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B767 flight crew reports carbon brake disk failure which is discovered by maintenance during post flight inspection. Reporter indicates this may be a frequent occurrence that could be difficult to detect.
| Attributes | |
| ACN | 880126 |
| Time | |
| Date | 201003 |
| Local Time Of Day | 0001-0600 |
| Place | |
| Locale Reference | ZZZZ.Airport |
| State Reference | FO |
| Aircraft 1 | |
| Make Model Name | B767-300 and 300 ER |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Parked |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Normal Brake System |
| Person 1 | |
| Function | Captain |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Person 2 | |
| Function | First Officer |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical |
Narrative:
Number three brake disk found shattered during mechanic's post flight inspection. Landing and deceleration were normal. Number three brake wear pins were protruding 1/4 inch with the brakes parked. Note this is the third such failure discovered by maintenance at this airport. The others may have been a result of the cockpit crews' entry of a braking problem in the logbook on arrival. The frequency that has been experienced here is more than coincidental. I suspect that the new carbon brakes fail at a point well above the minimum approved service limits of the wear indicator pins being just beyond flush. The carbon disk may have an adverse harmonic reaction to brake chatter as the mass changes through wear; or it may be another problem; however common to this braking system. I would recommend a fleet wide inspection on overnights. Of significant note is that the brake and associated wear pins would look serviceable based on current flight crew preflight inspection procedures. Only a more detailed inspection with illumination would reveal this problem. Also significant is the hazard to a heavy aircraft aborting a takeoff with measurably reduced braking available due to this failure mode.
Original NASA ASRS Text
Title: B767 flight crew reports carbon brake disk failure which is discovered by maintenance during post flight inspection. Reporter indicates this may be a frequent occurrence that could be difficult to detect.
Narrative: Number three brake disk found shattered during Mechanic's post flight inspection. Landing and deceleration were normal. Number three brake wear pins were protruding 1/4 inch with the brakes parked. Note this is the third such failure discovered by maintenance at this airport. The others may have been a result of the cockpit crews' entry of a braking problem in the logbook on arrival. The frequency that has been experienced here is more than coincidental. I suspect that the new carbon brakes fail at a point well above the minimum approved service limits of the wear indicator pins being just beyond flush. The carbon disk may have an adverse harmonic reaction to brake chatter as the mass changes through wear; or it may be another problem; however common to this braking system. I would recommend a fleet wide inspection on overnights. Of significant note is that the brake and associated wear pins would look serviceable based on current flight crew preflight inspection procedures. Only a more detailed inspection with illumination would reveal this problem. Also significant is the hazard to a heavy aircraft aborting a takeoff with measurably reduced braking available due to this failure mode.
Data retrieved from NASA's ASRS site as of April 2012 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.