Narrative:

I was performing my duty as maintenance controller when I received a phone call from ZZZ line technician that there was a fault with the low pressure light for the right-hand forward fuel boot pump; and he wanted to place it on MEL. Upon reviewing the MEL manual; I determined that there were 2 possible mels available; depending on the specific fault. MEL 28-3A for the light itself; or 28-3E if some other component in the warning light system was causing the light to not work. I made the decision to use 28-3A after asking the technician if it was just the light that was not working. He responded with yes it is the light. The next day at the start of my shift and during the turnover; I learned that a pressure switch had been identified and entered in maintenance tracking system as a required part. Since this part is a component of the warning light 'system;' the MEL was changed to 28-3E by one of the third shift controllers. The controller then called ZZZ2 where the aircraft roned and had the second MEL 28-1B applied as is required by 28-3E. At the time of this writing; I am confused as to how the pressure switch was identified by a technician in ZZZ3 while the aircraft was in ZZZ2 all night and apparently not troubleshot. There is not troubleshooting information in maintenance tracking system that would have been necessary to find the faulty pressure switch. As an added measure to ensure the correct MEL is applied for this warning light system; I will insist that the aircraft be taken out of service long enough to verify the cause of the faulty circuit before applying an MEL.

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Original NASA ASRS Text

Title: After applying an MEL 28-3A for a fault with the low pressure light for the right forward fuel boost pump on a B737-400; a Maintenance Controller is later informed a pressure switch had been identified; even though no one had done any troubleshooting.

Narrative: I was performing my duty as Maintenance Controller when I received a phone call from ZZZ Line Technician that there was a fault with the low pressure light for the right-hand forward fuel boot pump; and he wanted to place it on MEL. Upon reviewing the MEL manual; I determined that there were 2 possible MELs available; depending on the specific fault. MEL 28-3A for the light itself; or 28-3E if some other component in the warning light system was causing the light to not work. I made the decision to use 28-3A after asking the technician if it was just the light that was not working. He responded with yes it is the light. The next day at the start of my shift and during the turnover; I learned that a pressure switch had been identified and entered in Maintenance Tracking System as a required part. Since this part is a component of the warning light 'system;' the MEL was changed to 28-3E by one of the third shift controllers. The Controller then called ZZZ2 where the aircraft RONed and had the second MEL 28-1B applied as is required by 28-3E. At the time of this writing; I am confused as to how the pressure switch was identified by a technician in ZZZ3 while the aircraft was in ZZZ2 all night and apparently not troubleshot. There is not troubleshooting information in Maintenance Tracking System that would have been necessary to find the faulty pressure switch. As an added measure to ensure the correct MEL is applied for this warning light system; I will insist that the aircraft be taken out of service long enough to verify the cause of the faulty circuit before applying an MEL.

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.