Date: 201709
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Cessna Aircraft Undifferentiated or Other Model
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Descent
Airspace: Class E ZZZ
ATC / advisory: UNICOM ZZZ
Reporter organization: Personal
Reporter function: Pilot Flying
Reporter qualification: Flight Crew Private; Flight Crew Instrument
Human factors: Communication Breakdown; Situational Awareness
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General None Reported / Taken
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: VFR Flight to ZZZ - upon pre-flight review of NOTAMs it was noted that [one runway] was closed and there was an airspace notice of aerobatic activity within 1 mile radius of ZZZ VOR which is co-located on the field. As the field was not NOTAMed closed and RWY 5-23 was still open I took the NOTAM to mean there may be activity in the area and to use caution (similar to a warning that there may be parachute jumping in an area near an airport). Upon approaching the airport from the South I made the usual CTAF calls at 10 MI and 5 MI announcing intent to land on RWY 5 with a midfield cross wind pattern entry. Other aircraft were in the pattern for RWY 5 and making position calls. No aerobatic activity was being announced nor observed. When I called at 3 MI South a Unicom call was made advising me that an 'aerobatic box' was hot and to use left downwind but not to cross RWY 5. I complied and went around the airport by several miles and entered left downwind for 5 on the 45. Landing was uneventful and no aerobatic activity was being performed at any time while I was approaching the airport or in the pattern. After landing we discovered there was a local aerobatic competition and the 'box' was really the SE corner of the airfield made by the intersection of 5-23 and [the other runway]. No Airboss was in use.While nothing happened and no potential aircraft conflicts occurred it seemed that this was a potentially dangerous situation. Even though NOTAMs were reviewed; they did not give me a full picture of what was happening at the airport and how to safely plan. After rechecking the NOTAMs it seemed that more specific information in the NOTAM would have been helpful. The general description of a 1 MI radius around ZZZ did not accurately explain what the organizers considered to be their box. A more specific description in the NOTAM and recommended approach and departure procedures would also have been helpful. After landing it became clear that the organizers assumed a lot of local knowledge about their event which I did not possess.In the future - I can take additional action to call the FBO and inquire about local events when NOTAMs lack specifics and leave ambiguity about the situation about the reason for a RWY closure or special activities that may be taking place.




Synopsis: General aviation pilot reported that a NOTAM for aerobatic activity did not provide adequate information to prepare a non-participating pilot for arrival.