A Line Mechanic reports about the problems associated with B757-200 brake write-ups made during their 'A' checks; that were intended to prevent brakes from continuing in service beyond their operational wear limits; affected by Airworthiness Directive (AD) 92-17-04.

Narrative

Aircraft had 'A' check accomplished and #2 forward brake was deferred per job card with 1/16 inch pin remaining. The problem is that after we defer these brakes to be rechecked as required to comply with the instructions of the 'A' check job cards the following stations clear the items without replacing the brake per the Maintenance Manual. The brake wear check to comply with the wear requirements of Airworthiness Directive note 92-17-0 was removed from the service check on B757. The note if indicator pin is 1/8 inch or less create maintenance write-up to recheck at the next service. These brakes are directly affected by Airworthiness Directive note 92-17-04 and the result of these items being signed off is resulting in the aircraft being flown with brakes worn beyond the Airworthiness Directive limits. Callback conversation with Reporter revealed the following information: Reporter stated the Maintenance Controller was unaware of his own company procedures that required Mechanics who performed an 'A' check to make a write-up to have a recheck performed on any B757 brake at the next 75 hour Service Check; and the following Service Checks; when a brake wear indicator pin was only showing 1/8th of an inch length remaining on the pin. But at the Service Check; mechanics saw the brake(s) write-up and signed off the brake as within limits; which at that point; it still was. Reporter stated the intent of the brake write-up was to monitor the brake; or brakes; that were getting close to minimum wear limits. Because mechanics did not understand the purpose of the write-up as a monitoring tool; they just signed off the brake write-up. As a result; the noted brake never got checked again until the next 'A' check approximately 400 to 500 hours later. That allowed many brakes to wear beyond; and even below; the minimums allowed for continued service. The Airworthiness Directive (A.D.); AD-92-17-04 required operators of B757's with certain part numbers to satisfy compliance for worn brakes. Rejected Take Off (RTO) braking effectiveness is the primary concern. Reporter stated his carrier has changed their procedures to have any B757 brake; with only 1/8th inch wear length remaining on the wear pin; be replaced at their 'A' check.