Narrative:

The problem arose from a problem that I had during taxiing. I had gotten stuck in the mud, and wanted to expedite the departure to my destination airport. There was a sick baby and a medical crew on board, who had helped extricate the airplane from the mud. I had done a proper calculation of the accelerate stop distance under conditions present at the time, which included only a 5 KT tailwind component. By the time we had gotten unstuck from the mud, the 5 KT tailwind was as much as a 15 KT tailwind. In my hurry to depart, I heard the unicom operator say '15 KTS,' but I didn't really listen. I discovered my error on the takeoff roll. It took quite a while for the airspeed to 'come alive' at 40 KTS. I glanced downfield to assess the remaining runway, and felt that sufficient runway was left to get off. The airspeed hung for a while at 60 KTS. It was at this time that I 'discovered' that the 5 KT tailwind that I had calculated was much higher, extreme fear set in. I fought through the fear and logically assessed that the airplane was pwrful enough to make it to vr (95 KTS) by the end of the runway. It was accelerating quite well and I figured that even if I didn't make it to vr, I would certainly be above stall speed. It would be better to go off the runway above, airborne, but below VMC than it would to fail at aborting and simply fall off of the cliff at the end. As I reasoned, I made it to vr with runway left. In fact, I rotated at 115 KTS, vr + 20. I looked at the ground falling away while the gear was retracting and just knew that the tailwind was more than just 5 KTS. This was not a judgement issue. If I had judged, I would have waited for less wind. I didn't listen to the unicom winds because of my hurry to leave after being stuck in the mud. I just wanted to go. (I guess this is the opposite of 'get homeitis'.) I wanted to leave the embarrassing situation of being stuck in the mud. I didn't care what the winds were. In addition, I had the inner security of having calculated my performance already, albeit with winds that no longer existed. My own corrective action is well established. Nothing that anyone can tell me will make more of an impact than the thoughts that I had at 60 KTS and holding. For the rest of the aviation community, all that I can say is: 'tailwinds can kill!'

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Original NASA ASRS Text

Title: TKOF PROC TAILWIND TKOF FROM SINGLE RWY OP BY AIR AMBULANCE PLT IN A BE200 KING AIR.

Narrative: THE PROB AROSE FROM A PROB THAT I HAD DURING TAXIING. I HAD GOTTEN STUCK IN THE MUD, AND WANTED TO EXPEDITE THE DEP TO MY DEST ARPT. THERE WAS A SICK BABY AND A MEDICAL CREW ON BOARD, WHO HAD HELPED EXTRICATE THE AIRPLANE FROM THE MUD. I HAD DONE A PROPER CALCULATION OF THE ACCELERATE STOP DISTANCE UNDER CONDITIONS PRESENT AT THE TIME, WHICH INCLUDED ONLY A 5 KT TAILWIND COMPONENT. BY THE TIME WE HAD GOTTEN UNSTUCK FROM THE MUD, THE 5 KT TAILWIND WAS AS MUCH AS A 15 KT TAILWIND. IN MY HURRY TO DEPART, I HEARD THE UNICOM OPERATOR SAY '15 KTS,' BUT I DIDN'T REALLY LISTEN. I DISCOVERED MY ERROR ON THE TKOF ROLL. IT TOOK QUITE A WHILE FOR THE AIRSPD TO 'COME ALIVE' AT 40 KTS. I GLANCED DOWNFIELD TO ASSESS THE REMAINING RWY, AND FELT THAT SUFFICIENT RWY WAS LEFT TO GET OFF. THE AIRSPD HUNG FOR A WHILE AT 60 KTS. IT WAS AT THIS TIME THAT I 'DISCOVERED' THAT THE 5 KT TAILWIND THAT I HAD CALCULATED WAS MUCH HIGHER, EXTREME FEAR SET IN. I FOUGHT THROUGH THE FEAR AND LOGICALLY ASSESSED THAT THE AIRPLANE WAS PWRFUL ENOUGH TO MAKE IT TO VR (95 KTS) BY THE END OF THE RWY. IT WAS ACCELERATING QUITE WELL AND I FIGURED THAT EVEN IF I DIDN'T MAKE IT TO VR, I WOULD CERTAINLY BE ABOVE STALL SPD. IT WOULD BE BETTER TO GO OFF THE RWY ABOVE, AIRBORNE, BUT BELOW VMC THAN IT WOULD TO FAIL AT ABORTING AND SIMPLY FALL OFF OF THE CLIFF AT THE END. AS I REASONED, I MADE IT TO VR WITH RWY LEFT. IN FACT, I ROTATED AT 115 KTS, VR + 20. I LOOKED AT THE GND FALLING AWAY WHILE THE GEAR WAS RETRACTING AND JUST KNEW THAT THE TAILWIND WAS MORE THAN JUST 5 KTS. THIS WAS NOT A JUDGEMENT ISSUE. IF I HAD JUDGED, I WOULD HAVE WAITED FOR LESS WIND. I DIDN'T LISTEN TO THE UNICOM WINDS BECAUSE OF MY HURRY TO LEAVE AFTER BEING STUCK IN THE MUD. I JUST WANTED TO GO. (I GUESS THIS IS THE OPPOSITE OF 'GET HOMEITIS'.) I WANTED TO LEAVE THE EMBARRASSING SIT OF BEING STUCK IN THE MUD. I DIDN'T CARE WHAT THE WINDS WERE. IN ADDITION, I HAD THE INNER SECURITY OF HAVING CALCULATED MY PERFORMANCE ALREADY, ALBEIT WITH WINDS THAT NO LONGER EXISTED. MY OWN CORRECTIVE ACTION IS WELL ESTABLISHED. NOTHING THAT ANYONE CAN TELL ME WILL MAKE MORE OF AN IMPACT THAN THE THOUGHTS THAT I HAD AT 60 KTS AND HOLDING. FOR THE REST OF THE AVIATION COMMUNITY, ALL THAT I CAN SAY IS: 'TAILWINDS CAN KILL!'

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.