Lake Worth, FL, USA
N297DB
CESSNA 421C
The twin-engine airplane was released to the owner after an annual inspection and repainting of the airplane had been completed. The pilot/owner had completed a post-maintenance test flight with the mechanic/proprietor of the maintenance facility, and minor discrepancies noted during the flight were corrected prior to final release of the airplane. The pilot performed a ground run of the airplane for several minutes before taxiing to the approach end of the departure runway. The airplane lifted off about halfway down the runway and climbed at a normal rate. The mechanic then observed the airplane suddenly yaw to the left for a second or two and the airplane's nose continued to pitch up before rolling left and descending vertically, nose-down, until it disappeared from view. Several witnesses provided similar accounts of the accident sequence. One witness, a certificated flight instructor said, "The airplane just kept pitching up, and then it looked like a VMC roll." Examination of the No. 1 (left) engine revealed signatures consistent with contact made between the piston domes and the valves. The crankcase halves were separated and the No. 1 main bearing was rotated, and damaged and distorted severely, with bearing fragments located in the oil sump. Bearing material was extruded from its steel backing. The No. 3 cylinder main bearing displayed signatures consistent with accelerated wear and wiping of the Babbitt material. Damage and signatures consistent with excessive heat due to oil starvation were displayed on the No. 1 and No. 3 main bearing journals, as well as the No. 1 and No. 2 connecting rod journals. The camshaft gear was damaged, with five gear teeth found sheared from the gear. A review of engine maintenance records revealed no maintenance was performed on the engine that would have required breaking of crankcase thru-bolt torques (such as cylinder removal) since overhaul. Examination of the wreckage revealed that the landing gear was in the down and locked position, the left propeller blades were in the feathered position, and the left fuel selector valve was in the off position. Examination of the manufacturer's Pilot Operating Handbook revealed that if properly configured, with the landing gear retracted, the airplane was capable of a 500 feet-per-minute rate of climb on the day of the accident. As found, the airplane was not configured in accordance with the after-takeoff checklist or either engine failure after takeoff checklist.
HISTORY OF FLIGHTOn December 8, 2012, at 1334 eastern standard time, a Cessna 421C, N297DB, operated by a private individual, was destroyed when it collided with trees and terrain following a loss of control after takeoff from North Palm Beach County Airpark (LNA), Lantana, Florida. The commercial pilot was fatally injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight, which was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. The pilot took delivery of the airplane from a maintenance facility that had just completed an annual inspection and repainting of the airplane. According to the owner of the facility, who was a certificated pilot and an airframe and powerplant mechanic, the pilot completed the preflight inspection and the airplane was towed outside. The pilot started the airplane, but then shutdown to resolve an alternator charging light. Afterwards, the pilot stated that he planned to fly to Okeechobee, Florida, complete a few landings, and then continue to Miami. According to the mechanic, the pilot performed a ground run of the airplane for several minutes before taxiing to the approach end of Runway 3 for takeoff. The airplane lifted off about halfway down the runway and climbed at a "normal" rate. The mechanic then observed the airplane suddenly yaw to the left "for a second or two" and the airplane's nose continued to pitch up before rolling left and descending vertically, nose-down, until it disappeared from view. Several witnesses provided similar accounts to a Federal Aviation Administration (FAA) inspector and the local sheriff's department. One witness, a certificated flight instructor said, "The airplane just kept pitching up, and then it looked like a VMC roll." PERSONNEL INFORMATIONThe pilot held a commercial pilot certificate with ratings for airplane single-engine land and sea, airplane multiengine land and instrument airplane. His most recent FAA third-class medical certificate was issued on February 27, 2008. An examination of the pilot's logbook revealed that he had logged 1,217 total hours of flight experience, of which 175 hours were in multiengine airplanes. AIRCRAFT INFORMATIONAccording to FAA and maintenance records, the airplane was manufactured in 1980. Its most recent annual inspection was completed December 3, 2012, at 7,039.9 aircraft hours. The airplane had accrued 2.2 hours of flight time after the inspection.The No 2 (right) engine was overhauled at RAM Aircraft, Waco, Texas, on September 13, 2006. At the time of its most recent annual inspection, the engine had accrued 966.3 hours since major overhaul (SMOH).The No. 1 (left) engine was overhauled at RAM Aircraft, Waco, Texas, on October 16, 2009. At the time of its most recent annual inspection, the engine had accrued 312.6 hours SMOH.Oil samples were taken from each engine at the most recent annual inspection, and sample testing was completed at Aviation Oil Analysis, Phoenix, Arizona, on October 29, 2012. According to the report, for metals and contaminants content, "All values appear normal." The owner of the maintenance facility where the annual inspection was completed held FAA commercial pilot, flight instructor, and airframe and powerplant certificates. In an interview, he said he performed a test flight with the accident pilot at the completion of the annual inspection. Prior to takeoff on the test flight, the propeller rpm was matched on both engines on the ground, but after takeoff the left engine showed 100 rpm above maximum when the right engine was at maximum. Once the rpm was matched manually by the pilot, the fuel flow on the left engine was about 1.5 to 2.0 gallons per hour below that of the right engine. The fuel flow rate on the left engine was also below that prescribed in the engine maintenance guidance. (SID 97-3). The airplane was flown for 1.2 hours, and during the flight cabin pressurization, prop synchronization, flight controls, and the autopilot were tested. About mid-flight, the left alternator segment light illuminated, and the ampmeter/voltmeter showed a drop in voltage. About 5 minutes later, the light extinguished, and the ampmeter/voltmeter showed normal voltage for the remainder of the flight. After landing, the airplane was shut down, and the accident pilot was told that the propeller rpm and the fuel flow needed adjustment on the left engine only. There were also some cosmetic corrections that needed to be made. After the corrections were made and prior to delivery of the airplane to the pilot, a complete run-up was performed, and the maintenance records were reviewed to confirm all the work that was done during the annual inspection. The airplane was equipped with two hydraulic pumps, and therefore the hydraulic system would remain pressurized with only one engine operating. METEOROLOGICAL INFORMATIONAt 1332, the weather reported at Palm Beach International Airport (PBI), 5 miles north of LNA included a scattered cloud layer at 2,600 feet and a broken ceiling at 3,500 feet. The wind was from 110 degrees at 11 knots. The temperature was 27 degrees C, the dew point was 20 degrees C, and the altimeter setting was 29.97 inches of mercury. WRECKAGE AND IMPACT INFORMATION The wreckage was examined at the accident site on December 9, 2012, and all major components were accounted for at the scene. The airplane was consumed by postimpact fire back to the aft pressure bulkhead. The wing spars were intact, and control cable continuity was established from the cockpit to the flight control surfaces. Examination of the main landing gear actuators revealed positions consistent with a down-and-locked configuration. Both engines were significantly damaged by postcrash fire. All three propeller blades of the left engine were attached at the hub, and in the "feathered" position. The right engine's propeller blades were destroyed by impact and fire. One blade was separated and not recovered. The remaining blades showed positions consistent with low pitch.Examination of the right fuel selector valve revealed that it was in the "main" position. Examination of the left fuel selector valve revealed that it was in the "off" position. Preliminary external and borescope examinations of both engines revealed continuity throughout and no mechanical anomalies. The engines were retained for detailed examination at a later date. MEDICAL AND PATHOLOGICAL INFORMATION The Office of the District Medical Examiner, West Palm Beach, Florida, performed the autopsy on the pilot. The autopsy revealed the pilot died from blunt force and thermal injuries. The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed forensic toxicology on specimens from the pilot. Thirty percent (30%) carbon monoxide, and 3.86 (ug/ml) cyanide were detected in the specimens tested. These levels are consistent with exposure to products of combustion. TESTS AND RESEARCH The engines were examined in Mobile, Alabama from February 19 to 22, 2013 under the supervision of an FAA inspector. Each was a 520 cubic-inch, six-cylinder, horizontally-opposed, air-cooled, fuel-injected, turbo-charged, geared engine that produced 375 horsepower at 3,350 rpm.Examination of the No. 2 (right) engine revealed no preimpact mechanical anomalies.Examination of the No. 1 (left) engine revealed signatures consistent with contact made between the piston domes and the valves. The crankcase halves were separated and the No. 1 cylinder main bearing was "rotated," and "damaged and distorted severely," with bearing fragments located in the oil sump. Bearing material was extruded from its steel backing. The No. 3 main bearing displayed signatures consistent with accelerated wear and "wiping" of the Babbitt material.Damage and signatures consistent with excessive heat due to oil starvation were displayed on the No. 1 and No. 3 main bearing journals, as well as the No. 1 and No. 2 connecting rod journals. The camshaft gear was damaged, with five gear teeth found sheared from the gear.Examination of maintenance records revealed that the manufacturer's main bearings and rod bearings were installed in the engine during overhaul. Further examination of the records revealed that no maintenance was performed on the engine that would have required breaking of crankcase thru-bolt torques (such as cylinder removal) since overhaulThe item 98 write-up on the most recent annual inspection invoice stated, "Investigate no oil pressure on left engine; reprime left oil pump, filter, standpipe." When interviewed, the proprietors at the maintenance facility said that the airplane's engines sat idle for an extended period (weeks) due to the annual inspection and the painting of the airplane. Because engine oil has a tendency to "settle" in the sump, and cause the oil pump to lose its prime, the engines were motored. When motored, the left engine showed no oil pressure. The oil system was then primed, and oil pressure was restored prior to engine start. Examination of maintenance records revealed that as of the most recent inspection, all Airworthiness Directives were complied with and up to date. ADDITIONAL INFORMATIONThe manufacturer's normal procedure for "TAKEOFF:1. Power – SET FOR TAKEOFF2. Mixtures – CHECK fuel flows in the white arc3. Engine Instruments – CHECK4. Air Minimum Control Speed – 80 KIAS5. Takeoff and climb to 50 feet – 100 KIAS at 7450 pounds"The manufacturer's normal procedure for "AFTER TAKEOFF:1. Landing Gear – RETRACT2. Best Angle-of-Climb Speed – 86 KIAS at sea level to 92 KIAS at 20,000 feet with obstacle3. Best Rate-of-Climb Speed With Wing Flaps Up – 111 KIAS at sea level and 7450 pounds"The manufacturer's emergency procedure for "ENGINE FAILURE DURING TAKEOFF (Speed below 100 KIAS or Gear Down):1. Throttles – CLOSE IMMEDIATELY2. Brake or Land and Brake – AS REQUIRED"The manufacturer's emergency procedure for "ENGINE FAILURE AFTER TAKEOFF (Speed above 100 KIAS with Gear Up or In Transit):1. Mixtures – FULL RICH2. Propellers – FULL FORWARD3. Throttles – FULL FORWARD4. Landing Gear – CHECK UP5. Inoperative Engine:a. Throttle – CLOSEb. Mixture – IDLE CUT-OFFc. Propeller – Feather6. Establish Bank – 5 [degrees] toward operative engine7. Climb to Clear 50-Foot Obstacle – 100 KIAS8. Climb at One Engine Inoperative Best Rate-of-Climb Speed – 111 KIAS9. Trim Tabs – ADJUST 5 [degrees] toward operative engine…10. Inoperative Engine – SECURE as follows:a. Fuel Selector – OFF (Feel for Detent)"A WARNING at the end of the procedure stated: "The propeller on the inoperative engine must be feathered, landing gear retracted and wing flaps up or continued flight may be impossible."Using weather conditions that were current at the time of the accident, interpolation of the airplane manufacturer's "RATE-OF-CLIMB – ONE ENGINE INOPERATIVE" chart revealed that with the landing gear retracted, and the propeller on the inoperative engine feathered, the airplane was capable of an approximate climb rate of 400 feet per minute. With the landing gear down and locked, as found, the airplane was capable of an approximate climb rate of 50 feet per minute.The FAA Airplane Flying Handbook defined VMC as: "Minimum control speed. The minimum flight speed at which the airplane is controllable with a bank of not more than 5 [degrees] into the operating engine when one engine suddenly becomes inoperative and the remaining engine is operating at takeoff power… At low airspeed and high-power conditions, the downward moving propeller blade of each engine develops more thrust than the upward moving blade…When the right engine is operative and the left engine is inoperative, the turning force is greater… In other words, directional control is more difficult when the left engine (the critical engine) is suddenly made inoperative."
The pilot's failure to follow established engine-out procedures and to maintain a proper airspeed after the total loss of engine power on one of the airplane’s two engines during the initial climb. Contributing to the accident was the total loss of engine power due to a loss of torque on the crankcase bolts for reasons that could not be determined because of impact- and fire-related damage to the engine.
Source: NTSB Aviation Accident Database
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