Date: 201307
Local time of day: 1201-1800
Location: ZHU.ARTCC, TX
Weather elements / visibility: Thunderstorm; Turbulence; Rain; Hail; Icing
Light: Daylight
Aircraft: Super King Air 200
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Descent
Airspace: Class A ZHU
ATC / advisory: Center ZHU
Reporter organization: Personal
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Commercial
Human factors: Communication Breakdown; Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Weather; Aircraft; Human Factors
Primary problem: Ambiguous

Narrative: There was confusion between ATC and myself. Headed south from PNH to BAZ; I was asked to reroute to STV and descend from 270 to 240 by ABQ Center 80 NM northwest of LLO. I informed them that the weather ahead was extreme and asked to deviate to the east around the large cell around the LLO VOR. She said that HOU Center would be able to give that to me. Switched over to Houston and was given descent instructions to FL230 and I advised ZHU that was unable for 2 minutes. I was in heavy icing conditions and needed to let the de-ice cycle complete. He told me I should be able to at least descend to FL230 and I told him was unable without at least 15- 20 degrees to the right. I was in the tops of the edge of the cell. He then gave me a deviation ok and told me to descend to 15 thousand; and I informed him that it would not be possible for me to do that until I got past the STV VOR due to the weather. I then understood him to say; ok continue at FL240 and down to 15;000 when able direct to destination. After clearing the storm I continued direct to BAZ and started down from FL240. He then asked me what my intentions were and if I was in a descent? I said yes; and he informed me that wasn't my clearance and to listen to him and that he had never been turned down on the FL230 descent clearance like I had done. He then recleared me to 15;000 and I told him I guess I misunderstood. I informed him sorry and that the Nexrad was not showing what was there and I saw early on it did not look as bad as it actually was. I also noticed that a B737 asked 2 times for a turn to avoid HENLY and he didn't get it. Then said he was in a slow turn towards SJT and informed him of that. Controller then told them ok and went back to me. The B737 was 20 NM farther west than I and I was at FL240 and it was a 45-50k top system and temperature was -3; with major chop; severe turbulence; icing and small hail. I informed SAT Approach of the weather conditions after that. I have TCAS and no other aircraft were in the vicinity; closest was 30 miles and lower; a TBM700 who deviated west of Kerrville to clear this storm. I believe that due to the level 5+ thunderstorm I would have endangered the passengers and myself by not standing my ground and refusing to accept a lower altitude and a heading of his choosing. All others were making major deviations and he wanted to put me in the middle of it. I know what he was looking at on his weather and I was not able to fly at FL320 to get around the edges like the jets.




Synopsis: King Air pilot reports a thunderstorm encounter over Texas and difficulties getting clearance for the heading and altitude of his choosing. A Nexrad display was being used for weather avoidance.