Date: 201703
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Night
Aircraft: Skylane 182/RG Turbo Skylane/RG
Operator: Personal
Operating under: Part 91
Mission: Personal
Flight phase: Initial Climb
Airspace: Class G ZZZ
ATC / advisory: CTAF ZZZ
Second aircraft: Chinook (CH-47)
Reporter organization: Personal
Reporter function: Single Pilot
Reporter qualification: Flight Crew Private
Human factors: Communication Breakdown
Anomaly: Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Observer
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Airspace Structure; Airport; Human Factors
Primary problem: Human Factors

Narrative: I landed at ZZZ to offload a passenger; who is also a pilot. As I was landing I heard a CH-47 (Helicopter Number 1) declare his intentions to land at ZZZ. I taxied to the ramp; and offloaded my passenger. I then taxied back to the end of Runway XX for departure to ZZZ1. As I was taxing I heard a second CH-47 (Helicopter Number 2) declare his intentions to do a low approach to Runway XX at ZZZ. I was in constant communication with Number 2 sending and receiving our respective intentions. Number 2 made his low approach and I watched him make a standard pattern departure. There was no communication with Number 1 and it was my understanding he had departed ZZZ. I performed my normal preflight checklist and as Number 2 turned downwind for Runway XX I announced my intentions to take off on Runway XX and notified Number 2 that I had him insight and would pass well behind him. It should be noted that there is no line of sight between runway ends. I took off and made a normal pattern departure with Number 2 insight at all times and then turned direct ZZZ1. After landing at ZZZ1 my passenger called from ZZZ very concerned and informed me that I had flown over helicopter Number 1 and it was possible that he was still on the runway. At no time during taxi; takeoff or pattern departure did I have any visual on Number 1 and Number 1 never acknowledged any of my radio call regarding taxing or takeoff and his position at the airport. It is possible that I could not see his beacon due to the grade of the runway and the position of the helicopter. Number 2 responded to every radio call as I did his. After discussing the event my passenger we concluded that it was very likely that part of helicopter Number 1 was either very close to or over the hold short line at the exit at the very end of Runway XX. To add to the my belief that Number 1 had departed there was a star/planet that was very bright directly of the approach end of Runway XX that I believed was helicopter Number 1 making a second approach to ZZZ. In the future I will make a dedicated effort confirm the position of any second aircraft and especially a flight of 2 prior to entering a runway and taking off. I could have asked Number 2 if he knew the position of the other aircraft.




Synopsis: C182 pilot reported that during takeoff at a non-towered airport he flew over a helicopter that was at the end of the runway.