Delta, CO, USA
N2012Y
CESSNA 182T
The airplane experienced a loss of propeller control during cruise flight, which resulted in the pilot's inability to attain the propeller speed needed to maintain flight. The airplane struck a power line during the subsequent forced landing to a highway. Upon landing, the right main landing gear separated from the airplane, and the airplane veered off the road. Postaccident examination of the engine did not reveal oil supply obstructions to the propeller control system. Component level testing and examination of the propeller system, which was limited due to propeller damage, did not reveal any anomalies that would result in a loss of propeller control. The reason for the loss of propeller control could not be determined.
On May 2, 2013, at 1127 mountain daylight time, a Cessna 182T, N2012Y, experienced a loss of propeller control during cruise flight. The pilot performed a forced landing on a highway after the airplane was unable to maintain altitude. The airplane impacted power lines and terrain during a forced landing near Delta, Colorado. The airplane sustained substantial damage to the fuselage. The private pilot was uninjured. The airplane was registered to Janair LLC and operated by Colorado Flight Center under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed and a flight plan had not been filed for a local flight that originated from Grand Junction Regional Airport (GJT), Grand Junction, Colorado, at 1045 and was returning to GJT. The pilot stated that he performed touch and go landings at Montrose Regional Airport, Montrose, Colorado, and was returning to GJT during the accident flight. During the return flight to GJT, he reduced manifold pressure to 19 inches of mercury and began to reduce propeller speed from 2,400 rpm to 2,250 rpm shortly after the airplane leveled off at a cruise altitude of 8,000 feet mean sea level. While adjusting propeller speed, the propeller speed "dropped abruptly" to about 2,100 rpm while he was turning the propeller speed control knob. He then pushed the propeller speed control knob full in, but there was no change in propeller speed. He then pushed the throttle control in to full power. The airplane airspeed was about 110 knots indicated airspeed (KIAS), but was decreasing. The pilot descended the airplane to 7,500 feet msl at which point the airspeed stabilized at 85 KIAS, and the manifold pressure was 20.9 inches Hg. After a few miles, the propeller speed became erratic, ranging from 2,150 rpm to 2,040 rpm. The pilot tried to adjust the propeller speed again by cycling the propeller and returning the propeller control knob to the full in position, but the propeller speed remained erratic, above and below 2,100 rpm. The pilot said that shortly after diverting the flight to Blake Field Airport, Delta, Colorado, he heard a clunking sound from the front of the airplane. He said that is was not a ringing or rapping sound, but a heavy muffled clunking sound. The airplane lost all thrust, and he performed a forced landing with no flaps extended in attempt to attain a landing to a highway. The pilot turned to airplane to fly between power lines, but the airplane struck the power lines while in the turn. The airplane touched down on the highway and went off the right shoulder after the right main landing gear had separated. The last inspection of the airplane was an annual inspection with an airplane logbook entry date of March 8, 2013, at a total airframe tachometer times of 1,627.0 hours. The entry stated that the propeller governor was overhauled. The next entry was dated April 17, 2013, and stated that an overhauled propeller was installed. The propeller was a McCauley 83D36C431-C/80VSA-1, serial number 051726, three-blade propeller with a total time since new of 1,643.7 hours, and a time since overhaul of 0 hours. On-scene examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the flaps were retracted, the fuel selector was in the off position, the cockpit mixture and throttle controls were at their forward stop, the cockpit propeller control was at the aft stop, and the fuel boost pump switch was in the off position. Propeller control continuity was confirmed prior to removal of the propeller and propeller governor. The propeller and propeller governor were removed by the operator's maintenance personnel and sent to McCauley Propeller Systems, Wichita, Kansas. On July 19, 2013, the propeller and governor were tested and examined under the supervision of a National Transportation Safety Board (NTSB) Air Safety Investigator. The number 1 propeller blade was part number I-80VSA-1 and serial number ZJ26152; the number 2 blade was part number I-80VSA-1 and serial number ZL26036; the number 3 blade was part number I-80VSA-1 and serial number ZL26038. The propeller hub was part number B3D36C431-C and serial number 051726. All three propeller blades were able to be rotated by hand pressure while within the hub. The blades did not exhibit bending/twisting. The number 1 blade had two leading edge dings/gouges located near the outboard 1/4 span. The number 2 blade had a ding/tear near the tip. The number 3 blade had a dent/gouge located near 1/4 span. The blades were removed from the hub and all three pitch change links were fractured, and the fracture features were consistent with overstress. No other internal components exhibited damage. A liquid consistent with water along with oil was present when the piston assembly was removed from the cylinder. The governor, part number DC290 D1F/T8, serial number 051824 was missing four of its cap screws. Oil drained from the governor did not contain liquid consistent with water. Four cap screws were installed onto the governor in preparation for a bench test. The test results indicated that the maximum governor speed was 2,350 rpm (specification limit was 2,275 rpm). The pressure relief valve regulated pressure to 305 psi. Flow testing of governor revealed an input oil pressure of 50 psi and an output oil pressure of 124 psi. The flow value was 5.9 quarts/minute (minimum limit was 5.0 quarts/minute, no maximum limit value). An internal leakage rate test revealed the leakage rate was 2 quarts/hour (maximum limit was about 10 quarts/hour). On March 6, 2013, the NTSB Investigator-In-Charge presented questions to the McCauley party coordinator regarding test and examination following receipt of the McCauley Teardown Inspection Report dated March 3, 2014. The report stated that recovery personnel indicated that rain likely entered the propeller during its storage in a truck bed with the propeller mount flange uncovered. Four of the six propeller governor cap screws were missing, and the remaining two screws were finger tight. In response to the question of whether the propeller blades/actuating piston were sticking, the party representative stated that shimming was in place on each propeller blade, which was shimmed properly and could be rotated freely and smoothly. When asked the condition of the piston seal, the representative stated that the seal was undamaged and engine oil in the cylinder dome and the red oil in the propeller were not intermixed. When asked if a compression test was performed of the propeller dome, the representative stated that all the actuation links were broken in tension during the propeller strike and a pressure check of the cylinder dome would not have rotated the blades; a pressure check was not performed. When asked what the low and high pitch stop settings were, the representative stated that the pitch stops were set with shim washers on the propeller, which were in place. The angle verification of the stops was not performed due to breakage of all the actuation links that connect the piston to the blades; the stack heights did not appear unusual. The representative also stated that the top cover of the governor had been removed; therefore, control arm clocking/travel could not be verified. The engine was overhauled at a repair facility following the airplane's recovery. Maintenance personnel from the facility stated that the engine underwent a pressure differential test across the front nose bearing per Lycoming Service Instruction 1462A. At a delivery pressure of 35 psi, the indicated pressure was 18 psi (the limits was 6 to 35 psi). There was no obstruction in the front main bearing for oil delivery. The fuel pump and fuel servo (Bendix RSA-5AD1, part number 2576544-3, serial number 70A72401) were tested and noted to be within test limits. The mechanic from the overhaul facility stated that engine oil travel travels down the left hand case half that eventually feeds the propeller governor. The propeller governor receives the oil and amplifies the pressure and then transfers the oil through a passage down to the center of the front main bearing. It then travels through the cavity in the front bearing to where it passes through the transfer tube in the crankshaft exits the propeller hub. He said that it was a closed system from the governor to the propeller hub.
The loss of propeller control for reasons that could not be determined because postaccident examinations revealed no anomalies that would have precluded normal operation and the airplane’s subsequent collision with power lines during the forced landing.
Source: NTSB Aviation Accident Database
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