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Conditions for approval required by: Julien Gauther
Certification of Aerospace Products to international quality Standards
Certification of Aerospace Products to international quality Standards
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On ASD-CERT website, EN/AS9100 certificate validity is expired (11/06/2019).
On FAIR, for all EN4129 part references, in column “Character. Designator”, it is written “minor” for all characteristics.
How do we interpret “minor”?
If we consider ISO7689, 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 ISO7689, 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.
ISO7689 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 MPI report for EN4129-040, batch size is 122 bolts.
20 bolts were MPI inspected.
However, as per ISO7689, tables 3 and 4, AQL = 0,065% for discontinuities detection.
Thus, in ISO7689 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 sample size (200) exceeds mfg batch size, a 100% MPI inspection should have been done 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 MPI. If it is, could you please confirm that actions have been taken to apply right sampling plans?
On MPI report for EN4129-050, batch size is 142 bolts.
20 bolts were MPI inspected.
However, as per ISO7689, tables 3 and 4, AQL = 0,065% for discontinuities detection.
Thus, in ISO7689 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 sample size (200) exceeds mfg batch size (142), a 100% MPI inspection should have been done 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 MPI. If it is, could you please confirm that actions have been taken to apply right sampling plans?
On MPI report for EN4129-060, batch size is 144 bolts.
144 bolts were MPI inspected, which is in line with ISO7689, tables 3 and 4.
AQL = 0,065% for discontinuities detection.
Thus, in ISO7689 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 (144), a 100% inspection was done.
On MPI report for EN4129-080, batch size is 158 bolts.
32 bolts were MPI inspected.
However, as per ISO7689, tables 3 and 4, AQL = 0,065% for discontinuities detection.
Thus, in ISO7689 table 4, column AQL 0,065%, we have a down arrow marked against production batch size “151 to 280”. 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 sample size (200) exceeds mfg batch size (158), a 100% MPI inspection should have been done instead of 32.
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 MPI. If it is, could you please confirm that actions have been taken to apply right sampling plans?
For double shear test on EN4129-040 bolts, could you please precise if these test values were obtained at break? If we consider CoC, it is written “NF”, so, no failure. It means that load values applied were just above the minimum double shear load required. Could you please confirm?
Same questions for double shear tests on EN4129-050 bolts, EN4129-060 bolts and EN4129-080 bolts.
On EN4129-040 and EN4129-050 and EN4129-060 macrographic cuts, we can see some laps on the crests of thread. Could you please confirm that these laps are within the tolerances specified in ISO7689, table 8?
Many thanks in advance for replying.
Regards.
Julien
Please see “EN4129 comments.pdf” under Additional Documents section.
Best Regards
Alper
Thank you for replying. So, after reading your answers (additional documents section), 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