Narrative:

On VFR flight plan, destination houston hull airport at sugarland, tx. At ela had overcast layer below. Called center (houston) for IFR handling to descent through cloud layer. Houston center passed me to houston approach 128.0. After contact with houston approach I understood instructions as descend to 4000', maintain present heading, and intercept 250 right from hobby VOR (117.6). Controller might have given me another squawk code but I inadvertently did not pick up. I acknowledged receipt. At that point I was already in IMC (clouds) descending and trying to hold plane level in descent. I broke out of clouds and was already below ATC assigned altitude of 4000' and was not at 2500' MSL. A different controller came on and asked if I was assigned a 4000' altitude. I acknowledged that I was below the assigned altitude. I in fact, was at 2500' MSL in VMC. Controller also advised of new squawk code and then vectored me to 060 degree at 2000' MSL. Approximately 5 NM southwest of houston-hull, controller asked if I could see the airport which I could. I then understood the controller to request that I cancel IFR through houston center or in the air. I cancelled IFR handling at this point. The controller, which was not the same one as at eagle lake, may have told me to telephone houston center after landing but I misunderstood or didn't hear the instruction to do so. Having advised the controller that I was requesting to cancel IFR the controller told me to contact hull unicom which I did and had an uneventful landing. If I had understood that the controller had made a request for me to call center, I certainly would have. I did go below the assigned altitude of 4000' MSL and it was inadvertent. With my wife and children aboard I was trying to maintain control and went through the assigned altitude. Callback conversation with reporter revealed the following information. Reporter states his ADF went out just as he entered clouds so was setting up VOR radial, keeping aircraft level, etc. Such distraction kept him from realizing altitude until he broke out of clouds. He has accepted remedial training as result of FAA investigation.

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Original NASA ASRS Text

Title: SMA REQUESTS IFR POP UP CLRNC TO DESCEND THROUGH CLOUDS. DESCENDS BELOW ASSIGNED ALT.

Narrative: ON VFR FLT PLAN, DEST HOUSTON HULL ARPT AT SUGARLAND, TX. AT ELA HAD OVERCAST LAYER BELOW. CALLED CTR (HOUSTON) FOR IFR HANDLING TO DSNT THROUGH CLOUD LAYER. HOUSTON CTR PASSED ME TO HOUSTON APCH 128.0. AFTER CONTACT WITH HOUSTON APCH I UNDERSTOOD INSTRUCTIONS AS DSND TO 4000', MAINTAIN PRESENT HDG, AND INTERCEPT 250 R FROM HOBBY VOR (117.6). CTLR MIGHT HAVE GIVEN ME ANOTHER SQUAWK CODE BUT I INADVERTENTLY DID NOT PICK UP. I ACKNOWLEDGED RECEIPT. AT THAT POINT I WAS ALREADY IN IMC (CLOUDS) DSNDING AND TRYING TO HOLD PLANE LEVEL IN DSNT. I BROKE OUT OF CLOUDS AND WAS ALREADY BELOW ATC ASSIGNED ALT OF 4000' AND WAS NOT AT 2500' MSL. A DIFFERENT CTLR CAME ON AND ASKED IF I WAS ASSIGNED A 4000' ALT. I ACKNOWLEDGED THAT I WAS BELOW THE ASSIGNED ALT. I IN FACT, WAS AT 2500' MSL IN VMC. CTLR ALSO ADVISED OF NEW SQUAWK CODE AND THEN VECTORED ME TO 060 DEG AT 2000' MSL. APPROX 5 NM SW OF HOUSTON-HULL, CTLR ASKED IF I COULD SEE THE ARPT WHICH I COULD. I THEN UNDERSTOOD THE CTLR TO REQUEST THAT I CANCEL IFR THROUGH HOUSTON CTR OR IN THE AIR. I CANCELLED IFR HANDLING AT THIS POINT. THE CTLR, WHICH WAS NOT THE SAME ONE AS AT EAGLE LAKE, MAY HAVE TOLD ME TO TELEPHONE HOUSTON CTR AFTER LNDG BUT I MISUNDERSTOOD OR DIDN'T HEAR THE INSTRUCTION TO DO SO. HAVING ADVISED THE CTLR THAT I WAS REQUESTING TO CANCEL IFR THE CTLR TOLD ME TO CONTACT HULL UNICOM WHICH I DID AND HAD AN UNEVENTFUL LNDG. IF I HAD UNDERSTOOD THAT THE CTLR HAD MADE A REQUEST FOR ME TO CALL CTR, I CERTAINLY WOULD HAVE. I DID GO BELOW THE ASSIGNED ALT OF 4000' MSL AND IT WAS INADVERTENT. WITH MY WIFE AND CHILDREN ABOARD I WAS TRYING TO MAINTAIN CTL AND WENT THROUGH THE ASSIGNED ALT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. RPTR STATES HIS ADF WENT OUT JUST AS HE ENTERED CLOUDS SO WAS SETTING UP VOR RADIAL, KEEPING ACFT LEVEL, ETC. SUCH DISTR KEPT HIM FROM REALIZING ALT UNTIL HE BROKE OUT OF CLOUDS. HE HAS ACCEPTED REMEDIAL TRAINING AS RESULT OF FAA INVESTIGATION.

Data retrieved from NASA's ASRS site as of July 2007 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.