Small Aircraft; Low Wing; 2 Eng; Retractable Gear
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 130; Flight Crew Total 20000; Flight Crew Type 1100
Communication Breakdown
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Clearance
Human Factors; Procedure; Weather
While flying to JZI we were trying to get around weather and comply with ATC southwest of ATL. ATL Center told us we would have to proceed south of our course or descend from 11000 ft to 7000 ft . Neither looked like a good idea for the weather so we decided to descend to 7000 ft. When we changed freq to ATL approach just north of CSG. I checked in that we were descending out of 9000 ft for 7000 ft and that we need a heading to the north for weather and requested a climb back to 11000 ft ASAP. The controller said to turn right to heading of 130. I said we are unable due to weather. He replied turn right immediately I said we can give you that heading in 5 miles. He responded turn right to 130. I said if I need to [exercise emergency PIC authority] I will but I am not able to turn to that heading. He said emergency acknowledged; descend to 7000 feet; cleared direct BOWLN. We were not give a crossing restriction which if we had may have prevented the conflict if there was one.
General aviation pilot encountered weather enroute requiring a deviation from ATC assigned instructions. Pilot exercised emergency authority to deviate.