Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument
Flight Crew Last 90 Days 40; Flight Crew Total 3700; Flight Crew Type 1500
Distraction; Human-Machine Interface
ATC Issue All Types; Conflict NMAC
General None Reported / Taken
Human Factors; Weather; Airport; Environment - Non Weather Related
While level at 7;300 feet in cruise; I was the pilot not flying and was heads down programming the approach to Runway 8 at RHP. The pilot flying in the left seat was monitoring the aircraft [while also monitoring for traffic.] We were level at the lowest altitude that ATC could allow due to terrain in the area and we were flying in and out of the tops of a cumulus layer. Out of the corner of my eye I saw what I thought was a shadow flash by the copilot's (my) side window. I commented to the pilot flying that I thought I saw a shadow and he stated it was an aircraft. The pilot flying stated the aircraft was close enough for him to tell it was white with brown wing tips and appeared to be a Piper Cherokee and it appeared the aircraft was climbing. At the time of the near miss we were under positive radar control with Atlanta Center and were not advised of any nearby traffic. After landing a passenger advised she thought she saw an aircraft go by. Possible causes are believed to be high terrain; possible poor ATC radar coverage for primary targets; and IFR conditions at the altitude we were at which did not allow us to see an aircraft in the clouds.
A CE560 flight crew suffered an NMAC with what they believed to be a Piper Cherokee while being vectored for an approach at ATC's minimum vectoring altitude in hilly terrain. ATC was unaware of the other aircraft.