Skyhawk 172/Cutlass 172
Flight Crew Private
Flight Crew Last 90 Days 25; Flight Crew Total 1250; Flight Crew Type 1150
Situational Awareness
Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
General None Reported / Taken
Human Factors
CDC has many helicopters training in the area.  I landed for fuel on runway 02; taxied to the east side of the airport for self-serve fuel.  I refueled and the immediately adjacent runway - 26 - was favorable for my intended direction of travel; and to the best of my recollection it was favored by light winds from the NW.  I also was considering the training helicopter activity on the ramp and the 26 departure put me on the runway quickly; allowing me to expedite my departure from the busy training environment.  I heard other aircraft inbound; but they were a comfortable distance out.  I saw no traffic creating a conflict for a 26 departure.  I announced a 26 departure.  As I was climbing out; I noticed a R44 helicopter at the west end of 26; blades turning; sitting on the ground.  It was not close call.  I routinely have closer interactions using the taxiway at my home airport with training helicopters in the pattern.  The R44 was on the ground at the time and I had substantial altitude.  A minute or so later; I heard the R44 pilot announce a movement.  Knowing then that the pilot was on CTAF; I asked the pilot why he had not said something on the radio when I announced I was using 26.  He replied the runway was closed.  He was correct; and when he said that; I in fact recalled the NOTAM.  Nothing on the AWOS or on the ground prior to 26 entry indicated closure.  The runway was in fine condition from what I could see.  I do not agree that a runway being NOTAMed closed suggests that one then shouldn't use the radio to tell someone where you are at or better; point out the closure.  Factors affecting my decision making include not rechecking NOTAMs prior to takeoff and wanting to quickly leave the training environment and continue my x-country flight.  Also; distance or possibly runway crown prevented me from seeing the R44 at the opposite end prior to takeoff.
C172 unknowingly departed from closed Runway 26 at CDC causing some concern to a helicopter training crew.