History of Flight
On May 30, 2008, at 1158 eastern daylight time, a Piper PA-28-235, registration N9376W, sustained substantial damage due to impact with terrain and fire after takeoff from runway 23 at Highland County Airport (HOC), Hillsboro, Ohio. Witnesses reported smoke from the front of the airplane before it banked left, descended, and struck a tree with its left wing. The airplane then hit a corn field and was consumed by fire. Visual meteorological conditions prevailed. The flight was operating under 14 CFR Part 91 without a flight plan. Both pilots received fatal injuries. The flight was originating at the time, en route to Andy Barnhart Memorial Airport (3OH0), New Carlisle, Ohio, for autopilot maintenance.
The airplane was based at 3OH0, where both pilots were members of the Flying Angels, Inc. flying club. They had flown to HOC earlier that day, arriving about 0900 for autopilot maintenance. After the maintenance, the airplane initially departed but returned due to reported smoke in the cockpit. A technician from the maintenance facility checked the cockpit and autopilot but found no discrepancies.
On the second takeoff, a witness observed the airplane depart from runway 23 and climb to about 300-400 feet before grey smoke appeared from the right front side. The smoke blackened, and the airplane veered left, disappearing from sight. Another witness described "a lot of black smoke" in "individual clouds."
Personnel Information
The left seat pilot held a private pilot certificate with an airplane single-engine land rating, issued June 12, 1977, and an instrument airplane rating from December 8, 1984. His total flight time was 309.4 hours. His last flight review was administered by the right seat pilot; the review date is not listed but the preceding log entry is dated April 17, 2008. The right seat pilot's logbook indicates a flight review for the left seat pilot on April 21, 2008, in N9376W, lasting 1.3 hours. The left seat pilot's most recent medical certificate was third class, issued August 11, 2006, with a limitation requiring glasses for near vision. He reported 1,000 total flight hours, with 10 in the past 6 months.
The right seat pilot held a commercial pilot certificate with airplane multiengine land (limited to center thrust) and instrument airplane ratings, issued April 27, 1990, based on military competence. He had 190 total hours at issuance. He earned an airplane single-engine land rating on September 2, 1993, after an FAA flight examination at 1,160 hours. He held a flight instructor certificate (CFI) with airplane single-engine rating, issued April 14, 1994 (expired April 30, 1996). The centerline thrust limitation was removed on April 24, 1995. His CFI was reissued April 25, 1996 (expired April 30, 1998). He received a DC-9 type rating on October 3, 2005. His CFI was reinstated with an instrument airplane rating on October 20, 2006 (expires October 31, 2008). He held a flight engineer certificate with turbojet rating, issued September 21, 1996, with a limitation removed December 6, 1996. He was a Lt. Colonel in the U.S. Air Force Reserve, serving as a C-5 Aircraft Commander. His most recent medical certificate was August 25, 2005, with no limitations; he reported 3,500 total hours, with 30 in the past 6 months. His logbook entry for May 30, 2008, reads: "Flew to HOC w [left seat pilot] for autopilot work."
Aircraft Information
The airplane was a 1968 Piper PA-28-235, registered to the left seat pilot and another individual as a partnership. An application for registration to the left seat pilot's corporation was pending. Logbook entries show the previous five annual inspections were performed by the same mechanic: May 26, 2008 (1,210.4 hours), May 20, 2008 (1,204.4 hours), March 22, 2006 (1,196.15 hours), March 8, 2005 (1,178.2 hours), and March 8, 2004 (1,168.0 hours).
The 1973 Piper PA-28-235 flight manual describes fire indications and emergency procedures: if in-flight engine fire, set fuel selector off, throttle closed, mixture idle cut-off, heater and defroster off, and land immediately if terrain permits.
Wreckage and Impact Information
The main wreckage—fuselage, right wing, empennage, and engine—was about 0.5 miles south of HOC in a fallow corn field. The wreckage path was about 180 feet long on a heading of about 030 degrees. The westernmost part consisted of broken trees about 30 feet west of the corn field edge. A ground scar consistent with impact was about 100 feet east of the field edge, with the left wing adjacent. The main wreckage was about 40 feet east of the scar, upright, oriented on a tail-to-nose heading of about 340 degrees.
The engine cowling, cockpit, cabin, and right wing were destroyed by fire. The left wing showed fire damage near the outboard fuel tank. The flap handle was in the 0-degree position. The cockpit mixture control was full aft (idle cutoff), and the fuel selector was in the right tip-tank position.
Engine examination: spark plugs removed, engine rotated by hand expelled air from each plug hole. Intake and exhaust valves and rear accessory gears moved. Oil was present with no metallic debris in filter or screen. Fuel and oil lines were intact. Both magnetos produced sparks when rotated.
Medical and Pathological Information
Autopsy of the left seat pilot by the Montgomery County Coroner on May 31, 2008, listed cause of death as blunt force injuries of head and chest. FAA toxicology reported: no carbon monoxide, 0.58 ug/ml cyanide in blood, no ethanol, no listed drugs.
Autopsy of the right seat pilot on the same date listed cause of death as blunt force and thermal inhalation injuries. Toxicology reported: no carbon monoxide, no cyanide, no ethanol, naproxen detected in urine.
Test and Research
The Piper Cherokee Service Manual (January 31, 2008) provides a 12-page checklist for 50- and 100-hour inspections. Section B, Engine Group, includes items for exhaust system inspection: item 35 (inspect exhaust stacks, connections, gaskets) and item 36 (inspect muffler, heat exchange, baffles).
The mechanic who performed the previous five inspections also performed 42 annual inspections of other aircraft in the past year. He worked from his hangar without calibrated tools and was the airport manager at 3OH0. The checklist he used for the airplane had 16 items; one pertained to the muffler with only a check mark.
The muffler and right exhaust stack were examined by the NTSB Materials Laboratory. A hole was found in the inwardly deformed lower portion of the muffler housing, adjacent to its left end. The left portion showed deposits and residual burnt insulating material. The hole edges were ragged with radially oriented cracks. The forward and rear edges could not be mated, indicating missing material. The inner surface at the rear of the hole showed corrosion deterioration; patches of brown flakes revealed an undulating surface. Thickness measurements: undisturbed area 0.032-0.033 inch; corroded area 0.019-0.020 inch. A second sample from the forward edge also showed corrosion, with corroded area thickness averaging 0.021 inch versus undisturbed 0.031 inch. The housing drawing specified type 321 stainless steel at 0.032 inch thickness.
The right exhaust stack's middle pipe was mechanically damaged, tapered, and out-of-round. The damaged end showed inward deformation and a longitudinal cut with inward bends. The muffler's center pipe mirrored the out-of-round shape. The effective circumference of the middle pipe was 8.0 inches (diameter 2.54 inches) at one point and 7.375 inches (diameter 2.35 inches) at the damaged end, indicating significant taper. The original specified diameter for the right middle exhaust tube assembly was 2.510-2.480 inches in a restrained round condition.