Big Bear City, CA, USA
N7292W
Piper PA-28-180
While flying on a moonless night in mountainous terrain to an airport in a mountain valley, the aircraft encountered mountain wave conditions and downdrafts in the 500 to 1,000 foot-per-minute range, which resulted in a collision with mountainous terrain. The two-man aircrew participated in a Civil Air Patrol (CAP) search and rescue training exercise (SAREX) being held over the weekend, and had flown from the mountain valley airport along the accident route of flight that morning. The CAP group was informed that high winds were expected the following day and flying operations might be cancelled. The aircrew decided to return to their home base in a small mountain town (elev: 6,748 feet) instead of staying at the SAREX base for the night. The aircrew had commented to the CAP Incident Commander that they had experienced some moderate turbulence on the flight out of the mountains severe enough to have their heads hit the cockpit canopy and toss a cell phone out of the passenger's shirt pocket. They departed the SAREX base at night and there was no moon illumination at the time they approached the 8,000-9,000 foot mountain ridgeline. The airplane approached the mountains at 10,300 feet, and shortly thereafter entered a mountain wave, and experienced turbulence and downdrafts. Radar data showed that the airplane steadily descended through 8,000 feet during the last 4 minutes of the flight. The airplane impacted the side of the mountain at the 6,970 foot elevation with low energy, in a very steep left turn; left wing down. Analysis of the weather conditions established that mountain wave conditions existed at 9,000 feet with a wavelength of 2.79 miles, amplitude of 717 feet, and a maximum vertical velocity of 1,185 fpm. This wave had a potential for moderate to severe turbulence. There is no record that the pilot requested or received a weather briefing. At the cruise altitude of the airplane, the performance charts show that it had a maximum climb capability of about 400 feet per minute.
HISTORY OF FLIGHT On November 21, 2003, about 2100 Pacific standard time, a Piper PA-28-180, N7292W, collided with mountainous terrain 9 miles east of Big Bear City Airport, California. The airplane was a privately owned airplane operated by the Civil Air Patrol under the provisions of 14 CFR Part 91. The commercial pilot and single observer/crewmember sustained fatal injuries and the airplane was destroyed. Visual meteorological conditions prevailed and a visual flight plan had not been filed. The flight originated at Palm Springs Airport, California at 2028. The two-man aircrew was participating in a Civil Air Patrol (CAP) search and rescue training exercise (SAREX) being held at the Palm Springs Airport over the weekend. The crew arrived in Palm Springs about 1730. They attended a class room training session. The group was informed that high winds were expected the following day and flying operations might be cancelled. The aircrew decided to return to their home base at Big Bear Airport instead of staying in Palm Springs for the night. The aircrew had commented to the CAP Incident Commander that they had experienced some moderate turbulence on the flight out of Big Bear severe enough to have their heads hit the cockpit canopy and toss a cell phone out of the passenger's shirt pocket. Palm Springs Airport tower recorded that the airplane departed at 2028. The aircrew never returned to the Palm Springs Airport for the CAP Search and Rescue exercise (SAREX) the next day. The CAP notified the FAA of a missing airplane and the wreckage was located by the San Bernardino County Sheriff Air Support Unit at 1700, Saturday, November 22, on the north west slopes of Tip Top Mountain, at 6,900 feet. No record was found of a weather briefing given to the pilot either under his name or the registration number of the aircraft. PERSONNEL INFORMATION: The pilot obtained his commercial pilot certificate with single engine land, multiengine land, and instrument airplane rating s on June 13, 1971. He received his Certified Flight Instructor Certificate on October 6, 1977. His third class medical was dated September, 2002. Examination of the pilots log book revealed that he had logged 2,640 total flight hours with 224 hours at night, 322 hours simulated instrument, and 30 hours multiengine. Interviews with friends and family revealed that the pilot had lived in Big Bear for the last 3 years and was very familiar with the local flying area. Another pilot that had flown with the accident pilot said that he felt the pilot was a careful and conscientious pilot. The passenger was not a rated pilot but was a current Civil Air Patrol member. AIRCRAFT INFORMATION: The four seat, low wing airplane was powered by a Lycoming O-360-A36A, 180 horsepower engine with a fixed pitch Sensenich propeller. The airplane and engine underwent its last 100 hour/annual inspection on July 1, 2003. At that time the airframe had a total of 4,364 hours, total engine time was 2,390 hours with 232 hours since major overhaul (SMOH). The airplane was equipped with an Aztek 40 autopilot. A hand held GPS receiver was found at the accident site. Airplane performance information available in the Piper Cherokee B Owners Handbook shows that at a max gross weight of 2,400 pounds and between 8,000 and 10,000 feet density altitude the airplane had a maximum climb performance of 360 to 410 feet per minute. METEORLOGICAL INFORMATION: The Safety Board performed a full meteorological study surrounding the day, time, and location of this accident. The full factual report is available in the official docket. Meteorological Synopsis The surface analysis chart shows an approximate 12-mb change in pressure across southern California, which resulted in strong westerly surface winds. Meteorological stations west of the accident site indicate calm winds at the surface with fog or mist, broken cloud cover, temperature and dew points in the mid 50's (degrees Fahrenheit), with a temperature-dew point spread of 1 degree F. Other coastal locations across southern California indicated westerly winds with overcast skies. The constant pressure chart depicted a long wave trough of low pressure extending over northern California and into the Pacific Ocean. The accident site was on the front side of the upper level trough with westerly winds. Weather Advisories AIRMET Sierra was active during the time of the accident and warned of IFR conditions and mountain obscuration over California AIRMET Tango was active over portions of California, Nevada, Utah, Colorado, Arizona, and New Mexico, and warned of occasional moderate turbulence below 16,000 feet due to moderate-to-strong winds over rough terrain. Pilot Reports Numerous pilot reports (PIREPS) were recorded over southern California surrounding the time of the accident and reported turbulence and down drafts around 500 fpm. Terminal Aerodrome Forecasts Big Bear City Airport does not have a terminal aerodrome forecast (TAF) issued for the airport. The departure airport of Palm Springs terminal aerodrome forecast issued at 2320Z (1530 PST) and valid from 0000Z to 2400Z (24 hours, 1600-1600 PST) expected between 0200Z (1800 PST) and 0800Z (2400PST) winds from 320 degrees at 10 knots gusting to 20 knots, visibility better than 6 miles, scattered cloud at 15,000 feet. At 0316Z (1916PST) the forecast was amended changing the winds between 0300Z and 0600Z (1900 to 2200 PST) to wind form 320 degrees at 15 knots gusting to 25 knots, wind temporary conditions to winds variable at 5 knots. Mountain Wave Information The RAOB mountain wave module was used to help identify the mountain wave activity over the region during the period. The 1600PST sounding on November 21, 2003, from San Diego (KMYF) indicated favorable conditions for mountain wave activity with the primary wave at approximately 19,000 feet, with several secondary waves. The lowest wave at 6,000 feet had a wavelength of 2.23 miles, amplitude of 551 feet, and a maximum vertical velocity of 568 feet per minute (fpm). The wave also had a potential for producing light to moderate turbulence. The1600PST sounding from the next closest station at Mercury/Desert Rock (KDRA), Nevada, located 100 miles northeast of the accident site also confirmed favorable conditions for mountain wave activity. That sounding indicated the potential for a wave at 9,000 feet with a wavelength of 2.79 miles, amplitude of 717 feet, and a maximum vertical velocity of 1,185 fpm. This wave had a potential for moderate to severe turbulence. Astronomical Information Data collected from the U.S. Naval Observatory indicated sunset at Big Bear City to be 1640 PST and no moon illumination during the period between 1800 and 2300 PST. AIDS TO NAVIGATION: Big Bear Airport is serviced from the east by a GPS RWY 26 instrument approach. The final approach course is 256 degrees, a minimum altitude to start the approach is 9,600 feet at the initial approach fix, and a visual descent point is set at a minimum altitude of 8,600 feet, 5.1 miles from the airport. The glide slope angle is 3.34 degrees. WRECKAGE AND IMPACT INFORMATION: The San Bernardino Mountain Range runs roughly east-west. Big Bear City is located in a valley, at 6,748 feet, in the San Bernardino Mountains, and is surrounded by 8,000 to 9,000 foot mountain to the north and south and 7000 foot mountains to the east. To the northeast, east, and southeast of the San Bernardino Mountains is sparsely populated high desert terrain. The airplane wreckage was located at 34 degrees 15.452 minutes North latitude and 116 degrees 41.723 minutes West longitude at 6,900 feet msl on a northeast facing mountain slope. The terrain was moderately populated with small cedar like pine trees and 12 foot high shrubs on a 30 degree sand and gravel slope. The ridge line directly above the wreckage elevation was 6,970 feet and the highest points to either side were about 7,200 feet, msl. The wreckage debris field was 45 feet in length on a bearing of 220 magnetic. The debris field was designated by a gray ash colored area that extended 40 feet to the left, 10 feet to the right and descended down hill 45 feet from the main wreckage. Four distinct compact circular ground scars were identified along the western edge of the debris field extending from the furthest up hill centerline location radiating 12 and 13 feet down hill. The main wreckage consisted of the empennage tail section, the engine, the propeller, and the melted down remains of the fuselage and wings. The first identified point of impact was the left position light and red lens fragments identified 45 feet east of the wreckage below a large brush like tree. The tree had a vertical split of broken branches above the red lens fragments. Plexiglas shards were distributed 10 to 15 feet away from the main wreckage along the lower northwestern side of the debris field. The engine was embedded slightly into the ground nose down with the propeller detached but inline with the engine centerline on a easterly bearing (up hill). A section of the outboard portion of the right wing was 8 feet up hill from the center of the main wreckage with a semicircular 6 inch diameter indentation perpendicular to its leading edge. Bush located in the middle of the debris field had no foliage, were dark gray in color, and branches extended vertically with no evidence of horizontal shearing or topping. A 5 foot section of tail was the only remaining fuselage structure discernable. The empennage, vertical stabilizer, rudder, and stabilator had some discoloration along the leading edge but no structural damage was evident. The left stabilator fiberglass tip had become a white fiberglass cloth with no rigidity. The empennage section was charred black along the entire circumference of the structure, making the remaining 2 letters of the airplanes N number almost unrecognizable. The fiberglass tail cone section containing the stabilator trim jackscrew was consumed by fire. The jackscrew had 6 threads extended vertically. Rudder, stabilator, and stabilator trim control cables were all attached to their respective tail section bell cranks. The cables were traced to their respective sprockets on the cockpit control column and rudder bar. The aileron control cables were traced from their bell cranks to its sprocket on the cockpit control column. The aileron balance cable was separated at the chain linkage on the yolk and exhibited a broom straw type of separation on the starboard side. The rudder and stabilator balance weights were all located attached to their respective control surfaces. The cockpit area was completely destroyed and melted down by fire. The artificial horizon, turn and bank indicator, VHF radio stack, and ILS course and glide slope indicator were found, undamaged by fire, a few feet north of the main wreckage. The directional gyro (bug read 020), altimeter (read 29.90), vertical speed indicator, and engine RPM gauges, fire damaged and in the center of the wreckage. The left cockpit seat, only recognizable by its steel frame and springs, was attached to the floor rails on an approximate bearing of 265 magnetic. The wing carry thru spar was split along the lateral axis, separating the bottom and top spar caps. Both main wing spars detached at the port and starboard splice location. The right wing was located immediately to the southeast of the engine, 75 percent of the wing was completely melted down into the earth. A 4 foot outer wing section had a 2 foot length crushed aft at a 30 degree angle from the outer wing tip to the leading edge. The fiberglass cloth wing tip was attached and the control balance weight arm was identified but the lead weight was not present. A section of the left wing spar with the landing gear strut attached was laying slightly above the melted remains of the right wing. An 4.5 foot outer section of the left wing was located 3 feet up hill of the right wing behind a burned out brush like tree. This wing section had leading edge aft crushing at tip end with a semicircular indentation in the middle. The fiberglass tip was ripped and burned, the control balance weight was present. The engine was partially embedded in to the ground, facing up hill, with a slight lean to the left, nose down, on an approximate bearing of 220 magnetic. The air box and carburetor were destroyed. The propeller drive shaft was cleanly torsionally sheared off at the engine casing, exhibiting 45degree fracture face between the drive shaft inner and outer diameters. The fixed pitch propeller was resting in line with the engine drive shaft, embedded in the sloped ground. Both blades exhibited chordwise scratches. One blade was bent aft, the other blade had a slight forward bend at the tip and a slight sinusoidal bend along the trailing edge. The wreckage was taken to an aircraft recovery company in Corona, California, where the debris was laid out and the engine examined. MEDICAL AND PATHOLOGICAL INFORMATION: The San Bernardino County Coroner conducted the autopsy on the pilot. According to the coroner's report, the pilot died instantaneously as a result of multiple blunt force injuries. The FAA Civil Aero Medical Institute (CAMI), Oklahoma City, Oklahoma, performed toxicological analysis from samples obtained during the autopsy. The results from analysis of specimens were negative for carbon monoxide, cyanide, volatiles, and tested drugs. FIRE: The airplane was consumed by a post impact fire. The wreckage area was covered by a dusting of light gray ash. Since airplane was categorized as missing and subject to an air search, fire crews were unable to arrive on scene in time to extinguish the fire. TESTS AND RESEARCH: Engine: Examination of the exterior of the engine revealed that the oil cooler was pushed aft about 4 inches, with ductile bending of the left exhaust headers, and no observed damage to the intake headers. No damage was observed to the right intake and exhaust headers. The forward cylinder cooling fins had no deformation and the valve train pushrods were unbent. The nose of the engine case crankshaft oil seal area was missing its left-hand upper quarter section from the 9 o’clock to the 12 o’clock locations. The engine dynafocal mount was deformed to the left. The engine was slung from a hoist and the top spark plugs removed. All spark plugs were clean with no mechanical deformation. The spark plug electrodes were gray in color, which corresponded to normal operation according to the Champion Aviation Check-A-Plug AV-27 Chart. The engine could not be rotated. Holes were drilled into the engine case and a bore scope inspection performed on the interior crankshaft, connecting rods, cam shaft, and oil sump. The inspection revealed no discoloration or mechanical deformation of the crank shaft, cam shaft, or connecting rods. The oil screen was clear of debris. Bore scope inspection of the cylinders revealed no mechanical deformation on the valves, cylinder walls, or internal cylinder head. Both Bendix magnetos were damaged by fire and untestable. The vacuum pump drive gear remained unbroken, and the vacuum pump turned freely. All vacuum pump vanes were whole, in position, and moved freely. The oil sump screen was clean and open. The governor screen was clean. The oil screen filter was clean. The oil pump gears were free of debris and scoring. The fuel pump was damaged by fire, none of the rubber components remained. The fuel selector valve was in the left main tank position. The MARVEL-SCHEBLER MA-4-5 carburetor was fractured and detached across the barrel section and mostly destroyed. The mixture arm was detached. The throttle was at the 3/4 full position. ADDITIONAL INFORMATION Radar Plots Two radar plots were generated from the collected radar data. A track plot for the last 13.5 minutes of flight shows the airplane approaching the mountain ridge between 10,000 and 10,300 feet on a steady westerly course. A profile plot shows a steady descent of the airplane from 10,300 feet to 8,000 feet during the last 4 minutes of fli
The pilots inadequate preflight planning and intentional flight into known adverse weather conditions. Contributing to this accident was the fact that it was a dark night with no moon illumination.
Source: NTSB Aviation Accident Database
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