FTW03FA211

The reported loss of engine power for undetermined reasons. A contributing factor was the failure to maintain clearance with the safety fence during the aborted takeoff, which resulted in a dynamic rollover of the helicopter.

During departure from a rooftop helipad, the pilot reported the helicopter sustained a loss of engine power and he aborted the takeoff. During the aborted takeoff, a main landing gear struck a safety fence, the main rotor blades contacted the helipad, the helicopter rolled over and came to rest on the helipad. According to the pilot and medical crew, the engine start-up and before takeoff checks were normal. While in a 3 to 4-foot hover above the helipad, the pilot verified the engine and systems prior to departure. As the helicopter transitioned over the edge of the rooftop, the engine warning horn sounded and warning and caution lights illuminated. The medical crew reported the engine and rotor noise suddenly decreased, and noticed a slight drop in altitude. After the helicopter came to rest, the engines were still running at an unknown power level, and the pilot and medical crew shutdown the engines. No anomalies were noted during the functional tests and examinations of the engines and helicopter systems. The reason for the reported loss of engine power was not determined.

HISTORY OF FLIGHT On September 3, 2003, approximately 1959 central daylight time, an Agusta A109E twin-engine helicopter, N143CF, sustained substantial damage when it impacted a safety fence and rolled over during an aborted takeoff following a partial loss of engine power from the Methodist Dallas Medical Center helipad, near Dallas, Texas. The commercial pilot sustained minor injuries, the flight paramedic and flight nurse were not injured. The helicopter was registered to and operated by North Central Texas Services, Inc., Grand Prairie, Texas, doing business as (d.b.a.) CareFlite. Night visual meteorological conditions prevailed, and a company flight plan was filed for the 14 Code of Federal Regulations Part 91 positioning flight. The flight was originating at the time of the accident and was responding to a medical emergency near Crowley, Texas. Prior to departure, the pilot performed his normal walk around inspection and no anomalies were noted. After boarding the helicopter, the pilot turned the #2 engine Power Management Switch (PMS) to the IDLE position, the #2 engine stabilized, and the pilot turned the switch to FLT (100 percent) position. The pilot then completed the same engine start sequence with the #1 engine. After the engine starts and before takeoff checks were complete, the pilot brought the helicopter to a hover. While in a 3 to 4-foot hover above the helipad, the pilot verified "all pressure and temps normal." After the nurse and paramedic stated they were ready for takeoff, the pilot applied power for takeoff, and "the [RPM selector switch] was applied to 102 percent at the same time." The pilot stated, "just as we were going over the edge [of] the helipad (to the north), we started a slight climb, but had not reached CDP (critical decision point). As the fuselage cleared the helipad, the engine out warning horn sounded, accompanied by both yellow and red warning lights on the instrument panel. [The pilot] quickly glanced at the power settings and stats were going down, "red and yellow lights were flashing," and he heard "ding-dongs, bells and whistles." The pilot aborted the takeoff and attempted to land back onto the helipad. During the attempted landing, one of the main landing gears struck a safety fence, and subsequently, the helicopter rolled over. The main rotor blades contacted the helipad, and the helicopter came to rest on its right side on the helipad. After the helicopter came to rest, the engines were running at an unknown power level; and the pilot turned both engine mode switches to the IDLE position, and the #2 PMS to the OFF position. Due to the pilot partially pinned by the helicopter, he was unable to turn the #1 PMS from the IDLE to the OFF position and was assisted by the flight nurse. The flight nurse turned the switch to the OFF position, and the pilot turned off the fuel switches. The flight nurse, who was seated in the left front, stated that after she entered the helicopter, the pilot turned the #2 PMS to the fly position, and the #1 PMS to the idle position. The flight nurse obtained the destination coordinates from the communication center and entered them into the global positioning system (GPS). While in the hover and prior to transitioning forward, the nurse heard the pilot say "102 percent (RPM selector switch), three in the green (landing gear)." As the helicopter transitioned forward, the flight nurse "could hear the engines powering back and a slight drop in altitude." The pilot stated they had a problem, and the nurse noted "red lights" on the instrument panel. The flight nurse turned off the left (#1) PMS, and the pilot turned off the right (#2) PMS. The flight paramedic, who was seated in the right forward-facing rear seat, stated that prior to takeoff, "all engine noise sounded as though [the engines] both were at flight RPM... As we came over the net and walkway, building edge, [the paramedic] heard a sudden decrease in the noise that [he] would associate with the engines and main rotor, and felt the aircraft start to descend." The paramedic looked at the instrument panel and saw two warning indicator lights flashing. PERSONNEL INFORMATION The pilot was hired by CareFlite on April 17, 1996. On July 31, 2002, the pilot completed the Agusta A109E initial flight course and pilot transition ground course, which was administered by Agusta Aerospace Corporation, Grand Prairie, Texas. On September 18, 2002, he satisfactorily completed his most recent annual recurrent ground and flight training for the A109E. According to the flight maneuver grade sheet (Federal Aviation Administration (FAA) Form 8410-3), the pilot received a satisfactory rating for simulated engine failure, and landing with simulated power plant (s) failure. The pilot held a commercial certificate with a rotorcraft helicopter and instrument helicopter ratings. The pilot was issued a second class medical certificate with a limitation for corrective lenses. According to the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) completed by CareFlite, the pilot had accumulated approximately 8,000 rotorcraft flight hours. In an interview with the NTSB investigator-in-charge, the pilot stated he had accumulated approximately 200 flight hours in the accident helicopter make and model. The two flight crewmembers, a flight nurse and flight paramedic, were employed by CareFlite. AIRCRAFT INFORMATION The 2002-model orange, blue and white helicopter, serial number 11142, was powered by two 561-horsepower Pratt and Whitney Canada, Inc. (PWC) PW206C turbo shaft engines, serial numbers PC-E BC0315 and PC-E BC0320, left and right respectively, and equipped with a four bladed main rotor system, and a two bladed tail rotor. The two engines are controlled by the PW206C Engine Control System, which controls the engine power plant by scheduling fuel flow in response to the load demanded by the helicopter's rotor system. The Engine Control System is comprised of two major components, an engine mounted Fuel Metering Module (FMM) and an off-mounted Electronic Engine Control (EEC). The system was also comprised of sensors, wiring harnesses, and ancillary components. The FMM is an electro-hydromechanical unit to modulate the engine fuel flow over the operational envelope of the engine. The unit has automatic and mechanical backup modes of operation. According to PWC, the EEC is a single channel digital Electronic Engine Control used in conjunction with the FMM and a network of sensors to control the engine gas generator and power turbine speeds. The EEC is a full authority as it controls fuel from start to full power within the established limits. The EEC controls the engine for normal flight, with selection provided through the console mounted PMS switches. The 3 modes are as follows: OFF: Fuel shutoff by the shutoff solenoid; IDLE: Control governs the power turbine (Npt) at a speed of approximately 65 percent Npt; FLT: Control provides power turbine/main rotor speed governing at the nominal governing speed (100 percent or 102 percent). 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) toggle switch, which simulates OEI that is governed approximately 90 percent Npt. There are two cockpit indications to warn the pilot that the EEC is not operating normally. A "Caution" (yellow) annunciator indicates that the control system is operating with a system fault (non-critical fault) which may result in degraded engine operation. Full governing by the EEC is maintained during this mode, and a fault code is stored by the EEC. A "Warning" (red) annunciator indicated that the control system is not operating (critical fault), and the control reverts to the manual mode of operation. The EEC