Date: 201408
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Helicopter
Operator: FBO
Operating under: Part 91
Mission: Training
Flight phase: Initial Climb
Airspace: Class E ZZZ
ATC / advisory: CTAF ZZZ
Aircraft component: Reciprocating Engine Assembly
Component problem: Malfunctioning
Reporter organization: FBO
Reporter function: Instructor; Pilot Flying
Reporter qualification: Flight Crew Rotorcraft; Flight Crew Flight Instructor; Flight Crew Commercial
Human factors: Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Person Flight Crew
When detected: In-flight
Result: Aircraft Equipment Problem Dissipated; Flight Crew Landed in Emergency Condition; Flight Crew Diverted
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: We suffered what turned out to be a stuck valve as we reached top of climb departing [the airport] at the end of a training flight. This manifested as a sudden vibration felt through the airframe and controls; roughness of the engine and an increase in manifold pressure. At the time we did not know the cause but suspected a lost magneto.We reduced our power setting; descended and circled in order to position for an into-wind landing place; the wind was greater than 10 knots at the time. As we were over a populated area; I determined that the safest place for the helicopter would be a large parking lot; this would also ensure ease of access for maintenance/rescue vehicles if necessary. As we got lower we saw that the only place without power lines or trees was a parking lot in a mall area. At the southern (windward) side was an empty row and we landed there without causing damage to any buildings; people or cars. We took particular note that there was no FOD in the area and our downwash was not blowing anything towards the parked cars.We shut down in order to conduct a magneto check and engine inspection; and after telephoning our Maintenance Department we assessed that the problem had probably cleared during descent and that we should attempt to fly back to base. Start up; takeoff; and return to base were uneventful and we were on the ground for under 5 minutes.Due to the fact that helicopters conducting this sort of flight do not regularly keep in contact with an ATC agency; we did not radio anyone during this event but continued to monitor the [airport's] CTAF. Perhaps if having a flight following service was more common/mandatory this would simplify the decisions like 'who to call?' and 'do I declare an emergency or just inform?' In this case; had I had flight following; I could have informed (in this case) TRACON of the developing situation. A more standardized communications procedure for helicopters would remove one decision from all other decisions necessary during an already-busy landing.




Synopsis: Helicopter pilot experiences a power loss during initial climb and elects to land in a parking lot. The engine anomaly appears to clear up during descent but the approach is continued to landing as a precaution. Visual inspection on the ground reveals no anomalies and the helicopter is flown back to base.