Narrative:

Upon arriving at the aircraft at approximately XX00 am in ZZZ we noticed several ceiling panels were removed inside the passenger cabin and both engine and APU bleed switches had placards warning 'not to operate.' logbook not in the aircraft. After a period of time, several mechanics arrived and informed us that the aircraft was going to be removed from the gate for operational test of the pneumatic and pressurization system. Inbound crew that night had written a discrepancy for the left wing anti-ice valve and a loud noise near mid cabin during flight. When we reboarded the aircraft, we found that the left wing anti-ice valve was already locked open and placed on MEL and maintenance was finishing with the logbook. Prior to boarding the aircraft I was watching the mechanic technician manually open the wing anti- ice valve and disconnect the cannon plug securing it with a tie wrap. After reviewing the logbook and thoroughly reading through the MEL procedure, the first officer and I had some questions as to the procedures and limitations provided under the action and exceptions column of the MEL. 1) how could we comply with the MEL procedure that called for the anti-ice valve in question to be closed during the #2 engine start when maintenance had just finished locking the valve open and secured the access panel. 2) what is the purpose for the xbleed start of the #1 engine. 3) since the procedure would require starting at least 1 engine with the wing anti-ice valve open, how were we going to operate out of ZZZ where their metar was already reporting a temperature of 12 degrees C, exceeding the aircraft tai limitation of 10 degrees C. Manifold must be depressurized anytime temperature is above 10 degrees C. (How could we start the #1 engine without exceeding the limitation in the MEL procedure.) I contacted xyz in maintenance control reference these questions, this was after conversing with ZZZ maintenance at great length about the above issues over the radio before opting to take the MEL book into operations and communicating with YYY maintenance via the phone. After considerable time on the phone with xyz in YYY maintenance control, I was assured that the current temperature in ZZZ would provide necessary pressure and temperature protection for engine start in ZZZ and he would notify ZZZ. The first officer and I discussed at great length the implications of flying the aircraft to ZZZ within the limitations of the MEL. We decided that we had explained our position clearly to YYY maintenance and were told quite simply that we were 'ok to leave ZZZ.' after pushback we attempted to start the #2 engine but only made 15% N2 with 12 psi showing on the duct pressure gauge. I aborted the start and closed the APU bleed valve. It was questionable about whether or not 30 psi would be enough pressure to start. I told the first officer to contact ZZZ maintenance via radio. After contacting ZZZ maintenance, they requested we cycle the APU bleed switch several times. Maintenance then requested we try several other bleed switch position while trying to isolate a possible bleed leak in the pneumatic system. They insisted that the engine should start with the wing anti-ice valve locked open, that there should be sufficient air pressure. Ground control called and informed us that flow control was now in progress for ZZZ and to state our intentions. The first officer was trying to communicate with maintenance and operations relaying information to me while I was monitoring ground control. I was talking to the tug driver for a tow to the gate and gathering information as to where to park the aircraft. During this time the APU bleed valve was left open. As we were being towed back to the gate, maintenance personnel on the ground were trying to get our attention. Flight attendants reported that something in the cabin smelled very hot. I opened my window and mechanics were telling us to close the APU bleed valve. A tremendous amount of heat was radiating off of left wing leading edge. Passenger noticed smoke from left wing area. Several passenger deplaned after seeing the smoke as we opened the left forward exit. I was concerned as to the damage to the left wing leading edge devices because there is no overheat protection with the anti-ice valve locked open and cannon plug disconnected. ZZZ maintenance extended the leading edge devicesand no visible damage was noticed. A maintenance technician informed me that while I was in operations, they had hooked up an air start cart and insufficient air pressure was available for start. At first, they kept insisting that the anti-ice valve was locked closed, but they were looking at the wrong valve. I went outside to the location of the access panel which covers the wing anti-ice valve and they had opened a panel right next to the correct access panel covering the wing valve. The leading edge was then inspected for damage again per a phone communication with boeing, as explained to me by the maintenance manager in ZZZ who met with me in the crew lounge. They insisted that the aircraft was returned to service and a full boat of passenger was waiting to depart. Upon further review of the logbook, no corrective action or inspections had been logged. There was no technical data to support maintenance's inspection of the aircraft for damage. My discrepancy, recorded in the logbook, indicated possible overheat to the left leading edge devices, because of the valve being locked open during initial start attempt. After discussing this situation with more than a dozen individuals in dispatch, system operation control, maintenance control, and flight operations, abc in the office of the chief pilot, supported my decision not to accept the aircraft for dispatch.

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Original NASA ASRS Text

Title: A B737-300 WITH THE L WING AIRFOIL ANTI-ICE VALVE INOP LOCKED OPEN AND DEFERRED, THE L WING OVERHEATED WHEN THE APU BLEED AIR WAS USED FOR STARTING.

Narrative: UPON ARRIVING AT THE ACFT AT APPROX XX00 AM IN ZZZ WE NOTICED SEVERAL CEILING PANELS WERE REMOVED INSIDE THE PAX CABIN AND BOTH ENG AND APU BLEED SWITCHES HAD PLACARDS WARNING 'NOT TO OPERATE.' LOGBOOK NOT IN THE ACFT. AFTER A PERIOD OF TIME, SEVERAL MECHS ARRIVED AND INFORMED US THAT THE ACFT WAS GOING TO BE REMOVED FROM THE GATE FOR OPERATIONAL TEST OF THE PNEUMATIC AND PRESSURIZATION SYS. INBOUND CREW THAT NIGHT HAD WRITTEN A DISCREPANCY FOR THE L WING ANTI-ICE VALVE AND A LOUD NOISE NEAR MID CABIN DURING FLT. WHEN WE REBOARDED THE ACFT, WE FOUND THAT THE L WING ANTI-ICE VALVE WAS ALREADY LOCKED OPEN AND PLACED ON MEL AND MAINT WAS FINISHING WITH THE LOGBOOK. PRIOR TO BOARDING THE ACFT I WAS WATCHING THE MECH TECHNICIAN MANUALLY OPEN THE WING ANTI- ICE VALVE AND DISCONNECT THE CANNON PLUG SECURING IT WITH A TIE WRAP. AFTER REVIEWING THE LOGBOOK AND THOROUGHLY READING THROUGH THE MEL PROC, THE FO AND I HAD SOME QUESTIONS AS TO THE PROCS AND LIMITATIONS PROVIDED UNDER THE ACTION AND EXCEPTIONS COLUMN OF THE MEL. 1) HOW COULD WE COMPLY WITH THE MEL PROC THAT CALLED FOR THE ANTI-ICE VALVE IN QUESTION TO BE CLOSED DURING THE #2 ENG START WHEN MAINT HAD JUST FINISHED LOCKING THE VALVE OPEN AND SECURED THE ACCESS PANEL. 2) WHAT IS THE PURPOSE FOR THE XBLEED START OF THE #1 ENG. 3) SINCE THE PROC WOULD REQUIRE STARTING AT LEAST 1 ENG WITH THE WING ANTI-ICE VALVE OPEN, HOW WERE WE GOING TO OPERATE OUT OF ZZZ WHERE THEIR METAR WAS ALREADY RPTING A TEMP OF 12 DEGS C, EXCEEDING THE ACFT TAI LIMITATION OF 10 DEGS C. MANIFOLD MUST BE DEPRESSURIZED ANYTIME TEMP IS ABOVE 10 DEGS C. (HOW COULD WE START THE #1 ENG WITHOUT EXCEEDING THE LIMITATION IN THE MEL PROC.) I CONTACTED XYZ IN MAINT CTL REF THESE QUESTIONS, THIS WAS AFTER CONVERSING WITH ZZZ MAINT AT GREAT LENGTH ABOUT THE ABOVE ISSUES OVER THE RADIO BEFORE OPTING TO TAKE THE MEL BOOK INTO OPS AND COMMUNICATING WITH YYY MAINT VIA THE PHONE. AFTER CONSIDERABLE TIME ON THE PHONE WITH XYZ IN YYY MAINT CTL, I WAS ASSURED THAT THE CURRENT TEMP IN ZZZ WOULD PROVIDE NECESSARY PRESSURE AND TEMP PROTECTION FOR ENG START IN ZZZ AND HE WOULD NOTIFY ZZZ. THE FO AND I DISCUSSED AT GREAT LENGTH THE IMPLICATIONS OF FLYING THE ACFT TO ZZZ WITHIN THE LIMITATIONS OF THE MEL. WE DECIDED THAT WE HAD EXPLAINED OUR POS CLEARLY TO YYY MAINT AND WERE TOLD QUITE SIMPLY THAT WE WERE 'OK TO LEAVE ZZZ.' AFTER PUSHBACK WE ATTEMPTED TO START THE #2 ENG BUT ONLY MADE 15% N2 WITH 12 PSI SHOWING ON THE DUCT PRESSURE GAUGE. I ABORTED THE START AND CLOSED THE APU BLEED VALVE. IT WAS QUESTIONABLE ABOUT WHETHER OR NOT 30 PSI WOULD BE ENOUGH PRESSURE TO START. I TOLD THE FO TO CONTACT ZZZ MAINT VIA RADIO. AFTER CONTACTING ZZZ MAINT, THEY REQUESTED WE CYCLE THE APU BLEED SWITCH SEVERAL TIMES. MAINT THEN REQUESTED WE TRY SEVERAL OTHER BLEED SWITCH POS WHILE TRYING TO ISOLATE A POSSIBLE BLEED LEAK IN THE PNEUMATIC SYS. THEY INSISTED THAT THE ENG SHOULD START WITH THE WING ANTI-ICE VALVE LOCKED OPEN, THAT THERE SHOULD BE SUFFICIENT AIR PRESSURE. GND CTL CALLED AND INFORMED US THAT FLOW CTL WAS NOW IN PROGRESS FOR ZZZ AND TO STATE OUR INTENTIONS. THE FO WAS TRYING TO COMMUNICATE WITH MAINT AND OPS RELAYING INFO TO ME WHILE I WAS MONITORING GND CTL. I WAS TALKING TO THE TUG DRIVER FOR A TOW TO THE GATE AND GATHERING INFO AS TO WHERE TO PARK THE ACFT. DURING THIS TIME THE APU BLEED VALVE WAS LEFT OPEN. AS WE WERE BEING TOWED BACK TO THE GATE, MAINT PERSONNEL ON THE GND WERE TRYING TO GET OUR ATTN. FLT ATTENDANTS RPTED THAT SOMETHING IN THE CABIN SMELLED VERY HOT. I OPENED MY WINDOW AND MECHS WERE TELLING US TO CLOSE THE APU BLEED VALVE. A TREMENDOUS AMOUNT OF HEAT WAS RADIATING OFF OF L WING LEADING EDGE. PAX NOTICED SMOKE FROM L WING AREA. SEVERAL PAX DEPLANED AFTER SEEING THE SMOKE AS WE OPENED THE L FORWARD EXIT. I WAS CONCERNED AS TO THE DAMAGE TO THE L WING LEADING EDGE DEVICES BECAUSE THERE IS NO OVERHEAT PROTECTION WITH THE ANTI-ICE VALVE LOCKED OPEN AND CANNON PLUG DISCONNECTED. ZZZ MAINT EXTENDED THE LEADING EDGE DEVICESAND NO VISIBLE DAMAGE WAS NOTICED. A MAINT TECHNICIAN INFORMED ME THAT WHILE I WAS IN OPS, THEY HAD HOOKED UP AN AIR START CART AND INSUFFICIENT AIR PRESSURE WAS AVAILABLE FOR START. AT FIRST, THEY KEPT INSISTING THAT THE ANTI-ICE VALVE WAS LOCKED CLOSED, BUT THEY WERE LOOKING AT THE WRONG VALVE. I WENT OUTSIDE TO THE LOCATION OF THE ACCESS PANEL WHICH COVERS THE WING ANTI-ICE VALVE AND THEY HAD OPENED A PANEL RIGHT NEXT TO THE CORRECT ACCESS PANEL COVERING THE WING VALVE. THE LEADING EDGE WAS THEN INSPECTED FOR DAMAGE AGAIN PER A PHONE COM WITH BOEING, AS EXPLAINED TO ME BY THE MAINT MGR IN ZZZ WHO MET WITH ME IN THE CREW LOUNGE. THEY INSISTED THAT THE ACFT WAS RETURNED TO SVC AND A FULL BOAT OF PAX WAS WAITING TO DEPART. UPON FURTHER REVIEW OF THE LOGBOOK, NO CORRECTIVE ACTION OR INSPECTIONS HAD BEEN LOGGED. THERE WAS NO TECHNICAL DATA TO SUPPORT MAINT'S INSPECTION OF THE ACFT FOR DAMAGE. MY DISCREPANCY, RECORDED IN THE LOGBOOK, INDICATED POSSIBLE OVERHEAT TO THE L LEADING EDGE DEVICES, BECAUSE OF THE VALVE BEING LOCKED OPEN DURING INITIAL START ATTEMPT. AFTER DISCUSSING THIS SIT WITH MORE THAN A DOZEN INDIVIDUALS IN DISPATCH, SYS OP CTL, MAINT CTL, AND FLT OPS, ABC IN THE OFFICE OF THE CHIEF PLT, SUPPORTED MY DECISION NOT TO ACCEPT THE ACFT FOR DISPATCH.

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.