Narrative:

I was acting as rii inspector on the inspection. A previous night weekend crew disassembled the right-hand engine fan blades. Fan blades were laying on the table numbered; when we came into work. During reassembly of the right-hand engine we found the hub to be marked with a felt tip marker 24; 1; 2; 3; 4; 5. Myself; as inspector/mechanic X; and mechanics Y and Z all agreed that this is where the blades should go. The computerized maintenance program (cmp) jobcard calls out to label the blades with a felt tip marker. We also replaced two annulus fillers during the process which may have contributed to the vibration. Over the following weekend the engine was run and resulted in a N1 vibration exceedance and damage to the abradable liner. The weekend crew disassembled the engine and claimed that we had assembled the fan blades approximately 180 degrees off. There were scribed marks on the hub which we did not see. One; with an arrow pointing counter-clockwise (ccw); [positions] 2; 3; it is not clear who put the numbers on the hub with felt tipped marker. The same crew reassembled the engine in what they thought was the correct location of the blades. [Several days later] january 2012; I and three other mechanics disassembled the right-hand engine and found the blades to be clocked-off by one position. (# 1 blade was in # 24 position). Night turn [night shift that evening] reassembled [the blades] in the correct position. Suggest creating a standard method of marking and disassembling for each type of engine. Marking the number one position or top dead center (tdc) on the hub and taking a picture before disassembly. Print picture and have it in the work order (west/O) package. Have the same crew reassemble the engine that disassembled it; if at all possible. There were already photo illustrations of the correct procedure for marking the hub that someone had created for this engine. They were not at the aircraft during the process. Most of the people were not aware that the photos existed. I got a copy of the photos january 2012. The process to do it correctly was already created; it just wasn't available during this inspection.

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Original NASA ASRS Text

Title: An Inspector and Mechanic describe how the lack of a standard method of marking and disassembling the inlet fan blade positions on a BMW Rolls Royce BR710 engine for a Gulfstream V aircraft led to vibration exceedences and damage to the engine inlet abradable liner after reassembly.

Narrative: I was acting as RII Inspector on the inspection. A previous night weekend crew disassembled the right-hand engine fan blades. Fan blades were laying on the table numbered; when we came into work. During reassembly of the right-hand engine we found the Hub to be marked with a felt tip marker 24; 1; 2; 3; 4; 5. Myself; as Inspector/Mechanic X; and mechanics Y and Z all agreed that this is where the blades should go. The Computerized Maintenance Program (CMP) Jobcard calls out to label the blades with a felt tip marker. We also replaced two Annulus fillers during the process which may have contributed to the vibration. Over the following weekend the engine was run and resulted in a N1 Vibration Exceedance and damage to the Abradable Liner. The weekend crew disassembled the engine and claimed that we had assembled the fan blades approximately 180 degrees off. There were scribed marks on the hub which we did not see. One; with an arrow pointing Counter-Clockwise (CCW); [positions] 2; 3; it is not clear who put the numbers on the hub with felt tipped marker. The same crew reassembled the engine in what they thought was the correct location of the blades. [Several days later] January 2012; I and three other mechanics disassembled the right-hand engine and found the blades to be clocked-off by one position. (# 1 blade was in # 24 position). Night turn [Night shift that evening] reassembled [the blades] in the correct position. Suggest creating a standard method of marking and disassembling for each type of engine. Marking the Number One position or Top Dead Center (TDC) on the hub and taking a picture before disassembly. Print picture and have it in the Work Order (W/O) package. Have the same crew reassemble the engine that disassembled it; if at all possible. There were already photo illustrations of the correct procedure for marking the hub that someone had created for this engine. They were not at the aircraft during the process. Most of the people were not aware that the photos existed. I got a copy of the photos January 2012. The process to do it correctly was already created; it just wasn't available during this inspection.

Data retrieved from NASA's ASRS site as of July 2013 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.