Englewood, CO, USA
N421FR
Cessna 421
The pilot's father had just purchased the airplane for his daughter, and she was receiving model-specific training from a contract flight instructor. Her former flight instructor was aboard as a passenger. The engines were started and they quit. They were restarted and they quit again. They were started a third time, and the airplane was taxied for takeoff. Shortly after starting the takeoff roll, the pilot reported an unspecified engine problem. The airplane drifted across the median and parallel runway, then rolled abruptly to the right, struck the ground, and cartwheeled. The landing gear was down. Neither propeller was feathered. Disassembly of the right engine and turbocharger revealed no anomalies. Disassembly and examination of the left engine and turbocharger revealed the mixture shaft and throttle valve in the throttle and fuel control assembly were jammed in the idle cutoff and idle rpm positions, respectively. Manifold valve and fuel injector line flow tests produced higher-than-normal pressures, indicative of a flow restriction. Disassembly of the manifold valve revealed the needle valve in the plunger assembly was stuck in the full open position, collapsing the needle valve spring. A scribe was used to free the needle valve, and the manifold valve and fuel injector lines were again flow tested. The result was a lower pressure. Plunger disassembly revealed the threads had been tapped inside the retainer and metal shavings were found between the retainer and spring. The Teledyne Continental Motor (TCM) retainer has no threads. GPS download showed that 2,698 feet had been covered between the start of the takeoff roll and the attainment of rotation speed. Maximum speed attained was 132 mph. Computations indicated distance to clear a 50-foot obstacle was 2,000 feet, distance to clear a 50-foot obstacle (single engine) was 2,600 feet, and accelerate-stop distance was 3,000 feet.
HISTORY OF FLIGHT On December 17, 2004, at 1522 mountain standard time, a Cessna 421, N421FR, registered to and piloted by a commercial pilot, was destroyed when it impacted terrain 0.5-mile south-southwest of Centennial Airport (APA), Englewood, Colorado. Visual meteorological conditions prevailed at the time of the accident. The instructional flight was being conducted under the provisions of Title 14 CFR Part 91 without a flight plan. The pilot, flight instructor, and pilot certificated-passenger were fatally injured. The flight was originating at the time of the accident, and was en route to the Fort Collins-Loveland Airport (FNL), Fort Collins, CO. The airplane arrived at Centennial Airport between 1330 and 1400, and the three occupants had lunch at the airport restaurant. The airplane was not refueled. According to a Denver Jet Center East employee, approximately 1500 a "pretty" female boarded the airplane and sat in the left seat. She was followed by "two older gentlemen, the one wearing a baseball cap, [who] sat in the right seat." She said that after both engines were started, the right engine quit, followed by the left engine. Her first impression was that the pilot had retarded the mixture handles. After some effort, the engines were restarted, but they quit one after another shortly thereafter. "It took many cranks to get them going again," she said. "They messed with the engines for at least 10 minutes." As the airplane taxied out for takeoff, she noticed a puff of black smoke but she could not be sure "which engine it was coming from." According to the pilot's father, his daughter called him from the airport and told him they were having "engine problems" or "fuel problems," and that something had been "hooked up backwards." She asked that he notify the repair facility that they were returning the airplane for repairs. That was the last contact he had with his daughter. The airplane was cleared for takeoff on runway 17L at 1521:41. At 1522:30 a female reported, "centennial tower four two one foxtrot romeo we're having engine trouble just to let you know." (See Transcript of Radio Communications, EXHIBITS). At 1522:43, there was a garbled transmission from the pilot. The airplane was seen to drift right across the median and runway 17R, then roll abruptly to the right and descend in a steep nose-low attitude. The airplane struck the ground, cartwheeled, and came to rest 1,017 feet southwest of the departure end of runway 17R (251º magnetic). There were numerous witnesses to the accident (see EXHIBITS). One (witness #1) of two linemen working outside the Signature Flight Support facility, located near the intersection of runways 17L and 11, said that as the airplane passed his position, it did not appear to be climbing. "The aircraft appeared to be using right rudder as the nose of the aircraft had yawed to the right." His co-worker (witness #2) agreed that there was "full right rudder deflection." He then observed the airplane bank right "at a rapid rate . . . very steep bank angle . . . 90 degrees or more . . . [It] began to sink very fast . . . The aircraft hit the ground without changing its bank angle." Another employee (witness #3) inside the building said the airplane was crabbing "significantly to the right . . . The left wing would dip (in the down position) and the pilot would recover. This action continued 3 or 4 more times . . . The aircraft did not seem to gain or lose altitude . . . The aircraft's landing gear was extended." Another witness (#4) who was driving home saw the airplane bank to the right and slowly descend. "I noticed the gear were still in transit mode coming up slow." He did not hear any unusual engine sounds, or notice any smoke or windmilling propellers. Two flight instructors observed the accident. One instructor (witness #5) was on landing approach. He said the airplane "appeared to be aligned with its axis along the runway (17L) centerline, and about the same altitude as I was (250 feet agl) . . . It began to drift slowly to the right. The axis always was parallel to the departure runway, with wings level, no turn was initiated. The plane continued to drift over the grass between runways 17L and 17R, with no apparent climb or descent . . . Rather suddenly, the left wing rose, and in a continuing descending arc to the right, the aircraft made ground impact, followed by a cartwheel." The other instructor (witness #6) was departing on the downwind leg. He said the airplane "flying very slowly and pointed in a southwesterly direction. The left wing came up and the airplane did what appeared to be a Vmc roll." The accident occurred during the hours of daylight at a location of 39 degrees, 33.367' north latitude, and 104 degrees, 51.249' west longitude. The accident site was at a GPS (Global Positioning System) elevation of 5,916 feet msl. PERSONNEL (CREW) INFORMATION First Pilot The first pilot held an airline transport pilot certificate with an airplane multiengine land rating, and commercial privileges in airplanes single-engine land, dated October 8, 1986. He also held a flight instructor certificate with airplane single/multiengine and instrument ratings, dated May 30, 2003, and a ground instructor certificate with an advanced rating, dated January 14, 1987. His second class airman medical certificate, dated May 6, 2004, contained the restriction, "Must wear corrective lenses." He was the owner and chief executive officer of Aircraft Training Resources. According to his most recent application for medical certification, he estimated he had logged the following flight time (in hours): Total Time: 11,000 Last 6 Months: 250 Two pages of the pilot's logbook (which was kept on a computer, were provided by his daughter. The first page contained entries from March 31, 2003, to December 5, 2003, and the second page contained entries from January 1, 2004, to July 26, 2004, to wit (in hours): Total Time: 222.7 197.5 Single-engine: 5.4 Multiengine: 217.3 197.5 Turboprop: 66.4 143.7 Night: 11.2 13.8 Actual Instruments: 20.9 18.3 Simulated Instruments: 0.5 87.5 Solo: 1.2 Pilot-in-Command: 224.7 197.5 Instruction Received: 1.5 Instruction Given: 205.8 187.7 Cessna 421: 74.7 5.5 According to his sister, the pilot's resume, updated in November 2004, showed the following flight time (in hours): Total Time: 12,000 Multiengine: 7,850 Turboprop: 4,900 Total Instruments: 2,120 Pilot-in-Command: 11,700 Instruction Given: 3,500 His last biennial flight review, 1.5 hours duration, was dated May 30, 2003, and was taken in a Cessna 172. Second Pilot The second pilot, age 20, was a student at Metropolitan State College of Denver, majoring in aviation technology, and aspired to become an airline pilot. She held a commercial pilot license with airplane single/multiengine land and instrument ratings, dated July 12, 2004. Her third class airman medical certificate, date January 2, 2003, contained no restrictions or limitations. According to her logbook, containing entries from November 14, 2002, to December 4, 2004, she had accrued the following flight time (in hours): Total Time: 414.6 Single-engine: 180.8 Multiengine: 247.1 Pilot-in-Command: 303.3 Instruction Received: 212.0 Night: 32.1 Actual Instruments: 8.7 Simulated Instruments: 53.5 Simulator: 14.0 Cessna 421: 31.9 Her commercial single/multiengine practical tests, taken in a Cessna 182 and a Piper PA-23-250 on July 12, 2004, respectively, constituted her biennial flight review. Third Pilot The third pilot held a commercial pilot certificate with airplane single/multiengine land and instrument ratings, dated February 15, 1974. He also held a flight instructor certificate with airplane single/multiengine land and instrument ratings, dated December 8, 2002. He was the second pilot's former flight instructor. His second class airman medical certificate, dated August 10, 2004, contained the restriction, "Must wear corrective lenses and possess glasses for near and intermediate vision." He was a retired General Electric and Woodward Governor engineer. According to his logbook, he had accumulated the following flight time (in hours): Total Time: 3,928.2 Single-Engine: 3,766.5 Multiengine: 164.0 Pilot-in-Command: 3,759.9 Instruction Received: 163.7 Instruction Given: 663.0 Night: 333.7 Actual Instruments: 490.4 Simulated Instruments: 173.5 Simulator: 8.6 Cessna 421:4.0 His last biennial flight review/instrument proficiency check, taken in a Piper PA-28C-180, was dated June 30, 2003. AIRCRAFT INFORMATION N421FR (s/n 421-0069), a model 421, was manufactured in 1968 by the Cessna Aircraft Corporation. It was powered by two Continental GTSIO-520-D engines (s/n 188137-7-D, left; 219426R, right), each rated at 375 horsepower, driving two McCauley 3-blade, all-metal, constant speed propellers (m/n 3AF34C92-R; s/n 800799, left; 799841, right). According to the aircraft maintenance records, the last airframe annual/engine 100-hour inspections were accomplished on August 26, 2004. At that time, the airframe and both engines and propellers had accrued 2,666.2 total hours. The left engine and right engines which were overhauled on September 21, 1998, and October 24, 1994, respectively, and had since accrued 804.2 and 822.7 hours, respectively. Both propellers were overhauled on March 6, 2001, and each had since accrued 251.7 hours. The last pitot-static and altimeter checks and transponder/encoder systems checks were accomplished on October 27, 2004. During the last annual inspection, both engine oil filters and induction air filters were replaced and the fuel filter screens were cleaned. The fuel injectors were removed, inspected and cleaned, and replaced with new seals and O-rings. The spark plugs were cleaned, gapped, and rotated, and the left engine air/oil separator was removed "for weld repair due to chaffing." On November 2, 2004, the left fuel transfer pump and left landing light circuit breaker were replaced because the circuit breaker, which controls the transfer pump and landing light, kept opening. These were the only recent maintenance items accomplished. METEOROLOGICAL INFORMATION The following APA AWOS (automatic weather observation station) observations was recorded at 1536 (see EXHIBITS): Wind, 210 degrees at 3 knots; visibility, 10 statute miles (or greater); sky conditions, few clouds at 9,000 feet, scattered clouds at 11,000 feet; ceiling, 14,000 feet broken, 22,000 feet broken; temperature, 6 degrees C.; dew point, -6 degrees C.; altimeter, 30.27 inches of mercury; remarks: altocumulus standing lenticular clouds distant southwest. COMMUNICATIONS According to the tower communications transcript, the second pilot called for taxi clearance at 1514:54. Takeoff clearance was give at 1521:41. At 1522:30 the second pilot reported, "centennial tower four two one foxtrot romeo we're having engine trouble just to let you know." The airplane was cleared to land one any runway. At 1522:43 the pilot said, "we'll let . . . " (unintelligible, broken transmission). This was the last transmission from the airplane. AERODROME INFORMATION Centennial Airport (APA) is an IFR-certified airport, situated at an elevation of 5,883 feet msl, and located at coordinates 39 degrees, 34.21' latitude, and 104 degrees, 50.96' west longitude. The Denver Automated Flight Service Station (AFSS) is located on the field. At the time of the accident, the control tower was in operation. N421FR took off on runway 17L-35R, which is 10,002 ft. x 100 ft., made of asphalt and grooved. WRECKAGE AND IMPACT INFORMATION The on-scene investigation was conducted on December 18, 2004. The wreckage path was aligned on a magnetic heading of 240 degrees. There was a 27-foot long ground scar, consistent with the right wing, followed by a crater containing pieces of the right propeller and engine. A crater, containing nose dome Fiberglass, was 12 feet beyond, next to the main body of wreckage. The main body of wreckage was aligned on a magnetic heading of 310 degrees. Underneath the cockpit area were both wings. The left engine remained attached to the wing. The cockpit and cabin areas were destroyed by fire. The empennage sustained impact damage but not severely burned. Fifteen feet beyond the main wreckage was another crater, containing pieces of the left propeller and some engine parts. Most of the cockpit instruments were destroyed by fire. Engine instruments and controls that were discernible were: left/right tachometers, 600/400 rpm; left/right fuel flow, 0/0; left/right manifold pressure, 31/49 inches; left/right throttle, full forward/retarded 1.5 inches; left/right mixture controls, retarded 1.5 inches; left/right propeller controls, retarded 2.0 inches, respectively. The landing gear bellcrank was extended. Measurement of the flap chain and sprockets were consistent with the flaps being retracted. The upright right engine came to rest 40 feet to the left of the main wreckage and was 130 feet along the wreckage path. The right propeller was 70 feet up and 20 feet to the right of the wreckage path, near the engine. The spinner was crushed, torn, and sustained some thermal damage. Blade A (arbitrarily labeled) was relatively undamaged. Both blades B and C bore chordwise scratches on the cambered surface near the tips. In addition, blade C had leading edge damage gouges and was twisted about 30 degrees back and bowed about aft about 25 degrees. The left propeller was partially buried along the wreckage centerline. The spinner was crushed and torn. Blade A was relatively undamaged. Blade B was bowed back about 20 degrees and bore some chordwise scratches on the cambered surface near the tip. Blade C was bowed aft about 25 degrees, was slightly twisted, and had some leading edge damage. On December 20, 2004, the airframe and powerplants were examined at the facilities of Beegles Aircraft Services in Greeley, Colorado. The left engine had sustained thermal damage. All cylinders had compression when the crankshaft was turned, and there was continuity from the accessory section to the propeller shaft. The top leads of both magnetos sparked. There was some thermal damage to the fuel control unit (FCU), but the screen was clear of foreign debris. The throttle was closed and the mixture control arm was at the midpoint position. The fuel pump was thermally damaged and the top of the swirl chamber was broken off. Although the coupler was intact, it would not turn freely. Numbers 1 and 5 top spark plugs were oil-soaked, and there was corrosion on the electrode of the number 4 top spark plug. The left turbocharger turned freely. There was leading edge damage to six of the turbine blades, but there was no scoring on the housing. The wastegate was jammed in the closed position. The right engine had sustained impact but no thermal damage. The oil pump drive shaft turned with difficulty. The fuel pump coupler was intact and turned freely. All cylinders had compression when the crankshaft was turned, and there was continuity from the accessory section to the propeller shaft. The top leads of both magnetos sparked. The top leads of both magnetos sparked. The fuel manifold valve diaphragm was intact, the screen was clear of debris, and the chamber contained fuel. Although the fuel pump was broken into four pieces and scattered along the wreckage path, the coupler was intact, and the drive turned with difficulty. The upper deck pressure line had a ½-mm hole in the backside, just aft of the right magneto. It did not appear to be due to chaffing, but was more consistent with two chisel marks. The top spark plugs were clean and showed normal wear but needed changing. The electrodes were dark in color. The right turbocharger could not be turned. There was scoring on the compressor case, and two blades were bent opposite the direction of rotation. There was no scoring on the turbine case. The wastegate was almost fully closed. MEDICAL AND PATHOLOGICAL INFORMATION Autopsies were performed on all three occupants by the Douglas County Coroner's Office. In addition, FAA's Civil Aeromedical Institute (CAMI) conducted t
loss of engine power due to fuel starvation, and the instructor's failure to maintain aircraft control. Contributing factors were a partially blocked fuel line resulting in restricted fuel flow, the instructor's failure to perform critical emergency procedures, and his failure to abort the takeoff in a timely manner.
Source: NTSB Aviation Accident Database
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