Hernando, MS, USA
N158MT
Beech 58
Approximately 7 minutes after the flight departed while flying at 6,000 feet mean sea level (msl), the pilot radioed the controller advising, "star check four eighty four we're gonna shut the master switch off we've got a electrical fire." The controller asked the pilot to repeat the transmission to which he again reported he was going to shut off the master switch. The controller advised the pilot of the location of a nearby airport to which the pilot replied, "standby." Approximately 20 seconds after the pilot first advised the controller of an electrical fire, the pilot declared an emergency and advised the controller the flight was descending. The controller advised the pilot of a nearby grass airstrip to which the pilot questioned the location and, "...we need to land immediately." The controller again advised the pilot of the location of the grass strip; there were no further communications from the accident pilot. Witnesses located near the accident site reported seeing smoke or what was described as "vapor trail" or "dust" trailing the airplane before it impacted the water on Arkabutla Lake. Radar data indicates transponder beacon returns continue every 4.6 seconds when reviewed in 1-minute increments beginning at 1154:06, until 1201:54, when the last transponder beacon return indicated the airplane was at 5,400 feet msl. A primary uncorrelated radar return was observed in close proximity to the last correlated transponder return, and continue approximately every 4-5 seconds until 1203:31. Review of the primary radar returns revealed between 1201:59, and 1203:21, the target was noted to bank to the left from a southerly heading to a northeasterly heading; the final two uncorrelated radar returns indicates the airplane banked to the right where the last return was noted over a section of Arkabutla Lake. Before recovery of the airplane, a section of the horizontal stabilizer was noted above the surface of the water. The right wing and cockpit from the forward carry-thru spar forward were fragmented. The left wing was separated but comprised of mainly 1 piece. Examination of the cockpit revealed heat damage was localized on the pilot's side of the airplane behind the instrument panel. The battery switch was found in the off position while both alternator switches were found in the on position. A 10-gauge electrical wire which acts as a jumper between the W15 and W11 bus bars on the left hand subpanel was fractured and exhibited evidence of arching on the supply side wire. The surface of a pilot air control located in the area of the arched 10-gauge wire exhibited arching damage on the surface which was comprised in part of tin. Tin was not detected on the undamaged area of the pilot air control. The damaged 10-gauge wire was noted to be comprised in part of tin. A rigid aluminum line for the left fuel flow and pressure indicator gauge was noted to be cracked, sooted, and bulged in the area on the pilot's side of the instrument panel near the combination oil pressure/oil temperature/cylinder temperature gauge. The line exhibited features associated with overstress fracture at an elevated temperature. A rigid aluminum line for left oil pressure was noted to have a section missing; the line exhibited features associated with overstress fracture at an elevated temperature. Post accident testing to duplicate the as-found condition of the 10-gauge wire revealed the large ball on the end of the accident wire could be duplicated when a compressive load was applied to the 10-gauge wire shorting it to ground, and current from the batteries supplying current to the 10-gauge wire. Additional post accident testing of current limiters with various loads applied revealed the current limiters opened at decreasing times with an increase in current applied. Review of the emergency checklist for the airplane pertaining to electrical smoke or fire revealed a pilot is directed to shut off the battery and both alternator switches.
HISTORY OF FLIGHT On July 17, 2000, about 1203 central daylight time, a Beech 58, N158MT, registered to and operated by AirNet Systems, Inc., as Star Check Flight 484, experienced a pilot reported electrical fire in-flight and crashed into Arkabutla Lake, Hernando, Mississippi. Visual meteorological conditions prevailed at the time and an instrument flight rules (IFR) flight plan was filed for the 14 CFR Part 135 non-scheduled, domestic, cargo flight, from Memphis, Tennessee, to Houston, Texas. The airplane was destroyed and the commercial-rated pilot, the sole occupant, was fatally injured. The flight originated about 1154, from the Memphis International Airport, Memphis, Tennessee. According to a transcription of communications with Memphis Air Traffic Control Tower (Memphis ATCT), at 1150:04 the pilot received IFR clearance to William P Hobby Airport, Houston, Texas, and at 1150:48, received clearance to taxi to runway 18L. At 1152:58, the pilot contacted local control and advised the controller that the flight was ready to depart. The controller advised the pilot to position the airplane and hold on runway 18L, which the pilot acknowledged. At 1153:49, the flight was cleared to takeoff and at 1154:39, the local controller advised the pilot to contact departure control. At 1154:50, the pilot established contact with the Memphis ATCT Departure Control West controller and advised that the flight was at 1,000 feet, climbing to 3,000 feet on an assigned heading of 220 degrees. Radar contact with the airplane was established at 1155:08, and at 1155:37, the controller cleared the flight to climb and maintain 6,000 feet. The pilot acknowledged the climb clearance and at 1157:12, the controller cleared the flight to fly heading 200 degrees, which the pilot also acknowledged. The flight continued and the Memphis ATCT transcription of communications further indicates that at 1201:16, the pilot radioed, "star check four eighty four we're gonna shut the master switch off we've got a electrical fire." The controller asked the pilot to repeat his last transmission and at 1201:22, he advised the controller, "sir we gonna shut the master switch off we've got a electrical fire sir." The controller responded, "...ah tunica airport's the closet [sic] one to you it's about twelve miles off to your southwest", to which the pilot responded, "standby." At 1201:36, the pilot radioed, "okay sir we need to declare emergency we are descending", to which the controller advised the pilot of a grass airstrip located 4 miles northeast of the aircraft's position. At 1202:39, the pilot radioed, "star check four eighty four are you ah where's that airport sir we need to land immediately." The controller advised the pilot, "roger heading ah zero two zero it's northeast your position four miles hernando mississippi." The pilot did not respond to the controller. The controller again broadcast on the frequency for the pilot that the nearest airport was located 4 miles and 020 degrees from the airplane's present position; the pilot did not reply to that transmission. The controller vectored another airplane to the last known radar position of the airplane; the flightcrew of the vectored airplane radioed the accident pilot but two-way communications were not established. The flight crew advised the controller of seeing a column of black smoke and boats proceeding to the direction of the smoke (see transcript of communications). Review of recorded radar data provided by Memphis ATCT revealed 103 transponder beacon returns were recorded from the accident airplane beginning at 1154:06 (altitude of 200 feet), and continue approximately every 4.6 seconds when reviewed in 1-minute increments, until 1201:54 (altitude of 5,400 feet). Further review of the radar data revealed the airplane climbed to a maximum altitude of 6,000 feet, reaching that altitude at 1200:59, and remained at that altitude for an additional five radar returns. The radar data indicates the airplane then began descending. Review of recorded radar data provided by Memphis Air Route Traffic Control Center (Memphis ARTCC) revealed transponder beacon returns from the accident airplane were recorded beginning at 1154:32, and continue approximately every 10 seconds until the last radar return at 1201:55. The last radar return was located at 34 degrees 46 minutes 02 seconds North latitude and 090 degrees 08 minutes 24 seconds West longitude; the recorded altitude was 5,500 feet mean sea level. The accident site was located 3.14 nautical miles and 108 degrees from the last radar return recorded at the Memphis ARTCC. Review of radar plots and data provided by the airplane manufacturer revealed transponder beacon code radar returns were noted from 1154:31, until 1201:54. Uncorrelated primary radar returns were observed between 1201:59, and 1203:31. Further review of the radar data revealed at 1201:59, an uncorrelated primary radar target was observed 170 degrees and .25 nautical mile from the last transponder beacon code return. Additionally, between 1201:59, and 1203:21, radar targets indicate the airplane made a left turn flying from a southerly to a northeasterly heading. The final two uncorrelated radar returns at 1203:26, and 1203:31, indicate the airplane began a right turn where radar contact was lost over a section of Arkabutla Lake. Several witnesses located near the crash site reported seeing smoke or what was described as "vapor trail" or "dust" trailing the airplane in flight. A witness reported a fire on the water after impact lasted an estimated 4-5 minutes. PERSONNEL INFORMATION According to FAA records, the pilot held a commercial pilot certificate with airplane single and multi-engine land, instrument airplane ratings. He also held an airframe and powerplant mechanic certificate, and a flight instructor certificate with airplane single engine and instrument airplane ratings. He was issued a first class medical certificate on April 18, 2000, with no limitations. The pilot was hired by Airnet Systems, Inc., on July 8, 1999, and was authorized to fly Cessna 310's and the Beech 58 aircraft only. His last Part 135 checkride occurred in a Beech 58, on July 8, 1999. The employment application completed by him indicates that he had accumulated a total time of 1,528 hours, of which 16 hours were in multi-engine airplanes, and 1,512 hours were in single-engine airplanes. Of the 16 hours in multi-engine airplanes, 6 hours were logged as pilot-in-command. A review of the pilot's logbook revealed at the time of the accident, he logged a total time of approximately 2,629 hours, of which 1,611 hours were in single-engine airplanes and 1,018 hours were in multi-engine airplanes. He logged a total of approximately 2,368 hours as pilot-in-command. He also logged a total time of 290 hours in the last 90 days, and 90 hours in the last 30 days, all in the accident make and model airplane. The company reported the pilot had accumulated 900 hours in the accident make and model airplane, all as pilot-in-command. AIRCRAFT INFORMATION The airplane was a Beech 58, serial number TH-1186, manufactured in 1980, and equipped with two Continental IO-520-CB engines rated at 285 horsepower, and two Hartzell PHC-J3YF-2UF propellers. Electrical wiring consisting of MIL-W-5086/1 of the single wire type was installed in the cockpit and cabin areas of airplane. It was also equipped with a cabin fire bottle. The airplane was certificated in the normal category in accordance with Civil Air Regulations Part 3 (CAM 3), titled, "Airplane Airworthiness Normal, Utility, and Acrobatic Category", as amended May 15, 1956, and 14 CFR Part 23.1385(c), 23.1387(a), and 23.1387(e) of Federal Aviation Regulations. Review of the maintenance records revealed the airplane was last inspected in accordance with a Raytheon Aircraft 100-Hour inspection on June 14, 2000. The airplane had accumulated approximately 80 hours since the inspection, and approximately 4,870 hours since manufacture at the time of the accident. Review of the discrepancy sheets associated with the 100-Hour inspection revealed no discrepancies associated with electrical wiring or fuel lines in the cockpit. A mechanic and inspector initialed for inspecting electrical wiring and equipment in the cabin and baggage compartment for condition, security, and signs of chafing during the last 100-Hour inspection. A mechanic and an inspector also initialed for inspecting plumbing in the cabin and baggage compartment for security, leakage, and general condition during the last 100-Hour inspection. The maintenance records also reflect that the pilots attitude gyro was removed and replaced on June 7, 2000; the airplane had accumulated approximately 101 hours since the installation at the time of the accident. The inflatable door seal motor and power supply were removed on February 19, 1999; the components had been installed in accordance with a supplemental type certificate. On October 27, 1997, the airplane was modified for flight into known icing conditions. The modification included in part, installation of a segment of bus bar to the pitot heat circuit breaker located on the left hand and right hand pitot heat bus bar, which is installed on the left side panel. Additionally, a circuit breaker (heavy-duty stall warning vane) was installed on the added segment of bus bar. Review of "Maintenance Log" sheets recovered from the wreckage that go back to at least June 19, 2000, revealed no logged discrepancies related to electrical wiring, or to flight or engine instruments. Prior to the accident flight, the airplane was last flown on July 14th, for a total flight time of 4.5 hours on 8 flight legs. The pilot who last flew the airplane reported nothing abnormal with the airplane or systems. That same pilot also flew the airplane a total of 11.7 hours between July 10th and the 13th; again he reported no discrepancies on any of the days or flight legs. The airplane was equipped with two 100-ampere, 24 volt, engine-driven alternators, and two 12-volt lead acid batteries connected in series. Electrically, in part, both alternators and/or the batteries provide electrical power to a bus identified as "W30", labeled, "current limiter bus" which is located in the nose section of the airplane. A 4-gauge electrical cable labeled "P6A4" provides an electrical path from the W30 bus to a bus identified as "W15", labeled, "circuit breaker bus bar", which is located on the lower portion of the instrument panel on the pilot's side of the airplane and has ten switch/circuit breakers. A 10-gauge electrical wire labeled "P5A10" provides an electrical path from the W15 bus to a bus identified as "W11", labeled, "left hand and right hand pitot heat bus bar", located next to the W15 bus. During manufacturing, the length of the P5A10 wire was fabricated to fit by the installing technician. Two circuit breakers (pitot heat and stall warning vane heater) are installed at the W11 bus. An 80-amp current limiter identified as p/n FLLB, is installed at the current limiter bus and protects the circuit consisting of the 4-gauge wire from the current limiter bus to the W15 bus, the W15 bus, the 10-gauge wire from the W15 to the W11 bus, and the W11 bus. A dual (left and right) direct reading fuel flow and pressure indicator gauge calibrated to indicate fuel flow was installed in the instrument panel above the throttle quadrant to the left of the audio panel. Direct reading combination oil pressure/oil temperature/cylinder temperature gauges were installed for each engine. The gauges were installed side by side in the lower left portion of the instrument panel on the pilot's side of the airplane, above the switch/circuit breakers installed on the W15 and W11 bus bars. Rigid 1/4 inch outside diameter aluminum tubing connects at a union located at the left wing root area for left fuel flow and oil pressure, and continue into the cockpit under the instrument panel where the tubing connects either to a union near the upper middle portion of the instrument panel then to the gauge (left fuel flow and pressure indicator), or directly to the gauge (left oil pressure). METEOROLOGICAL INFORMATION A METAR weather observation taken at the Memphis International Airport, Memphis, Tennessee, on the day of the accident at 1216, which was approximately 13 minutes after the accident, indicates the wind was from 160 degrees at 5 knots, the visibility was 10 statute miles, the sky condition was clear and the temperature and dew point were approximately 91 and 68 degrees Fahrenheit, respectively. The altimeter was 30.03 inHg. The accident site was located approximately 192 degrees and 18.4 nautical miles from the Memphis International Airport. COMMUNICATIONS The pilot was last in contact with the Memphis Air Traffic Control Tower. WRECKAGE AND IMPACT INFORMATION The airplane crashed into Arkabutla Lake, near Hernando, Mississippi. The main wreckage was located at 34 degrees 44.867 minutes North latitude and 090 degrees 04.868 minutes West longitude. That location when plotted was 192 degrees and 18.4 nautical miles from the Memphis International Airport. The tip of the right horizontal stabilizer was noted above the water level (see photograph 1); heat damage to the tip was noted. The airplane was recovered and identifiable wreckage pieces were placed in proper location for further examination (see photograph 2). Examination of the airplane revealed the fuselage was fragmented from the main spar forward; the forward spar carry-thru was complete. Both wings were structurally separated from the airplane; the left wing was nearly complete while the right wing was fragmented. The spar carry-thru cover map case had plastic from the pilot's cooler melted onto it in two places on the co-pilot's side. The lower fuselage was structurally separated at fuselage station (FS) 100, and the instrument panel/firewall assembly were structurally separated but were recovered as a unit (see photograph 3). Both horizontal stabilizers and vertical stabilizer remained attached to the airframe. The left propeller remained attached to the engine; the engine and propeller were structurally separated from the airframe. The right propeller separated from the engine; the engine remained secured to a portion of the airframe structure. The landing gears, which were structurally separated, were extended at the time of impact; the flaps were extended 30 degrees. Heat damage along a defined line was noted on the right main and nose landing gear tires. Examination of the flight controls for roll, pitch, and yaw revealed no evidence of preimpact failure or malfunction. Heat damage to the lower empennage skin along a defined line was noted beginning at FS 190, and continued aft (see photograph 4). The lower skin surfaces of both horizontal stabilizers exhibited heat damage. No fire or heat damage was noted on the fuselage interior from FS 94 to approximately FS 207. No fire or heat damage was noted to the wiring bundle on the left side of the fuselage from FS 94 to FS 247. Examination of the pilot's seat revealed heat damage, a witness later reported it was floating and on-fire after the accident. The pilot's seatbelt was located unfastened; damage to the release cover was noted. Examination of the cabin door of the airplane revealed soot on the outer skin below and aft of the storm window; scratches in the sooted area of the outer skin of the door were noted (see photographs 5 and 6). The storm window hinge was missing; no soot was noted in the area where the hinge would normally be installed on the window (see photograph 7). The cabin door window was fractured, only several small sections remained. Soot was also noted on the manufactured surface of the storm window; no soot was noted on the fracture surfaces of the window. Blistering and discoloration of paint was observed on skin near the middle section of the instrument panel immediately forward of the windshield (see photograph 8). Examination of the instrument panel and firewall of the airplane revealed extensive heat damage to the electrical wiring behind the instrument panel. The damage was localized on the pilot'
The arcing of an electrical wire behind the instrument panel and the associated cracking of fuel and oil lines. Also causal was the pilot's inappropriate remedial action not in accordance with the emergency checklist.
Source: NTSB Aviation Accident Database
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