Skyhawk 172/Cutlass 172
Flight Crew Flight Instructor; Flight Crew Commercial
Flight Crew Last 90 Days 80; Flight Crew Total 5400; Flight Crew Type 2500
Confusion; Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented
Human Factors; Procedure
Receiving flight following from Patuxent Approach. [I] was cruising at 3;000 feet when Controller advised that I was about one mile from penetrating a restricted area. I was told to turn to a heading of 090 and vectored away from R-4006. I did not penetrate the restricted area. After landing; I confirmed my understanding that R-4006 begins at 3;500 feet to FL250. As I was cruising at 3;000 feet; I did not understand. I contacted Patuxent via land line and was advised that an 'Altitude Reservation' was in effect; extending the restricted area to the surface. I did receive a standard weather briefing prior to the flight and there was no mention of an 'Altitude Reservation'. If I would not have chosen to receive a standard briefing; I would have been unaware of the Altitude Reservation and would have penetrated restricted airspace.
C172 pilot reported confusion regarding a restricted area that was subject to an 'Altitude Reservation' procedure.