Glenwood, NM, USA
N42XT
Eldredge NXT
While cruising at an airspeed of 300 knots at an altitude of 12,500 feet, the airplane "hit a pocket of wind shear." Shortly thereafter, the pilot noticed smoke entering the cockpit. When the pilot noticed an increase in engine oil temperature, he reduced the engine power. The pilot attempted to locate an area to execute a forced landing and declared a "mayday" to air traffic control. In an attempt to reduce the smoke continuing to enter the cockpit, the pilot shut down the engine, and feathered the propeller. The smoke in the cockpit dissipated, and the pilot attempted a forced landing to a dirt runway. Due to oil on the windshield, the pilot's visibility was reduced during the approach and landing. During the landing, the airplane departed the dirt runway surface and impacted rocks and terrain. Examination of the engine revealed that the crankshaft oil seal was partially extruded at the six o'clock position. No additional anomalies were noted with the engine that would have precluded engine operation. The aircraft was equipped with a Christen air/oil separator. No evidence of improper installation was noted, and all of the lines were secure at their respective fittings. The separator was removed and the ball check valve within the separator was free to move and no obstructions were noted. An alternate warm air source (whistle slot) was located in the crankcase vent line and mounted on the left side of the firewall. The oil breather tube exited the airframe on the lower left side of the fuselage.
On April 11, 2006, approximately 1000 mountain daylight time, an Eldredge NXT single-engine experimental airplane, N42XT, sustained substantial damage during a forced landing at the Glenwood-Catron County Airport (E94), Glenwood, New Mexico. The commercial pilot, who was the sole occupant and registered owner of the airplane, was not injured. Visual meteorological conditions prevailed, and a visual flight rules flight plan was filed for the Title 14 Code of Federal Regulations Part 91 personal flight. The flight departed Las Cruces, New Mexico, and was en route to Palmdale, California. According to the pilot, during cruise flight approximately 300 knots at an altitude of 12,500 feet, the airplane "hit a pocket of wind shear." Shortly thereafter, the pilot noticed smoke entering the cockpit. After the pilot noticed an increase in engine oil temperature, he reduced the engine power. The pilot attempted to locate an area to execute a forced landing and declared a "mayday" to air traffic control. In an attempt to reduce the smoke continuing to enter the cockpit, the pilot shut down the engine, and feathered the propeller. The smoke in the cockpit dissipated, and the pilot initiated a forced landing to E94. Due to oil on the windshield, the pilot's visibility was reduced during the approach and landing. During the landing, the airplane departed the dirt runway surface and impacted rocks and terrain. Examination of the airplane by the pilot and a local mechanic revealed the left main landing gear was collapsed, and the right main landing gear was separated. The left wing forward spar was damaged. At 0600, the 12,000-foot upper air temperature observation for Santa Teresa, New Mexico, (located approximately 125 nautical miles southeast of the airplane's route of flight) reported a temperature of 31 degrees Fahrenheit, a dew point of 24 degrees Fahrenheit, and a relative humidity of 74 percent. On April 17, 2006, the airframe and engine were examined in a hangar at E94 by the NTSB investigator-in-charge (IIC) and representatives of Lycoming Engines. Examination of the Lycoming TIO-540-X186 engine (serial number L-1589-X) revealed that the crankshaft oil seal was partially extruded at the six o'clock position. The top spark plugs were removed and exhibited no damage to the electrodes. The electrodes exhibited varying degrees of discoloration and no oil residue was noted. The cylinder combustion chambers were visually examined with a lighted borescope and exhibited no evidence of foreign object ingestion or detonation. The piston domes and valves were intact and no damage was noted. The oil suction screen was removed and free of visible contaminates. The turbo-charger impellers were free to rotate by hand and no evidence of foreign object damage was noted. The engine was removed from the airframe for further examination at the manufacturer's facility. The pilot reported the total time on the engine at the time of the accident was 102 hours. The aircraft was equipped with a Christen air/oil separator. According to the pilot, the separator was installed on the airframe approximately 20 hours prior to the accident. No evidence of improper installation was noted, and all of the lines were secure at their respective fittings. The separator was removed and the ball check valve within the separator was free to move and no obstructions were noted. An alternate warm air source (whistle slot) was located in the oil breather tube and mounted on the left side of the firewall. The oil breather tube exited the airframe on the lower left side of the fuselage. On May 31, 2006, the engine was examined and disassembled at the facilities of Lycoming Engines, Williamsport, Pennsylvania, under the supervision of the NTSB IIC. The cylinders were all Lycoming Nitride. The cylinder assemblies, pistons, piston rings and valves were unremarkable. The crankcase parting surfaces, main bearings, and main bearing saddles were unremarkable. The crankshaft main bearing journals, connecting rod bearing journals, and crankshaft gear were unremarkable. The crankshaft counterweights were intact and free to move. The connecting rods, connecting rod bearings, camshaft and tappets were unremarkable. The crankshaft nose seal was extruded at the six o'clock position and the remaining seal was secured to the crankcase. Material examination of the nose seal revealed no anomalies. The nose seal area of the crankcase was dimensionally checked and dimensions were within engineering specifications. The engine disassembly revealed no anomalies that would have precluded engine operation.
the loss of engine power due to the partial failure of the crankcase nose seal for undetermined reasons. A contributing factor was the pilot's diminished visibility during the forced landing due to oil on the windscreen, resulting in a runway excursion and subsequent impact with rocks and terrain.
Source: NTSB Aviation Accident Database
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