Narrative:

On climbing out VFR from 4r2 airport, I called center (ZHU) to get a 'pop-up' IFR clearance. I called at 5000 ft and no response. I again called at 5800 ft and got an answer of 'maintain 6000 ft' and a squawk code. My present climb rate was +2500 FPM. I gave a readback and began to level off but had to descend out of 6400 ft by that time. I set the squawk code while leveling. Center called and said 'I see your out of 6000 ft, climb and maintain 14000 ft and fly direct uua.' I did. I did not expect such a sudden altitude limit. I was climbing quickly as a matter of procedure to climb up away from lower level traffic and turbulence. To have leveled off so quickly would surely have resulted in a negative 'G' load (floating passenger) so I did return to 6000 ft as quickly as was reasonably possible. I feel that the 6000 ft altitude restr was to keep me below traffic flying into austin, tx, until my position could be located on radar. This altitude deviation was quick, minor and seemed a non event. However, it was a deviation that was unavoidable. Also, I was VFR at that time since I had yet to receive a clearance. No other aircraft was involved. I am not sure what ATC uses as a rule for lead time on an altitude assignment but this one was a little tight.

Related reports:

Google
 

Original NASA ASRS Text

Title: ALT OVERSHOOT IN TEXAS ACCOUNT LATE ALT ASSIGNMENT AND A HIGH RATE OF CLB.

Narrative: ON CLBING OUT VFR FROM 4R2 ARPT, I CALLED CTR (ZHU) TO GET A 'POP-UP' IFR CLRNC. I CALLED AT 5000 FT AND NO RESPONSE. I AGAIN CALLED AT 5800 FT AND GOT AN ANSWER OF 'MAINTAIN 6000 FT' AND A SQUAWK CODE. MY PRESENT CLB RATE WAS +2500 FPM. I GAVE A READBACK AND BEGAN TO LEVEL OFF BUT HAD TO DSND OUT OF 6400 FT BY THAT TIME. I SET THE SQUAWK CODE WHILE LEVELING. CTR CALLED AND SAID 'I SEE YOUR OUT OF 6000 FT, CLB AND MAINTAIN 14000 FT AND FLY DIRECT UUA.' I DID. I DID NOT EXPECT SUCH A SUDDEN ALT LIMIT. I WAS CLBING QUICKLY AS A MATTER OF PROC TO CLB UP AWAY FROM LOWER LEVEL TFC AND TURB. TO HAVE LEVELED OFF SO QUICKLY WOULD SURELY HAVE RESULTED IN A NEGATIVE 'G' LOAD (FLOATING PAX) SO I DID RETURN TO 6000 FT AS QUICKLY AS WAS REASONABLY POSSIBLE. I FEEL THAT THE 6000 FT ALT RESTR WAS TO KEEP ME BELOW TFC FLYING INTO AUSTIN, TX, UNTIL MY POS COULD BE LOCATED ON RADAR. THIS ALTDEV WAS QUICK, MINOR AND SEEMED A NON EVENT. HOWEVER, IT WAS A DEV THAT WAS UNAVOIDABLE. ALSO, I WAS VFR AT THAT TIME SINCE I HAD YET TO RECEIVE A CLRNC. NO OTHER ACFT WAS INVOLVED. I AM NOT SURE WHAT ATC USES AS A RULE FOR LEAD TIME ON AN ALT ASSIGNMENT BUT THIS ONE WAS A LITTLE TIGHT.

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.