Narrative:

On sep/sat/02 a call for aircraft maintenance was made by the pilot with regard to the right ram air door full open light which remained illuminated during flight. The MEL procedure for the B737-800 is unclr about the lockout procedure for the left/right pack ram air system. The system and sequence numbers pertaining to the discrepancy is 21-05-01 for the left pack and 21-05-02 for the right pack. When deactivating the system it says to pull and collar 2 circuit breakers. The 2 circuit breakers are the ram air mod left circuit breaker (A4 left) (B4 right) and the air conditioning ram air mod controller left(right) circuit breaker. Next, the MEL book specifies to open the ram air actuator panel, disconnect an electrical connector, place a rig pin to lock out the door, and safety wire the actuator rod end. The MEL then says to close associated circuit breakers. The process for closing circuit breakers is vague. The MEL should specify exactly which circuit breakers need to be closed since the circuit breaker has been pulled and collared for intended flight and there is an electrical connector disconnected. It is to my knowledge that others have also left this circuit breaker open when it should have been closed. This was brought to my attention by a technician who was working this problem at another station. I have informed technical pubs and I have submitted a technical pubs change request, giving some ideas on how to clarify the procedure.

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Original NASA ASRS Text

Title: A B737-800 WAS DISPATCHED WITH THE R PACK RAM AIR DOOR DEFERRED AS INOP PER THE MEL BUT CIRCUIT BREAKER CONDITION FOUND VAGUE AND CONFUSING.

Narrative: ON SEP/SAT/02 A CALL FOR ACFT MAINT WAS MADE BY THE PLT WITH REGARD TO THE R RAM AIR DOOR FULL OPEN LIGHT WHICH REMAINED ILLUMINATED DURING FLT. THE MEL PROC FOR THE B737-800 IS UNCLR ABOUT THE LOCKOUT PROC FOR THE L/R PACK RAM AIR SYS. THE SYS AND SEQUENCE NUMBERS PERTAINING TO THE DISCREPANCY IS 21-05-01 FOR THE L PACK AND 21-05-02 FOR THE R PACK. WHEN DEACTIVATING THE SYS IT SAYS TO PULL AND COLLAR 2 CIRCUIT BREAKERS. THE 2 CIRCUIT BREAKERS ARE THE RAM AIR MOD L CIRCUIT BREAKER (A4 L) (B4 R) AND THE AIR CONDITIONING RAM AIR MOD CTLR L(R) CIRCUIT BREAKER. NEXT, THE MEL BOOK SPECIFIES TO OPEN THE RAM AIR ACTUATOR PANEL, DISCONNECT AN ELECTRICAL CONNECTOR, PLACE A RIG PIN TO LOCK OUT THE DOOR, AND SAFETY WIRE THE ACTUATOR ROD END. THE MEL THEN SAYS TO CLOSE ASSOCIATED CIRCUIT BREAKERS. THE PROCESS FOR CLOSING CIRCUIT BREAKERS IS VAGUE. THE MEL SHOULD SPECIFY EXACTLY WHICH CIRCUIT BREAKERS NEED TO BE CLOSED SINCE THE CIRCUIT BREAKER HAS BEEN PULLED AND COLLARED FOR INTENDED FLT AND THERE IS AN ELECTRICAL CONNECTOR DISCONNECTED. IT IS TO MY KNOWLEDGE THAT OTHERS HAVE ALSO LEFT THIS CIRCUIT BREAKER OPEN WHEN IT SHOULD HAVE BEEN CLOSED. THIS WAS BROUGHT TO MY ATTN BY A TECHNICIAN WHO WAS WORKING THIS PROB AT ANOTHER STATION. I HAVE INFORMED TECHNICAL PUBS AND I HAVE SUBMITTED A TECHNICAL PUBS CHANGE REQUEST, GIVING SOME IDEAS ON HOW TO CLARIFY THE PROC.

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.