Date: 201807
Local time of day: 1201-1800
Location: VKX.Airport, MD
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Operator: Personal
Operating under: Part 91
Flight plan: VFR
Mission: Training
Flight phase: Final Approach
ATC / advisory: TRACON PCT
Second aircraft: Helicopter
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Instrument; Flight Crew Private
Human factors: Situational Awareness; Training / Qualification
Anomaly: Conflict NMAC
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Aircraft; Procedure
Primary problem: Procedure

Narrative: My flight instructor and I were descending through 1;300 feet on final approach to Runway 06 at VKX within the DC FRZ; and had just been handed off by Potomac TRACON to the CTAF for VKX when what appeared to be a helicopter crossed directly in front of us from left to right at a horizontal distance of approximately 500 feet and a vertical distance of approximately 200 feet.  Prior to the hand-off by Potomac TRACON we were not advised that there was a helicopter in the vicinity of VKX or which was on a course to cross the established final approach path that we were on for VKX Runway 6 at or around the final approach/pattern altitude.  After making an immediate evasive maneuver to avoid a collision (i.e.; an abrupt descending left turn); my instructor contacted Potomac TRACON on 125.12 and notified them of the near collision.  We were informed by the controller that the helicopter was talking to DCA/National Tower and not to Potomac; and that he 'would speak to them about this.'Proposed corrective actions: That proper procedures are put in place for routing helicopter flights (and any other aircraft); so that they avoid transiting across the airspace used for arrivals and departures at VKX and immediately adjacent W32 at altitudes that would conflict with such arriving and departing traffic. If such transiting is required due to the aircraft's mission; then put in place enhanced safety procedures that may include 1) requiring all such transiting flights to monitor and announce their intentions and positions on the CTAF for those airports; and 2) enhancing coordination and communication between ATC facilities (DCA/National Tower; Andrews ADW) Tower; and Potomac TRACON) which are controlling those flights; and between those ATC facilities and any conflicting air traffic arriving at and departing from VKX and W32. This may include putting in place procedures for the responsible control towers to hand off to Potomac TRACON the control of all aircraft on course to transit the critical airspace/altitudes surrounding VKX and W32 before they reach a certain distance from those airports (10 NM?); so that Potomac is talking to both the transiting aircraft; and the aircraft arriving to or departing from VKX and W32 (who are required to be talking to Potomac under FRZ rules) so that both aircraft can be advised of a potential conflict in a timely manner.  These procedures should augment the general 'see and avoid' responsibility of all pilots under these circumstances.




Synopsis: Piper Cherokee pilot reported a NMAC with a helicopter on final approach.