Date: 201411
Local time of day: 1801-2400
Location: PDK.Airport, GA
Flight conditions: VMC
Weather elements / visibility: 10
Light: Night
Aircraft: Learjet 31
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class D PDK
ATC / advisory: Tower PDK
Reporter organization: Corporate
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion; Situational Awareness
Anomaly: Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Airport; Chart Or Publication; Human Factors
Primary problem: Ambiguous

Narrative: We were on about a 7-8 mile base leg vector with ATL approach for a night visual approach to runway 21L at PDK. We had briefed a visual approach and were backing it up with the RNAV (GPS) Y Rwy 21L approach which was loaded in the FMS. During the approach preparation/briefing I did not fully recognize the 15 degree offset of the final approach course that was noted on the approach plate. I noticed that the inbound course was 221 on the chart and that it had straight-in minimums; therefore thinking to myself that it was within a few degrees of the runway 21L heading. When we visually picked up the airport; I called the field in sight and we were cleared for a visual approach and handed off to PDK tower. I checked in and we were cleared to land runway 21L. As we were approaching the final approach course for the RNAV approach; I noticed it appeared that we were going through the extended runway centerline; but we still had not reached the final approach course for the RNAV approach. The flying pilot began turning to join the inbound course; which may have been a little too late and also I believe we a had a tailwind on base leg that helped to push us further past the RNAV inbound course. I stated to the pilot flying that we needed to return to the right to rejoin the RNAV inbound course and realized that it appeared to be offset significantly from the runway. At that point I brought up the localizer frequency for the ILS and noticed we were significantly left of course. I began to question our position and as a last attempt before calling for a go-around/discontinuation of the approach; I queried tower if he had us in sight and if we appeared to be lined up on final for 21L. The tower controller stated he had us in sight and turned up the approach lights at which point we were able to verify we were correctly lining up for the correct runway and airport. The controller also stated that we were not the first aircraft to have this problem. From this point we were able to continue on a stabilized approach and landed uneventfully. There did not appear to be any traffic conflicts and I do not believe we encroached on any other airspace. ATC did not say anything more about it after our initial query. PDK is in a high density area and was not a familiar airport for me at night. If I could do it over again; I would have loaded the ILS and requested vectors onto the localizer and waited until I was lined up on final before calling the airport in sight. Also; I feel that the note on the jeppesen approach plate stating the 15 degree offset of the final approach course could be better located or made bold to help prevent overlooking that important detail. I noticed in further research after the flight; that the government approach plate has the offset course note located next to the final approach course depiction on the plan view; which seems like a more logical spot for it.




Synopsis: Lear 31 Captain experiences difficulty locating PDK Runway 21L during a night visual approach. The RNAV Y to Runway 21L had been loaded in the FMC for situational awareness but the 15 degree offset was not noticed; causing confusion.