TALLAHASSEE, FL, USA
N3455X
Mooney M20F
During cruise flight at 5,000 feet msl in night visual conditions, the pilot reported a rough engine. ATC provided vectors to the nearest airport. Before reaching the airport, the engine quit. A forced landing was made about 2 miles short of the airport in a densely wooded area. After colliding with trees, the airplane impacted the ground, inverted. A postcrash ground fire destroyed the airplane. The engine crankshaft was found fractured through the #1 rod journal. Fracture features were mechanically damaged; the precise origin of the fracture could not be determined during a metallurgical examination. Examination of the airplane and engine records revealed no evidence of a propeller strike or previous impact damage.
HISTORY OF FLIGHT On August 11, 1997, about 0125 eastern daylight time, a Mooney M20F, N3455X, collided with the ground during a forced landing at Tallahassee, Florida. The airplane was operated by the owner under the provisions of Title 14 CFR Part 91, and instrument flight rules (IFR). An instrument flight plan had been filed for the personal flight. Night, visual meteorological conditions prevailed. The commercial flight instructor, and the student pilot were fatally injured, and the airplane was destroyed by a post crash fire. The flight originated from the Lakefront Airport, New Orleans, Louisiana, about 2201 central daylight time, and was destined for the Vandenberg Airport, Tampa, Florida. Subsequent times contained in this report are eastern daylight time based on the 24 hour clock. According to the Federal Aviation Administration Aircraft Accident Package prepared by Jacksonville Air Route Traffic Control Center (JAX ARTCC), the pilot of Mooney N3455X telephoned the DeRidder Automated Flight Service Station (AFSS) and obtained a preflight pilot brief for an IFR flight from New Orleans, Louisiana, Lakefront Airport (NEW) to Tampa, Florida, Vandenberg Airport (X16). An IFR flight plan was also filed. According to the JAX ARTCC report, after departure the flight climbed to 5,000 feet mean sea level (msl) and proceeded on route. At 0106:18, while in contact with JAX ARTCC, N3455X requested vectors to the nearest airport and reported "...we're having a little bit of engine trouble here." Radar data obtained from the Federal Aviation Administration's (FAA) National Track Analysis Program (NTAP) plot depicted the radar position of N3455X, at that time, as 30:15:44 North latitude and 084:59:52 West longitude. That position, when plotted on a Sectional Aeronautical Chart, corresponded with a position about 34 Nmi west of Tallahassee, Florida, about 36 Nmi south of Marianna, Florida, about 36 Nmi east of Panama City, Florida and about 33 Nmi northeast of Tyndall Air Force Base, Florida. Following the request, vectors toward the Tallahassee, Florida, airport were provided by JAX ARTCC. At 0107:27, the flight reported that the engine was rough and had "...cleared up a little bit...." The NTAP plot indicated that the airplane proceeded toward Tallahassee and climbed to 6,100 feet, msl. At 0117:06, N3455X reported that the engine had quit. The air traffic controller responded that the airport was located fifteen miles at 090 degrees from the airplane. The NTAP plot depicted the airplane as approximately 5,800 feet, at that time. The NTAP plot indicated that the airplane descended toward the airport at an average descent rate of about 651 feet per minute, until radar contact was lost. Radar and radio contact with the flight were lost at 0123:40, about three miles west of the airport. The last encoding altitude for the flight was 1,500 feet, mean sea level. The wreckage was subsequently located about one mile west of the airport, in a densely wooded national forest. PERSONNEL INFORMATION The owner/student pilot and a flight instructor were in the airplane. According to records obtained from the FAA, the student pilot was issued a third class medical certificate and student pilot certificate on April 3, 1997. The total pilot time reported on the medical certificate application on that date was 20 hours, all acquired within the previous six months. His pilot log was not located. The form also indicated that no prior application for a medical certificate had been made. The report of medical examination, contained on the same application, indicated that the student pilot had "Post surgical changes, both eyes; Radial Keratotomy, 6 months." A letter from the FAA Aeromedical Certification Division, dated September 5, 1997, indicated that the student pilot was eligible for a third-class medical certificate. The instructor pilot held commercial pilot certificate number 227434337, with airplane single engine, multi engine, and instrument ratings. His last rating was issued on April 22, 1996. He held a certified flight instructor (CFI) certificate with airplane single engine , multi engine and instrument ratings. His CFI single engine rating was obtained on July 27, 1996. An instrument airplane rating to his CFI certificate was added on August 29, 1996. The instructor's pilot log was examined. The last entry was dated August 5, 1997. According to his logbook, the instructor had 945 total flight hours, with 569 flight hours as an instructor. His total hours at night were 91; total actual instrument hours, 12; and total simulated instrument hours were 52. He had 29 total hours in the same make and model airplane, all within the 90 days prior to the accident. His total CFI hours in the same make and model airplane were 15, with 34 hours as CFI at night. A duty-time sheet was found in the instructor's logbook that reflected an additional 21 total flight hours, that were not logged in his pilot's log. Additional pilot information is found in this report on page 3 under First Pilot Information, and Supplement E. AIRCRAFT INFORMATION According to the airplane logbook, an annual inspection was conducted on February 12, 1997, at a total airframe time of 3,733 hours, and a tachometer time of 2,059 hours. An entry in the airplane log indicated that the transponder and the altimeter were inspected on May 30, 1997. The engine log indicated that a Lycoming IO-360-A1A, serial number L-6890-51A was installed in N3455X on June 14, 1985. The log indicated that the engine had 1460 total hours at that time, with zero hours since major overhaul (SMOH). An entry in the engine log dated May 14, 1986, indicated that a top overhaul with four fresh chrome cylinders was accomplished, at 109 hours SMOH. On March 27, 1987, at 192 hours SMOH, according to the engine log, the engine was removed "to replace engine mount." Another log entry indicated that the cylinders were replaced "with new steel barrel" on May 27, 1987, at a time SMOH of 212 hours. According to the log, on June 17, 1993, all four cylinders were removed and new rings, gaskets, and seals installed, at 760 hours SMOH. The log indicated that on August 18, 1995, at a time SMOH of 1,063 hours, the propeller was removed and sent for overhaul because of a worn hub due to improper spinner installation. The subject propeller was not on the aircraft at the time of the accident. According to the log, a three blade propeller was installed on the airplane on February 12, 1997, and replaced with a two blade propeller four flight hours later, which according to the propeller log was on June 5, 1997. The engine log and propeller log indicated that the serial number of the propeller installed on June 5, 1997, was 731. The propeller found on the airplane at the accident site was a Hartzell Model HC-C2YK-BF with hub serial number CH21253. The previous owner, an airplane dealer, provided a copy of engine and propeller log entries, that had not been inserted in the engine and propeller log, that indicated that the installed propeller was hub serial number CH21258. The copies of the log entries stated that the propeller was balanced in accordance with Chadwick Helmuth Smooth Propeller. The dealer stated that propeller CH21258 was installed in place of 731, and the owner had not provided the logs at the time of the propeller exchange so that the entries could be placed in the logs. There was no indication in the airplane, engine, or propeller log of previous damage to the propeller. A maintenance release card (yellow tag) for propeller 731, dated May 10, 1968, contained the entry that damaged tips were repaired, however, propeller 731 was not installed on 3455X until June 5, 1997, and was removed on July 24, 1997. Additional aircraft information is found in this report on page 2 under the heading Aircraft Information. METEOROLOGICAL INFORMATION The Aviation Routine Weather Report (METAR), at 0052 for Tallahassee, Florida, was wind 080 degrees at 5 knots, visibility 10 miles; sky clear; temperature 24, dew point 23; and altimeter 30.10. Additional weather information is found in this report on pages 4 and 5, under the heading Weather Information. WRECKAGE AND IMPACT INFORMATION A swath was found through the trees with broken limbs on the ground that led to the main wreckage. The ends of the broken limbs were not darkened. The swath was aligned with a magnetic heading of about 086 degrees with a total length of about 243 feet. Looking east, toward the Tallahassee airport, the right wing outer panel was found first, followed by a gouge in the ground that contained the engine cowling, a VHF antenna, and windshield material. The rudder and vertical stabilizer were found next, west of the main wreckage, separated from the airframe. The main wreckage consisted of the propeller, engine, fuselage, horizontal stabilizer and the elevator, left wing, and the inboard remainder of the right wing. The airplane was inverted and exhibited fire damage from the nose of the propeller aft to the rear of the cabin, outboard to include all of the right wing with the main wreckage, and the left wing outboard to the broken off outboard panel. The left wing outboard panel remained with the main wreckage. Except for the truss frame, the cabin was nearly consumed by fire, including the instrument panel. The vertical stabilizer and rudder had been pulled away from the airplane. The propeller blades were essentially straight, exhibited no chordwise scratches, and the nose of the spinner was crushed aft and formed around the hub. The engine and engine compartment exhibited severe fire damage. The leading edges of the wings had concave indentations, and the separated right wing outboard panel exhibited tree bark transfer. The flaps were up and the landing gear was retracted. There was continuity of the flight control tubes from the cockpit area to the area of the ailerons, except at the juncture of the right aileron/flap where the right wing was separated. The elevator control tube was burned in two at the tail cone splice, concurrent with fuselage fire damage. The rudder control tube was connected between the area of the rudder and the cockpit. Ground fire damage was confined to within ten feet of the main wreckage. Separated pieces of the airplane outside the burned ground did not exhibit any fire damage. MEDICAL AND PATHOLOGICAL INFORMATION Post mortem examinations of the pilots were performed by the Leon County, Florida, medical examiner's office, Tallahassee, Florida. Toxicological examinations of the pilots were performed by the Toxicology and Accident Research Laboratory, FAA Oklahoma City, Oklahoma. The reports indicated that no cyanide, ethanol, nor drugs were detected. The report for the flight instructor indicated that Carbon monoxide analysis was not done because of a lack of a suitable specimen. The report for the student pilot indicated that no carboxyhemoglobin was detected. The Leon County Florida medical examiner's report indicated that 22.2% carbon monoxide was detected during the examination of the CFI, and 27.0% carbon monoxide was detected during the examination of the owner/student pilot. TESTS AND RESEARCH The engine was moved from the accident site to a hangar that was occupied by the U.S. Forestry Service at the Tallahassee airport and disassembled. The exterior and interior of the engine was discolored and blackened consistent with the evidence of ground fire at the accident site. After removing the propeller spinner, balance weights were observed on the propeller bulkhead. There was extensive fire damage to the accessory section with melting of the magnetos and cooking of the mechanical fuel pump. Foreign material found in the sump was attracted by a magnet. The spark plugs were Champion REM 38, massive and fine wire. They were worn and exhibited a lean burning condition when compared to a manufacturer's condition chart. After opening the crankcase, the crankshaft was found fractured through the number one cylinder rod journal. A metallurgical examination of the broken crankshaft, the connecting rods, and the bearings was conducted at the NTSB Materials Laboratory, Washington, D.C. The number 1 rod cap was deformed, and both bolts were broken. Magnified examinations of the bolts and cap found evidence of tensile or bending overstress separations. The crankshaft had broken into three pieces, one small piece of the journal itself, and two large pieces of the crankshaft. Optical examinations of the fracture surfaces found severe rotational mechanical damage as well as thermal damage that obliterated the majority of the fracture features. Some fracture features remained on both fracture faces of the crankshaft. On the forward fracture face an area of original fracture indicated fatigue with an initiation area near the aft journal radius. This origin area was located directly opposite the number one cylinder when the piston is at the top of its stroke, (top dead center). The number one journal had severe circumferential scoring and localized oxidation indicative of severe heating. Disassembly of the number 2, 3, and 4 rods revealed distinct demarcations of soot and heat patterns indicating stationary heating. ADDITIONAL INFORMATION The airplane wreckage, and the aircraft logs and records, were returned to the owner's insurance representative David R. Lucas, Dave Lucas International 1609 Oakmont Drive Brandon, Florida 33511. The flight instructor's pilot logs were returned to Wendy Morgan.
fatigue failure of the crankshaft for undetermined reasons. Related factors were: darkness, and obstructions (trees) in the emergency landing area.
Source: NTSB Aviation Accident Database
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