Narrative:

First time working this particular problem. This event occurred almost two months ago; while I remember working the airplane; particularly the krueger flap deflector; the rest of the operation are a bit sketchy due to the fact there were a handful of people working the airplane at the same time; on this krueger flap deflector. I don't recall pulling breakers or doing the deactivation called out in the MM. I can only stipulate what might have happened; due to past practices. One past practice we commonly do to deactivate a system on an aircraft; when no other maintenance or operations are in effect; is to de-power the airplane once the desired configuration is achieved. Again; I don't recall if this in fact is the procedure we used; I can only assume it's the procedure we did; because it has been a commonly used; company wide practice during my airline career. The company has since; put into practice; removing aircraft power for the purpose of isolating a system in lieu of pulling breakers. Technicians have requested a procedure to remove and isolate aircraft electrical power; in lieu of using current circuit breaker collaring/tagging guidance. Currently; no; one; particular procedure exists; to remove and isolate aircraft electrical power that provides the same level of lockout/tagout electrical hazard protection; as pulling and collaring circuit breakers of aircraft systems. Partial procedures exist in the B737 amm removal of external power and battery removal. Engineering has drafted and published online; a procedure based the two B737 amm procedures; that provides electrical isolation by: removing electrical power from the aircraft; disconnects the main battery (or batteries) and isolates the hot battery bus by pulling required circuit breakers; (thus preventing application of electrical power). Installs required danger tags.engineering has incorporated a procedure to restore the aircraft back to normal configuration and accomplish required maintenance testing procedures for return to service. These procedures will make available to technicians; an alternate means of removing/isolating electrical power. Particularly; this will benefit when multiple aircraft systems are disturbed; such as at longer maintenance visits and provide the same level of safety and system isolation. You will find these procedures in (chapter) 24-22-00 section of each fleet's amm. This procedure was not available at the time; but I think it adds some weight; to the way we have been working these airplanes since day one (this notice is not available to all technicians). As far as not logging circuit breakers in the log book; even at the time of this writing; is still a relatively new procedure considering how long I've been with the company. Safety is and always has been the most important factor in working these airplanes; removing power from the airplane has always been a past practice; considered to be a safe operation for de-energizing and isolating electrical systems on aircraft.

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Original NASA ASRS Text

Title: A Mechanic reports on events surrounding repair of a krueger flap deflector on a B737-700 aircraft. Also; no single procedure exists to remove and isolate aircraft electrical power; that provides the same level of lockout tagout electrical hazard protection; as pulling and collaring circuit breakers of aircraft systems.

Narrative: First time working this particular problem. This event occurred almost two months ago; while I remember working the airplane; particularly the krueger flap deflector; the rest of the operation are a bit sketchy due to the fact there were a handful of people working the airplane at the same time; on this krueger flap deflector. I don't recall pulling breakers or doing the deactivation called out in the MM. I can only stipulate what might have happened; due to past practices. One past practice we commonly do to deactivate a system on an aircraft; when no other maintenance or operations are in effect; is to de-power the airplane once the desired configuration is achieved. Again; I don't recall if this in fact is the procedure we used; I can only assume it's the procedure we did; because it has been a commonly used; company wide practice during my airline career. The company has since; put into practice; removing aircraft power for the purpose of isolating a system in lieu of pulling breakers. Technicians have requested a procedure to remove and isolate aircraft electrical power; in lieu of using current circuit breaker collaring/tagging guidance. Currently; no; one; particular procedure exists; to remove and isolate aircraft electrical power that provides the same level of Lockout/Tagout electrical hazard protection; as pulling and collaring circuit breakers of aircraft systems. Partial procedures exist in the B737 AMM removal of external power and battery removal. Engineering has drafted and published online; a procedure based the two B737 AMM procedures; that provides electrical isolation by: Removing electrical power from the aircraft; disconnects the main battery (or batteries) and isolates the hot battery bus by pulling required circuit breakers; (thus preventing application of electrical power). Installs required danger tags.Engineering has incorporated a procedure to restore the aircraft back to normal configuration and accomplish required maintenance testing procedures for return to service. These procedures will make available to technicians; an alternate means of removing/isolating electrical power. Particularly; this will benefit when multiple aircraft systems are disturbed; such as at longer Maintenance Visits and provide the same level of safety and system isolation. You will find these procedures in (chapter) 24-22-00 section of each fleet's AMM. This procedure was not available at the time; but I think it adds some weight; to the way we have been working these airplanes since day one (this notice is not available to all technicians). As far as not logging circuit breakers in the log book; even at the time of this writing; is still a relatively new procedure considering how long I've been with the company. Safety is and always has been the most important factor in working these airplanes; removing power from the airplane has always been a past practice; considered to be a safe operation for de-energizing and isolating electrical systems on aircraft.

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.