Aviation Accident Summaries

Aviation Accident Summary SEA06FA015

Olympia, WA, USA

Aircraft #1

N950AL

Agusta A109E

Analysis

In preparation for departure from the hospital's second story roof helipad, the pilot stated that once both engines were running he put both engine control switches to FLIGHT and verified that there were no caution lights. The aircraft's DO/VERIFY checklist was then verified after all pre-takeoff items had been completed. He then set the rotor rpm switch to the 102% position, pulled enough collective to bring the helicopter to a hover, and then verified 102% rpm before pulling collective for takeoff power and adding forward cyclic to start the climb-out. As the aircraft started its forward motion the pilot heard "ROTOR LOW" in his headset as the helicopter began to settle. The aircraft's tail rotor subsequently impacted the helipad's concrete barrier, resulting in the helicopter descending over a dirt filled courtyard, which was bordered on the east by a building approximately 40 feet away. The aircraft subsequently impacted the building, coming to rest on its right side after spinning around 180 degrees. There was no post-crash fire. The pilot then shut down both engines and aided in the evacuation of the helicopter's occupants. A post-accident examination conducted by an FAA inspector shortly after the accident revealed that both engine control switches were in the OFF position. Testing of various components and both engines failed to reveal any anomalies which would have precluded normal operation of the helicopter. Data from the Enhanced Ground Proximity Warning System (EGPWS) revealed that the number 1 engine was producing normal and abnormally high torque values during the takeoff sequence, while a zero torque value but proper Ng values were observed from data on the number 2 engine during takeoff; this is consistent with the number 2 engine control switch remaining in the IDLE position. The pilot's total time in all helicopters was 7,923 hours, with 15 hours in make and model. The pilot reported that during both his transition ground school training and flight training courses on the type accident helicopter, he had questioned the instructors about previous accidents involving the position of the engine control switches during the start sequence. A comparison of the Agusta Rotorcraft Flight Manual and the Agusta General Familiarization Training Manual revealed they provided inconsistent instructions about when to move the engine control switches from the IDLE to the FLIGHT position. The pilot also revealed that the operation of the limit override switch was never demonstrated during his training and remembered that it was in an awkward position. The limit override switch was not activated during the takeoff sequence, as the pilot was unsuccessful in locating it.

Factual Information

HISTORY OF FLIGHT On October 28, 2005, at 2324 Pacific daylight time, a twin-engine Agusta A109E helicopter, N950AL, sustained substantial damage after impacting an object and subsequently terrain during takeoff at the Providence St. Peter Hospital, Olympia, Washington. The helicopter was operated by CJ Systems Aviation Group of West Mifflin, Pennsylvania, under contract to Airlift Northwest of Seattle, Washington. The airline transport pilot, one flight nurse, and the patient were not injured. A second flight nurse sustained minor injuries. Visual meteorological conditions prevailed for the air ambulance flight, which was being operated in accordance with 14 CFR Part 135, and a company flight plan was filed. The flight was originating at the time of the accident, with its destination being the Harborview Medical Center, Seattle, Washington. In telephone conversations with the NTSB investigator-in-charge (IIC), and according to the Pilot/Operator Aircraft Accident/Incident Report (NTSB form 6120.1), the pilot reported that following his preflight activities, and after both engines were online (started) and the avionics were on, "...I turned both engine controls to flight and verified that there were no caution lights, except the parking brake. I set the rotor rpm switch to 102% position and looked for the little yellow band at the top of the rotor rpm indicator. I said 'coming up' and pulled enough collective to bring the aircraft to a hover for just a second while I verified 102% RPM and caution lights out, then started pulling collective for takeoff power and added forward cyclic to start [the] climb-out. Just as I reached the point of no return I heard 'ROTOR LOW' in the headset and the aircraft began to settle. I started to look back inside at the instruments, but realized that the aircraft was settling fast and focused my attention back outside because there was a building in front of me. I reached for the Limit Override button with my thumb but could not find it. Then it was too late. I realized the aircraft was going to impact the building in front of me and there was nothing I could do to prevent it." The pilot stated that the next thing he remembered was the aircraft facing 180 degrees from the takeoff track and rolling over on its right side. The pilot reported that about 5 or 6 seconds after the aircraft had come to a stop he managed to reach the engine control knobs and shut down the engines. The pilot stated that after he confirmed that both flight nurses and the patient were all right, he shut off the electrical power and exited the helicopter. The pilot further stated that the wreckage was contained in a garden space between the main hospital building and an adjoining building. The pilot reported that the space was not more than 40 feet wide and the aircraft had impacted the side of the adjoining building and fallen to the ground beside it facing southwest. There was no post-crash fire. The pilot also reported that prior to the takeoff he had completed the company's' DO/VERIFY checklist procedure. In a statement submitted to the IIC dated November 28, 2005, one of the two flight nurses on board the helicopter, who was seated in the forward aft facing seat, reported that as she and the other flight nurse were preparing the patient for the flight, the pilot was starting the helicopter's engines. "The helicopter sounded like it usually does during this process. [The pilot] asked if we were ready to depart and each of us responded in the affirmative. As we lifted from the helipad there was a distinct and dramatic reduction in the noise we usually hear, and we immediately seemed to lose our lift. We had moved forward on the helipad and I could see we were partially over the small wall that goes around the perimeter of the helipad. At this point it was clear that we were going to crash. I could see that we were not only losing lift, but we were actually losing what little altitude we had. There was violent shaking and violent noise for several seconds, and then we impacted the ground." The nurse reported that after the helicopter came to rest she assessed that the other nurse and the patient were okay, and that the pilot was talking and shutting the aircraft down. In a statement submitted to the IIC, dated April 21, 2006, the second flight nurse, who was seated in the aft forward facing seat, stated that she was able to see the monitors and gauges in the front of the aircraft; she noted no anomalies. The nurse reported that the helicopter lifted off approximately 5 to 10 feet and prepared to move forward in a nose down attitude. The nurse stated, "At that point I heard a noise that sounded like powering down. I also heard the verbal warning stating 'rotor low, rotor low', as we began to fall. The aircraft's underside made contact with the side of the helipad structure as we were falling and the aircraft rotated prior to hitting the ground. After the impact we waited until the rotors had stopped turning. I have no recollection of the events that transpired until I was inside the emergency room." The aircraft was recovered and transported to a secured storage facility for further examination by representatives of the NTSB, Federal Aviation Administration, Pratt and Whitney Canada, CJ Systems Aviation Group, Airlift Northwest, and Agusta Aerospace. PERSONNEL INFORMATION The pilot held an airline transport pilot certificate for helicopters, a BV-234 type rating, and commercial privileges for airplane single-engine land, airplane multiengine land, and instrument airplane. The pilot reported a total flight time in all aircraft of 8,014 hours and 6,911 hours total time as pilot-in-command. The pilot also reported 7,923 hours total time in all helicopters, 6,897 hours as pilot-in-command of helicopters, 15 hours total time in make and model, and 1625 hours in the Agusta A109AII helicopter. The pilot reported that he had flown 71 hours in the preceding 90 days, 20 hours in the last 30 days, and 1 hour in the last 24 hours. The pilot was issued a first class medical certificate on August 3, 2005, with a limitation for corrective lenses. According to records supplied by CJ Systems, the pilot was hired by the company on April 17, 2000. The pilot successfully completed an Airman Competency/Proficiency Check on the Agusta A109AII aircraft on April 26, 2000. The pilot subsequently completed Agusta A109E differences training on July 7, 2005, followed by successfully completing the Agusta A109E Initial Flight Course on August 16, 2005, which consisted of 3.5 hours of flight training and an evaluation of maneuvers. AIRCRAFT INFORMATION The red and white helicopter, a 2004-model Agusta A109E aircraft, serial number 11628, was powered by two Pratt & Whitney Canada engines (serial numbers PCE BC 0500 and PCE BC 0501), each rated at 735 horsepower. The aircraft was equipped with a Full Authority Digital Engine Control (FADEC) system. According to the manufacturer the FADEC system ensures accurate control of the engine output speed and fast response changes in power demand. The helicopter was also equipped with a new ergonomic cockpit design, multifunctional liquid crystal display, a four-bladed fully articulated main rotor system, and a retractable landing gear. According to the manufacturer, the helicopter's FADEC system incorporates all control units and accessories for complete automatic and manual control of the engine. It is comprised of three main components, the Fuel Management Module (FMM), the Electronic Engine Control unit (EEC) and the Permanent Magnet Alternator (PMA). The FMM is an electro-mechanical unit driven by the accessory gear box, which governs the fuel flow through the entire operational envelope of the engine. It can operate in the automatic mode (fuel flow controlled by the EEC) or in the manual mode mechanical back-up, (fuel flow controlled by the power lever angle of the FMM through the Engine Control Levers in the cockpit overhead panel and/or through the Engine Control Trim Switches on the collective stick). The FMM installed on the accessory gear box incorporates an electrical interface with the EEC, and through the EEC with the Integrated Display System (IDS). The PMS is an engine driven power unit which provides electrical power to both the EEC and the FMM during normal engine operations. The backup power to the FMM and the EEC is provided by the aircraft's electrical system. The EEC is a single channel digital electronic control unit, which, in conjunction with the FMM and a network of sensing devices, provides control of the engine over the complete operating range, achieved by modulating the fuel flow for each particular operating condition. The EEC controls the engine gas generator and power turbine speeds in response to the load demanded by the rotorcraft's rotor system. The EEC also controls fuel flow from engine start to full power within the established limits, and also controls the engine for normal flight, with selection provided through the two console mounted three (3) positioned Power Management Switches (PMS). The three modes are: OFF - fuel shutoff by the shutoff solenoid; IDLE - control governs the power turbine (Npt) at a speed of approximately 65 percent Npt; and FLT - control provides power turbine/main rotor speed governing at the nominal governing speed (100 percent or 102 percent). An ENGINE OUT warning is automatically displayed on the #1 Electronic Display Unit together with an Aural Warning and the Master Warning Light anytime an engine out condition exists (N1<50%). The ENGINE OUT warning is suppressed if the related PMS is set to the OFF position. A one engine inoperative (OEI) advisory mode is also automatically presented on the #1 Electronic Display Unit when an ENGINE OUT condition exists or when one of the two ENG MODE switches is set to OFF. The OEI advisory mode is also presented when one PMS is set to IDLE (the other PMS is set to FLT) but only when the aircraft becomes airborne (weight on wheels inactive). In the OEI advisory mode and OEI legend is vertically displayed adjacent to N1, TOT and Torque scales, and the operative ranges are rearranged with the OEI limits. The IDLE legend is also vertically displayed adjacent to N2 and the N2 pointer turns red when the PMS is selected to IDLE. The OEI advisory mode is not presented on either the Master Warning light or Master Caution light warning system unless a real ENGINE OUT condition exists (N1<50%). A Limit Override switch, located on the collective, is available for emergency situations to allow the EEC to operate the engine above pre-determined limits. The system is also equipped with a one-engine inoperative (OEI TNG) toggle switch, which simulates OEI that is governed at approximately 90 percent Npt. In this case an OEI TNG legend is vertically displayed adjacent to N1, TOT and Torque scales on the #1 Electronic Display Unit. When the control system is in normal AUTO mode the EEC controls the engine fuel flow and consequently the engine Ng speed for all operating conditions of the powerplant. In the back-up (MANUAL) mode, the fuel flow can only be changed by moving the Engine Power Levers and/or activating the Engine Control Trim Switches to set an engine power condition. The helicopter's Integrated Display System (IDS) is composed of two identical Electronic Display Units (EDUs) and a dual redundant Data Acquisition Unit (DAU). The IDS displays Primary and Secondary aircraft data, as well as Warning, Caution and Advisory messages. In the normal operating mode the #1 EDU displays Primary parameters (RPMs, TOT, Torque), and the #2 EDU displays Secondary parameters (temperatures, pressures, electrical quantities, etc.). Various display modes are possible, depending on the aircraft's status (i.e. in flight or on ground) and the System status (i.e. both EDUs operating or one EDU operating). The DAU and both EDUs receive primary engine parameters from both EECs, as well as additional parameters such as discretes, status and fault words from both EECs. The DAU also repeats EEC data to the EDUs, such as N1, TOT, Torques and NR/N2. According to CJ Systems maintenance personnel the helicopter was maintained in accordance with the approved Extended Inspection Program, which was started in August, 2005. At the time of the accident the airframe and engines had accumulated a total of 189.6 hours since new. Aircraft logbooks reveal that the most recent inspection was conducted on October 28, 2005, at a total time of 186.4 hours. PERFORMANCE According to the Agusta A109E Rotorcraft Flight Manual, the following performance data was derived for Hovering Ceiling In and Out of Ground Effect with one engine inoperative: 1) HOVERING CEILING IN GROUND EFFECT ONE ENGINE INOPERATIVE - 6,500 pounds; 2) HOVERING OUT OF GROUND EFFECT ONE ENGINE INOPERATINVE - 5,600 pounds. At the time of takeoff the pilot reported the weight of the helicopter was 6,403 pounds. AERDOME INFORMATION The hospital's helipad is located on the second story rooftop directly over the emergency room department. The 3-foot thick concrete helipad measures 41 feet by 41 feet, and is identified by a medical symbol painted in red with elevated amber lights bordering its perimeter. The second story roof is bordered on the east, west, and south sides by an elevated concrete barrier measuring 2 feet 8 inches high by 18 inches wide. The distance from the barrier to the east side of the helipad is 11 feet 3 inches, 10 feet 6 inches to its south side, and 107 feet 3 inches to the helipad's west border. Access to the elevated helipad is provided by a 59 foot long by 8 foot wide concrete walkway, which extends from the building's second story south entry/exit door to the north side of the helipad. Each side of the walkway is bordered by elevated blue lighting. The helipad is also equipped with a lighted windsock. METEOROLOGICAL INFORMATION At 2254, approximately 30 minutes prior to the accident, the Automated Surface Observing System (ASOS) at the Olympia Airport (OLM), Olympia, Washington, located about 6 nautical miles south-southwest of the accident site, reported wind 240 degrees at 3 knots, 9 statute miles of visibility, light rain, broken clouds at 1,000 feet, overcast at 3,500 feet, temperature 9 degrees Centigrade, dew point 8 degrees Centigrade, and an altimeter setting of 30.02 inches of Mercury, with the ceilings reported to be variable between 800 feet and 1,400 feet. At 2354, about 30 minutes after the accident occurred, the OLM ASOS reported wind 230 degrees at 3 knots, visibility 10 statute miles, overcast clouds at 800 feet, temperature 9 degrees Centigrade, dew point 8 degrees Centigrade, and an altimeter setting of 30.04 inches of Mercury. It was also reported that the rain had ended at 34 minutes past the hour, and ceilings were variable between 700 feet and 1200 feet. WRECKAGE AND IMPACT INFORMATION The helicopter departed from the hospital's second story helipad located at coordinates 47 degrees 03.40 minutes north latitude and 122 degrees 50.60 minutes west longitude, at an elevation of 317 feet msl. An initial impact signature was evidenced by red and yellow paint transfer observed on the inside portion of the building's 2 foot 8 inch protective concrete barrier, approximately 36 feet from the helicopter's departure point and in line with its departure path. Several pieces of the helicopter's tail rotor blades were located in close proximity to the initial impact area. (The helicopter's tail rotor blades are painted red and yellow.) Subsequent to the initial impact the helicopter descended across an open atrium area of approximately 65 feet before striking the west side of the adjacent powerplant building. Numerous slash marks on the side of the powerplant building were observed. The helicopter then spun around approximately 180 degrees before coming to rest on its right side in the dirt-filled courtyard, at coordinates 47 degrees 03.120 minutes north latitude and 122 degrees 50.833 minutes west longitude at an elevation of 225 feet msl. There was no post crash fire. A Federal Aviation Administration (FAA)

Probable Cause and Findings

The pilot's improper positioning of the number 2 Power Flight Control switch and his inability to obtain the proper climb rate to clear a concrete wall barrier. Contributing factors included the checklist not being followed and the limit override switch not being activated.

 

Source: NTSB Aviation Accident Database

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