Narrative:

Captain of flight ZZZ-ZZZ1 reported during preflight passenger entry door one right evacuate/evacuation slide bottle pressure gauge needle was out of the green band on the low side into the red. Per our maintenance manual 25-61-35, a short duration pressure pointer excursion outside of the green band of up to 1/2 the green bandwidth are acceptable (either on low side or high side). The maximum allowable duration of the excursion is approximately 2 hours. I informed the captain of this statement, and she said the needle was much less than the 1/2 width requirement, and was just in the red. With this information we made a logbook write-up and carried forward the slide for the 2 hour rechk. The slide was checked at the termination of the flight ZZZ1 (approximately 1 hour flight time), and was still in the red. The slide was replaced per the effective maintenance manual procedures. During follow-up review of the maintenance manual, not sure it was properly interpreted. The statement about short excursions outside of the green band is in the same paragraph that talks about rapid heating or cooling of the cabin air, which will result in the pressure gauge falsely indicating high or low. The aircraft overnighted at ZZZ, so temperature should have been stable. Also, the manual does not say a carry forward item can be made to have the bottle pressure rechked within the 2 hour period. As a result of this manual not being completely clear, we have asked the fleet engineering group to clarify the intent of the statement and revise the manual as required.

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Original NASA ASRS Text

Title: A B737-500 WAS DISPATCHED WITH DOOR #1 R SLIDE PRESSURE OUT OF THE GREEN BAND AND INTO THE RED BAND DUE TO CONFUSING AND CONFLICTING MANUAL LIMITS.

Narrative: CAPT OF FLT ZZZ-ZZZ1 RPTED DURING PREFLT PAX ENTRY DOOR ONE R EVAC SLIDE BOTTLE PRESSURE GAUGE NEEDLE WAS OUT OF THE GREEN BAND ON THE LOW SIDE INTO THE RED. PER OUR MAINT MANUAL 25-61-35, A SHORT DURATION PRESSURE POINTER EXCURSION OUTSIDE OF THE GREEN BAND OF UP TO 1/2 THE GREEN BANDWIDTH ARE ACCEPTABLE (EITHER ON LOW SIDE OR HIGH SIDE). THE MAX ALLOWABLE DURATION OF THE EXCURSION IS APPROX 2 HRS. I INFORMED THE CAPT OF THIS STATEMENT, AND SHE SAID THE NEEDLE WAS MUCH LESS THAN THE 1/2 WIDTH REQUIREMENT, AND WAS JUST IN THE RED. WITH THIS INFO WE MADE A LOGBOOK WRITE-UP AND CARRIED FORWARD THE SLIDE FOR THE 2 HR RECHK. THE SLIDE WAS CHKED AT THE TERMINATION OF THE FLT ZZZ1 (APPROX 1 HR FLT TIME), AND WAS STILL IN THE RED. THE SLIDE WAS REPLACED PER THE EFFECTIVE MAINT MANUAL PROCS. DURING FOLLOW-UP REVIEW OF THE MAINT MANUAL, NOT SURE IT WAS PROPERLY INTERPED. THE STATEMENT ABOUT SHORT EXCURSIONS OUTSIDE OF THE GREEN BAND IS IN THE SAME PARAGRAPH THAT TALKS ABOUT RAPID HEATING OR COOLING OF THE CABIN AIR, WHICH WILL RESULT IN THE PRESSURE GAUGE FALSELY INDICATING HIGH OR LOW. THE ACFT OVERNIGHTED AT ZZZ, SO TEMP SHOULD HAVE BEEN STABLE. ALSO, THE MANUAL DOES NOT SAY A CARRY FORWARD ITEM CAN BE MADE TO HAVE THE BOTTLE PRESSURE RECHKED WITHIN THE 2 HR PERIOD. AS A RESULT OF THIS MANUAL NOT BEING COMPLETELY CLR, WE HAVE ASKED THE FLEET ENGINEERING GROUP TO CLARIFY THE INTENT OF THE STATEMENT AND REVISE THE MANUAL AS REQUIRED.

Data retrieved from NASA's ASRS site as of July 2007 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.