. Starter ring gear and engine cowling pieces about 11 ft beyond. Main wreckage 52 ft beyond FPIC. Two navigational instruments found 140 ft beyond, left main wheel assembly 342 ft beyond.
Examination: engine, firewall, instrument panel, fuselage separated just forward of wing leading edges. Instrument panel fragmented. All major structural components within debris path. Flight control continuity established. Stall warning lift detector separated from wing, attached by one wire; vane bent; continuity verified. Stall warning horn recovered and audible when powered.
Engine examination: all four cylinders attached; oil filter, propeller, right magneto, carburetor separated; left magneto partially separated. Crankshaft rotated manually; rotational continuity established; thumb compression on all cylinders. Propeller blades: one with "S" bending and twisting opposite rotation, chordwise scratching and polishing; other with slight bend opposite rotation and light scratching.
No mechanical anomalies observed that would have precluded normal operation.
Medical and Pathological Information
Autopsy of the CFI on August 16, 2011, by the State Medical Examiner determined cause of death as "Blunt force injuries." Toxicology tests by CAMI on the CFI showed positive for unspecified amounts of Atenolol in liver and kidney, Chlorpheniramine in liver and kidney, and Diphenhydramine in liver and kidney.
Autopsy was not conducted on the student pilot. Toxicology tests on the student pilot were negative for carbon monoxide, cyanide, volatiles, and drugs.
Tests and Research
A Garmin GPSMap 295 GPS was removed from the wreckage and sent to NTSB Vehicle Recorders Laboratory for data extraction; no recorded data was extracted.