Narrative:

Our aircraft weighed approximately 154200 pounds at pushback. Sky was sunny. Engine manifold pressure 35 degrees C (using onboard sat reading). After stopping in line-up at point described above, aircraft would not move using more than normal taxi power. Aircraft behind complained of jet blast, ground created clear space. Aircraft still wouldn't move using well above normal taxi power (2 engines). 40% N1 is normal, we tried 68% N1. Called for tug, tow bar shear pin brake. Deplaned passenger, broke another tow bar. Restarted engines with only flight crew onboard (pilots and flight attendants) and with aircraft weight now approximately 30000 pounds less, we broke free at +/-75% N1. We taxied to known solid spot on ramp. Mechanic and I inspected aircraft gear and tires, reboarded flight, taxied for takeoff and flew to destination. Lessons learned: lga has soft spots on txwys on hot days. (We sank 6 inches into taxiway.) B737-800 has heavy footprint (my guesstimate had us near 2000 psi). Nyc port authority/authorized was responsive and helpful (very). Same for lga ground control and my company's local ramp personnel. B737-800 tow bar shear pin shears easily (too easily?). Ideas to prevent recurrence: with correct technical data, certain aircraft types idented as heavy footprint types could, on hot days: 1) be held at gate until expeditious taxi to takeoff or known solid holding area is possible (much like lga's de-/anti-icing program). 2) be routed over known solid txwys. 3) re-pave lga's txwys with concrete. The cost of any program to prevent aircraft getting stuck in lga's asphalt would have to be weighed against the threat of such recurrence. I don't think what happened to us is an everyday event. That's a good thing -- because it wasn't fun!

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Original NASA ASRS Text

Title: B737-800 FLC BECAME STRANDED ON TXWY DURING TAXI OUT DUE TO SINKING INTO ASPHALT TXWY AFTER HOLDING FOR TKOF.

Narrative: OUR ACFT WEIGHED APPROX 154200 LBS AT PUSHBACK. SKY WAS SUNNY. ENG MANIFOLD PRESSURE 35 DEGS C (USING ONBOARD SAT READING). AFTER STOPPING IN LINE-UP AT POINT DESCRIBED ABOVE, ACFT WOULD NOT MOVE USING MORE THAN NORMAL TAXI PWR. ACFT BEHIND COMPLAINED OF JET BLAST, GND CREATED CLR SPACE. ACFT STILL WOULDN'T MOVE USING WELL ABOVE NORMAL TAXI PWR (2 ENGS). 40% N1 IS NORMAL, WE TRIED 68% N1. CALLED FOR TUG, TOW BAR SHEAR PIN BRAKE. DEPLANED PAX, BROKE ANOTHER TOW BAR. RESTARTED ENGS WITH ONLY FLC ONBOARD (PLTS AND FLT ATTENDANTS) AND WITH ACFT WT NOW APPROX 30000 LBS LESS, WE BROKE FREE AT +/-75% N1. WE TAXIED TO KNOWN SOLID SPOT ON RAMP. MECH AND I INSPECTED ACFT GEAR AND TIRES, REBOARDED FLT, TAXIED FOR TKOF AND FLEW TO DEST. LESSONS LEARNED: LGA HAS SOFT SPOTS ON TXWYS ON HOT DAYS. (WE SANK 6 INCHES INTO TXWY.) B737-800 HAS HVY FOOTPRINT (MY GUESSTIMATE HAD US NEAR 2000 PSI). NYC PORT AUTH WAS RESPONSIVE AND HELPFUL (VERY). SAME FOR LGA GND CTL AND MY COMPANY'S LCL RAMP PERSONNEL. B737-800 TOW BAR SHEAR PIN SHEARS EASILY (TOO EASILY?). IDEAS TO PREVENT RECURRENCE: WITH CORRECT TECHNICAL DATA, CERTAIN ACFT TYPES IDENTED AS HVY FOOTPRINT TYPES COULD, ON HOT DAYS: 1) BE HELD AT GATE UNTIL EXPEDITIOUS TAXI TO TKOF OR KNOWN SOLID HOLDING AREA IS POSSIBLE (MUCH LIKE LGA'S DE-/ANTI-ICING PROGRAM). 2) BE ROUTED OVER KNOWN SOLID TXWYS. 3) RE-PAVE LGA'S TXWYS WITH CONCRETE. THE COST OF ANY PROGRAM TO PREVENT ACFT GETTING STUCK IN LGA'S ASPHALT WOULD HAVE TO BE WEIGHED AGAINST THE THREAT OF SUCH RECURRENCE. I DON'T THINK WHAT HAPPENED TO US IS AN EVERYDAY EVENT. THAT'S A GOOD THING -- BECAUSE IT WASN'T FUN!

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.