Hillsboro, OH, USA
N9376W
PIPER PA28
The airplane had undergone five previous annual inspections performed by a mechanic where the airplane was based. The airplane departed its base airport to Hillsboro, Ohio, where the airplane's autopilot was worked on by an avionics repair station. After the repair had been done, both pilots departed Hillsboro, but returned after noticing smoke in the cockpit. A check of the cockpit and autopilot by an avionics technician did not reveal any discrepancies associated with those areas. The airplane then again departed Hillsboro. Witnesses reported that after takeoff there was smoke observed coming from the front of the airplane. The witnesses then saw the airplane bank left, descend, strike a tree with its left wing, and then impact in a fallow corn field about 1/2 mile south of the airport. An examination of the airplane's fuel selector showed that it was still in the "on" position. The flaps were in the fully retracted position, which was not consistent with the airplane manufacturer's fire and emergency landing procedures. An examination of the airplane revealed a hole in the muffler, which also exhibited a loss of material due to internal corrosion. The severity of the corrosion also suggests that the hole in the muffler should have been evident at earlier annual inspections.
HISTORY OF FLIGHT On May 30, 2008, at 1158 eastern daylight time, a Piper PA-28-235, N9376W, sustained substantial damage due to impact with terrain and fire after take off from runway 23 (3,520 feet by 75 feet, asphalt) at Highland County Airport (HOC), Hillsboro, Ohio. A witness reported there was smoke from the front of the airplane before it banked left, descended, and impacted a tree with its left wing. The airplane then struck a corn field, and the airplane was consumed by fire. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 flight was not operating on a flight plan. Both pilots received fatal injuries. The flight was originating at the time of the accident and was en route to Andy Barnhart Memorial Airport (3OH0), New Carlisle, Ohio, to have maintenance performed on the airplane's autopilot. The airplane was based at 3OH0 where both pilot's were members of the Flying Angels, Inc. flying club. Both pilots met at 3OH0 and flew to HOC where they arrived about 0900 for maintenance for the airplane autopilot. According to a Federal Aviation Administration (FAA) inspector, after the maintenance on the autopilot was completed, the airplane initially departed and circled for a return to HOC due to reported smoke in the cockpit. A technician from the facility, which had conducted maintenance on the autopilot, checked the cockpit and autopilot but did not find any discrepancies. On the second takeoff, a witness observed that the airplane departed from runway 23 and attained an altitude of about 300-400 feet before grey smoke emanated from the right front side of the airplane. As the smoke blackened, the airplane "veered" to the left and out of the witness's sight. Another witness stated that there was "a lot of black smoke," which were "individual clouds" of smoke coming from the airplane. PERSONNEL INFORMATION The left seat pilot was issued a private pilot certificate with an airplane single-engine land rating on June 12, 1977. He was issued an instrument airplane rating on December 8, 1984, with a total airplane flight time of 309.4 hours. The left seat pilot's logbook shows his last flight review was received from the right seat pilot. The date of the flight review is not listed in the entry, but the preceding entry is dated April 17, 2008. There are no entries following the flight review entry. The right seat pilot's logbook shows that on April 21, 2008, a flight review was given to the left seat pilot in N9376W with a flight duration of 1.3 hours during a local flight that departed from 3OH0. The left seat pilot received his last airman medical certificate on August 11, 2006, which was a third class medical with the following limitation: holder must have available glasses for near vision. On the application of this medical certificate, he reported a total flight time of 1,000 hours of which 10 hours were in the past 6 months. The right seat pilot received a commercial pilot certificate with an airplane multiengine land limited to center thrust and instrument airplane ratings on April, 27, 1990, on the basis of military competence in T-37 and T-38 aircraft. At the time of issuance, he had a total airplane flight time of 190 hours. He was issued an airplane single-engine land rating on September 2, 1993, following completion of an FAA flight examination at a total airplane time of 1,160 hours. He was issued a flight instructor certificate (CFI) with an airplane single-engine rating at a total flight time of 1,250 hours on April 14, 1994 (expired April 30, 1996). On April 24, 1995, the centerline thrust limitation on his commercial pilot certificate was removed on the basis of military competency in C-130 aircraft. His CFI certificate was reissued on April 25, 1996 (expired April 30, 1998), He was issued a DC-9 type rating on October 3, 2005, on completion of an air carrier's approved training program. His CFI certificate was reinstated with an added instrument airplane rating on October 20, 2006 (expires October 31, 2008). He was issued his initial flight engineer certificate with a turbojet powered airplane rating on September 21, 1996, with a limitation which was removed on December 6, 1996. The right seat pilot held the rank of Lt. Colonel in the United States Air Force Reserve where he served as a C-5 Aircraft Commander. The right seat pilot received his last airman medical certificate on August 25, 2005, with no limitations. On application of this medical certificate, he reported a total flight time of 3,500 hours of which 30 hours were in the past 6 months. The right seat pilot's logbook entry dated May 30, 2008, contains the following entry, "Flew to HOC w [left seat pilot] for autopilot work." AIRCRAFT INFORMATION The airplane was a 1968 Piper PA-28-235, which was registered to the left seat pilot as a partnership with another individual. An application for registration to the left seat pilot's corporation was pending at the time of the accident. Airplane logbook entries show that the previous five annual inspections were performed by the same mechanic. May 26, 2008, at 1,210.4 hours (the "Work Log" associated with the inspection lists 6 hours next to "labor") May 20, 2008, at 1,204.4 hours March 22, 2006, at 1,196.15 hours March 8, 2005, at 1,178.2 hours March 8, 2004, at 1,168.0 hours The 1973 Piper PA-28-235 flight manual states that the presence of fire is noted through smoke, smell, and heat in the cabin. It is essential that the source of fire be promptly identified through instrument readings, character of the smoke, or other indications, since the action to be taken differs somewhat in each case. The emergency procedures for an in-flight engine fire are: a. Fuel Selector - Off b. Throttle - Closed c. Mixture - Idle Cut-Off d. Heater - Off (In all cases of fire) e. Defroster - Off (In all cases of fire) f. If terrain permits, land immediately WRECKAGE AND IMPACT INFORMATION The main wreckage, which consisted of the fuselage, right wing, empennage, and engine, was approximately 0.5 miles south of HOC in a fallow corn field. The wreckage path was about 180 feet in length along a heading of about 030 degrees. The western most portion of the wreckage path consisted of broken tree(s) about 30 feet west of the corn field edge. There was a ground scar consistent with an impact about 100 feet east of the corn field edge. The left wing was adjacent to the ground scar. The main wreckage was about 40 east of the ground scar. The main wreckage was in an upright position and 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 displayed fire damage near the outboard fuel tank. The flap handle was in the 0-degree flap position. The cockpit mixture control was in the full aft position consistent with the idle cutoff position. The fuel selector control located behind the main wing spar was in the right tip-tank position. During the engine examination, the spark plugs were removed and the engine was rotated by hand. Air was expelled from and drawn into each spark plug hole while the engine was rotated. All of the intake and exhaust valves sequentially moved and the rear engine accessory gears also moved while the engine was rotated. Oil was present within the engine and there was no metallic debris noted within the engine oil filter and screen. The fuel and oil lines were intact. A spark was produced from each magneto lead when the magneto drive shafts were rotated by hand. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy of the left seat pilot was conducted by the Montgomery County Coroner on May 31, 2008. The Coroner listed the cause of death as blunt force injuries of the head and chest. The FAA Final Toxicology Fatal Accident Report for the left seat pilot reported: no carbon monoxide detected in blood, 0.58 (ug/ml) cyanide detected in blood, no ethanol detected in vitreous, no listed drugs detected in blood. An autopsy of the right seat pilot was conducted by the Montgomery County Coroner on May 31, 2008. The Coroner listed the cause of death as blunt force and thermal inhalation injuries. The FAA Final Toxicology Fatal Accident Report for the right seat pilot reported: no carbon monoxide detected in blood, no cyanide detected in blood, no ethanol detected in vitreous, naproxen detected in urine. TEST AND RESEARCH The Piper Cherokee Service Manual, dated January 31, 2008, provides a 12-page checklist for 50-hour and 100-hour inspections of PA-28-235 airplanes. Within section B. Engine Group of this checklist, there are 54 items, of which item numbers 35 and 36 pertain to the exhaust system. Item 35 states, "Inspect exhaust stacks, connections and gaskets per Exhaust System Inspection. (see Special Instructions, Procedures.) Replace gaskets as required." Item 36 states, "Inspect muffler, heat exchange and baffles per Exhaust System Inspection. (see Special Instructions, Procedures.) According to the FAA, the mechanic who performed the previous 5 inspections of N9376W also performed 42 annual aircraft inspections of other aircraft during the past year. The mechanic would work out of his hangar and did not possess any calibrated tools used in his maintenance of aircraft. The mechanic was also the airport manager for 3OH0. The checklist that the mechanic used in the inspection of the airplane lists the "Tack [sic] time" at 1,210.4 hours. The checklist is one page in length and contains 16 items. One of the items pertained to the muffler had only the following verbiage: "Muffler," with a check mark annotated next to it. The muffler and right exhaust stack were examined by the National Transportation Safety Board Materials Laboratory. The hole was observed in the inwardly deformed lower portion of the muffler's housing, adjacent to its left end. The left portion of the muffler displayed deposits and residual burnt insulating material consistent with it being engulfed in a fire. The edges of the hole were ragged and displayed radially oriented cracks, predominately on the forward and right edges. Manipulation of the protruding portion of the edge revealed that they could be separated from the muffler by applying as few as three bending cycles. The forward and rear ragged edges of the hole could not be mated, suggesting that there was some material missing. A sample of the muffler skin inner surface at the rear of the hole displayed areas of an undulating surface consistent with corrosion deterioration. Other areas were covered with brown patches, which when rubbed with the wooden end of a cotton tipped applicator, fell off in flakes to reveal a similar undulating surface. The thickness of the sample, in the undisturbed area, was measured and found to be 0.033, 0.033, and 0.032 inch. The thickness along the forward edge of the sample, in the textured and corroded area, was measured and found to be 0.020, 0.019, and 0.019 inch. A second sample was removed from the forward edge of the hole. Corrosion was observed on the inner surface of this sample adjacent to the ragged edge. Multiple thickness measurements in the corroded area along the rear edge of the sample averaged 0.021 inch, and multiple thickness measurements in the undisturbed area along the forward edge (cut) edge of the sample averaged 0.031 inch. The housing assembly was detailed in the muffler assembly drawing. The housing drawing specified housing material as type 321 stainless with a thickness of 0.032 inch. The right exhaust stack was extracted from the muffler to reveal that the middle pipe portion of the exhaust stack normally installed in the muffler was mechanically damaged, visibly tapered, and out-of-round. Examination of the damaged end of the middle pipe revealed several localized areas of inward deformation and a longitudinal cut with inward bends. The out-of-round shape of the exhaust stack's middle pipe was mirrored in the shape of the muffler's center pipe. The effective circumference of the middle pipe was measured at 8.0 inches (a diameter of 2.54 inches) and the effective circumference at the damaged end was measured at 7.375 inches (a diameter of 2.35 inches), indicating that a significant taper had been produced. The right middle exhaust tube assembly revealed that the original specified diameter of the damaged end was 2.510 - 2.480 inches in a restrained round condition.
The pilot's failure to maintain control of the airplane due to an in-flight fire as a result of a corrosion hole in the muffler that was not identified by the mechanic. Contributing to the accident was the improper emergency procedure performed for an in-flight fire.
Source: NTSB Aviation Accident Database
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