Narrative:

I'm filing this report because I think there was a problem with maintenance processes as it related to brake wear determination. While doing the walkaround for flight; I found the #3 brake forward wear indicator pin below the position of flush with the brake housing. It was retracted enough that I could feel a definite recess of the pin in relation to the housing. A credit card slid across the housing would not hang up on the wear pin. I was not present when the amt signed my entry as within limits for a through flight; so I called maintenance control for clarification of the through flight limits. I was also concerned that the next morning's departure would not be considered a through flight. Maintenance control quoted section X of the maintenance manual as saying the shorter of the 2 wear pins is used to determine brake condition. It also states that for a through flight; flush or less requires brake replacement. I advised station maintenance that maintenance control said the brake needed replacement. The same amt returned and said he could hang a fingernail on the pin; which is what they use to determine brake limits for a through flight. With both of us at the main landing gear; he once again said he could hang a fingernail on the pin. I found that because the wear pin has a loose fit in the brake housing; it was possible to catch a fingernail on the pin below the flush point on the housing. I suggested he use a straight edge to see that the pin was below flush. He said all they use is a fingernail. I told him the brake needed to be changed. I find it disturbing that this brake was first written up on (date) and then again on (following date). The signoff on the (date) stated that flush or slightly below flush was within limits for a through flight. The signoff on the (following date) stated the brake was within limits because the aft wear pin was above the flush. Both of these are contrary to what maintenance control stated to me as limits. The (following date) signoff also said engineering services was advised for follow-up. The airplane had 3 overnights between the first signoff and my flight. Because the brake wasn't replaced in a timely manner after multiple write-ups; we paid room and board for 148 passenger and the next day's flts were significantly delayed. While it was certainly not my intention or desire to ground an airplane; I will not take an airplane with questionable brakes to a 7000 ft MSL airport knowing it will be a mlw landing followed by an mtow takeoff using improved performance procedures. I even called maintenance control back the next day to make sure I had understood the limits correctly.

Related reports:

Google
 

Original NASA ASRS Text

Title: A B737-800 ACFT PILOT RAISES CONCERNS ABOUT BRAKE WEAR LIMITS BEING EXCEEDED; BRAKE WRITE-UPS BEING SIGNED-OFF AND MTOW TAKEOFF NOT REALISTIC.

Narrative: I'M FILING THIS RPT BECAUSE I THINK THERE WAS A PROB WITH MAINT PROCESSES AS IT RELATED TO BRAKE WEAR DETERMINATION. WHILE DOING THE WALKAROUND FOR FLT; I FOUND THE #3 BRAKE FORWARD WEAR INDICATOR PIN BELOW THE POS OF FLUSH WITH THE BRAKE HOUSING. IT WAS RETRACTED ENOUGH THAT I COULD FEEL A DEFINITE RECESS OF THE PIN IN RELATION TO THE HOUSING. A CREDIT CARD SLID ACROSS THE HOUSING WOULD NOT HANG UP ON THE WEAR PIN. I WAS NOT PRESENT WHEN THE AMT SIGNED MY ENTRY AS WITHIN LIMITS FOR A THROUGH FLT; SO I CALLED MAINT CTL FOR CLARIFICATION OF THE THROUGH FLT LIMITS. I WAS ALSO CONCERNED THAT THE NEXT MORNING'S DEP WOULD NOT BE CONSIDERED A THROUGH FLT. MAINT CTL QUOTED SECTION X OF THE MAINT MANUAL AS SAYING THE SHORTER OF THE 2 WEAR PINS IS USED TO DETERMINE BRAKE CONDITION. IT ALSO STATES THAT FOR A THROUGH FLT; FLUSH OR LESS REQUIRES BRAKE REPLACEMENT. I ADVISED STATION MAINT THAT MAINT CTL SAID THE BRAKE NEEDED REPLACEMENT. THE SAME AMT RETURNED AND SAID HE COULD HANG A FINGERNAIL ON THE PIN; WHICH IS WHAT THEY USE TO DETERMINE BRAKE LIMITS FOR A THROUGH FLT. WITH BOTH OF US AT THE MAIN LNDG GEAR; HE ONCE AGAIN SAID HE COULD HANG A FINGERNAIL ON THE PIN. I FOUND THAT BECAUSE THE WEAR PIN HAS A LOOSE FIT IN THE BRAKE HOUSING; IT WAS POSSIBLE TO CATCH A FINGERNAIL ON THE PIN BELOW THE FLUSH POINT ON THE HOUSING. I SUGGESTED HE USE A STRAIGHT EDGE TO SEE THAT THE PIN WAS BELOW FLUSH. HE SAID ALL THEY USE IS A FINGERNAIL. I TOLD HIM THE BRAKE NEEDED TO BE CHANGED. I FIND IT DISTURBING THAT THIS BRAKE WAS FIRST WRITTEN UP ON (DATE) AND THEN AGAIN ON (FOLLOWING DATE). THE SIGNOFF ON THE (DATE) STATED THAT FLUSH OR SLIGHTLY BELOW FLUSH WAS WITHIN LIMITS FOR A THROUGH FLT. THE SIGNOFF ON THE (FOLLOWING DATE) STATED THE BRAKE WAS WITHIN LIMITS BECAUSE THE AFT WEAR PIN WAS ABOVE THE FLUSH. BOTH OF THESE ARE CONTRARY TO WHAT MAINT CTL STATED TO ME AS LIMITS. THE (FOLLOWING DATE) SIGNOFF ALSO SAID ENGINEERING SVCS WAS ADVISED FOR FOLLOW-UP. THE AIRPLANE HAD 3 OVERNIGHTS BTWN THE FIRST SIGNOFF AND MY FLT. BECAUSE THE BRAKE WASN'T REPLACED IN A TIMELY MANNER AFTER MULTIPLE WRITE-UPS; WE PAID ROOM AND BOARD FOR 148 PAX AND THE NEXT DAY'S FLTS WERE SIGNIFICANTLY DELAYED. WHILE IT WAS CERTAINLY NOT MY INTENTION OR DESIRE TO GND AN AIRPLANE; I WILL NOT TAKE AN AIRPLANE WITH QUESTIONABLE BRAKES TO A 7000 FT MSL ARPT KNOWING IT WILL BE A MLW LNDG FOLLOWED BY AN MTOW TKOF USING IMPROVED PERFORMANCE PROCS. I EVEN CALLED MAINT CTL BACK THE NEXT DAY TO MAKE SURE I HAD UNDERSTOOD THE LIMITS CORRECTLY.

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.