Aviation Accident Summaries

Aviation Accident Summary LAX03FA187

Santa Nella, CA, USA

Aircraft #1

N4696W

Rockwell International Aero-Commander 112TC

Analysis

The single engine airplane collided with mountainous terrain while flying beneath a cloud overcast, in low visibility, through a mountain pass. The pilot, accompanied by his certified flight instructor (CFI), was flying to a location across a mountain range in another valley for the pilot's commercial check ride. The instrument rated pilots were visually trying to follow a highway through a mountain pass. Prevailing weather conditions in the mountain pass were overcast ceiling at the mountaintops and ridges, and less than a mile visibility in fog. A resident who lives 1 mile from the crash site said the visibility was less than 300 feet in fog at the time of the accident. Extensive examination of the wreckage disclosed no evidence of a preimpact mechanical malfunction, failure, or fire.

Factual Information

HISTORY OF FLIGHT On June 9, 2003, about 0900 Pacific daylight time, a Rockwell International Aero-Commander 112TC, N4696W, collided with mountainous terrain approximately 7 miles west of Santa Nella, California. The airplane was operated by the private pilot and owner under the provisions of 14 CFR Part 91. The private pilot received fatal injuries and the on board certified flight instructor (CFI) received serious injuries; the airplane was destroyed. Instrument meteorological conditions prevailed and a flight plan had not been filed. The flight originated at Reid-Hillview Airport, San Jose, California, around 0830. The pilot rated passenger, who has a CFI certificate, and was in the hospital recovering from severe burns, spoke to a Federal Aviation Administration (FAA) inspector 43 days after the accident. He said there might have been a fire on the left side of the airplane but he couldn't recall the details because it happened too fast. They were following Highway 152 and were prepared to call for an instrument flight rules (IFR) clearance if the visibility got worse. He could not recall the airplane's flight altitude or configuration because he was not the one flying. The CFI then spoke to the National Transportation Safety Board investigator 71 days after the accident. He said that they were en route to Castle Airport, Merced, California, for the airplane owner's commercial check ride. They were to meet the FAA examiner at Castle Airport. The CFI had flown a number of flights during the previous week, performing his CFI role, with the owner in preparation for the check flight. The cloud overcast was at the hilltops in some places, and above the hilltops in others. They were flying below the overcast following Highway 152 through the Pacheco Pass. About 1 minute prior to the accident, the passenger noticed that there was fire and smoke coming from the left seat rudder pedal area. The pilot tried to move away from the flames and keep the airplane level. The CFI did not remember what occurred after recognizing the fire until he had extracted himself from the wreckage and was exposed to fresh air. Once his head cleared he yelled for the pilot to get out of the burning airplane but the flames were too intense. He made his way down to Highway 152 and received help from a passing truck driver. AIRCRAFT INFORMATION The airplane was a low wing, single engine, four place airplane with retractable landing gear. The airplane was powered by a 210-horsepower Lycoming TO-360-C1A6D engine. The airplane logbooks were not located during the investigation and presumed to have been destroyed. An acquaintance of the pilot said that he had heard from another pilot that the airplane had experienced some electrical problems in the past. A maintenance invoice from a repair shop at Reid-Hillview Airport showed that the airplane had been brought in because of a loss of electrical power. The battery relay and master switch were replaced on May 16, 2003. The battery relay switch is located in the tail section by the battery. The master switch is located on the instrument panel. No other recent invoices for this airplane were found. PERSONNEL INFORMATION A review of FAA airman records revealed that the pilot held a private pilot certificate with single engine land and instrument (airplane) ratings. The pilot obtained his second-class medical on December 4, 2002. His medical certificate was issued with no limitations. The pilot's logbook was not located during the investigation and presumed to have been destroyed within the wreckage. The pilot records on file in the Airman and Medical Records Center located in Oklahoma City, Oklahoma, showed that on December 12, 2002, the pilot reported a total estimated flight time of 430 hours. The pilot rated passenger held a commercial pilot certificate with single and multiengine ratings and an instrument airplane rating. He held a flight instructor certificate with single engine and instrument airplane ratings. He obtained his second-class medical on September 12, 2000. His medical certificate was issued with no limitations. He reported in the Pilot/Operator Accident Report that he had 610 flight hours and 296 instructing hours. METEOROLOGICAL INFORMATION The nearest weather reporting facility was Salinas (SNS), which was located 30 miles to the southwest. At the time of the accident Salinas was reporting 800 feet overcast and 10 miles statute visibility. The airport of departure, Reid-Hillview, was reporting at 0750, winds of 150 degrees at 8 knots; 7 statute mile visibility; 1,100 feet overcast; temperature 15C; and dew point 12C. A resident, who's house is about a mile from the accident site, reported that around 0830 ground fog was present with a visibility of less than 300 feet. Merced/Macready Airport, 6 miles south of the destination airport, was reporting clear skies at 0853. WRECKAGE AND IMPACT INFORMATION The wreckage was located on a mountain hillside approximately 7 miles west of Santa Nella, and less than 1/2 mile south of Highway 152. The wreckage coordinates were 37 degrees 02.775 minutes north latitude, 121 degrees 15.516 minutes west longitude, and an elevation of 1,402 feet mean sea level. The mountainside was populated with long prairie grass and mature oak trees. The airplane was resting upright on 20-degree sloped terrain. The airplane was found oriented on a heading of 130 degrees magnetic from tail to nose. The earth around the airplane was burned from the midsection of the right wing extending down hill approximately 75 feet in a teardrop outline traveling back towards the tail/empennage section. Approximately 90 feet from the cockpit area, on a bearing to the plane of 098 degrees, and in line with the right wing main landing gear, was an oak tree limb fractured at about 20 feet above the ground. This is the first identified point of contact. A V-shaped ground scar was identified 34 feet from the cockpit along the same 098 bearing line as the fractured tree and right wing main landing gear mount. The entire center section of fuselage from the engine firewall aft to the empennage was destroyed by fire. The only remaining identifiable items were the steel components of seat frames, flight control cables, and flight control column. The wing spar section that joins the left and right wings was completely melted down. The right wing was present at its appropriate location on the fuselage starting at the wing root. The wing exhibited about a 80-degree aft bend starting at the landing gear strut. The right main landing gear strut was extended and the downlock was fractured at the lower through bolt. The landing gear actuator was extended. The center leading edge portion of the outboard section of wing was fire damaged revealing the main wing spar. The aileron and its balance weight was attached to the wing at its hinge points. The right flap was laying on top of the wing bent almost 90 degrees at the same location as the aft bend of the wing. Behind the wing spar at the landing gear mount location the wing skins exhibited a "ballooning" between the upper and lower skin. The underside wing skin exhibited extreme hydraulic deformation, ballooning, and ripping along the lateral axis. The empennage was detached from the main fuselage but was in its appropriate location relative to the scorched remains of the airplane. Thermal damage was apparent at the forward most portion. The right horizontal stabilizer appeared minimally damaged with a 4-inch impact mark on the leading edge at midspan. The elevator and trim tab was attached at its hinge point, bolted, and cotter keyed. The vertical stabilizer leading edge was consumed by fire. The rudder was seemingly undamaged, attached to its hinge pints, bolted, and cotter keyed. The left horizontal stabilizer appeared the same as the right but with no leading edge impact marks. The rudder and elevator balance weights were all present. Overall the empennage surface appeared clean, fairly undamaged, with no longitudinal soot streaks, or horizontal burning or charring marks. The left wing was found in its appropriate location relative to the burned outline of the airplane. The wing appeared wedged between two trees, level, on the leading edge and trailing edge of the wing. At the wing root the wing spar had melted down to the bottom spar cap. The lower aft outboard corner of the flap was crushed inboard and there was a 4-inch diameter tree at the flaps corner location. The leading edge of the wing, except for the last 2 feet, was melted aft down to the wing spar. A semicircular leading edge crush 2 feet across was identified 1.5 feet inboard of the wing tip longitudinal rivet line. The aileron was attached to its hinge points and the balance weight was present. Skin on the top of the wing aft of the spar was folded over back on its self. The left main landing gear was detached from the main wing spar. The wheel axle mount was fractured, the downlock fractured, and the landing gear actuator was extended. Both tips of the Hartzell propeller had a tip sections fractured and separated. One blade exhibited chordwise striations on the tip the other blade exhibited an s-curve bending of the trailing edge. The spinner was crushed with a clockwise twist and clockwise striations. Forty-five feet to the north of the airplane the top engine cowling was located. It exhibited no apparent structural damage, thermal damage, or discoloration. MEDICAL AND PATHOLOGICAL INFORMATION The Santa Clara County Medical Examiner-Coroner conducted an autopsy on the pilot. According to the coroner's report, the pilot died of extensive thermal injuries and smoke inhalation. Toxicology test for ethanol and drugs were negative. FIRE The pilot rated passenger reported that about 1 minute prior to the collision with terrain that there was smoke originating from the pilots left rudder pedal area. The cabin quickly filled with smoke. The ensuing fire after the ground impact destroyed the entire cockpit and cabin. No evidence of an in flight internal cockpit fire was found. No rivet shadowing, soot streaks, or molten metal tailings were identified on the remaining external fuselage sections. TESTS AND RESEARCH Flight Controls The flight control chains were found on the control column sprockets. The flight control cables were verified attached to their appropriate bellcranks and continuity verified to the ailerons and elevator. Both sides of the rudder cable appeared separated at the same location, at the flap torque tube, and all four cable ends had a q-tip like look to them. One side of the elevator trim cable had been cleanly separated at approximately the same location. The flap jackscrew was measured as extended 7/8 inch. Commander Aircraft technical representative reported that would correspond to less than 10 degrees of flap deployment. Engine The engine controls were attached between the cockpit and throttle, mixture, turbo waste gate, and prop governor. The engine was rotated by hand. Valve continuity was verified with all valves moving approximately the same distances and in proper sequence. All spark plugs exhibited a gray coloration relating to a normal operating range according to the Champion AV-27 Check-A-Plug chart. Thumb compression was achieved on all cylinders. The single drive dual magneto was completely destroyed by fire. The carburetor was found to be in full throttle and full mixture settings. Upon disassembly the fuel screen had black carbon like debris deposited in the interior. The float was present but thermally damaged. The throttle valve was observed to be in the full open configuration. Landing Gear Hydraulic System The landing gear are extended and retracted via a hydraulic system. According to the Rockwell Commander 112TC Maintenance Manual, the landing gear hydraulic system is powered by an electric-hydraulic power pack located in the left forward area of the aft fuselage section. When the landing gear is retracted the main landing gear hydraulic actuators are extended and the nose landing gear hydraulic actuator is retracted. The gear is kept in place by the hydraulic power pack maintaining residual pressure on the actuators. If hydraulic pressure is lost then the landing gear will free fall into the down position. In the down position the main mount actuators are retracted and the nose strut actuator is extended. ADDITIONAL INFORMATION The Safety Board released the wreckage to the owner's representative on June 17, 2004.

Probable Cause and Findings

The pilot's inadequate in-flight planning/decision by conducting VFR flight into IMC, and his failure to maintain terrain clearance. Contributing factors were low clouds, fog, and mountainous terrain.

 

Source: NTSB Aviation Accident Database

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