Calibration Anomaly Before Acceptance
You are the lead engineer for the environmental qualification of a naval seeker. Thirty-six hours before the customer acceptance review, a junior engineer reports that the 200 Hz vibration run shows a 15% amplitude exceedance above the qualification limit. The data-acquisition calibration sticker expired two days before the run. Your manager says, 'Log it as an anomaly, note the calibration issue, and proceed-the schedule cannot slip.' The junior proposes a 48-hour re-test costing $20,000. A metrology team says it can cross-check the suspect channel against a backup sensor in six hours. The customer representative is pressing for sign-off and has hinted that a delay will damage the programme's reputation. The seeker is intended for a crewed platform. You have authority to halt the test but not to change the schedule without the programme director's approval. The qualification limit exists to prevent in-service cracking.
1. What is the most defensible immediate action, and why?
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The immediate action should be to pause acceptance sign-off and authorise the six-hour backup-sensor cross-check, while informing the programme director and customer that the data are under validity review. This is defensible because the exceedance may be real or may be an artefact of an out-of-calibration channel; the cross-check is the fastest way to distinguish those cases. Proceeding with an anomaly note would convert an unresolved safety question into an accepted risk on a crewed platform. Jumping straight to a 48-hour re-test is thorough but premature and costly if the channel is faulty. The cross-check buys evidence at low cost and keeps the schedule decision open. Transparency with the customer is part of the action, not an afterthought.
2. Rank these options and justify the ranking: (a) proceed with the anomaly note; (b) order the 48-hour re-test immediately; (c) run the six-hour cross-check, then decide.
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Best is (c): it produces decision-quality evidence quickly and preserves the option to re-test only if the exceedance is credible. Second is (b): it is conservative and likely to produce valid data, but it consumes 48 hours and $20,000 before the cheaper diagnostic is tried, and it may still be inconclusive if the test article is damaged. Worst is (a): it treats unverified data as acceptable and relies on a calibration note to neutralise a 15% exceedance. On a crewed platform, the cost of a missed crack is not comparable to a schedule slip. The ranking follows evidence value, safety consequence, and proportionality: diagnose first, re-test if needed, never sign off on unresolved safety data.
3. The manager later asks you to sign a statement that 'the test met requirements with a minor anomaly.' Outline your response and explain the work-style behaviour being tested.
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I would decline to sign that wording and propose accurate alternatives: 'At 200 Hz, the measured amplitude exceeded the qualification limit by 15% on a channel whose calibration had expired. Data validity is under investigation. Acceptance has not yet been demonstrated.' I would escalate to the programme director, document the decision trail, and ask the customer for a short hold while the cross-check runs. The behaviour tested is integrity under schedule pressure: evidence-based judgement, courage to dissent from a manager, transparent communication, and safety ownership. It is not disloyalty to escalate a safety-relevant data-integrity issue; it is the role of a lead engineer. Signing a misleading statement would damage trust more than a delay, and it would leave the programme exposed if the anomaly later proved real.