History of Flight
On January 28, 2018, about 1400 central standard time, an Airbus Helicopters EC 130 T2, registration N894GT, was involved in an incident at the Regional One Health Medical Center heliport in Memphis, Tennessee. The helicopter was operating as a Title 14 Code of Federal Regulations (CFR) Part 135 air ambulance flight. The pilot, flight nurse, flight paramedic, and patient were not injured. The helicopter incurred minor damage.
The pilot reported that during a long final approach to the rooftop heliport with a left crosswind, he reduced collective pitch control friction three times to move the collective faster. After reaching the heliport, he hovered, turned right, and landed. Post-landing, he started the after-landing checklist, turned the throttle twist grip from "FLY" to "IDLE," believing the collective lock was engaged, and muted the horn. As he reached for the clock start button, the collective "popped up," and the helicopter became airborne. He immediately grabbed the cyclic and collective, twisted the grip to "FLY," and the helicopter landed hard, activating the emergency locator transmitter (ELT). Security camera video showed the rotor pitch change and coning as the helicopter became airborne.
Personnel Information
The pilot held a commercial pilot certificate with rotorcraft-helicopter and instrument helicopter ratings, and private privileges for airplane single-engine land. He attended an EC 130 pilot transition class from November 6 to 10, 2017, and completed his 14 CFR Part 135 Airman Competency/Proficiency Check on January 17, 2018. He reported 6,267 total flight hours, about 9 of which were in the incident helicopter make and model.
Aircraft Information
The single-rotor helicopter was of conventional design with a three-bladed Starflex main rotor and a Fenestron tail fan anti-torque device. Its 802-shaft horsepower Turbomeca Arriel 2D turboshaft engine was equipped with full authority digital engine control (FADEC) and a dual hydraulic system. The helicopter could be converted between dual-pilot and single-pilot configurations.
Airport Information
The heliport was located on a building roof about 85 feet above street level, surrounded by obstacles except for the northeast-facing portion. The touchdown and liftoff area (TLOF) measured 75 feet by 75 feet, marked with a red "H" centered inside a white cross, a white border, a lighted windsock, and yellow perimeter lights.
Flight Recorders
The helicopter was equipped with an engine data recorder (EDR) that recorded FADEC parameters, and an Appareo Vision 1000 unit recording images, audio, and parametric data. Onboard video and EDR data showed the collective rising from an unlocked position with the engine transitioning from "Idle" to "Flight," consistent with the pilot's statement.
Wreckage and Impact Information
Examination revealed minor damage: the skid landing gear was spread out, both landing gear cross tubes were deformed, forward belly panels were dented from contact with the forward cross tube, and aft closeout panels were dented from contact with the aft cross tube.
Maintenance Findings
On January 31, 2018, an FAA inspector examined the collective system at Air Evac's Jackson, Tennessee, base. Two days before the incident, a mechanic had removed the right seat flight controls and configured the helicopter for single-pilot operation. When the collective was placed in the full-down position and the mechanic removed his hand before attaching a spring scale, the collective immediately climbed unassisted to approximately mid-travel, indicating improper balance for single-pilot configuration. The spring force was approximately twice that required in the upward direction.