Narrative:

I was assigned to a B737-900 aircraft on the night shift. It became very blustery outside and so the decision was made to put the aircraft in the hangar. I changed the #1 tank refueling valve without incident. The last task on the installation of this valve is a bonding check which I called to the line to get an avionics technician (tech) to perform. He arrived at the hangar without the necessary equipment because he did not yet know exactly what he was needed for. After reading the manual and determining what equipment he needed he went back to the line to retrieve it. He was gone for awhile and when he returned I went to the wing with him where he performed the bonding check. The bonding was well within limits and so I proceeded to apply power and transfer the fuel. I cleaned my local area and prepared the aircraft to be towed to the gate. I completed the paperwork and in doing so signed for the complete installation; not providing a spot for the avionics tech to sign off his bonding check. I signed for the bonding check because I witnessed it being accomplished. We pushed the aircraft out of the hangar. [About an hour later] I was approached by my lead and the avionics technician who told me that the meter that was used to do the bonding check was out of calibration. My lead informed me that she had already stopped the flight from departing at which time we went back to the line and another avionics tech performed a new bonding check using a meter that was within calibration. The first avionics tech stepped up and informed the lead of the mistaken choice to use an out of calibration tool. There were events that happened at the line while I was at the hangar that I was not a witness to. The flight departure was stopped and the maintenance actions necessary for the completion of my work were accomplished. Out of calibration tools should not be placed in an area where anyone has access to them for maintenance.

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Original NASA ASRS Text

Title: Two Mechanics report about their involvement with the paperwork and use of an 'out of calibration' multi-meter during an electrical resistance bonding check on a B737-900 after the #1 fuel tank refueling valve was replaced. A Maintenance Supervisor had directed the use of the 'out of calibration' multi-meter.

Narrative: I was assigned to a B737-900 aircraft on the night shift. It became very blustery outside and so the decision was made to put the aircraft in the hangar. I changed the #1 tank refueling valve without incident. The last task on the installation of this valve is a bonding check which I called to the Line to get an Avionics Technician (Tech) to perform. He arrived at the hangar without the necessary equipment because he did not yet know exactly what he was needed for. After reading the manual and determining what equipment he needed he went back to the Line to retrieve it. He was gone for awhile and when he returned I went to the wing with him where he performed the bonding check. The bonding was well within limits and so I proceeded to apply power and transfer the fuel. I cleaned my local area and prepared the aircraft to be towed to the gate. I completed the paperwork and in doing so signed for the complete installation; not providing a spot for the Avionics Tech to sign off his bonding check. I signed for the bonding check because I witnessed it being accomplished. We pushed the aircraft out of the hangar. [About an hour later] I was approached by my Lead and the Avionics Technician who told me that the meter that was used to do the bonding check was out of calibration. My Lead informed me that she had already stopped the flight from departing at which time we went back to the Line and another Avionics Tech performed a new bonding check using a meter that was within calibration. The first Avionics Tech stepped up and informed the Lead of the mistaken choice to use an out of calibration tool. There were events that happened at the Line while I was at the hangar that I was not a witness to. The flight departure was stopped and the maintenance actions necessary for the completion of my work were accomplished. Out of calibration tools should not be placed in an area where ANYONE has access to them for maintenance.

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.