Narrative:

We; the crew; were not aware that we would be picking up aircraft directly from contract maintenance at sat until we were in the van on the way to the airport. When we arrived at maintenance we waited until an escort could be found to take us directly to the airplane. At the airplane the technical representative met us and told us that this had been a routine wkend check. A review of the logbook also indicated this to be the status. Each crew member performed their respective duties and a normal takeoff was made. At 100 ft AGL a loud rush of air was heard and a pressure bump was felt and heard. On the pressurization panel a climb in excess of 1500 FPM was noted for about 10 seconds; then a normal stabilized pressurization started and remained normal throughout the flight. Leveling off at FL210 and accelerating through 280 KIAS; we heard a loud thump and felt a sudden but very brief vibration. Our location was about 50 mi ene of sat. Past experience made me think that it could have been a wheel assembly or some comat in the forward cargo compartment that had fallen over. As a precaution; we did not continue to fly the airplane in excess of 280 KTS. We had not opened any compartments so we didn't have any direct information on any of the contents in the lower holds. On the postflt inspection in iah; mechanic came aboard and reported that we had access panels open and missing from the bottom of the air conditioner bays. I can only speculate as to the exact chain of events; but my best guess is that on takeoff the turbine on the air cycle machine stalled. It could have been a pack valve or just some rain from the heavy thunderstorm the night before. This unlatched; unhinged or started the uncovering of the air conditioning bay. Beyond 280 KTS these doors will not stay attached.

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Original NASA ASRS Text

Title: A B727 ON TKOF CLB AT 100 FT A PRESSURE BUMP WAS FELT AND PRESSURIZATION PANEL INDICATED 1500 FT CLB. AT FL210 HAD LOUD THUMP THEN VIBRATION. AT FLT TERMINATION GND CREW DISCOVERED AIR CONDITIONING PACK DOORS MISSING.

Narrative: WE; THE CREW; WERE NOT AWARE THAT WE WOULD BE PICKING UP ACFT DIRECTLY FROM CONTRACT MAINT AT SAT UNTIL WE WERE IN THE VAN ON THE WAY TO THE ARPT. WHEN WE ARRIVED AT MAINT WE WAITED UNTIL AN ESCORT COULD BE FOUND TO TAKE US DIRECTLY TO THE AIRPLANE. AT THE AIRPLANE THE TECHNICAL REPRESENTATIVE MET US AND TOLD US THAT THIS HAD BEEN A ROUTINE WKEND CHK. A REVIEW OF THE LOGBOOK ALSO INDICATED THIS TO BE THE STATUS. EACH CREW MEMBER PERFORMED THEIR RESPECTIVE DUTIES AND A NORMAL TKOF WAS MADE. AT 100 FT AGL A LOUD RUSH OF AIR WAS HEARD AND A PRESSURE BUMP WAS FELT AND HEARD. ON THE PRESSURIZATION PANEL A CLB IN EXCESS OF 1500 FPM WAS NOTED FOR ABOUT 10 SECONDS; THEN A NORMAL STABILIZED PRESSURIZATION STARTED AND REMAINED NORMAL THROUGHOUT THE FLT. LEVELING OFF AT FL210 AND ACCELERATING THROUGH 280 KIAS; WE HEARD A LOUD THUMP AND FELT A SUDDEN BUT VERY BRIEF VIBRATION. OUR LOCATION WAS ABOUT 50 MI ENE OF SAT. PAST EXPERIENCE MADE ME THINK THAT IT COULD HAVE BEEN A WHEEL ASSEMBLY OR SOME COMAT IN THE FORWARD CARGO COMPARTMENT THAT HAD FALLEN OVER. AS A PRECAUTION; WE DID NOT CONTINUE TO FLY THE AIRPLANE IN EXCESS OF 280 KTS. WE HAD NOT OPENED ANY COMPARTMENTS SO WE DIDN'T HAVE ANY DIRECT INFO ON ANY OF THE CONTENTS IN THE LOWER HOLDS. ON THE POSTFLT INSPECTION IN IAH; MECH CAME ABOARD AND RPTED THAT WE HAD ACCESS PANELS OPEN AND MISSING FROM THE BOTTOM OF THE AIR CONDITIONER BAYS. I CAN ONLY SPECULATE AS TO THE EXACT CHAIN OF EVENTS; BUT MY BEST GUESS IS THAT ON TKOF THE TURBINE ON THE AIR CYCLE MACHINE STALLED. IT COULD HAVE BEEN A PACK VALVE OR JUST SOME RAIN FROM THE HVY TSTM THE NIGHT BEFORE. THIS UNLATCHED; UNHINGED OR STARTED THE UNCOVERING OF THE AIR CONDITIONING BAY. BEYOND 280 KTS THESE DOORS WILL NOT STAY ATTACHED.

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.