Flight Crew Private; Flight Crew Instrument
Flight Crew Last 90 Days 30; Flight Crew Total 2400; Flight Crew Type 1500
Communication Breakdown
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance
Airport
Landed to drop off a passenger and taxied to GA hangars to drop him off. Proceeded to return to take off asked ground for progressives and he responded 'return the way you came in'.I proceeded the way I came in and the taxiway ended in the middle of the runway (there was not a parallel taxiway) and I inadvertently stopped on the do not cross markings. Contact was then made with the tower for back taxi on the active runway and then takeoff.Perceptions: I proceeded on a clearance of 'return the way you came in' which included taxiing down the runway to the exit point. I was prepared to taxi down the runway as a taxiway but stopped on the do not cross markings to confirm and contacted the tower for continued taxi.I believe what caused the problem was the knowledge that the flying that the controllers were there to control (national guard) was done for the day and the controller and the pilot were unusually relaxed about the communications.More professional radio work would result in more professional reactions for both parties.
When asked for a 'Progressive' Taxi in a Lake Amphibian LA-4; the pilot misunderstood the Controller's instructions. The pilot didn't realize the instructions included taxiing down an active runway.