EA500 captain reports communication difficulties with ATC while attempting to change destination or ...

Narrative:

On IFR flight plan to ecp. Weather was rapidly deteriorating accompanied by severe thunderstorms and moderate to extreme precipitation. Aircraft is equipped with nexrad weather; but not on-board sweeping weather radar. Approximately 30 miles from severe reported weather (as reported by prior aircraft and confirmed by nexrad equipment) I attempted to change destination to cew to avoid entering extreme weather exceeding capability of aircraft. Requested change of destination from filed destination (ecp) to cew approximately three times over 5 minute period. ATC did not acknowledge transmission; and descended aircraft to assigned altitude of 17;000. During descent to 17;000 ATC advised to level off at 18;000. I then advised ATC that if I could get descent below 18;000 I would cancel IFR clearance and precede VFR. ATC advised 'standby' and then assigned 17;000. During descent below 18;000 I requested to 'cancel IFR' more than once to remain VFR prior to entering extreme weather and precede VFR; but transmission was not acknowledged. After announcing to controller I was canceling IFR aircraft descended below last assigned IFR cleared altitude of 17;000. Aircraft descended to approximately 16;300 MSL at which time ATC advised assigned altitude was 17;000. Better flight planning and earlier decision making regarding a more suitable alternate would have mitigated problem. This would have given ATC and me more time to sequence and plan aircraft's intended course of action.

Original NASA ASRS Text

Title: EA500 Captain reports communication difficulties with ATC while attempting to change destination or descend and and cancel IFR due to weather. A deviation below the ATC assigned altitude of 17;000 FT occurs prior to the Controller acknowledging IFR cancellation request.

Narrative: On IFR flight plan to ECP. Weather was rapidly deteriorating accompanied by severe thunderstorms and moderate to extreme precipitation. Aircraft is equipped with NEXRAD weather; but not on-board sweeping weather radar. Approximately 30 miles from severe reported weather (as reported by prior aircraft and confirmed by NEXRAD equipment) I attempted to change destination to CEW to avoid entering extreme weather exceeding capability of aircraft. Requested change of destination from filed destination (ECP) to CEW approximately three times over 5 minute period. ATC did not acknowledge transmission; and descended aircraft to assigned altitude of 17;000. During descent to 17;000 ATC advised to level off at 18;000. I then advised ATC that if I could get descent below 18;000 I would cancel IFR clearance and precede VFR. ATC advised 'standby' and then assigned 17;000. During descent below 18;000 I requested to 'cancel IFR' more than once to remain VFR prior to entering extreme weather and precede VFR; but transmission was not acknowledged. After announcing to Controller I was canceling IFR aircraft descended below last assigned IFR cleared altitude of 17;000. Aircraft descended to approximately 16;300 MSL at which time ATC advised assigned altitude was 17;000. Better flight planning and earlier decision making regarding a more suitable alternate would have mitigated problem. This would have given ATC and me more time to sequence and plan aircraft's intended course of action.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1026404
Time
Date	201207
Local Time Of Day	1201-1800
Place
Locale Reference	ZJX.ARTCC
State Reference	FL
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	Eclipse 500
Operating Under FAR Part	Part 91
Flight Phase	Descent
Route In Use	Direct
Flight Plan	IFR
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 20 Flight Crew Total 5100 Flight Crew Type 400
Events
Anomaly	ATC Issue All Types Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Inflight Event / Encounter Weather / Turbulence

EA500 captain reports communication difficulties with ATC while attempting to change destination or descend and and cancel IFR due to weather. A deviation below the ATC assigned altitude of 17;000 ft occurs prior to the controller acknowledging IFR cancellation request.