Aviation Accident Summaries

Aviation Accident Summary DEN04FA109

Fort Collins, CO, USA

Aircraft #1

N69CL

Beech 58P

Analysis

The pilot obtained a "standard weather briefing," filed an instrument flight rules flight plan, and took off. Four minutes later, after several routine radio communications, the controller issued the pilot a radar vector. He did not acknowledge. The controller repeated the vector. There was a squelch break and in the background, a noise and tone could be heard. The pilot reported, "We have got some sort of malfunction going on here." Witnesses reported hearing an engine "sputtering" and losing power. The airplane emerged from a low overcast in a flat counterclockwise spin. The airplane impacted a street and driveway in a residential subdivision. On-scene investigation disclosed the landing gear and flaps were retracted. Both elevators were deflected up and jammed by impact. Subsequent examination of the airplane revealed the cockpit fuel selector handles were in the LEFT TANK-LEFT ENGINE/RIGHT TANK-RIGHT ENGINE positions. The left and right fuel selector valves, located in the wheel wells, were OFF and ON, respectively. Analysis of the ATC communications tape revealed two engines operating until the pilot reported the "malfunction," then which only one engine sound could be heard. A steady 1,000-hertz tone, similar to an aural stall warning system, was also heard. Both engines, turbochargers, and propellers were later disassembled and examined. No anomalies were noted. Neither propeller was feathered. On the day before the accident, the pilot had undergone recurrent ground and flight training, a flight review, and an instrument proficiency check in the airplane. Flight time totaled 5.3 hours.

Factual Information

HISTORY OF FLIGHT On July 24, 2004, at 1207 mountain daylight time, a Beech 58P, N69CL, piloted by a private pilot, was destroyed when it impacted terrain in a residential area of Fort Collins, Colorado. Visual meteorological conditions (VMC) prevailed at the time of the accident. The personal cross-country flight was being conducted on an instrument flight rules (IFR) flight plan under the provisions of Title 14 CFR Part 91. The pilot and two passengers sustained fatal injuries. The flight originated from Fort Collins-Loveland Airport (FNL) at 1202, and was en route to Eppley Field (OMA), Omaha, Nebraska. According to Jet Center records, the airplane was serviced with 76.7 gallons of 100-LL aviation-grade gasoline prior to its departure from Fort Collins-Loveland Airport. According to FAA documents, the pilot telephoned the Denver (DEN) Automated Flight Service Station (AFSS) at 1037 and obtained a "standard weather briefing" for an IFR flight from FNL to OMA. When the briefing ended, the pilot filed an IFR flight plan. At 1151, the pilot inadvertently contacted Denver terminal radar control (TRACON) instead of the Denver AFSS. The controller obtained and issued the pilot his IFR clearance, and the pilot read it back correctly. At 1156, the pilot advised the controller he was ready for takeoff on runway 15. The controller said there would be a 20-minute delay due to inbound IFR traffic. The controller suggested that if the pilot would be willing to depart on runway 33, he could release him almost immediately. The pilot said he would taxi to and depart on runway 33. At 1202, the pilot said he was ready for takeoff. The controller "released" the flight and instructed the pilot to turn right to a heading of 350 degrees and climb and maintain 8,000 feet. The pilot was given an IFR clearance void time of 1205. At 1204, the pilot reported passing 5,800 feet. The controller advised the pilot that he was in radar contact. At 1205, the controller instructed the pilot to climb and maintain 8,000 feet and the pilot acknowledged. The controller then instructed the pilot to turn right to a heading of 080 degrees. The pilot acknowledged. At 1206, the controller instructed the pilot to turn right to a heading of 100 degrees. The pilot did not acknowledge. The controller repeated the instruction. There was a squelch break and in the background, noise and a tone could be heard. The controller then asked the pilot, "How do you hear?" The pilot answered, "We hear you loud and clear. We have got some sort of malfunction going on here." The controller asked if he was having communications difficulties. There was no reply from the pilot, nor were there any further communications. The controller then contacted the Fort Collins Police Communications Center and advised that the airplane was believed to have crashed northwest of Fort Collins. At 1207, the controller advised the pilot that radar contact had been lost. It was also at this time that the Fort Collins Police Communications Center received the first of numerous 9-1-1 calls. At 1244, the police department notified Denver TRACON and confirmed that the airplane had crashed in a Fort Collins neighborhood. Telephone interviews or written statements were taken from 16 witnesses. Witness 3 heard "an abrupt decrease in engine noise," and witness 7 heard "erratic revving of a plane motor, followed by the sound of a motor stalling. [It] sputtered four times before dying." Witness 4 heard "erratic engine noise." Witness 5 said the "engines were missing, sputtering, cutting to silence, then sputtering again." Witness 8 heard the airplane "lose an engine," and witness 11 said "the engine quit." Witness 12 said "the engines didn't sound normal...kind of higher pitched...like he was climbing. Engines were revved at high RPMs...[Then] the sound changed, [like] when a plane is diving to make a run." Witness 16 said the plane's engine sounded "like it was failing or under heavy load (higher RPM)," and witness 14 thought "the pilot had slowed the engine down." The airplane was seen to emerge from the overcast in a flat spin. Several witnesses (1, 6, 10, 16) said the airplane fell "straight down," and witness (10) added, "with no forward motion." Witnesses 1 and 7 said the airplane was spinning counterclockwise. Witness 3 said "it appeared the right hand engine propeller had stopped turning. Witness 4 said "one engine [was] dead (prop not spinning on starboard side)." This witness added, "The elevator on the aircraft was fully deflected in the up position during the descent and at impact." The airplane impacted the street and driveway in front of 3027 Stonehaven Drive. Fuel flowed underneath a parked automobile and into the storm drain. Seconds later, the fuel ignited and engulfed the airplane and the parked automobile and blew off four manhole covers. PERSONNEL INFORMATION The pilot, age 50, held a private pilot certificate with airplane single/multiengine land and instrument ratings, dated March 29, 2002. He also held and third class airman medical certificate, dated March 17, 2003, with the limitation, "must have available glasses for near vision." The pilot's two logbooks were examined. The first logbook contained entries from February 26, 1997, when he took his first flying lesson, to September 10, 2003. The second logbook contained entries from September 23, 2003, to July 28, 2004. He began taking multiengine instruction in a Beech 55 on November 6, 2001, and received an airplane multiengine land rating on March 29, 2002. He did not fly multiengine airplanes again until the following year. Between March 5 and 8, 2003, the pilot received 15 hours of instruction in a Beech 58P simulator from Simcom, including "pressurization, instrument emergency, single engine procedures, and high altitude descents." His logbook was endorsed as having satisfactorily completed "training requirements outlined in Advisory Circular 91-91H, paragraph 7(i)," and "an instrument proficiency check required by FAR 61.57(d)." After that, the only multiengine airplane the pilot flew was the Beech 58P, N69CL. On July 23, 2004, the day before the accident, the pilot received 5.3 hours of instruction from ATM (Aviation Training Management) of Vero Beach, Florida. The training included "preflight operations, line inspection, aircraft servicing, use of checklists, cockpit orientation, start, taxi, run up, takeoff, climb to altitude, normal operations, simulated emergency engine/electrical/cockpit fires, medium, steep bank 360's, unusual attitudes, partial panel operations, VOR radial intercept, track, hold, multiple instrument approaches, autopilot coupled approaches, go around, land, GPS operations, single engine operations." His logbook was endorsed as having satisfactorily completed "the recurrent ground and flight training," a "flight review required by FAR 61.56," and "and instrument proficiency check FAR 61.57(d)(2)." The pilot had accumulated the following flight time (in hours): Total time: 1,397.4 Pilot-in-command: 1,271.1 Instruction received: 119.4 Single engine: 1,153.2 Multiengine: 211.6 Cross-country: 852.7 Night: 46.6 Actual instruments: 80.4 Simulated instruments: 71.0 Simulator: 16.0 The pilot had logged 171.0 hours in the Beech 58P, N69CL, of which 16.0 hours were in a simulator, 2.3 hours were in simulated instrument conditions, and 31.4 hours were in actual instrument conditions. AIRCRAFT INFORMATION N69CL (s/n TJ-444), a model 58P Baron, was manufactured by the Beech Aircraft Corporation in 1984, and was registered to L-Petrel LLC, of Dover, Delaware. It was equipped with two Continental TSIO-520-WB(3) engines (s/n 248186-R, left; 274490-R, right), rated at 325 hp at 2700 rpm, driving two Hartzell all metal, 3-blade, full-feathering constant speed propellers (m/n 3AF32C511-C). The airframe, both engines, and both propellers were given an annual inspection on May 20, 2004, at a Hobbs meter reading of 1,068.0 hours. At that time, airframe total time was 2,100.5 hours. The left engine (s/n 248186-R) had accumulated 1,027.4 hours since major overhaul on May 8, 1998. On June 7, 2000, it was disassembled, cleaned, inspected, and reassembled as a result of a propeller ground strike. At that time, the engine had accrued 1,065.3 total hours and 387.7 hours since major overhaul. The right engine (s/n 274490-R) had accumulated 639.7 hours since factory remanufacture on September 15, 2000. Both the left and right propellers (s/n 001568, left; 001562, right) had accumulated 639.7 hours since being newly installed. The most recent weight and balance was made on May 5, 2004, as a result of the removal old avionics and the installation of newer equipment. The calculated new empty weight was 4,409.12 pounds, the useful load was 1,790.88 pounds, and the center of gravity was 76.74 inches aft of datum. METEOROLOGICAL INFORMATION The following weather observations were recorded before and after the 1206 accident by the Fort Collins-Loveland Municipal Airport's Automatic Weather Observation Station (AWOS): 1155: Wind, 090 degrees at 9 knots; visibility, 10 statute miles (or greater); ceiling, 1,100 broken, 1,900 broken, 7,000 broken; temperature, 14 degrees C.; dew point, 9 degrees C.; altimeter, 30.45 inches of mercury. 1215: Wind, 100 degrees at 11 knots; visibility, 10 statute miles (or greater); ceiling, 1,600 broken, 7,000 broken; temperature, 14 degrees C.; dew point, 9 degrees C.; altimeter, 30.44 inches of mercury. AIDS TO NAVIGATION There were no known difficulties with aids to navigation. COMMUNICATIONS There were no reported communications difficulties. WRECKAGE AND IMPACT INFORMATION NTSB was notified of the accident approximately 1215, and arrived on scene approximately 1300. The airplane had impacted the driveway and street in front of 3027 Stonehaven Drive, in the English Ranch subdivision. Seconds later, it exploded and burned. Fuel, which had leaked out of the breached fuel tanks, spilled into the storm drain and exploded, blowing off four manhole covers and destroying a 1999 Chrysler minivan parked in front of the house. The area was temporarily evacuated to allow firefighters time to flush out the flammable vapors from the sewer system. The airplane was aligned on a magnetic heading of 350 degrees. The entire airplane was accounted for at the accident site. Control continuity was established. The landing gear and flaps were retracted. The empennage was circumferentially severed just below the dorsal fin. The cabin area had been consumed by fire from about the aft cabin window forward to the nose. The cabin roof was charred. The intact vertical stabilizer had broken at the spar and had pivoted aft. The rudder had snapped at the hinges, and only the bottom half remained attached. Both elevators were deflected up and jammed by impact. Cockpit examination revealed that both throttles were closed, and both propeller controls were full forward (low pitch, high rpm). The left engine mixture control was at idle cutoff, and the right engine mixture control was in the mid-range position. Both boost pumps were off. The left magneto switch was in the RIGHT position, and the right magneto switch was in the BOTH position. Only one of three blades remained attached to the right propeller assembly. The second blade was in the street nearby and the third blade was found across the street in the driveway of 3902 Carrick Road. Two blades remained attached to the left propeller assembly. The third blades were found in the street nearby. Of the two blades that remained attached, one was relatively straight; the other blade was curled at the tip and bore 90-degree spanwise scratches on the cambered surface. There were gouges in the asphalt pavement, similar to propeller strikes. There was a circumferential split extending from the cabin door aft to the wing trailing edge. The wreckage was retrieved and transported to the facilities of Beegles Aircraft Service, Greeley, Colorado, where, during the following week, it was further examined in greater detail. The left engine was partially disassembled. No anomalies were noted. Both magnetos were removed and bench tested. The left magneto sparked; the right magneto was burnt. The right engine was boroscoped. No anomalies were noted. Both magnetos sparked. Examination of both turbochargers revealed four turbine blades discolored and ground down. Scoring was noted on both cases in the same location. The vacuum pumps were removed and examined. The left vacuum pump could not be turned by hand. Disassembly revealed the vanes and drive were intact. Disassembly of the right vacuum pump revealed the drive was melted, and one vane was broken in three pieces. Both engines and turbochargers were packed and shipped to Teledyne Continental Motors in Mobile, Alabama, for further examination. The cockpit fuel selector handles were in the LEFT TANK-LEFT ENGINE/RIGHT TANK-RIGHT ENGINE positions. The left and right fuel selector valves, located in the wheel wells, were in the OFF and ON, respectively. Examination of the landing gear bellcrank indicated the landing gear was up. The flap jackscrew was extended 2 inches, and the elevator, aileron, and rudder trim jackscrews were extended 1.1 inches, 1.5 inches, and 3.8 inches, respectively. According to the Beech Aircraft Company investigator, these measurements equated to the flaps being up, 6 degrees tab down (elevator up), 1 degree left tab up (wing down), and 1 degree tab left (right rudder deflection), respectively. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy (report #2004CA-75) was performed on the pilot at the McKee Medical Center, Loveland, Colorado. Toxicological screens performed by FAA's Civil Aeromedical Institute (CAMI) on the pilot and the two passengers were negative for carbon monoxide, cyanide, ethanol, and drugs. One passenger, however, tested positive [0.095 (ug/ml, ug/g)] for diphenhydramine (Benadryl) in blood. It was also detected in the liver (see EXHIBITS). TESTS AND RESEARCH Audio Tape and National Track Analysis Program (NTAP): A tape recording of radio communications between TRACON and N69CL was sent to NTSB's audio laboratory for audio spectrum analysis. According to the electronics engineer's factual report, when the pilot acknowledged the clearance to climb and maintain eight thousand feet at 1205, "two distinct rotating propeller sounds could be heard. One propeller was rotating at about 2,520 rpm and the other propeller was rotating at about 2,659 rpm. The propeller sounds were steady and continuous throughout the transmission. No additional background sounds could be heard during the transmission." Shortly thereafter, the pilot acknowledged the instruction to turn to 080 degrees. At this time, "one propeller was rotating at about 2,499 rpm and the other propeller was rotating at about 2,620 rpm At 1206, the controller instructed the pilot to turn to a heading of 100 degrees. The pilot failed to acknowledge this instruction. When the controller repeated the instruction, there was a 4-second squelch break, during which time "three breaths were heard: one at the beginning, one approximately in the middle, and one at the end" of the squelch break. In the background, "a steady 1,000-hertz tone was heard," similar to the aural stall warning system. Only one propeller sound was heard, rotating "at about 2,540 rpm." The operating engine "contained very noticeable 2nd, 3rd and 4th harmonics. These strong upper harmonics…[are] usually present when the propeller is producing a significant amount of thrust at a high blade angle. When the pilot reported he had "some sort of malfunction going on here," only one propeller sound was heard, rotating approximately 2,536 rpm. The same harmonic sound signatures were noted. The report concluded, "No determination could be made as to what engine/propeller (left or right) was producing the observed sounds." When the pilot was instructed to turn to a heading of 100 degrees, recorded radar data showed the airplane (at 1206:07) was at 7,200 feet msl and on a heading of 045 degrees. Fourteen

Probable Cause and Findings

the loss of engine power for undetermined reasons, and the pilot's failure to maintain adequate airspeed which resulted in a stall/spin. Clouds and the pilot's diverted attention were contributing factors.

 

Source: NTSB Aviation Accident Database

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