Narrative:

Service bulletin 777-78-0061 was introduced to our shop in 2006. At that time company X came to us to train the shop for working this service bulletin. In referencing this service bulletin; anytime that the fasteners are to be installed wet; it explicitly calls for this in the right-hand column of the instructions along with the boeing materials specification (bms) numbers. When any parts are to be faying sealed; it also calls out for this to be done in the right-hand column as well as the bms numbers to use. Company X manufactures the thrust reversers with the v-blades installed without sealant. The verbiage of the service bulletin refers to the v-blade; numerous times. During the transformation of the work going to another maintenance base; the service bulletin was interpreted by the new shop as the v-blade installation was to be wet with faying sealant. This was not the interpretation of our shop. The questioned step #26 refers to the v-blade fitting (different verbiage) to have less than 0.0620 of a gap -- a footnote of faying sealant with no bms number being called out for. We did not interpret this as sealing the entire v-blade until an email dated feb/09 that states an investigation was in progress to determine if all of the thrust reversers that had the service bulletin accomplished were installed with sealant. Nowhere in the service bulletin does it explicitly call out for the v-blade to be installed wet with sealant. It seems as if it were an afterthought. A review of the photos taken during the training of the shop by company X shows no sealant being used in the v-blade installation. There is also no reference in our shop manual of this being an airworthiness directive; nor pending airworthiness directive. But it has now come to our attention that it may be. Supplemental information from acn 824378: I was never under the impression that the v-blade and fasteners were to be installed wet. After studying service bulletin #777-78-0061 again; I still feel that particular step was never laid out. Boeing admitted they did not have them assembled wet; but that is what they wanted from us. Also; the v-blade is called a v-blade many times throughout the service bulletin. Why on this page it is called a v-blade fitting? Any why no bms number mentioned? I believe it was because the sealant for the small v-blade fitting was called out elsewhere in the service bulletin so it wasn't necessary to repeat it. Supplemental information from acn 824374: I never understood the service bulletin to specifically specify that the v-blade was to be installed wet. All the repair parts of this service bulletin are specifically called out to be installed wet. In my interpretation; the v-blade itself is not called out to be installed wet. Callback conversation with reporter acn 824375 revealed the following information: reporter stated the issues involve the v-blade on each of the two reverser halves on rolls royce rb-211 engines that secure the reverser halves to the aft end of the engine fan case. V-blade have been found cracked at the top and bottom ends. Any outer v-blade section found cracked; requires removal and a new configuration v-blade be installed. If no crack is found; the outer v-blade is still changed and installed with new support brackets at the top and bottom ends. These brackets are also called bathtub fittings; because they look similar to a bathtub. Reporter stated a resolution was reached by his company's engine shop engineering and boeing; that the cad plated fasteners; used to secure the v-blade; would be installed with a wet sealant referred to as bms 5-45; as the preferred method; although using a liquid primer bms 10-11; type 1; would be acceptable as an alternate. Reporter stated they would use the wet method sealant; because they believe the sealant would be more effective in preventing corrosion in the fastener holes. The faying sealant application on the v-blade; would also be optional.

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Original NASA ASRS Text

Title: Five mechanics report about their understanding of repair procedures related to Service Bulletin 777-78-0061; for the inspection and any necessary repairs; to the outer V-Blades on the thrust reversers of Rolls Royce RB-211 engines. Airworthiness Directive AD 2006-26-06.

Narrative: Service Bulletin 777-78-0061 was introduced to our shop in 2006. At that time Company X came to us to train the shop for working this service bulletin. In referencing this service bulletin; anytime that the fasteners are to be installed wet; it explicitly calls for this in the right-hand column of the instructions along with the Boeing Materials Specification (BMS) numbers. When any parts are to be faying sealed; it also calls out for this to be done in the right-hand column as well as the BMS numbers to use. Company X manufactures the thrust reversers with the V-Blades installed without sealant. The verbiage of the service bulletin refers to the V-Blade; numerous times. During the transformation of the work going to another maintenance base; the service bulletin was interpreted by the new shop as the V-Blade installation was to be wet with faying sealant. This was not the interpretation of our shop. The questioned step #26 refers to the V-Blade fitting (different verbiage) to have less than 0.0620 of a gap -- a footnote of faying sealant with no BMS number being called out for. We did not interpret this as sealing the entire V-Blade until an email dated Feb/09 that states an investigation was in progress to determine if all of the thrust reversers that had the service bulletin accomplished were installed with sealant. Nowhere in the service bulletin does it explicitly call out for the V-Blade to be installed wet with sealant. It seems as if it were an afterthought. A review of the photos taken during the training of the shop by Company X shows no sealant being used in the V-Blade installation. There is also no reference in our shop manual of this being an Airworthiness Directive; nor pending Airworthiness Directive. But it has now come to our attention that it may be. Supplemental information from ACN 824378: I was never under the impression that the V-Blade and fasteners were to be installed wet. After studying Service Bulletin #777-78-0061 again; I still feel that particular step was never laid out. Boeing admitted they did not have them assembled wet; but that is what they wanted from us. Also; the V-Blade is called a V-Blade many times throughout the service bulletin. Why on this page it is called a V-blade fitting? Any why no BMS number mentioned? I believe it was because the sealant for the small V-Blade fitting was called out elsewhere in the service bulletin so it wasn't necessary to repeat it. Supplemental information from ACN 824374: I never understood the service bulletin to specifically specify that the V-Blade was to be installed wet. All the repair parts of this Service Bulletin are specifically called out to be installed wet. In my interpretation; the V-Blade itself is not called out to be installed wet. Callback conversation with reporter ACN 824375 revealed the following information: Reporter stated the issues involve the V-Blade on each of the two reverser halves on Rolls Royce RB-211 engines that secure the reverser halves to the aft end of the engine fan case. V-Blade have been found cracked at the top and bottom ends. Any outer V-Blade section found cracked; requires removal and a new configuration V-Blade be installed. If no crack is found; the outer V-Blade is still changed and installed with new support brackets at the top and bottom ends. These brackets are also called bathtub fittings; because they look similar to a bathtub. Reporter stated a resolution was reached by his company's Engine Shop Engineering and Boeing; that the Cad plated fasteners; used to secure the V-Blade; would be installed with a wet sealant referred to as BMS 5-45; as the preferred method; although using a liquid primer BMS 10-11; type 1; would be acceptable as an alternate. Reporter stated they would use the wet method sealant; because they believe the sealant would be more effective in preventing corrosion in the fastener holes. The faying sealant application on the V-Blade; would also be optional.

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.