LAX02FA276

The main rotor blade separation while maneuvering for unknown reasons. A factor was the dark night condition.

At 0401, in dark night conditions, the helicopter departed its hospital base en route to an automobile accident. At 0414 the flight crew informed the ambulance crew at the accident site that they were 16 minutes out. At 0416 the flight crew made a radio call to company dispatch informing them that operations were normal. At 0420 the flight crew contacted the ambulance crew a second time and informed them that they were 3 minutes out. At 0427 company dispatch personnel made two attempts to contact the flight crew, both of which were unsuccessful. After passing over an interstate highway, the helicopter impacted terrain in a near 45 degree nose low attitude. Two witnesses observed the helicopter flying low and slow, one estimating between 150 to 200 feet, and shining its searchlight before hitting the ground. Another witness reported seeing a very strong light sweeping across the ground from side to side and traveling at a very low height, comparing it to a police helicopter hovering low when searching, and said the helicopter appeared to be trying to land. Examination of the accident site revealed evidence of a main rotor blade separation with a debris field consisting of main rotor blade skin, honeycomb, and paint chips located 938 feet upstream of the main impact crater. Post-accident examination of the helicopter's component parts, including the main rotor blades, failed to reveal the cause for the main rotor blade separation. Examination of the aircraft's engines revealed no pre-impact anomalies.

HISTORY OF FLIGHT On September 7, 2002, approximately 0430 Pacific daylight time, a Bell 222U twin-engine helicopter, N417MA, was destroyed after impacting terrain while maneuvering near Nipton, California. The helicopter was registered to the Wells Fargo Bank Northwest of Salt Lake City, Utah, and operated by Mercy Air Service, Inc., of Rialto, California. The instrument rated commercial pilot, flight nurse, and flight paramedic sustained fatal injuries. Dark night visual meteorological conditions prevailed for the 14 CFR Part 91 air medical transport flight for which a company visual flight rules (VFR) flight plan was filed. The flight, which departed from the operator's base near Pahrump, Nevada, at 0401, was en route to the site of an automobile accident near Baker, California. The flight departed the Pahrump, Nevada Hospital en route to the accident site located on Interstate Highway 15 near the Bailey Road intersection. At 0414 the flight crew informed the ambulance crew at the accident site that they were 16 minutes out. At 0416 the flight crew made a radio call to Mercy Air Dispatch personnel informing them that operations were normal. At 0420 the flight crew contacted the ambulance crew and informed them that they were approximately 3 minutes out. At 0427 Mercy Air Dispatch made two attempts to contact the flight crew, both with negative results. The wreckage of the helicopter was located approximately one-quarter mile east of Interstate 15 at Yates Well Road, about 5 miles south of State Line, Nevada. Witnesses reported observing the helicopter flying from the northwest to the southeast, crossing the interstate highway prior to impacting terrain. Five witnesses to the accident submitted statements to the NTSB investigator-in-charge (IIC). Four of the witnesses were in the process of traveling on the interstate highway when they observed the helicopter, while a fifth witness observed the helicopter after having exited the highway at the Yates Well Road exit and parking on the west side of the highway facing west. Witness #1 reported that as she was driving south she noticed a white vapor trail in the sky, which was visible in the upper left hand corner of her windshield. She stated that it had a red glow at the head of it and appeared to be approximately 150 to 200 feet in the air when she first saw it. "The trajectory was approximately 100 degrees, going from west to east, and the trail was over the northbound lanes of the interstate when I saw it. I saw it hit the ground and explode into a 'mushroom cloud' of flame." The witness stated that after calling an emergency operator on her cell phone, she saw two additional explosions. Witness #2 reported that as he was traveling north on I-15 coming down a mountain pass grade, he saw a helicopter flying just west of the highway with its searchlight on. The witness related, "It looked like it was looking for a place to set down. As I got further down the hill the helicopter was lower and was crossing over the highway to the east side. It just dropped like a rock and hit the ground, then exploded in a big fireball. Witness #3 stated that while traveling southbound on I-15 he observed an aircraft's navigation lights "coming down out of the sky at a slight angle to the surface. The aircraft hit the ground and blew up. The explosion was fairly large. I was approximately two miles from Yates Well Road when I saw the incident." Witness #4 stated she was traveling southbound on I-15 at around 0415. She said the helicopter was southbound and was moving low and slow as it crossed over the freeway. "It shined its light on the highway before crossing over it and crashing in the desert." She further stated that it [the helicopter] appeared to be looking for something, and then it fell rapidly to the ground. Witness #5 reported that after pulling off the interstate highway at an overpass and parking his car at a right angle to the highway facing west, he heard the sound of a helicopter approaching. The witness stated that he looked towards the sound and there was a light coming from the front of the helicopter. "The helicopter continued to head in the direction of our vehicle, traveling parallel to the highway. With the very strong light at the front sweeping across the ground from side to side, the helicopter was traveling at a very low height. I liken it to a police helicopter hovering low when searching." The witness further stated, ".... for a moment the light shone directly on us as it passed over us." The witness reported that the helicopter continued to pass over them and was parallel to the highway. "When it was maybe fifty to one hundred meters past us it made a left sweeping turn, moving much more quickly than previously, and went over the lanes of the highway toward the adjacent fields. The helicopter hovered there for a moment." The witness further stated that he was sure he heard the engine stop or [make] an odd sound which was similar to that of an old car backfiring. "Then the helicopter dropped, hitting the ground with a loud popping sound. There was an explosion, and another explosion with the mushroom clouds of flames and smoke." PERSONNEL INFORMATION The pilot held a commercial pilot certificate with ratings for rotorcraft-helicopter and instrument helicopter. His last FAA second-class medical certificate was dated April 23, 2002, with the limitation that the holder shall possess glasses that correct for near vision. Company records indicate the pilot was current and qualified in the BH-222 at the time of the accident. AIRCRAFT INFORMATION N417MA, (s/n 47527), a Bell 222U, was manufactured in 1984. Records provided by the operator indicated that main rotor blade S/N A 253 was overhauled on December 27, 2001, and main rotor blade S/N A 348 was overhauled on October 23, 2000. The aircraft was equipped with an OuterLink satellite position reporting system. The system recorded all portions of the flight and reported latitude/longitude coordinates and ground speed at one minute intervals. The last report was recorded at 0428:19 (see ATTACHMENT #2). METEOROLOGICAL INFORMATION At 0356, the Automated Weather Observing System (AWOS) at Las Vegas, Nevada, located 42 miles north of the accident site, was reporting winds from 200 degrees at 7 knots, visibility of 10 statute miles. Scattered clouds were reported at 9,500 feet, broken clouds at 13,000 and 18,000 feet, with a temperature of 24 degrees C, dew point of 12 degrees C, and an altimeter of 29.79 inches of Mercury. Based on the elevation of the accident site being 2,660 feet, the density altitude was calculated to be 4,956 feet at the time of the accident. WRECKAGE AND IMPACT INFORMATION Examination of the accident site revealed that the wreckage distribution path of 1,153 feet was along a measured magnetic heading of 135 degrees. The main wreckage came to rest in a flat desert area of sparse bushes 3 to 4 feet high at latitude North 35 degrees 32.25 minutes and longitude West 115 degrees 25.01 minutes, at an altitude of 2,660 feet mean sea level. The beginning of the wreckage path began 938 feet prior to the main impact site, evidenced by pieces of honeycomb, pieces of fiberglass consistent with the make-up of the main rotor blade, and paint chips. The high energy impact damage and post-impact fire destroyed the aircraft. The main impact crater, which measured 22 feet in length, 12 feet in width, and 18 inches in depth was located 29 feet from the north-south service road which bordered the impact crater on the west. A three-strand power line bordered the service road on the west, also running in a north-south direction. Interstate highway I-15 runs parallel to the service road, located approximately 1,100 feet west of the main impact area. Prior to the main impact crater, a debris field was evident. It was oriented from