TCM 1 392-1-10 LISI Aerospace [Bestas] Gazemir (TR) EN4127-050, -060, -080, -100

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Conditions for approval required by:  Julien Gauther

3 Replies to “TCM 1 392-1-10 LISI Aerospace [Bestas] Gazemir (TR) EN4127-050, -060, -080, -100”

  1. On FAIR, for all EN4127 part references, in column “Character. Designator”, it is written “minor” for all characteristics.
    How do we interpret “minor”?
    If we consider ISO9152, table 3, dimensional characteristics have not the same category of defects.
    Some dimensional characteristics are considered major with AQL = 1%, other dimensions are ranked as minor with AQL = 2,5% or 4%.
    So, for acceptance, do we have sample size for dimensional inspections as per ISO9152, tables 3 and 4? On FAI, sampling was done as per ANSI/ASQ Z1.4 general control level II and WI-SYS-30, but we do not have AQL applied.
    ISO9152 sampling (tables 3 and 4) is based on ISO2859-1, table II-A, single sampling, normal inspection. ISO2859-1 and ANSI/ASQ Z1.4 are really similar. From my point of view, this is the same way of sampling. Could you please confirm on your side?

    On FPI report for EN4127-050, batch size is 1500 bolts.
    125 bolts were FPI inspected.
    However, as per ISO9152, tables 3 and 4, AQL = 0,065% for discontinuities detection.
    Thus, in ISO9152 table 4, column AQL 0,065%, we have a down arrow marked against production batch size “1201 to 3200”. This down arrow means: “Use sampling plan below (sample size and Ac)”. In the case of sample size is equal to or greater than the batch size, a 100% inspection shall be performed.
    In this case, down arrow leads to sample 200 parts (with Ac = 0). So, 200 bolts should have been FPI checked instead of 125.
    This topic was already discussed in ASD-CERT Mechanical Workshop minutes (released in March 2019).
    These QTR was done before March 2019 since it is dated November 2018. This might explain why there is this sampling issue for FPI. If it is, could you please confirm that actions have been taken to apply right sampling plans?

    On FPI report for EN4127-060, batch size is 134 bolts.
    20 bolts were FPI inspected.
    However, as per ISO9152, tables 3 and 4, AQL = 0,065% for discontinuities detection.
    Thus, in ISO9152 table 4, column AQL 0,065%, we have a down arrow marked against production batch size “91 to 150”. This down arrow means: “Use sampling plan below (sample size and Ac)”. In the case of sample size is equal to or greater than the batch size, a 100% inspection shall be performed.
    In this case, down arrow leads to sample 200 parts (with Ac = 0). So, since this sample size (200) is greater than manufacturing batch (134), a 100% inspection should have been performed instead of 20.
    This topic was already discussed in ASD-CERT Mechanical Workshop minutes (released in March 2019).
    These QTR was done before March 2019 since it is dated November 2018. This might explain why there is this sampling issue for FPI. If it is, could you please confirm that actions have been taken to apply right sampling plans?

    On FPI report for EN4127-080, batch size is 600 bolts.
    80 bolts were FPI inspected.
    However, as per ISO9152, tables 3 and 4, AQL = 0,065% for discontinuities detection.
    Thus, in ISO9152 table 4, column AQL 0,065%, we have a down arrow marked against production batch size “501 to 1200”. This down arrow means: “Use sampling plan below (sample size and Ac)”. In the case of sample size is equal to or greater than the batch size, a 100% inspection shall be performed.
    In this case, down arrow leads to sample 200 parts (with Ac = 0). So, 200 bolts should have been FPI checked instead of 80.
    This topic was already discussed in ASD-CERT Mechanical Workshop minutes (released in March 2019).
    These QTR was done before March 2019 since it is dated November 2018. This might explain why there is this sampling issue for FPI. If it is, could you please confirm that actions have been taken to apply right sampling plans?

    On FPI report for EN4127-100, batch size is 306 bolts.
    50 bolts were FPI inspected.
    However, as per ISO9152, tables 3 and 4, AQL = 0,065% for discontinuities detection.
    Thus, in ISO9152 table 4, column AQL 0,065%, we have a down arrow marked against production batch size “281 to 500”. This down arrow means: “Use sampling plan below (sample size and Ac)”. In the case of sample size is equal to or greater than the batch size, a 100% inspection shall be performed.
    In this case, down arrow leads to sample 200 parts (with Ac = 0). So, 200 bolts should have been FPI checked instead of 50.
    This topic was already discussed in ASD-CERT Mechanical Workshop minutes (released in March 2019).
    These QTR was done before March 2019 since it is dated November 2018. This might explain why there is this sampling issue for FPI. If it is, could you please confirm that actions have been taken to apply right sampling plans?

    Hydrogen content on EN4127-050 bolts: in QTR, table 1, it is stated that 5 bolts were tested and results are recorded in Annex 4 (CoC). However, in Annex 4, we have only 3 results (DICKSON lab test report).
    As per ISO9152, for qualification, 3 bolts shall be tested for hydrogen content. For Acceptance, 1 bolt has to be hydrogen content tested.

    Hydrogen content on EN4127-060, -080 and -100 bolts: in QTR, table 1, it is stated that 5 bolts were tested and results are recorded in Annex 4 (CoC). However, in Annex 4, we have only 3 results.
    As per ISO9152, for qualification, 3 bolts shall be tested for hydrogen content. For Acceptance, 1 bolt has to be hydrogen content tested.

    On EN4127-050 and EN4127-060 macrographic cuts, we can see some crevices on the crests of thread. Could you please confirm that these surface irregularities are within the tolerances specified in ISO9152, table 10?
    Maybe this is in relationship with manufacturing process (reduction used for forming the thread roll diameter by forging, as indicted in manufacturing route).
    On EN4127-080 and EN4127-100 macrographic cuts, these crevices on crests of thread seem to be less visible.

    For fatigue test on EN4127-050 bolts, could you please precise which loads and frequency were applied?

    For fatigue test on EN4127-060 bolts, could you please precise which loads and frequency were applied?

    For fatigue test on EN4127-080 bolts, could you please precise which loads and frequency were applied?

    For fatigue test on EN4127-100 bolts, could you please precise which loads and frequency were applied?

    Many thanks in advance for replying.
    Regards.

    1. Please see “”EN4127 comments.pdf”under Additional Documents section.

      Best regards

      Alper

  2. Thank you for replying. So, after reading your answers, the only remaining topic that needs to be clarified, for me, is sampling plans for non-destructive testing.
    This topic will be processed later.
    Best regards.
    Julien

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