Narrative:

While working as a dispatcher, I received a call from one of my flts stating that his anti-skid system had failed while awaiting takeoff and needed dispatch approval before proceeding. Up until recently, it would have been necessary for the flight to return to the gate and have a mechanic placard the system and make a logbook entry. However, under a recent company policy, approved by the FAA, certain items that don't require a maintenance function may be placarded by the flight crew without returning to the gate. To determine if maintenance action was necessary, I consulted the MEL for the aircraft. The book lists the description of the item to be deferred, in this case, anti-skid system, the system number, and provisions for operating with the system inoperative. If there was a maintenance function required, the letter 'M' would appear next to the item, if there was a flight crew function the letter 'O' would appear. In quickly looking for the item, I found the item, anti-skid system, the number and the letter 'O' next to it meaning there was no maintenance function required. What I didn't realize, I was looking at a provision for operating with the anti-skid system inoperative for improved takeoff performance, which was formatted identical to the MEL item but was not actually an MEL item. The actual MEL item was listed above, with the letter 'M' beside it, which meant the flight must return to the gate and the item be deferred by a mechanic. I advised the flight, unknowingly, that they could placard the item and continue on. I probably would have never realized my error, but on landing rollout at the destination airport, the aircraft blew 3 tires. Because of this event, I reviewed the MEL procedure and rechked the performance data. The aircraft was within the operating limitations with the system inoperative, but had not followed the correct procedure in deferring the item. If I had gotten maintenance involved, they may have been able to resolve the problem with the anti-skid system and the situation avoided. My error was caused by not taking the time to fully read and review the item. In my haste, I was looking for the item and whether or no it had an 'M' or 'O' beside it, without reading it completely. The ambiguity in the format also caused my error, which I have brought to the attention of management and is under review. Supplemental information from acn 263058. On taxi out from the gate at kmsp our B737-300 aircraft had the 'autobrake disarm light' illuminate simultaneously with the 'anti-skid off' light. I announced it to the captain. He said this aircraft had a previous write-up of an anti-skid problem, so we got out the pilot's operating manual (pom) and accomplished the appropriate items for anti-skid inoperative when turning the autobrake switch to 'off' from 'ro' this light extinguished. The captain went off frequency to consult with the dispatcher about this problem on the company radio frequency. The captain completed his discussion with the dispatcher and told me that flight control concurred the takeoff was safe and that they checked the landing weights at slc and that we would be safe (and legal) for an anti-skid out landing there. The runway was covered with about 1/2 inch of wet slush. Deceleration was normal and I gently applied the brakes at about 110 KTS. Tower asked us to exit on the high speed as landing traffic was close behind us. The captain increased braking to attempt to comply. We both said something to each other about not being able to make this turnoff. I noticed the aircraft pointing to the left in an ever increasing angle and sliding down the runway. Tower again asked us if we cold make the turnoff and all I could reply was 'negative.' the aircraft acted like it had a stuck brake. I told that information to the tower, and that we would be unable to taxi. The aircraft was towed to the gate. I think the primary cause of this incident was brakes locking due to the lack of anti-skid. Secondary causes include: the pilot's instinctive reaction to an ATC request to turn off at an early taxiway. The fact that we did not communicate that we had the a-skid off to ATC and would require abnormal rollout procedures. This is usually not a problem.

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Original NASA ASRS Text

Title: DISPATCHER MISREADS MEL, DISPATCHES ACFT. 3 TIRES BLOW ON LNDG.

Narrative: WHILE WORKING AS A DISPATCHER, I RECEIVED A CALL FROM ONE OF MY FLTS STATING THAT HIS ANTI-SKID SYS HAD FAILED WHILE AWAITING TKOF AND NEEDED DISPATCH APPROVAL BEFORE PROCEEDING. UP UNTIL RECENTLY, IT WOULD HAVE BEEN NECESSARY FOR THE FLT TO RETURN TO THE GATE AND HAVE A MECH PLACARD THE SYS AND MAKE A LOGBOOK ENTRY. HOWEVER, UNDER A RECENT COMPANY POLICY, APPROVED BY THE FAA, CERTAIN ITEMS THAT DON'T REQUIRE A MAINT FUNCTION MAY BE PLACARDED BY THE FLC WITHOUT RETURNING TO THE GATE. TO DETERMINE IF MAINT ACTION WAS NECESSARY, I CONSULTED THE MEL FOR THE ACFT. THE BOOK LISTS THE DESCRIPTION OF THE ITEM TO BE DEFERRED, IN THIS CASE, ANTI-SKID SYS, THE SYS NUMBER, AND PROVISIONS FOR OPERATING WITH THE SYS INOP. IF THERE WAS A MAINT FUNCTION REQUIRED, THE LETTER 'M' WOULD APPEAR NEXT TO THE ITEM, IF THERE WAS A FLC FUNCTION THE LETTER 'O' WOULD APPEAR. IN QUICKLY LOOKING FOR THE ITEM, I FOUND THE ITEM, ANTI-SKID SYS, THE NUMBER AND THE LETTER 'O' NEXT TO IT MEANING THERE WAS NO MAINT FUNCTION REQUIRED. WHAT I DIDN'T REALIZE, I WAS LOOKING AT A PROVISION FOR OPERATING WITH THE ANTI-SKID SYS INOP FOR IMPROVED TKOF PERFORMANCE, WHICH WAS FORMATTED IDENTICAL TO THE MEL ITEM BUT WAS NOT ACTUALLY AN MEL ITEM. THE ACTUAL MEL ITEM WAS LISTED ABOVE, WITH THE LETTER 'M' BESIDE IT, WHICH MEANT THE FLT MUST RETURN TO THE GATE AND THE ITEM BE DEFERRED BY A MECH. I ADVISED THE FLT, UNKNOWINGLY, THAT THEY COULD PLACARD THE ITEM AND CONTINUE ON. I PROBABLY WOULD HAVE NEVER REALIZED MY ERROR, BUT ON LNDG ROLLOUT AT THE DEST ARPT, THE ACFT BLEW 3 TIRES. BECAUSE OF THIS EVENT, I REVIEWED THE MEL PROC AND RECHKED THE PERFORMANCE DATA. THE ACFT WAS WITHIN THE OPERATING LIMITATIONS WITH THE SYS INOP, BUT HAD NOT FOLLOWED THE CORRECT PROC IN DEFERRING THE ITEM. IF I HAD GOTTEN MAINT INVOLVED, THEY MAY HAVE BEEN ABLE TO RESOLVE THE PROB WITH THE ANTI-SKID SYS AND THE SIT AVOIDED. MY ERROR WAS CAUSED BY NOT TAKING THE TIME TO FULLY READ AND REVIEW THE ITEM. IN MY HASTE, I WAS LOOKING FOR THE ITEM AND WHETHER OR NO IT HAD AN 'M' OR 'O' BESIDE IT, WITHOUT READING IT COMPLETELY. THE AMBIGUITY IN THE FORMAT ALSO CAUSED MY ERROR, WHICH I HAVE BROUGHT TO THE ATTN OF MGMNT AND IS UNDER REVIEW. SUPPLEMENTAL INFO FROM ACN 263058. ON TAXI OUT FROM THE GATE AT KMSP OUR B737-300 ACFT HAD THE 'AUTOBRAKE DISARM LIGHT' ILLUMINATE SIMULTANEOUSLY WITH THE 'ANTI-SKID OFF' LIGHT. I ANNOUNCED IT TO THE CAPT. HE SAID THIS ACFT HAD A PREVIOUS WRITE-UP OF AN ANTI-SKID PROB, SO WE GOT OUT THE PLT'S OPERATING MANUAL (POM) AND ACCOMPLISHED THE APPROPRIATE ITEMS FOR ANTI-SKID INOP WHEN TURNING THE AUTOBRAKE SWITCH TO 'OFF' FROM 'RO' THIS LIGHT EXTINGUISHED. THE CAPT WENT OFF FREQ TO CONSULT WITH THE DISPATCHER ABOUT THIS PROB ON THE COMPANY RADIO FREQ. THE CAPT COMPLETED HIS DISCUSSION WITH THE DISPATCHER AND TOLD ME THAT FLT CTL CONCURRED THE TKOF WAS SAFE AND THAT THEY CHKED THE LNDG WTS AT SLC AND THAT WE WOULD BE SAFE (AND LEGAL) FOR AN ANTI-SKID OUT LNDG THERE. THE RWY WAS COVERED WITH ABOUT 1/2 INCH OF WET SLUSH. DECELERATION WAS NORMAL AND I GENTLY APPLIED THE BRAKES AT ABOUT 110 KTS. TWR ASKED US TO EXIT ON THE HIGH SPD AS LNDG TFC WAS CLOSE BEHIND US. THE CAPT INCREASED BRAKING TO ATTEMPT TO COMPLY. WE BOTH SAID SOMETHING TO EACH OTHER ABOUT NOT BEING ABLE TO MAKE THIS TURNOFF. I NOTICED THE ACFT POINTING TO THE L IN AN EVER INCREASING ANGLE AND SLIDING DOWN THE RWY. TWR AGAIN ASKED US IF WE COLD MAKE THE TURNOFF AND ALL I COULD REPLY WAS 'NEGATIVE.' THE ACFT ACTED LIKE IT HAD A STUCK BRAKE. I TOLD THAT INFO TO THE TWR, AND THAT WE WOULD BE UNABLE TO TAXI. THE ACFT WAS TOWED TO THE GATE. I THINK THE PRIMARY CAUSE OF THIS INCIDENT WAS BRAKES LOCKING DUE TO THE LACK OF ANTI-SKID. SECONDARY CAUSES INCLUDE: THE PLT'S INSTINCTIVE REACTION TO AN ATC REQUEST TO TURN OFF AT AN EARLY TXWY. THE FACT THAT WE DID NOT COMMUNICATE THAT WE HAD THE A-SKID OFF TO ATC AND WOULD REQUIRE ABNORMAL ROLLOUT PROCS. THIS IS USUALLY NOT A PROB.

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.