Aviation Accident Summaries

Aviation Accident Summary LAX93FA110

GORMAN, CA, USA

Aircraft #1

N79411

CESSNA 172K

Analysis

THE CERTIFICATED PRIVATE PILOT OBTAINED A STANDARD WEATHER BRIEFING BEFORE DEPARTING ON A CROSS COUNTRY FLIGHT WITH THREE PASSENGERS. VFR FLIGHT WAS NOT RECOMMENDED DUE TO LOW CEILINGS AND RAIN THAT EXISTED ALONG THE INTENDED ROUTE OF FLIGHT. GROUND WITNESSES OBSERVED THE AIRPLANE FOLLOWING A HIGHWAY TOWARD AN AREA OF RISING TERRAIN AND LOW CLOUDS. THE AIRPLANE CRASHED INTO A HILLSIDE, ABOUT 200 FEET BELOW A VOR STATION THAT WAS LOCATED ON THE ROUTE OF FLIGHT

Factual Information

History of the Flight On February 7, 1993, at about 1227 hours Pacific standard time, a Cessna 172-K, N79411, collided with terrain, about 1/2 mile north of Gorman, California. The airplane was being operated as a visual flight rules (VFR) cross country personal flight to San Jose, California, when the accident occurred. The airplane, co-owned and operated by the pilot, was destroyed. The certificated private pilot and three passengers received fatal injuries. Instrument meteorological conditions prevailed at the accident site and a flight plan was not filed. The flight originated from Burbank, California, at about 1156 hours. At about 1119 hours, the pilot obtained a weather briefing from the Riverside Automated Flight Service Station (AFSS) for the intended route of flight from Burbank to San Jose with an intermediate stop in Bakersfield, California. The pilot was informed that VFR flight was not recommended. The airplane departed Burbank from runway 8 to the north and the pilot contacted the Burbank Terminal Radar Approach Control (TRACON) facility. At about 1208 hours, the air traffic control specialist advised the pilot that radar contact with the airplane was lost, to change his transponder code to 1200 (VFR), and advised that a frequency change was approved. The pilot acknowledged the transmission. No further contact with the airplane was received. A witness reported that she was driving northbound on Interstate 5 around 1230 hours in the area of I-5 and Highway 138, which is located about 3 miles southeast of Gorman. She observed a high wing airplane that appeared to be following the highway northbound at an altitude of less than 200 feet above the ground (AGL). She estimated that the airplane was traveling about 95 MPH, and lost sight of the airplane in the area of Gorman. She reported that the weather conditions at the time were overcast conditions with the cloud base about 200 to 300 feet AGL. Due to rising terrain, the cloud base at Gorman was estimated at 150 feet AGL. The witness also indicated that the clouds obscured the surrounding mountain tops and the visibility below the clouds was about 1 mile. The flight was reported overdue on February 7, 1993, and was located by search personnel at about 1611 hours on February 8, 1993, about 3/4 mile northwest of Gorman. The accident occurred during the hours of daylight at latitude 34 degrees 48.08 minutes north and longitude 118 degrees 51.48 minutes west. Crew Information The pilot held a private pilot certificate with airplane single engine land and instrument airplane ratings. The most recent third class medical certificate was issued to the pilot on August 12, 1992, and contained no limitations. According to the pilot's logbook, the last entry was dated January 23, 1993. As of that date, the pilot's total aeronautical experience consisted of about 985.2 hours, of which at least 500 hours were accrued in the accident aircraft make and model. In the preceding 90 and 30 days prior to the accident, the logbook lists a total of 13.5 and 3.5 hours, respectively flown. The pilot received an airplane instrument rating on April 25, 1991. Since that date, the pilot had accrued an additional 5.4 hours under actual instrument conditions, and 8.5 hours under simulated instrument conditions, for a total of 11.3 hours of actual instrument and 74.5 hours of simulated instrument flight. In the previous 6 months, the pilot had accrued 1.4 hours and 4.4 hours, respectively. Aircraft Information The airplane maintenance records were not located by Safety Board investigators. Family members and the airplane's co-owner could not locate the records. The co-owner of the airplane provided information from the certificated airframe and powerplant mechanic who performed the last annual inspection. The records indicate that the last annual inspection was performed on April 4, 1992. At that time, the aircraft had a recording hour meter reading of 3,354.0 hours of operation. Notations found in the airplane indicated that the hour meter reading at the end of a flight conducted on February 6, 1993, was 3,439.04. The hour meter reading at the accident site was 3,439.55. Meteorological Information The closest official weather observation station south of the accident site is Burbank, California, which is located 43 nautical miles southeast of the accident site. At 1246 hours, a surface observation was reporting in part: Sky condition and ceiling, sky partially obscured, measured ceiling 2,000 feet overcast; visibility, 2 1/2 miles in light rain showers and fog; temperature, 59 degrees F; dew point, 52 degrees F; wind, 120 degrees at 20 knots; altimeter, 29.83 inHg. Bakersfield, California, the planned intermediate stop, is located 38 nautical miles north of the accident site. At 1054 hours, a surface observation was reporting in part: Sky condition and ceiling, 8,000 feet scattered, 15,000 feet scattered, estimated 20,000 feet overcast; visibility, 10 miles; temperature, 72 degrees F; dew point, 47 degrees F; wind, 140 degrees at 12 knots with gusts to 23 knots; altimeter, 29.76 inHg; remarks, blowing dust with visibility lower to the southeast through west. A pilot for the Los Angeles County Sheriff's Department reported that he was operating a departmental helicopter from a substation in Gorman on the accident date. At about 1210 to 1215 hours, he was forced to depart Gorman for another station located at a lower altitude. He indicated that at the time of his departure, the sky was overcast with a 200 foot ceiling. The surrounding mountain tops were obscured by clouds, including the hill northwest of the Gorman substation on which the Gorman VOR is located. The National Weather Service maintains an automated weather observation station at Sandberg, California, located about 9 miles east of Gorman. The 0800 and 0900 hours observation was indicating that the ceiling and visibility was zero/zero. The 1000 hours observation indicated that the ceiling was clear, visibility 5 miles. The 1100 to 1300 hour observation was missing. The 1400 hour observation was indicating that the ceiling and visibility was zero/zero; temperature, 45 degrees F; dew point, 44 degrees F; wind 140 degrees at 17 knots, gusts to 22 knots. Communications The pilot received a standard weather briefing before the flight. The flight service station specialist informed the pilot that flight precautions were in effect for the intended route of flight, including moderate icing conditions above 9,000 feet; moderate turbulence below 10,000 feet; mountain obscurement due to clouds and rain; VFR flight was not recommended. A transcript of the telephonic weather briefing between the pilot and the Riverside Automated Flight Service Station facility appears as Item 7 of this report. A continuous data recording (CDR) radar track of the airplane's flight path was retrieved from the Burbank TRACON. Review of the radar information revealed that after departure, the airplane was in radar contact with departure control until it was about 15 miles northwest of Burbank. The altitude of the airplane varied from 2,400 feet mean sea level (MSL) to 2,200 feet until radar contact was lost and VFR advisories terminated at about 1207 hours. A copy of the CDR plot appears as Item 12 of this report. Wreckage and Impact Information Safety Board investigators examined the airplane wreckage at the accident site on February 9, 1993. The accident site was located on the south face of a hill on which the Gorman VOR is installed. A VOR is a ground based electronic navigation aid transmitting very high frequency navigation signals, 360 degrees in azimuth, oriented from magnetic north. The elevation of the VOR station is about 4,900 feet mean sea level (MSL). Ground scars and the wreckage examination revealed that the airplane collided with the 31 degree upsloping terrain at about 4,650 feet MSL in a near nose and wing level attitude on about a 304 degree magnetic heading (all heading/bearings noted in this report are oriented toward magnetic north). All of the airplane's major components were found at the main wreckage area. The nose wheel strut was located buried in the soil at the initial point of impact that produced a 5 feet by 15 feet disruption of the ground. The nose wheel was separated from the strut and located about 30 feet downslope from the impact point. The fuselage was extensively damaged and came to rest about 70 feet from the point of impact, laying on its left side. The fuselage was situated horizontally on the mountain slope with the nose of the airplane oriented on about a 050 degree heading. The right main landing gear strut and right main landing gear was separated from the fuselage at its attach point. Both the right and left sides of the cabin/cockpit area were extensively torn open along the lower edge of the fuselage. The empennage was buckled and partially severed from the fuselage just aft of the rear seat. The right horizontal stabilizer exhibited upward and aft curling of the outboard end of the leading edge. The left horizontal stabilizer exhibited a downward bend of about 30 degrees at about mid span. The vertical stabilizer and rudder exhibited downward crushing at the upper end of each component and mid-height buckling to the right. The left and right wings were folded in an upward direction, coming to rest about parallel to one another and oriented perpendicular to the fuselage and hillside. The upper surface of the right wing came to rest over the upper surface of the left wing. Both wing upper lift struts were still attached to their respective mounting points. The right wing exhibited spanwise aft crushing and folding of the leading edge, with curling to the underside, about 2 feet inboard from the wing tip. The trailing outboard end of the right aileron exhibited localized downward crushing. The lower end of the right wing lift strut was still attached to the fuselage. The left wing exhibited spanwise aft crushing along the upper surface of the leading edge and curling in a downward direction, with diagonal wrinkling of the lower wing surface oriented from the midspan leading edge to the trailing outboard end. The lower end of the left wing strut was separated from the fuselage attach point. The flight control surfaces remained connected to their respective attach points. The elevator trim tab actuator was found extended 1.5 inches and the flap jackscrew actuator was retracted. According to the manufacturer, the extended trim tab actuator corresponds to a 10 degree tab up (nose down) setting. The flaps were retracted. Due to the impact damage, Safety Board investigators were unable to operate the flight controls by their respective control mechanisms; they were, however, able to establish continuity of the flight control cables to the point of impact related damage in the cabin area. There was no evidence of a pre-impact failure of any flight control system component. The upper engine cowling separated from the fuselage and was located about 80 feet downslope from the point of impact. The entire instrument panel and firewall separated from the fuselage as one unit and was located inverted between the initial point of impact and the fuselage point of rest. The right side control wheel assembly was separated at the instrument panel face. The left side control wheel assembly was still attached to the instrument panel; however, the right vertical portion of the control wheel was separated at the lower end of the wheel. The engine separated from the firewall and was located laterally along the hillside, about 40 feet west of the fuselage. The propeller assembly remained connected to the engine crankshaft. One propeller blade exhibited about a 40 degree aft bend about 12 inches inboard from the tip. The blade exhibited leading edge gouging, chordwise scratching, and torsional twisting at the tip. The second propeller blade exhibited extensive torsional twisting, spanwise curling and inboard bending of the tip, leading edge gouging, and chordwise scratching. The engine sustained impact damage to the underside/front portion of the engine. The front cylinder exhaust tubes and muffler exhibited ductile upward crushing signatures. The crankshaft could be rotated by the propeller. Gear and valve train continuity was established when the crankshaft was rotated by hand. The engine oil pressure screen was free of contaminants. The vacuum pump was removed and examined. The drive spline was intact and the pump could be rotated by hand. The interior of the pump contained moisture and dirt. The rotor and vanes were intact; however, the vanes were all missing the inboard ends. The magnetos produced spark at all terminals upon hand rotation. The sparks plugs were dry and exhibited sooty combustion signatures. The carburetor housing was broken and the lower half of the bowl and air box located on the ground between the point of impact and the instrument panel. The float assembly was missing. The upper half of the carburetor remained attached to the intake housing. The throttle valve was in the full open position. About 300 milliliters of fuel was recovered from the right wing fuel tank. The sample was almost clear in color and had the odor of automotive gasoline. There was no evidence of a pre-impact malfunction of the engine or propeller. Medical and Pathological Information A post mortem examination of the pilot was conducted by the Los Angeles County Coroner's Office on February 10, 1993. The examination revealed that the cause of death for the pilot was attributed to multiple blunt trauma injuries. No pre-existing conditions were noted during the autopsy which would have adversely affected the pilot's abilities to fly an aircraft. Toxicological examinations were conducted by the Los Angeles County Coroner and the FAA's Civil Aeromedical Institute (CAMI). The examinations were negative for alcohol or drugs. The examination revealed a 4 per cent carboxyhemoglobin (carbon monoxide) saturation in the blood. According to CAMI personnel, carbon monoxide saturations of 0 to 3 per cent are expected for non-smokers and 3 to 10 per cent saturation for smokers. Saturations above 10 per cent are considered elevated. Additional Information Wreckage Release The Safety Board released the wreckage, located at H.L.M. Air Services Inc., Santa Paula, California, to the owner's representatives on April 6, 1993. No parts or components were retained by the NTSB.

Probable Cause and Findings

THE PILOT'S CONTINUED FLIGHT INTO KNOWN ADVERSE WEATHER CONDITIONS AND CONTINUED VISUAL FLIGHT INTO INSTRUMENT METEOROLOGICAL CONDITIONS

 

Source: NTSB Aviation Accident Database

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