|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||0601 To 1200|
|Locale Reference||airport : zzz.airport|
|Altitude||agl single value : 0|
|Operator||common carrier : air carrier|
|Make Model Name||B777-200|
|Operating Under FAR Part||Part 121|
|Affiliation||company : air carrier|
|Function||maintenance : technician|
|Anomaly||aircraft equipment problem : critical|
maintenance problem : improper maintenance
maintenance problem : improper documentation
non adherence : published procedure
non adherence : far
|Independent Detector||other other : 1|
|Resolutory Action||none taken : detected after the fact|
|Maintenance||contributing factor : engineering procedure|
contributing factor : manuals
performance deficiency : scheduled maintenance
performance deficiency : non compliance with legal requirements
performance deficiency : testing
|Problem Areas||Maintenance Human Performance|
Chart Or Publication
|Primary Problem||Chart Or Publication|
Error occurred when shop order showed a specific engineering order and when I looked it up it showed a certain test pressure to which testing hoses. Turned over to lead mechanic to look up proper documentation. I pressure checked hoses to wrong specifications.callback conversation with reporter revealed the following information: reporter stated even though he had already tested approximately 15 B777 slide rafts using the manufacturer's component maintenance manual (cmm) specifications of 900 pounds test pressure on the hoses from the raft bottle to the inflation aspirator; he just felt the test pressure check was too low for the purpose of the hose. Reporter stated he decided to research further and discovered the manufacturer's cmm was incorrect. The test pressure required was actually supposed to be 4000 pounds. This would determine if the hose could handle the initial burst test and still be considered serviceable for continued use. This test is accomplished on these slides every 12 to 15 years. The slide raft manufacturer is working closely with his carrier and better diagrams and correct test pressures have been incorporated in the cmm's.
Original NASA ASRS Text
Title: MECHANIC REALIZED THE MANUFACTURER'S SLIDE/RAFT COMPONENT MAINTENANCE MANUAL THEY HAD BEEN FOLLOWING TO PRESSURE TEST AND CHECK THEIR B777 RAFT BOTTLE HOSES AT 900 POUNDS; SHOULD HAVE BEEN ACTUALLY TESTED AT 4000 LBS.
Narrative: ERROR OCCURRED WHEN SHOP ORDER SHOWED A SPECIFIC ENGINEERING ORDER AND WHEN I LOOKED IT UP IT SHOWED A CERTAIN TEST PRESSURE TO WHICH TESTING HOSES. TURNED OVER TO LEAD MECHANIC TO LOOK UP PROPER DOCUMENTATION. I PRESSURE CHECKED HOSES TO WRONG SPECS.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED EVEN THOUGH HE HAD ALREADY TESTED APPROXIMATELY 15 B777 SLIDE RAFTS USING THE MANUFACTURER'S COMPONENT MAINTENANCE MANUAL (CMM) SPECIFICATIONS OF 900 POUNDS TEST PRESSURE ON THE HOSES FROM THE RAFT BOTTLE TO THE INFLATION ASPIRATOR; HE JUST FELT THE TEST PRESSURE CHECK WAS TOO LOW FOR THE PURPOSE OF THE HOSE. REPORTER STATED HE DECIDED TO RESEARCH FURTHER AND DISCOVERED THE MANUFACTURER'S CMM WAS INCORRECT. THE TEST PRESSURE REQUIRED WAS ACTUALLY SUPPOSED TO BE 4000 POUNDS. THIS WOULD DETERMINE IF THE HOSE COULD HANDLE THE INITIAL BURST TEST AND STILL BE CONSIDERED SERVICEABLE FOR CONTINUED USE. THIS TEST IS ACCOMPLISHED ON THESE SLIDES EVERY 12 TO 15 YEARS. THE SLIDE RAFT MANUFACTURER IS WORKING CLOSELY WITH HIS CARRIER AND BETTER DIAGRAMS AND CORRECT TEST PRESSURES HAVE BEEN INCORPORATED IN THE CMM'S.
Data retrieved from NASA's ASRS site as of May 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.