Narrative:

While taxiing for takeoff we were nearing the departure end of the runway while back taxiing. Needing to make a 180 degree turn for takeoff; I noticed that the normal 60 ft wide runway was getting noticeably narrower as I neared the end. This appeared to be from grass growing on and through some cracks near the edge of the runway and growing inward about 4-5 ft toward the center of the runway. As things looked to be getting tight for the 180 degree turn; I tried to stay near the edge of the runway surface which meant rolling over some of the grass. As I approached the turning point; the right main gear started to become stuck and the aircraft would not turn left. As I tried to turn left; the aircraft continued drifting to the right and got stuck. After exiting the airplane; we saw that what we thought was the runway was in fact there but the asphalt crumbled and broke under the weight of the airplane. I can only assume that the grass that grew into and on the runway weakened the runway surface enough not to be able to support our airplane. We needed assistance to get the airplane out of the sinking area and then continued on an uneventful flight. I will never again trust that nearing the edge of a runway with grass growing through the cracks; that it still has all of its strength. Callback conversation with reporter revealed the following ingo: pilot stated that the normal runway width is 60 ft; but where the vegetation is growing through the runway surface; the usable width is about 48 ft. His aircraft weight at the time was about 11300 pounds. He estimates that the wheel weight was about 4500 pounds. In order to free the aircraft; the volunteer fire department used an airbag under the wing. While attempting to pull the aircraft out with a tug; it actually became more deeply stuck. The airport has very little jet traffic; but does occasionally.

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Original NASA ASRS Text

Title: A CESSNA CITATION'S R LNDG GEAR SANK INTO A VEGETATION SOFTENED RWY SURFACE AT 2R9.

Narrative: WHILE TAXIING FOR TKOF WE WERE NEARING THE DEP END OF THE RWY WHILE BACK TAXIING. NEEDING TO MAKE A 180 DEG TURN FOR TKOF; I NOTICED THAT THE NORMAL 60 FT WIDE RWY WAS GETTING NOTICEABLY NARROWER AS I NEARED THE END. THIS APPEARED TO BE FROM GRASS GROWING ON AND THROUGH SOME CRACKS NEAR THE EDGE OF THE RWY AND GROWING INWARD ABOUT 4-5 FT TOWARD THE CENTER OF THE RWY. AS THINGS LOOKED TO BE GETTING TIGHT FOR THE 180 DEG TURN; I TRIED TO STAY NEAR THE EDGE OF THE RWY SURFACE WHICH MEANT ROLLING OVER SOME OF THE GRASS. AS I APCHED THE TURNING POINT; THE R MAIN GEAR STARTED TO BECOME STUCK AND THE ACFT WOULD NOT TURN L. AS I TRIED TO TURN L; THE ACFT CONTINUED DRIFTING TO THE R AND GOT STUCK. AFTER EXITING THE AIRPLANE; WE SAW THAT WHAT WE THOUGHT WAS THE RWY WAS IN FACT THERE BUT THE ASPHALT CRUMBLED AND BROKE UNDER THE WEIGHT OF THE AIRPLANE. I CAN ONLY ASSUME THAT THE GRASS THAT GREW INTO AND ON THE RWY WEAKENED THE RWY SURFACE ENOUGH NOT TO BE ABLE TO SUPPORT OUR AIRPLANE. WE NEEDED ASSISTANCE TO GET THE AIRPLANE OUT OF THE SINKING AREA AND THEN CONTINUED ON AN UNEVENTFUL FLT. I WILL NEVER AGAIN TRUST THAT NEARING THE EDGE OF A RWY WITH GRASS GROWING THROUGH THE CRACKS; THAT IT STILL HAS ALL OF ITS STRENGTH. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INGO: PLT STATED THAT THE NORMAL RWY WIDTH IS 60 FT; BUT WHERE THE VEGETATION IS GROWING THROUGH THE RWY SURFACE; THE USABLE WIDTH IS ABOUT 48 FT. HIS ACFT WEIGHT AT THE TIME WAS ABOUT 11300 LBS. HE ESTIMATES THAT THE WHEEL WEIGHT WAS ABOUT 4500 LBS. IN ORDER TO FREE THE ACFT; THE VOLUNTEER FIRE DEPT USED AN AIRBAG UNDER THE WING. WHILE ATTEMPTING TO PULL THE ACFT OUT WITH A TUG; IT ACTUALLY BECAME MORE DEEPLY STUCK. THE ARPT HAS VERY LITTLE JET TFC; BUT DOES OCCASIONALLY.

Data retrieved from NASA's ASRS site as of January 2009 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.