LAX05FA053

A loss of control during the final approach to land for undetermined reasons.

The emergency medical services helicopter crashed while attempting to land in a mall parking lot to pickup an accident victim. Witnesses reported that the helicopter overflew the landing zone in right turns, then approached from the northeast. During the final approach at 100 feet agl, the helicopter was observed to become unstable. It rolled right about 30 degrees, then left about the same, then right about 45 degrees, pitched nose up to the left, and then descended while spinning to the left. The helicopter impacted the parking lot in a nose down attitude on the left side. In an interview several days after the accident, the pilot said she was at about 100 feet agl, and had slowed to 20 - 25 knots when she felt the helicopter nose come up and to the right gently, but not as a yaw or a roll. She said she corrected left with the cyclic, and the helicopter responded with a significant and violent roll to the left. She remembered the helicopter starting to spin (at least once), and saw the buildings of the strip mall. She then put the cyclic to the full left to avoid the building. She said she saw the hydraulic caution light on, but did not hear the aural warning. She then grabbed the cyclic with both hands and pulled back and right, but it didn't move. The anti-torque pedals appeared to work and stopped the spin. The helicopter then impacted the ground. The engine continued to run after the ground impact, and a surviving passenger and multiple rescue personnel moved numerous switches in the cockpit in an attempt to shutdown the engine, hence all postimpact switch positions are unreliable. A guarded hydraulic system on/off toggle switch is mounted on the end of the collective control that allows the pilot to manually turn off the hydraulic system. The collective control and the switch guard were damaged in the impact sequence; the hydraulic switch was found in the OFF position. The systems control panel on the center pedestal has 36 back-lighted, mechanically latched push-on/push-off switches. The hydraulic test switch, which deactivates the hydraulic system for a preflight check of the accumulator pressures, is located diagonally next to the landing light switch. The pedestal switch positions were documented the morning after the accident, and the hydraulic test switch was in the OFF position (OFF is normal, ON turns the system off). In the 3 months prior to the accident, four discrepancies were written against the helicopter for various control system problems, including stiff flight controls, excessive control inputs required for normal flight, and nuisance hydraulic warning light and horn activations. The most recent write-up was 1 month prior to the accident. The company maintenance department's corrective actions included cleaning the control system bearings, replacing the left hand and collective hydraulic system actuators, and repairing damaged electrical wiring and cannon plugs. No evidence of preimpact failure or malfunction was found in examinations of the control system and functional testing of the hydraulic system components. The hydraulic system accumulators were found to still have an unquantified amount of pressure after the accident. After this accident, the operator installed guards over the hydraulic test switch to prevent inadvertent activation.

1.1 HISTORY OF FLIGHT On December 14, 2004, at 2237 mountain standard time, a Eurocopter AS-350-B3, N971AE, operating under the call sign Air-Evac II, collided with terrain while attempting a landing in a shopping center parking lot at Apache Junction, Arizona. The helicopter was operated by Petroleum Helicopters, Inc., (PHI) as a positioning flight under the provisions of 14 CFR Part 91. The commercial pilot and a medical crewmember both received serious injuries; a second medical crewmember received fatal injuries. The helicopter was destroyed. The air medical flight originated at a local base of operation and was positioning for a patient recovery at the landing site and transport to a hospital. Visual meteorological conditions prevailed and a company flight plan had been filed. The wreckage was at 33 degrees 24.50 minutes north latitude and 111 degrees 27.15 minutes west longitude. The emergency landing zone was located in a store parking lot. The area for landing was secured by Apache Junction police and fire department personnel. The pilot was in communication with the ground personnel for a briefing on possible landing obstructions. The pilot confirmed the final landing zone and light pole obstructions that were pointed out to her. Witnesses reported that the helicopter overflew the landing zone in right turns, then approached from the northeast. The witnesses' observations of the final approach altitude were estimated at 100 to 300 feet above ground level. None of the ground witnesses reported seeing a landing light showing on the front of the helicopter. During the final approach the helicopter was observed by ground witnesses to become unstable. It rolled right on the longitudinal axis about 30 degrees, then left about the same, then right about 45 degrees, pitched nose up to the left, and descended while spinning to the left. The helicopter impacted the parking lot nose down on the left side. The left skid was destroyed and the right skid was intact. The engine continued to run after impact and was subsequently stopped by the fire department personnel spraying fire suppressant foam into the engine air inlet. Two witnesses heard the helicopter make a hissing sound while descending and spinning; the witnesses likened the sound to an "18 wheeler's (truck) air brakes bleeding off." The pilot was interviewed in the hospital on December 18 by a Federal Aviation Administration (FAA) inspector and management representatives of PHI. The pilot reported that it was her 5th day of flying nights. She stated that she was not fatigued, nor under any stress, and had eaten regular meals during the day. She said she was not on any prescription or OTC medications other than birth control. At 2200, her crew was paged for a scene response to Apache Junction for a trauma patient. The landing zone was a secured area in a strip mall parking lot secured by police and fire units from Apache Junction. As the medical crew arrived, she had the helicopter started and running, with all preflight checks completed. Prior to liftoff, she turned the exterior lights on to include the steerable search light, strobes, and rotating beacon; she did not turn these off while en route to the landing site. The night sun and taxi lights were off. She was wearing her own non-noise canceling headset and the volume control was normal (not all the way down). The pilot said the scene location was a parking lot, with the designated landing area surrounded by four tall light poles. There was a fire engine on each edge of the LZ. The winds were calm. She performed one full circle around the landing zone and setup to land to the southwest. On final approach, and on top of the power lines along the road, she remembers saying "clear of power lines." She was at about 100 feet above ground level (agl) and had slowed to 20 - 25 knots. At that time she felt the aircraft nose come up to the right gently, but not as a yaw or a roll. She said she corrected left with the cyclic and the helicopter responded with a significant roll to the left. She remembered the aircraft starting to spin (at least once) and saw the buildings of the strip mall. She then put the cyclic to the full left to avoid the building. The helicopter came close to the ground with a 90-degree nose down attitude. She said she saw a red light she thought was the hydraulic caution light on just before impact, but did not hear the warning gong. She then grabbed the cyclic with both hands and pulled back and right but it didn't move. The anti-torque pedals appeared to work and she thinks that is what stopped the spin. The helicopter then impacted the ground. The director of PHI Flight Safety provided a narrative history of flight on the Safety Board form 6120.1/2, Pilot/Operator Aircraft Accident Report. According to the statement: "Aircraft lifted off IWA at 2229 hours en route to a scene response in Apache Junction which was 9nm away. The LZ was in a strip mall parking lot and was identified by police and fire units on the ground. Upon arrival at the scene location the pilot made a high recon of the area to assess hazards and obstructions. She initiated her approach from the NNE and landing SSW. At approx. 100' and 20-25 knots and just after crossing wires on the approach the pilot states she felt the aircraft pull gently to the right and up. She moved the cyclic left and aircraft rolled violently left and started spinning. (At least once or twice). She saw a building. She pushed pedals to try and avoid buildings and aircraft was close to the ground and nose was approximately 90 degrees down. She grabbed the cyclic with both hands and couldn't move it. She remembers seeing a red caution light she thinks was the hydraulic caution light but does not remember hearing a gong." 1.2 PERSONNEL INFORMATION A review of the PHI company training records and FAA airman and medical record files revealed that the pilot held a commercial pilot certificate, with rotorcraft ratings for helicopters and instrument-helicopter, and a private pilot certificate for airplanes single engine land at the time of the accident. The pilot obtained her first pilot's certificate in her native land of Spain, a private certificate rated for single engine land airplanes. The FAA issued her a U.S. private certificate on October 11, 1994, at Oakland, California, on the basis of the certificate issued by Spain. The pilot was hired by PHI, on October 8, 2001. At that time the pilot reported a total helicopter flight time of 3,583 hours and 277 hours of fixed wing time. Of the helicopter hours, 3,084 were accrued in the Robinson R-22. At the time of the accident, the pilot had accrued a total helicopter time of 4,604 with 80 hours in the Eurocopter AS-350-B3. The pilot's flight instructor time was noted as 2,631 hours of R-22 time. With PHI, the pilot had accumulated about 300 hours PIC in the BO-105 helicopter and 300 hours in the Bell 206L. The pilot's most recent documented second-class flight physical occurred on May 10, 2004, with restrictions. A review of the pilot training records revealed the most recent Airman Competency/Proficiency Check occurred on September 16, 2004. The type of check was the 14 CFR 135.293 and 135.299, a 12-month check. The pilot's complete training file appears in the docket for this accident. In summary, the pilot completed three initial and multiple recurrent company 14 CFR Part 135 training programs on three different helicopters (Bell 206L, MBB BO-105, and the AS350) that have critical hydraulic systems. Emergency procedures for the hydraulic system are part of all the training programs, and include the criticality of the hydraulic cutoff and test switches for the AS350. Except for the BO-105 where complete loss of the hydraulic systems is catastrophic, actual flight training was conducted with simulated hydraulic system failures