N992SD

HISTORY OF FLIGHT

On January 30, 1999, at 1543 hours Pacific standard time, a McDonnell Douglas 369E, N992SD, collided with the ground after experiencing a loss of engine power near Lake Elsinore, California. The helicopter was destroyed. The pilot and observer suffered serious injuries. The public-use helicopter was being operated by the Riverside County Sheriff's Department for routine law enforcement patrol at the time of the accident. The flight originated at the Hemet-Ryan Airport in Hemet, California, at 1505, and a company flight plan was filed. Visual meteorological conditions prevailed.

The pilot reported that she and the non-pilot rated observer were responding to a routine dispatch call and were flying about 550 to 650 feet agl. She stated that the engine chip light (amber) became illuminated. She reported that she intended to head back to the airport, but changed her mind and began looking for a landing site. The observer radioed the dispatch center and notified them that they had "engine problems." He reported that about 30 seconds later he heard a grinding noise and heard the rpm decreasing. The pilot reported that the engine-out light (red) became illuminated and the engine-out horn came on. A few seconds later the engine quit. She saw an open field to her left (northwest) and turned toward it. She entered an autorotation by fully lowering the collective. She stated that she didn't roll off the throttle. The observer called dispatch and gave them a position report. The pilot reported that she didn't notice her airspeed in the turn, but remained focused on the landing site. She remembered that the tachometer gauge reflected that the rotor and engine rpm indicator needles were split and she recalled that the rotor rpm indicator needle reflected 420 to 430 rpm. The pilot stated that the angle of descent was good but was slightly steeper than normal. She reported that she initiated the landing flare about 100 feet agl.

The helicopter landed hard. Neither the pilot nor the observer recall the helicopter bouncing or having any forward movement after the landing. The pilot unfastened the observer's seat belt, then undid her own. She reported that the fuel shutoff valve handle was jammed and she was unable to turn it to the "off" position. She further reported that both cockpit doors were also jammed shut and they were not able to egress on their own. Rescue personnel arrived within minutes of the accident and forced the doors open.

Two witnesses reported seeing the helicopter circling overhead prior to impact. They stated that the main rotor blades were turning slowly; they could see each individual blade. There was no engine sound. They observed the helicopter descend at approximately a 45-degree nose-down attitude. The witnesses reported that the helicopter was descending about 50 to 60 mph; they felt that it was moving "too fast for landing." Their last view of the helicopter was at the tree line.

PERSONNEL INFORMATION

According to the Federal Aviation Administration (FAA) airman certification database, the pilot held a commercial pilot certificate with rotorcraft-helicopter rating and an instrument helicopter rating. The pilot indicated that at the time of the accident she had about 4,817 total hours of flight time, all in helicopters. She had 2,900 hours in the McDonnell Douglas 369E, including 200 hours in the last 90 days and 73 hours in the last 30 days. According to the FAA aeromedical certification database, the pilot held a second class medical, dated July 8, 1998, with no waivers or limitations.

The Sheriff Department's records reflected that the pilot had completed her last biennial flight review on March 29, 1998, which included emergency maneuvers. She was given satisfactory marks in all categories.

The observer was not a rated pilot. He had been performing duties as an observer since 1993.

AIRCRAFT INFORMATION

The aircraft maintenance records were reviewed. A review of the aircraft daily flight logs did not reveal any unresolved squawks, other than a history of 10 engine chip light activations over a period of approximately 72 flight hours. The records indicated compliance with all Manufacturer Service Notices and all applicable Federal Aviation Administration (FAA) Airworthiness Directives. The records revealed that at the time of the accident, the airframe had a total time of 4093.4 hours. The maintenance department adhered to an Annual and Manufacturer's Inspection Maintenance Program.

The maintenance records revealed that engine chip lights were reported on December 18, 1998, at approximately 4021 hours, and again on December 21, 1998. In both cases, the maintenance department removed and replaced the chip detectors, drained, flushed and replaced the engine oil, and performed a 30-minute ground run/leak check. No discrepancies were noted during either ground check. Following another reported chip light on December 29, the maintenance personnel replaced the turbine assembly, gear box and compressor assembly with overhauled parts. The records reflected that the gearbox and compressor assemblies were installed with "zero hours since overhaul," and the turbine assembly had 2389 hours since overhaul. A ground run, leak check and power assurance check were performed with no noted discrepancies. An engine chip light was reported again on December 30, 1998, and the mechanic reported that he found a small sliver on the bottom chip plug. He cleaned the plug and performed a ground check. Engine chip lights were reported again on January 21 and January 22, 1999. The aircraft did not fly until after a 100-hour inspection was performed on January 28, 1999, during which both chip detectors were examined. The bottom chip detector displayed fuzz. The engine oil was drained and flushed and a leak check was performed again with no reported abnormalities. On January 29, 1999, a pilot reported that the engine chip light came on twice during a 1.5-hour flight. The mechanics discovered a small metallic sliver on the bottom chip plug and removed the turbine assembly. The number 5 bearing spacer and snap ring were found spinning and a new number 5 bearing was installed. The mechanics reported that they reinstalled the turbine, as per the Allison Maintenance Manual. They purged the oil system and replenished it with 5 quarts of oil. The mechanic and pilot then completed a 0.8-hour maintenance flight, during which time the engine chip light became illuminated. The mechanic cleaned the plugs, then returned the engine to service after a ground run and leak check were performed with satisfactory results.

Both the pilot and the mechanic who performed the ground run reported that they visually checked the oil quantity level in the sight gauge before the accident flight and the level appeared adequate.

WRECKAGE AND IMPACT

The wreckage was located in a furrowed field of dry, loose dirt. The fuselage was in an upright position at a 45-degree angle to the furrows. The aircraft skids were spread outward to the point that the belly was touching the ground. Four of the five main rotor blades remained attached to the rotor head. The white blade had separated at the blade doubler. Two of the main rotor blades exhibited upward bends, and one blade tip had impacted the ground and displayed a break a few inches from the hub. A portion of the tail boom and tail rotor driveshaft were located forward of the fuselage. The tail rotor blades remained attached to the tail rotor gearbox and were also located forward of the aircraft. The tail boom stinger was the only aircraft component not located.

The exterior surface of the aircraft fuselage was wrinkled. The underside of the fuselage was cracked and torn, with much of the damage concentrated around the cargo hook attachment area. The lower canopy glass was fractured on both sides of the aircraft. The cockpit and cabin doors were intact but exhibited deformation. No plexiglass was broken from either cabin door. Both engine access doors were warped and twisted. The rescue personnel reported that the engine access doors were found open and they sprayed the interior with water and foam. There was no oil or residue noted on the engine itself or in the engine compartment.

The left and right extended landing gear were spread with both aft struts fractured approximately 12 inches outboard of the damper. The left forward strut elbow and damper assembly were pushed up into the seat support structure.

The tail boom was fractured and damaged at a point inside the plane of rotation of the main rotor blades. Three of the five main rotor blades displayed paint transfer the same color as the tail boom. The separated section of the tail boom remained attached to the upper and lower vertical and horizontal stabilizers.

The cockpit structure was compromised only on the right side floor where the SX-5 searchlight and FLIR pod mounts were pushed upward and had penetrated the lower cockpit structure. Both crew seats displayed deformation of about 1 1/2 inches in the seat pan structures. The seatbelt system remained intact. The crew seats were made of a mesh material and no foreign objects were noted under either seat.

The aircraft was configured for left seat command and was not equipped with dual flight controls. Continuity was established for the cyclic, collective and anti-torque flight control linkage. The collective stick would not move; the left front strut damper had been pushed upward and was contacting the collective interconnecting torque tube. Rescue personnel noted the collective in the full up position at the accident site and had pushed it down during the crew extraction. The N1 and N2 collective linkage continuity was confirmed back to the engine compartment where the control tubes and associated rod end bearings were fractured.

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