NTSB Factual Report

HISTORY OF FLIGHT

On March 22, 1996, at 1524 hours Pacific standard time, a Schweizer 269C helicopter, N155T, impacted a mountain slope 8 miles north of Ontario, California, at 4,600 feet mean sea level (msl). The aircraft was destroyed and the private pilot and one passenger were fatally injured. The personal flight departed from Hesperia, California, about 1500 destined for Brackett Field at La Verne, California. Visual meteorological conditions prevailed at Ontario and included a 4,900-foot msl overcast cloud layer.

A friend of the pilot, who had also been his flight instructor for his rotor wing rating, told the NTSB investigator that the pilot and his passenger departed from Brackett Field about 2100 on Thursday, March 21, for a night sightseeing flight. When they returned to Brackett the weather had "socked in" and, after loitering for about 2 hours, the pilot elected to land at Hesperia airport where air traffic controllers told him the weather was VFR. The pilot arrived at Hesperia about 0100 on Friday morning, March 22 and remained overnight.

About 1100 on Friday morning the pilot and his passenger departed Hesperia to return to Brackett Field, but soon returned due to inclement weather. They again departed Hesperia about 1500 on the accident flight. The route of flight is unknown.

An employee of Hesperia Aviation, Inc., reported that the aircraft was fueled once on the morning of March 22 about 1000. The aircraft was fueled to capacity (49 gallons) with 28.4 gallons of 100LL grade fuel. The employee commented that the pilot had made numerous telephone calls and appeared anxious to get home.

By coincidence, the same friend/flight instructor was en route on a flight through the Cajon Pass at 1600. He was VFR on top and reported that the pass and the mountains north of Ontario and Brackett Field were obscured by clouds with tops to 7,000 feet.

The pilot contacted SOCAL TRACON at 1506 and stated that he was en route from Hesperia to Brackett airport. The controller had difficulty understanding the pilot and asked him to speak more slowly. At 1515, radar contact was established with the aircraft 15 miles northeast of Brackett airport and the controller issued the Brackett airport weather along with instructions to maintain VFR. The weather given was measured ceiling 4,000 overcast, visibility 7 miles, wind calm, and altimeter 29.98 inHg. The pilot acknowledged the instruction to maintain VFR and, at 1517, reported that he was descending to 3,500 feet. At that time he was handed off to another SOCAL TRACON sector.

The controller receiving the hand-off established radio contact with the pilot who reported "descending at this time we try to uh descending through the four thousand now two thousand five hundred." The controller acknowledged the transmission and again instructed the pilot to maintain VFR at the lowest possible altitude and told the pilot that tops of the clouds over Pomona had been reported at 6,000 feet. The pilot acknowledged at 1518 and this was the last known communication with the pilot. Between 1524 and 1530 the controller transmitted to the pilot but did not receive a reply. The controller reported to his supervisor that he had lost radar and radio contact with the flight but thought they might have returned to Hesperia. The supervisor called the airport at Hesperia and was told by the CTAF operator that they had recently been in radio contact with the aircraft. On the basis of this report he did not issue an alert notice on the missing aircraft.

On Saturday morning, March 23, the pilot's wife called the same friend/flight instructor and said that she was concerned because she hadn't heard from her husband since he called her from Hesperia on Friday morning. The friend called the FAA Riverside (California) Flight Service Station and a search to locate the missing aircraft was commenced. The wreckage was located Sunday morning, March 24, about 0900 near the location where radar contact had been lost.

According to Continuous Data Recording (CDR) radar data provided by SOCAL TRACON, the last recorded radar return from the aircraft was at 1524:38. In the 4.5 minutes before radar contact was lost, the aircraft circled in the area approximately 8 miles north of Ontario and descended from 7,200 feet to 4,900 feet. At the end of the data, following about 65 seconds of flight at 5,400 to 5,600 feet, the last four returns from the aircraft show a descent from 5,500 feet to 4,900 feet in 13.878 seconds.

PERSONNEL INFORMATION

The non-instrument rated pilot held a private pilot license with airplane ratings for single engine land and helicopter. He was originally issued a license ratings for rotorcraft/helicopter on November 10, 1994, and on January 18, 1996, he added ratings for airplane single engine land. The pilot's logbook was not located after the accident. The hours shown in this report are based on those provided to the FAA by the pilot during his check ride on January 18, 1996.

AIRCRAFT INFORMATION

According to the pilot's flight instructor, the pilot picked up the helicopter at the Schweizer factory on June 19, 1995, and flew the aircraft to the west coast. At delivery the aircraft carried registration N61408. The pilot reserved special registration number N155T and requested that the FAA aircraft registry assign it to this aircraft on August 2, 1995. The hour meter for the aircraft was not recovered; however, on January 11, 1996, the aircraft logbook showed a total time since new of 139 hours.

METEOROLOGICAL CONDITIONS

At the time of the accident a marine stratus layer existed over the Southern California area from the ocean inland to the coastal mountains. The stratus clouds were overcast with bases about 5,000 feet and tops about 6,500 feet. The desert areas were clear with unrestricted visibility. At 1547, the weather at Ontario International Airport, 8 miles south of the accident site was estimated ceiling 2,000 foot broken, 4,000 foot overcast, and visibility 4 miles in haze.

WRECKAGE AND IMPACT INFORMATION

The point of initial impact was on the crest of a north-south ridge line. According to a LORAN measurement in the San Bernardino County Sheriff's Department helicopter, the latitude of the accident site is 34 degrees 11.9 minutes north, and the longitude is 117 degrees 34.6 minutes west. This site corresponds to about 355 degrees and 8.5 nautical miles from the Ontario International Airport. The elevation at the accident site is approximately 4,600 feet msl. From the initial impact point the wreckage was along a path down a mountain slope of approximately minus 25 degrees on a magnetic bearing of 260 degrees. The initial impact mark was made by the heel of the right hand skid.

There was an area of disturbed dirt, approximately 4 feet in diameter and 6 inches deep, 20 feet downslope from the initial impact point. The tail rotor guard was located at this point along with the rudder pedals, cockpit, Plexiglas and the right-hand skid which was imbedded about 2 feet into the ground, toe first on a 45-degree angle relative to horizontal.

At 80 feet downslope was the tail boom, tail rotor assembly, and the main rotor assembly. The tail boom had separated aft of the fuselage brace attachments. The tail rotor hinge pin was fractured on one side, and one of the tail rotor blades was imbedded in the dirt about 3 inches. The other tail rotor blade was undamaged.

The main rotor assembly was lying adjacent to the tail boom. The rotor mast had broken in a rearward direction at the transmission mating flange. The drive shaft disconnected at the spline coupling to the transmission. The entire red blade was attached to the hub. The yellow rotor blade was attached to the hub, except for the outboard 3 feet which had separated and was found upslope near the initial impact point. The blue blade, broken about 2 feet from the hub and again near the tip, was lying in a manzanita bush about 5 feet from the hub.

Between 120 and 180 feet from the impact point was a path of damaged and moderately burned dry grass about 5 feet wide. The cabin structure and engine were at the end of the path resting against a large manzanita bush. Although the structure and engine were damaged by fire, the surrounding vegetation was not. The cabin was laying nose down on its right side. The left skid was attached to the cabin structure. The heel of the right skid was still attached to the cabin area structure having broken at the boss for the ground handling wheels. The transmission separated from the aircraft and was about 5 feet from the cabin/engine wreckage. Both occupants of the aircraft were found at this location.

The aircraft was further inspected in storage on April 5, 1996. All three blades of the main rotor displayed upward bending. The entire red blade was attached to the rotor hub. The yellow blade was attached to the hub, however, about 3 feet of the blade tip was separated. The blue blade was broken into three sections. The elastomeric dampers for the yellow and blue blades remained attached to the hub and their respective blade. The damper from the red blade was found approximately 23 feet from the impact point and the mating lugs on the main rotor and rotor hub were separated. The main rotor mast separated in bending above the transmission and the drive shaft separated from the transmission at the mating splines.

The tail rotor exhibited impact damage to one blade tip aft of the leading edge spar and the hinge pin was sheared on one side. The tail rotor boom and drive shaft separated aft of the transmission. There was no torsion signature in the tail rotor shaft and the 90-degree gearbox rotated freely.

There was no fuel in any of the engine fuel components; however, the fuel servo screen was clear, the fuel pump was functional, and the fuel injection nozzles were clear. The spark plug electrodes were clear and gray. There was compression in all cylinders, the valve train functioned, and the accessory case gears turned when the engine was rotated. The intake air filter was consumed by fire and the muffler was unobstructed. The magneto operation could not be verified due to impact and fire damage. The engine power output shaft separated along a 45 degree shear face at the connection to the output pulley, and the fins on the cooling impeller were sheared opposite to the direction of engine rotation.

The mechanical continuity of the main transmission was verified. The transmission was opened and the gears and bearings were not visibly damaged. The freewheeling clutch on the transmission input shaft engaged and released normally when rotated by hand. The oil pump and chip detector were clear.

The cyclic, collective, and anti-torque control systems were broken at several locations. The cyclic control sticks and anti-torque pedals were broken off at their bases and the collective control was in the full "up" position.

Five light bulbs were available for inspection and none of the filaments showed evidence of stretching. The five light bulbs were from the tail navigation light, the LOW FUEL annunciator, the LOW VOLTAGE annunciator, the M/R TRNS TEMP/PRESS annunciator, and the T/R TRNS CHIP annunciator.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was performed on the pilot on March 27, 1996, by the San Bernardino County Coroner. A toxicological analysis was performed by the FAA's Civil Aeromedical Institute in Oklahoma City, Oklahoma. The toxicology test was negative for ethanol; however, tests for carbon monoxide and cyanide were not performed due to lack of a suitable specimen. The drug ephedrine was detected in the pilot's urine and liver fluid.

ADDITIONAL INFORMATION

An additional person participating in this investigation was Mr. Kenneth Larcher, a student intern at the NTSB Southwest Regional Office. Mr. Larcher is a graduate student at Embry Riddle Aeronautical University, Prescott, Arizona.

The NTSB examined the wreckage at the accident site but did not retain custody. After recovery, the NTSB reacquired custody of the wreckage at the facilities of H.L.M. Air Services, Inc., Santa Paula, California, on April 5, 1996, for further examination. After the examination, the wreckage was released to H.L.M. Air Services on April 5, 1996.

NTSB Probable Cause

The pilot's decision to attempt a VFR descent into instrument meteorological conditions resulting in spatial disorientation.