Narrative:

A B757-200 aircraft was being troubleshot for an [left forward] L-1 door air leak. This was a thru-flight. Debriefings of flight crew prior to pressurizing revealed air leak coming from L-1 door area at cruise and at start of descent. Following maintenance manual procedures outlined in amm; the aircraft was pressurized at the gate. No leakage was heard until the differential pressure was at approximately 6.5-7.0 psi; when the leaks were found and pinpointed.the aircraft was depressurized normally; and the aircraft was taken out of service due to repeated write-ups of this air leak. Once the aircraft was deemed 'out of service'; I entered an entry in the aircraft logbook; stating the locations of the air leaks; and at what differential pressure they were verified at. I was notified by a lead mechanic reviewing the logbook during the aircraft being repaired at the hangar that boeing was to be notified prior to pressurizing above 4.5 psi.while pressurizing this aircraft; I went above the 4.5 limit in order to find the air leak however; I did not have any means of contacting boeing while inside the flight deck performing my troubleshooting. I believe that boeing was notified while the aircraft was in the hangar; and the appropriate inspections where performed via notification from maintenance control and logbook review by the lead mechanic assigned to aircraft noting the pressure limits I recorded in my maintenance entry in the logbook.

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Original NASA ASRS Text

Title: A Line Mechanic reports having to pressurize a B757-200 to 6.0 PSI cabin differential pressure to locate a chronic air leak at cabin door 1-Left. Boeing Maintenance Manual procedures required Maintenance to coordinate with Boeing whenever cabin differential pressurization checks went above 4.50 PSI.

Narrative: A B757-200 aircraft was being troubleshot for an [left forward] L-1 Door air leak. This was a thru-flight. Debriefings of flight crew prior to pressurizing revealed air leak coming from L-1 door area at cruise and at start of descent. Following Maintenance Manual procedures outlined in AMM; the aircraft was pressurized at the gate. No leakage was heard until the differential pressure was at approximately 6.5-7.0 PSI; when the leaks were found and pinpointed.The aircraft was depressurized normally; and the aircraft was taken out of service due to repeated write-ups of this air leak. Once the aircraft was deemed 'Out of Service'; I entered an entry in the aircraft Logbook; stating the locations of the air leaks; and at what differential pressure they were verified at. I was notified by a Lead Mechanic reviewing the logbook during the aircraft being repaired at the hangar that Boeing was to be notified prior to pressurizing above 4.5 PSI.While pressurizing this aircraft; I went above the 4.5 limit in order to find the air leak however; I did not have any means of contacting Boeing while inside the flight deck performing my troubleshooting. I believe that Boeing was notified while the aircraft was in the hangar; and the appropriate Inspections where performed via notification from Maintenance Control and logbook review by the Lead Mechanic assigned to aircraft noting the pressure limits I recorded in my Maintenance entry in the Logbook.

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.