|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1801 To 2400|
|Locale Reference||airport : zzz.airport|
|Altitude||agl single value : 0|
|Operator||common carrier : air carrier|
|Make Model Name||B737-700|
|Operating Under FAR Part||Part 121|
|Affiliation||company : air carrier|
|Function||maintenance : technician|
|Qualification||technician : airframe|
technician : powerplant
|Affiliation||company : air carrier|
|Function||other personnel other|
|Anomaly||aircraft equipment problem : critical|
maintenance problem : improper maintenance
non adherence : far
non adherence : published procedure
|Resolutory Action||none taken : detected after the fact|
|Maintenance||performance deficiency : scheduled maintenance|
performance deficiency : training
performance deficiency : installation
performance deficiency : non compliance with legal requirements
|Problem Areas||Maintenance Human Performance|
|Primary Problem||Maintenance Human Performance|
On line ron I noticed that the #1 and #2 brakes were worn and in need of right&right. I right&right'ed the #1 and #2 brakes and after installing them proceeded to leak check them. I did so after running the #2 engine for leak check purposes; running both a and B system hydraulics. At the conclusion of the engine run I left the a and B system pumps on; set and released the brakes twice; reset the brakes and left the cockpit to leak check the brakes noting that I had good brake system psi. I used my flashlight to inspect my work and noted that I had no leaks and could see where the brake pins had actuated. Being satisfied that I had properly installed and leak checked the brakes; I returned to the cockpit to turn the a and B pumps off. I would like noted that no operational failing of the brake was noted by the crew on taxi out of or landing and taxi to the gate. Callback conversation with reporter revealed the following information: reporter stated the disconnected line was found on pushback by ramp crew. No inbound pilot write-up(south) indicating any braking discrepancies. The #2 hydraulic flex line was reconnected and the #1 brake line was checked for secure installation. No further incident. Reporter also stated the -700 hydraulic brake line attachment is completely different from the -200; 300 and 500 series 737's. The old shuttle valves that mechanics had to re-attach to the brake housing has been replaced with just a coarse threaded hydraulic flex line with spring loaded sleeve type collar. When installing this line to the brake housing; a noticeable 'click' will be heard indicating proper engagement and lock. Reporter and his carrier do not know for certain whether the sleeve collar was properly engaged.
Original NASA ASRS Text
Title: A B737-700 ACFT BRAKE LINE WAS FOUND DISCONNECTED DURING PUSHBACK AFTER BOTH BRAKES ON LEFT MAIN LNDG GEAR WERE CHANGED AT PREVIOUS STATION.
Narrative: ON LINE RON I NOTICED THAT THE #1 AND #2 BRAKES WERE WORN AND IN NEED OF R&R. I R&R'ED THE #1 AND #2 BRAKES AND AFTER INSTALLING THEM PROCEEDED TO LEAK CHK THEM. I DID SO AFTER RUNNING THE #2 ENG FOR LEAK CHK PURPOSES; RUNNING BOTH A AND B SYS HYDS. AT THE CONCLUSION OF THE ENG RUN I LEFT THE A AND B SYS PUMPS ON; SET AND RELEASED THE BRAKES TWICE; RESET THE BRAKES AND LEFT THE COCKPIT TO LEAK CHK THE BRAKES NOTING THAT I HAD GOOD BRAKE SYS PSI. I USED MY FLASHLIGHT TO INSPECT MY WORK AND NOTED THAT I HAD NO LEAKS AND COULD SEE WHERE THE BRAKE PINS HAD ACTUATED. BEING SATISFIED THAT I HAD PROPERLY INSTALLED AND LEAK CHKED THE BRAKES; I RETURNED TO THE COCKPIT TO TURN THE A AND B PUMPS OFF. I WOULD LIKE NOTED THAT NO OPERATIONAL FAILING OF THE BRAKE WAS NOTED BY THE CREW ON TAXI OUT OF OR LNDG AND TAXI TO THE GATE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THE DISCONNECTED LINE WAS FOUND ON PUSHBACK BY RAMP CREW. NO INBOUND PILOT WRITE-UP(S) INDICATING ANY BRAKING DISCREPANCIES. THE #2 HYD FLEX LINE WAS RECONNECTED AND THE #1 BRAKE LINE WAS CHECKED FOR SECURE INSTALLATION. NO FURTHER INCIDENT. REPORTER ALSO STATED THE -700 HYD BRAKE LINE ATTACHMENT IS COMPLETELY DIFFERENT FROM THE -200; 300 AND 500 SERIES 737'S. THE OLD SHUTTLE VALVES THAT MECHANICS HAD TO RE-ATTACH TO THE BRAKE HOUSING HAS BEEN REPLACED WITH JUST A COARSE THREADED HYD FLEX LINE WITH SPRING LOADED SLEEVE TYPE COLLAR. WHEN INSTALLING THIS LINE TO THE BRAKE HOUSING; A NOTICEABLE 'CLICK' WILL BE HEARD INDICATING PROPER ENGAGEMENT AND LOCK. REPORTER AND HIS CARRIER DO NOT KNOW FOR CERTAIN WHETHER THE SLEEVE COLLAR WAS PROPERLY ENGAGED.
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.