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Technician reported that material substitutions during a skin replacement were found to be out of compliance.
| Attributes | |
| ACN | 1689278 |
| Time | |
| Date | 201903 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Light | Night |
| Aircraft 1 | |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Parked |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Cargo Door |
| Person 1 | |
| Function | Technician |
| Qualification | Maintenance Powerplant Maintenance Airframe |
| Experience | Maintenance Technician 25 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Deviation - Procedural Maintenance |
Narrative:
Currently [maintenance] is working a skin change on a 737 forward cargo door. While drilling up a pre-shaped skin it was realized that this skin was not fabricated for use on this mpn or model door. During discussions about the discrepancy with the crew; it came up that one of these pre-formed skins had been used in the past for a same model; mpn door.a review of the records shows that earlier this year; [maintenance] produced a 737-800 cargo door by installing a skin fabricated by engineering order and drawing 52-XXXX-XXX.the skins fabricated per the engineering order and drawing are for a different model aircraft. This alone does not make these skins unusable but the fact that engineering based their approvals on a different aircraft model type; when approving the material substitution; does.the original substitution approvals were for an original skin bonded from two layers of 036 2024-T3; substituted for one single thickness skin of .071 2024-T42; for the aft cargo door of a 737-200/300.we installed this .071 2024-T42 on a forward cargo door where the original skin was .071 2024-T3. The engineering order; as stated; does not cover forward cargo doors or 737-800s. To use the structural repair manual material substitution chart in an effort to allow for the substitution of a -T42 skin vs a -T3 skin requires additional thickness due to the different heat treat properties.therefore the skin installed is an out of compliance situation.
Original NASA ASRS Text
Title: Technician reported that material substitutions during a skin replacement were found to be out of compliance.
Narrative: Currently [Maintenance] is working a skin change on a 737 forward cargo door. While drilling up a pre-shaped skin it was realized that this skin was not fabricated for use on this MPN or model door. During discussions about the discrepancy with the crew; it came up that one of these pre-formed skins had been used in the past for a same model; MPN door.A review of the records shows that earlier this year; [Maintenance] produced a 737-800 cargo door by installing a skin fabricated by Engineering Order and drawing 52-XXXX-XXX.The skins fabricated per the Engineering Order and drawing are for a different model aircraft. This alone does not make these skins unusable but the fact that engineering based their approvals on a different aircraft model type; when approving the material substitution; does.The original substitution approvals were for an original skin bonded from two layers of 036 2024-T3; substituted for one single thickness skin of .071 2024-T42; for the aft cargo door of a 737-200/300.We installed this .071 2024-T42 on a forward cargo door where the original skin was .071 2024-T3. The Engineering Order; as stated; does not cover forward cargo doors or 737-800s. To use the Structural Repair Manual material substitution chart in an effort to allow for the substitution of a -T42 skin vs a -T3 skin requires additional thickness due to the different heat treat properties.Therefore the skin installed is an out of compliance situation.
Data retrieved from NASA's ASRS site 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.