Narrative:

During the application of power for takeoff, and after stabilizing the engine power, the aircraft made a violent and rapid turn to the left. Despite the application of full abort procedures, including full brake application, the aircraft's left side departed the runway at which point some control was regained. By applying a small amount of forward thrust it was possible to keep the airplane moving and steer it back on to the runway. An inspection of the gear revealed #'south 2 and 4 tires deflated on the left side. I believe that the initial swing was caused by these tires deflating prior to takeoff. The very wet conditions, light aircraft weight, and aft center of gravity contributed to the difficulty in stopping the aircraft. Due to continual high landing weights, most B747 cargo aircraft are fitted with 200 series heavy duty gear. This aircraft had the less durable 100 series gear. The aircraft had made a maximum weight landing at XA10Z, followed by another at XG56 followed by a 3 mi taxi prior to the incident. Therefore, the tire failures were probably caused by accumulative heat build up. Because of the 'light gear' fitted to the aircraft, brake temperature gauges are installed on these type aircraft. However, the company recently permanently de-activated these on the grounds of cost. Had these gauges been working, the crew might have had some warning of the heat build-up. I recommend they be re-activated. Callback conversation with reporter revealed the following information: subject aircraft was repaired (tires changed), but afterward on several subsequent flts, had similar problems. Sometimes the aircraft would swerve rapidly to the left with or without flat tires. Reporter's company maintenance never did find the problem. But, after selling the aircraft to another air carrier, and, when it was going through 'C' check, it finally was discovered that faulty anti-skid modules on the left gear were causing the problem. Until the faulty anti- skid was discovered, reporter attributed the problem to heat build-up caused by lndgs at maximum weights and a very long taxi. Post incident follow-up the reporter checked the brake/weight charts and determined that the brakes should have been cool. However, with malfunctioning anti-skid modules, hot brakes could have resulted with the blown tires. Reporter faults his company maintenance for not discovering the problem during their troubleshooting. Reporter is a check airman and has discussed at length the landing gear swerving with his fellow lca's. Reporter's company has no intention of reactivating the brake temperature gauge or replacing the 100 series landing gear with the more substantial and reliable 200 series.

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Original NASA ASRS Text

Title: A B747 CAPT REPORTED THAT THE ACFT MONENTARILY DEPARTED THE RWY DURING TKOF ROLL AT GIG, WHICH WAS LATER FOUND TO BE DUE TO FAULTY ANTI-SKID MODULES.

Narrative: DURING THE APPLICATION OF PWR FOR TKOF, AND AFTER STABILIZING THE ENG PWR, THE ACFT MADE A VIOLENT AND RAPID TURN TO THE L. DESPITE THE APPLICATION OF FULL ABORT PROCS, INCLUDING FULL BRAKE APPLICATION, THE ACFT'S L SIDE DEPARTED THE RWY AT WHICH POINT SOME CTL WAS REGAINED. BY APPLYING A SMALL AMOUNT OF FORWARD THRUST IT WAS POSSIBLE TO KEEP THE AIRPLANE MOVING AND STEER IT BACK ON TO THE RWY. AN INSPECTION OF THE GEAR REVEALED #'S 2 AND 4 TIRES DEFLATED ON THE L SIDE. I BELIEVE THAT THE INITIAL SWING WAS CAUSED BY THESE TIRES DEFLATING PRIOR TO TKOF. THE VERY WET CONDITIONS, LIGHT ACFT WEIGHT, AND AFT CTR OF GRAVITY CONTRIBUTED TO THE DIFFICULTY IN STOPPING THE ACFT. DUE TO CONTINUAL HIGH LNDG WEIGHTS, MOST B747 CARGO ACFT ARE FITTED WITH 200 SERIES HVY DUTY GEAR. THIS ACFT HAD THE LESS DURABLE 100 SERIES GEAR. THE ACFT HAD MADE A MAX WT LNDG AT XA10Z, FOLLOWED BY ANOTHER AT XG56 FOLLOWED BY A 3 MI TAXI PRIOR TO THE INCIDENT. THEREFORE, THE TIRE FAILURES WERE PROBABLY CAUSED BY ACCUMULATIVE HEAT BUILD UP. BECAUSE OF THE 'LIGHT GEAR' FITTED TO THE ACFT, BRAKE TEMP GAUGES ARE INSTALLED ON THESE TYPE ACFT. HOWEVER, THE COMPANY RECENTLY PERMANENTLY DE-ACTIVATED THESE ON THE GROUNDS OF COST. HAD THESE GAUGES BEEN WORKING, THE CREW MIGHT HAVE HAD SOME WARNING OF THE HEAT BUILD-UP. I RECOMMEND THEY BE RE-ACTIVATED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: SUBJECT ACFT WAS REPAIRED (TIRES CHANGED), BUT AFTERWARD ON SEVERAL SUBSEQUENT FLTS, HAD SIMILAR PROBS. SOMETIMES THE ACFT WOULD SWERVE RAPIDLY TO THE L WITH OR WITHOUT FLAT TIRES. RPTR'S COMPANY MAINT NEVER DID FIND THE PROB. BUT, AFTER SELLING THE ACFT TO ANOTHER ACR, AND, WHEN IT WAS GOING THROUGH 'C' CHK, IT FINALLY WAS DISCOVERED THAT FAULTY ANTI-SKID MODULES ON THE L GEAR WERE CAUSING THE PROB. UNTIL THE FAULTY ANTI- SKID WAS DISCOVERED, RPTR ATTRIBUTED THE PROB TO HEAT BUILD-UP CAUSED BY LNDGS AT MAX WTS AND A VERY LONG TAXI. POST INCIDENT FOLLOW-UP THE RPTR CHKED THE BRAKE/WT CHARTS AND DETERMINED THAT THE BRAKES SHOULD HAVE BEEN COOL. HOWEVER, WITH MALFUNCTIONING ANTI-SKID MODULES, HOT BRAKES COULD HAVE RESULTED WITH THE BLOWN TIRES. RPTR FAULTS HIS COMPANY MAINT FOR NOT DISCOVERING THE PROB DURING THEIR TROUBLESHOOTING. RPTR IS A CHK AIRMAN AND HAS DISCUSSED AT LENGTH THE LNDG GEAR SWERVING WITH HIS FELLOW LCA'S. RPTR'S COMPANY HAS NO INTENTION OF REACTIVATING THE BRAKE TEMP GAUGE OR REPLACING THE 100 SERIES LNDG GEAR WITH THE MORE SUBSTANTIAL AND RELIABLE 200 SERIES.

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.