Narrative:

I called key west ground to pick up my IFR clearance to fll. Ground control advised me that the current WX was 1/2 mi visibility with visibility improving rapidly due to a thunderstorm that was passing over the field. They then asked me if I was ready to taxi. I replied negative, that I must wait for the conditions to improve before I could depart because my operation specification manual states that I must have at least the visibility required for the approach in use in order to takeoff, and at after about 10 mins of waiting, the storm appeared to have moved north of the field with the conditions improving dramatically. I advised ground that I was ready to taxi. They approved my request so I taxied to runway 27. I advised tower that I was holding short of the runway and I asked them if they could tell me the location of the storm before I departed. They said that they were unable to give me the location of the WX. I asked them if I could make a 360 degree turn on the taxiway so I could scan the local area with my radar so I could get a better idea of where the storm was moving. After completing a couple of turns and determining that the storm had moved north of the field, tower asked me if I was ready to go. I replied yes and that I would like to fly the runway heading until I was clear of the WX, then I would turn northeast to join the airway. They said 'roger, that was approved, cleared for takeoff.' the runway at key west is 4800 ft long, and at the time of my departure, I could see approximately 3/4 of a mi past the end of the runway making my visibility at least 1 1/2 mi. After reaching fll I realized that even though the WX at key west had improved dramatically before I took off, the tower at key west had not updated the current visibility report or at least I don't remember hearing them change it. Although the visibility had definitely improved to at least a mi, I should not have taken off until the tower had officially updated the visibility. But due to the pressure of the situation of feeling the need to hurry because of the possibility of the WX deteriorating again and the fact that I had other airplane behind me ready for takeoff, I just plain forgot to ask the tower for the current visibility. I know that such actions may be prevented in the future by just slowing myself down and concentrating on the situation at hand.

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Original NASA ASRS Text

Title: AN SMT ACR PLT FAILED TO GET A WX UPDATE BEFORE TKOF.

Narrative: I CALLED KEY WEST GND TO PICK UP MY IFR CLRNC TO FLL. GND CTL ADVISED ME THAT THE CURRENT WX WAS 1/2 MI VISIBILITY WITH VISIBILITY IMPROVING RAPIDLY DUE TO A TSTM THAT WAS PASSING OVER THE FIELD. THEY THEN ASKED ME IF I WAS READY TO TAXI. I REPLIED NEGATIVE, THAT I MUST WAIT FOR THE CONDITIONS TO IMPROVE BEFORE I COULD DEPART BECAUSE MY OP SPEC MANUAL STATES THAT I MUST HAVE AT LEAST THE VISIBILITY REQUIRED FOR THE APCH IN USE IN ORDER TO TKOF, AND AT AFTER ABOUT 10 MINS OF WAITING, THE STORM APPEARED TO HAVE MOVED N OF THE FIELD WITH THE CONDITIONS IMPROVING DRAMATICALLY. I ADVISED GND THAT I WAS READY TO TAXI. THEY APPROVED MY REQUEST SO I TAXIED TO RWY 27. I ADVISED TWR THAT I WAS HOLDING SHORT OF THE RWY AND I ASKED THEM IF THEY COULD TELL ME THE LOCATION OF THE STORM BEFORE I DEPARTED. THEY SAID THAT THEY WERE UNABLE TO GIVE ME THE LOCATION OF THE WX. I ASKED THEM IF I COULD MAKE A 360 DEG TURN ON THE TXWY SO I COULD SCAN THE LCL AREA WITH MY RADAR SO I COULD GET A BETTER IDEA OF WHERE THE STORM WAS MOVING. AFTER COMPLETING A COUPLE OF TURNS AND DETERMINING THAT THE STORM HAD MOVED N OF THE FIELD, TWR ASKED ME IF I WAS READY TO GO. I REPLIED YES AND THAT I WOULD LIKE TO FLY THE RWY HDG UNTIL I WAS CLR OF THE WX, THEN I WOULD TURN NE TO JOIN THE AIRWAY. THEY SAID 'ROGER, THAT WAS APPROVED, CLRED FOR TKOF.' THE RWY AT KEY WEST IS 4800 FT LONG, AND AT THE TIME OF MY DEP, I COULD SEE APPROX 3/4 OF A MI PAST THE END OF THE RWY MAKING MY VISIBILITY AT LEAST 1 1/2 MI. AFTER REACHING FLL I REALIZED THAT EVEN THOUGH THE WX AT KEY WEST HAD IMPROVED DRAMATICALLY BEFORE I TOOK OFF, THE TWR AT KEY WEST HAD NOT UPDATED THE CURRENT VISIBILITY RPT OR AT LEAST I DON'T REMEMBER HEARING THEM CHANGE IT. ALTHOUGH THE VISIBILITY HAD DEFINITELY IMPROVED TO AT LEAST A MI, I SHOULD NOT HAVE TAKEN OFF UNTIL THE TWR HAD OFFICIALLY UPDATED THE VISIBILITY. BUT DUE TO THE PRESSURE OF THE SIT OF FEELING THE NEED TO HURRY BECAUSE OF THE POSSIBILITY OF THE WX DETERIORATING AGAIN AND THE FACT THAT I HAD OTHER AIRPLANE BEHIND ME READY FOR TKOF, I JUST PLAIN FORGOT TO ASK THE TWR FOR THE CURRENT VISIBILITY. I KNOW THAT SUCH ACTIONS MAY BE PREVENTED IN THE FUTURE BY JUST SLOWING MYSELF DOWN AND CONCENTRATING ON THE SIT AT HAND.

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.