Top 10 Nadcap AC7117 Findings in 2024 and How to Prevent Them

Audit question reference: AC7117 §3.1 — "Is the equipment qualified for the process being used?"

Typical finding: Auditor observes that a nozzle was replaced with a different material (e.g., boron carbide to tungsten carbide) or a different bore diameter, but no new saturation curve was run and the EQR was not updated. The existing EQR references the old nozzle specification.

Root cause: Absence of a formal process change control (PCC) procedure that flags nozzle replacement as a requalification trigger. Maintenance personnel replace nozzles without notifying the quality system.

Prevention: Implement a formal PCC procedure with a requalification trigger matrix. Train maintenance personnel to complete a "process change notification" before replacing nozzles, adjusting machine components, or changing setup parameters. Require quality sign-off before the machine returns to production after any maintenance event.

Typical finding: The curve on file was established with only the nominal time T and one additional data point at approximately 1.5T. There is no data point at 2T, so the 10% saturation criterion cannot be verified from the record. Alternatively, the curve shows H(2T) > 1.10 × H(T) but was accepted anyway.

Root cause: Process engineers unfamiliar with SAE J443 saturation requirements, or historical curves established before the 10% criterion was clearly understood.

Prevention: Standardize the saturation curve form to require a minimum of four data points including explicit T and 2T pairs. Calculate and record H(2T)/H(T) on every curve form. Train all personnel who qualify saturation curves on SAE J443 requirements. Implement a second-reviewer requirement before curves are filed in the EQR.

Typical finding: The Almen arc height gage in use has a calibration sticker showing the last NIST-traceable calibration was 14 months ago. AMS 2430 requires calibration verification every 8 hours of use (or per a facility-defined interval approved by the customer). The facility cannot produce calibration records for intermediate verifications.

Root cause: Calibration interval is based on calendar time rather than hours of use, and the calibration tracking system is not integrated with machine usage logs.

Prevention: Track gage usage hours via machine log or time-stamped calibration checks. Perform and document gage verification with reference blocks at start-of-shift. Maintain a calibration log at each gage station showing date, time, reference block value, actual reading, and technician ID. Spare gages should be available and calibrated to prevent production interruption during calibration events.

Typical finding: Auditor requests the Certificate of Conformance for the current peening media lot in use. The facility cannot locate the C of C, or the C of C references an AMS specification revision that has been superseded, with no documentation that the media meets the current revision.

Root cause: Media C of Cs are received and filed without systematic linkage to media lots in use. Supplier delivers new media with C of C attached to the pallet, which gets discarded. No formal incoming inspection procedure.

Prevention: Implement a media receiving procedure requiring the C of C to be scanned and logged in the quality system before any new lot is placed in inventory. Link each media lot to its C of C in the production traveler. Establish a media lot control procedure with unique lot ID labels applied to all storage containers.

Typical finding: Production travelers contain the arc height value and strip type but are missing the machine ID, nozzle ID, or time of measurement. AMS 2430 §10 requires full traceability linking each production lot to the specific qualified equipment configuration used.

Root cause: Traveler template was designed years ago and was not updated to reflect current AMS 2430 traceability requirements. Operators fill in whatever fields are present on the form.

Prevention: Audit the shop traveler against AMS 2430 §10 documentation requirements. Add required fields: machine ID, nozzle/wheel ID, strip type, arc height, date, time, operator ID, media lot number. Consider an electronic traveler system that enforces required fields before sign-off.

Typical finding: Operators perform coverage inspection by visual examination but there is no written procedure defining the method (UV vs. visible light, magnification, tracer dye specification, acceptance criteria). Different operators apply different standards.

Root cause: Coverage inspection has historically been performed by experienced operators using tacit knowledge rather than a formal written procedure.

Prevention: Write a formal coverage inspection procedure per AMS 2430 §9.2. The procedure must specify: inspection method (UV/visible), light source wavelength and intensity (for UV), magnification (>10×), tracer dye type and application method, acceptance criteria (100% coverage definition), photographic coverage standards (10%, 50%, 80%, 98%/100%, 200%), and record requirements (photographs, date, inspector ID).

Typical finding: For AMS 2433 (manual shot peening), operator qualification requires demonstrated technique with witness test results. The facility has operators performing manual peening whose qualification cards show only classroom training, not a witnessed and documented performance demonstration. Additionally, refresher training intervals are not defined.

Root cause: Training program was established for automatic peening operations and was not updated when manual peening was added to the scope.

Prevention: Establish a separate qualification pathway for manual peening operators per AMS 2433. The qualification must include a witnessed peening demonstration with Almen strip intensity measurement and coverage inspection. Define refresher intervals (typically 2 years or after extended absence from the task). Maintain qualification cards that show initial and refresher training dates, trainer ID, and witness test results.

Typical finding: The facility's procedure requires monthly sieve analysis of the working mix per AMS 2431. The last sieve analysis on record is 9 weeks old and the facility cannot demonstrate that the working mix meets the qualified size distribution during the intervening period.

Root cause: Sieve analysis is treated as a routine task that gets deprioritized during high production periods. No automated reminder or hold system prevents production when the analysis is overdue.

Prevention: Link media analysis status to the production system so that machines are automatically flagged for a hold when sieve analysis is overdue. Schedule analyses as recurring quality tasks in the production planning system. Consider continuous classification equipment that maintains working mix composition in lieu of frequent analysis.

Typical finding: Review of production travelers reveals that arc heights on production verification strips for a batch processed two months prior were outside the ±15% tolerance band specified in AMS 2430 §9.1. No non-conformance was raised and the parts were shipped.

Root cause: Operators are aware of the arc height requirement but there is no built-in verification that each recorded value falls within tolerance before the traveler is signed off. Out-of-tolerance readings were not recognized as requiring a non-conformance.

Prevention: Add explicit acceptance limits to the strip data field on the traveler (pre-printed upper and lower limits). Train operators to recognize out-of-tolerance readings as stop-and-hold conditions requiring NCR initiation. Implement periodic traveler audits by quality to verify arc height compliance before record archival.

Typical finding: Facility received a single emergency lot of media from an alternate supplier not on their ASL. No supplier qualification was performed before use.

Root cause: Supply chain disruption led to emergency procurement without invoking the supplier qualification procedure. The shortcut was not documented and not approved by quality.

Prevention: Establish a supplier deviation or concession process for emergency procurement that requires quality approval with documented risk assessment before any non-ASL media is used. Pre-qualify 2–3 media suppliers per media type to provide flexibility without emergency ASL bypasses. Maintain minimum safety stock levels to avoid supply chain emergencies.