A Line Mechanic misinterpreted an Engineering Order (EO). He did not re-install a pressure relief blowout panel at the aft bulkhead of the forward pit of a B757-200; after installing a protective grille over the opening. Aircraft was released; but smoke and fire containment were compromised; a 'no-go' item.
Synopsis
A Line Mechanic misinterpreted an Engineering Order (EO). He did not re-install a pressure relief blowout panel at the aft bulkhead of the forward pit of a B757-200; after installing a protective grille over the opening. Aircraft was released; but smoke and fire containment were compromised; a 'no-go' item.
Narrative
I was approached by Union Representative Mr. 'X' asking me to help in a pending investigation about a job assignment I had September 2010. I was told there might be a possibility that I had accomplished an Engineering Order (EO) improperly and wanted [me] to explain what took place that night. I followed the EO; and accomplished the jobcard. At step #6; the jobcard stated to reinstall the blowout panel and grill; but when I looked at the illustration associated with the item; it appeared that the grill was now the replacement part without the blowout panel portion; so I installed the frame that was needed to support the grill. I returned the blowout panel to stores and told them it was a reclamation part and signed-off the jobcard.When approached about this initially in October; I looked at the part number for the panel assembly in the Maintenance Operations and it stated that the panel was not necessary due to the accomplishment of the Engineering Order. It further states that part [blowout panel] is removed from the B757 aircraft. I felt that I accomplished the EO as written. When looking into other aircraft; I found out that there are other configurations in our fleet. I would suggest standardizing our fleet (with or without the magic carpet system) and have the same panel/grill on all our 757's.
NASA callback
Reporter stated when he mentioned the 'Magic Carpet System' he was using a term that many mechanics and ramp personnel use when referring to B757 aircraft with a movable baggage loading system installed in the forward cargo pits. But some of the B757's his carrier has acquired over time did not have a baggage loading system installed. The Engineering Order (EO) was issued to install a protective grille over the blowout [pressure relief] panel at the aft bulkhead in the forward pit compartment of those B757's without a loading system. Many times when passenger bags were being loaded into the pit; blowout panels without a protective grille would be pushed back into the equipment bay; leaving an opening at the aft bulkhead.Reporter stated a damaged; distorted or pushed-in blowout panel is a 'No-Go' item and not deferrable. Smoke and fire containment is also compromised and is also a 'No-Go' item. But during the baggage loading process on B757's without a loading system installed; bags are loaded against the aft bulkhead and damage to the blowout panel goes unnoticed. Blowout panel damages are not generally an issue with aircraft having a loading system because the aft end of the loading container is a metal wall that stops forward of the aft bulkhead.Reporter stated he did install the grille; but not the blowout panel. He and another Mechanic both interpreted the EO and the illustration attached to the EO as indicating the blowout panel was not required after the grille installation. The missing panel was noticed during a 'B' Check and the aircraft was grounded.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.