LAX94FA185
LAX94FA185

On April 9, 1994, at 1108 Pacific daylight time, a Cessna 172N, N6242D, was destroyed by crash impact and postcrash fire after colliding with a mountainside near Julian, California. The aircraft was operated by Desert Sky Aviation and was on an IFR instructional cross-country flight under 14 CFR Part 91 of Federal Aviation Regulations. Instrument meteorological conditions prevailed at the accident site and an instrument flight plan had been filed for the operation. The certificated commercial pilot/instrument flight instructor sustained fatal injuries and the private pilot undergoing instrument instruction was seriously injured. The flight originated from Chandler, Arizona, airport at approximately 0630 mountain standard time on the day of the accident and had made an en route stop in Yuma, Arizona.

HISTORY OF FLIGHT

The student pilot reported that he obtained a weather briefing for the proposed flight from Chandler, Arizona, to Carlsbad, California. The Federal Aviation Administration (FAA) Prescott Automated Flight Service Station (AFSS) reported briefing the pilot of N6242D at 2200 on April 8, 1994, for a flight from Chandler to Yuma, Arizona. At 0600 on April 9, 1994, Prescott AFSS reported briefing the pilot of N6242D for a flight from Yuma, Arizona, to Carlsbad, California.

At 0607 on April 9, 1994 the pilot of N6242D called Prescott AFSS and filed an IFR flight plan from Chandler, Arizona, to Carlsbad, California.

After a refueling stop at Yuma International airport, the pilot requested and received an IFR clearance at 0918 to Carlsbad, California, via Bard, Victor 458, and Oceanside, with an assigned altitude of 8,000 feet. The aircraft departed at approximately 0931. Initial radio contact with the aircraft occurred at 0932 with radar contact established at 0933. The aircraft was handed off to Los Angeles Center, Sector 9 at 0944.

The student pilot reported that the weather was clear on departure from Yuma until the aircraft neared Plaster City, California, where they encountered some cloud build ups. The student reported that they entered the cloud layer at their cruising altitude of 8,000 feet.

As the student pilot tracked inbound to the Julian VORTAC on Victor 458, he reported that he was unable to maintain altitude due to downdrafts along their route of flight. He reported seeing the vertical speed indicator (VSI) showing a 2,000 fpm descent on several occasions. The student reported that because of the difficulty he was having in maintaining altitude, the flight instructor took the flight controls and made the radio calls.

The student stated that both he and the instructor were aware that they were flying in an area of higher terrain. He reported that the instructor attempted to climb, but in the existing conditions the aircraft was unable to gain or maintain altitude.

At 1104, the instructor advised San Diego TRACON that "cessna 6242D is in a downdraft." TRACON responded by clearing the aircraft to maintain 7,000 feet and asked the pilot if he was still in a downdraft. The pilot responded in the affirmative.

At 1106, the pilot again contacted TRACON advising them that he was descending through 6,300 feet and that the aircraft was still in a downdraft. Ten seconds later, the controller advised the pilot of a low-altitude alert and asked him to maintain 7,000 feet. The pilot replied that "we're trying."

The controller then called the aircraft and asked the pilot if he could see the ground. He replied in the negative and asked for radar vectors. The controller advised that the aircraft was below the minimum vectoring altitude and instructed to climb back to 7,000 feet as soon as possible. The pilot replied that "we'll try."

At 1107, the controller asked the pilot to say his altitude. The pilot replied that he was at 5,900 feet. The controller asked him to repeat and 7 seconds later the pilot reported the aircraft at 5,800 feet. The controller responded by telling the pilot that "you need to climb back to 7,000 as soon as possible" and that the aircraft was "in a very low altitude area." The pilot replied, saying that "we're trying as fast as possible, we're caught in a pretty major downdraft."

The controller then advised the pilot to fly heading 280 degrees and to climb to the highest altitude possible. There was no reply from anyone on board the aircraft. At 1108, all communication and radar contact was lost with the aircraft at 5,700 feet approximately 2 miles west of the Julian VORTAC.

The student reported that just before impact the aircraft broke out of the bottom of a cloud layer. As they broke out, he estimated that they were "about 30 to 40 feet above the trees." He recalled that the airspeed was slow due to the attempts to climb and that they were possibly in a shallow left turn. He also said that he was not aware of any aircraft mechanical or communications difficulties.

The wreckage was located by search and rescue personnel at approximately 1000 the next morning 1 mile north of the Julian VORTAC. No ELT signal was reported at any time after the accident.

Witnesses located in a cabin approximately 400 yards from the accident site reported that at the time of the accident they were experiencing estimated 60 mph winds and their cabin was fully enveloped in a fast moving cloud bank.

METEOROLOGICAL INFORMATION

Review of the recorded telephone conversations at Prescott AFSS revealed that the student pilot twice requested a telephonic weather briefing. First, at 1955 mdt on April 8, 1994, for the flight to Yuma, and then again at 0555 mdt on April 9. During the first briefing, Prescott AFSS provided a weather briefing for the proposed IFR flight from Chandler Municipal airport to Yuma International airport. The briefer conveyed that the latest forecast or reported "...moderate turbulence is forecast below fifteen thousand feet across your entire route...." There were no AIRMETS, SIGMETS, or PIREPS reported. During the second briefing, the specialists noted that "...the only significant weather probably will be the turbulence and winds near the surface from surface winds...." Again, there were no AIRMETS, SIGMETS or PIREPS reported.

A complete transcript of both recorded telephone briefings is attached to this report as an exhibit. In addition, the weather reports utilized during the briefing are also attached.

WRECKAGE AND IMPACT INFORMATION

The aircraft was found on an up-slope of approximately 45 degrees, on a heading of 200 degrees. The main wreckage was in an almost level attitude with the right wing toward the upward side of the slope with the left wing supported by heavy undergrowth. The flap actuator, which was located in the ashes, was not extended. The tail section and associated flight control surfaces had minimal damage. The elevator trim tab was positioned between 5 and 10 degrees tab up (nose down). The main landing gear struts, wheels, and tires were spread laterally and had extensive fire damage. The nose gear was collapsed aft and was not fire damaged.

The aircraft instrument panel was destroyed by fire and no readings or control positions were obtained.

The engine was damaged by both heat and fire. The accessory section had been fully engulfed in the postcrash fire. A teardown inspection did not reveal any discrepancies.

The dual type magneto had been consumed by fire. The impulse coupler and gear were found intact.

The carburetor was separated from the engine. The throttle plate was separated from the carburetor. The carburetor was equipped with metal floats and a two-piece venturi. The fuel screen was free of contamination. No fuel was visible in the carburetor bowl.

The propeller was found with one blade bent aft along the lower engine cowling. The was no chordwise scoring, nor leading or trailing edge damage. There was diagonal scarring on the forward surface of the blade which corresponded to several large rocks on which the blade was resting. The second blade had no visible damage. The spinner assembly remained attached and exhibited no rotational damage.

MEDICAL AND PATHOLOGICAL INFORMATION

The fatal injuries received by the instructor were identified by the San Diego County Coroner as smoke inhalation and thermal burns. The injuries sustained by the student pilot were limited to thermal burns.

FIRE

The cabin area was destroyed by fire. Both main fuel tanks were found to be ruptured and were involved in the postcrash fire. The cabin area of the aircraft was consumed by fire. Approximately half of the right wing from the wing root outboard, including the right flap, was burned away. The left wing was essentially intact, but fire damage was visible on the inboard section. A hole had burned through the left inboard rib; several gallons of fluid, which smelled like AVGAS, could be seen in the main tank. The rear fuselage was burned to a point aft of the baggage area.

SURVIVAL ASPECTS

The aircraft impacted the northeast face of Mt. Volcan in an area of dense undergrowth at the 4,800 foot level, 200 feet below the mountain crest. The wind, rain, and overcast conditions at the time of the accident were not conducive to aerial search and rescue operations.

The front seats were completely consumed by fire with no recognizable structure remaining. The rear seat was extensively burned with only the metal frame remaining. The seatbelt and shoulder harness buckles were located with the belts completely burned away. None of the seatbelt buckles were found in the latched position.

The student pilot was able to egress the aircraft after the crash. He was unable to recall any details of his evacuation.

The ELT was recovered from its position in the aft fuselage and the switch was found in the armed position. At no time after the accident were search and rescue personnel able to detect an ELT signal from the aircraft.

ADDITIONAL INFORMATION

The wreckage was released to representatives of the owner on June 6, 1994.

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