Small Aircraft
Flight Crew Private; Flight Crew Instrument
Flight Crew Last 90 Days 20; Flight Crew Total 418; Flight Crew Type 254
Communication Breakdown
ATC Issue All Types
Flight Crew Took Evasive Action
Human Factors; Procedure
Cleared for closed pattern work Runway 21R; PDK XA:50 local time; attempting to modify IFR flight plan which had been annotated from original filing by ATC; advised that communication with Atlanta Departure could only be done when airborne.  Requested closed pattern work to allow communication with Controller.  A request to the Tower granted permission to contact Controller and leave Tower frequency momentarily.  While speaking to [the] Departure Controller; he advised Tower was calling; switched back to Tower frequency while approaching 'R base 21R' and the Tower directed us to immediately turn 90 degrees left; which was done; to avoid close proximity to landing aircraft descending to 21L. Intentions were requested by Tower; responded that we needed to straighten out the anomalies in the ATC amended IFR flight plan; Tower cleared us to land and that they were working with the Controller to deal with modifying IFR flight plan.  Note: The aircraft had a 'new engine with only 5 hours accumulated time (in process break-in).'  The proposed modified IFR flight plan routed the flight across the mountain range to ZZZ at night and was considered a safety risk. It would seem that communications could have been accomplished while on the ground.  Ultimately; the flight plan was corrected and we were cleared to a waypoint of Chattanooga before proceeding to ZZZ (as originally filed).Secondary to communications and closed pattern traffic distraction; PDK airport runway lighting was dim and difficult to identify even in the traffic pattern; until the aircraft is on final and lined up with the appropriate runway/PAPI lighting is ok but - end of runway lighting seems to be less than adequate for pilots not familiar with the airport. This aircraft had a crew of two private pilots searching in a 'sea of lights' for runway identification lighting.
GA pilot reported that they had to communicate with Departure Control with flying the traffic pattern at PDK airport. Pilot also stated that airport runway lighting is inadequate.