Safety Critical Labs / Measured Evidence

Verification you can measure. On public data.

The framework is only as good as the evidence its requirements produce. These are measured results from applying SCL verification methods to a public dataset, NASA C-MAPSS turbofan degradation. Every number is reproducible from the open repository. The methods that failed their own subject are kept in view, because a verification bench that cannot fail is not a verification bench. Methods and thresholds are those of framework v3.7.

[ Requirements Defined by Failure ]

The failures these
requirements target.

Each requirement area exists because a class of AI failure has already happened in the field. These are documented public cases, each mapped to the area written to catch that failure mode. The mapping names the target. It does not claim any outcome would have changed.

Uber ATG · Tempe, 2018
An automated vehicle did not classify a pedestrian in time
The NTSB investigation found the automated driving system alternated between classifications for a pedestrian crossing outside a crosswalk, and did not brake in time to avoid a fatal collision.
AI-6The failure mode out-of-distribution detection targets.
Air Canada · Tribunal, 2024
A support chatbot stated a refund policy that did not exist
A civil resolution tribunal held the airline liable after its website assistant described a bereavement refund it did not in fact offer, and ruled the company responsible for what its bot said.
AI-5The failure mode hallucination prevention targets.
Zillow Offers · 2021
A home-pricing model drifted out of its market
Zillow wound down its algorithmic home-buying unit after model price forecasts diverged from a fast-moving housing market, taking an inventory writedown reported above 300 million dollars.
AI-4The failure mode continuous validation targets.
Amazon · Recruiting, 2018
A hiring model learned to penalize women
Amazon scrapped an internal recruiting model, reported in 2018, after finding it downgraded resumes that referenced women's activities, a bias absorbed from a decade of historical hiring data.
AI-2The failure mode addressing AI bias targets.
Cruise · San Francisco, 2023
A robotaxi mishandled the moment after a collision
California regulators suspended Cruise's driverless permits after one of its vehicles, following an initial impact from another car, executed a pull-over maneuver that dragged a pedestrian who was in its path.
AI-9The failure mode human and AI teaming targets.
Microsoft Tay · 2016
A live-learning bot was corrupted within a day
Microsoft withdrew its conversational bot Tay less than a day after release, when users exploited its habit of learning from live interactions to steer it into offensive output.
AI-13The failure mode continuous learning and adaptation targets.

The same classes of failure, run as pass and fail measurements on public data. NASA C-MAPSS FD001, methods and thresholds of framework v3.7.

AI-1Leakage caught
A leaky split inflates measured accuracy
Clean split 80.33 percent, leaky split 83.05 percent, on a 78 to 86 percent scale.
+2.72 pptest accuracy when engines are allowed to bleed across train and test, versus a clean unit-level split
This is the failure mode AI-1 targets: train, validation, and test separation with documented provenance. See it measured.
AI-4Monitor qualified
A drift monitor earned through four failed designs
First alert at 0.58 sigma and inhibit at 1.17 sigma of injected bias, on a 0 to 1.5 sigma scale.
0.58σ / 1.17σinjected bias at first alert and at inhibit, once the monitor was designed against a measured no-drift floor
This is the failure mode AI-4 targets: post-deployment drift monitoring with thresholds meaningful against a sampling floor. See it measured.
AI-6AI-12Denial finding
Softmax confidence detects OOD worse than chance
Max-softmax AUROC 0.117, Mahalanobis AUROC 1.0, chance 0.5.
AUROC 0.117for max-softmax OOD scoring: below 0.5 means the model is most confident exactly when it is most wrong
This is the failure mode AI-6 and AI-12 target: a characterized OOD response, not a confidence threshold assumed to work. See it measured.
AI-8AI-12Fail → pass
Confidence miscalibrated, then corrected and re-checked
Expected calibration error 0.160 before and 0.030 after temperature scaling, against a 0.05 pass criterion.
0.160 → 0.030expected calibration error before and after temperature scaling, against a 0.05 pass criterion
This is the failure mode AI-8 and AI-12 target: confidence that means what it says, demonstrated by measurement. See it measured.
[ Subject Under Test ]
Dataset
NASA C-MAPSSFD001 turbofan run-to-failure. Public.
Model
3-class RUL classifierNominal / degraded / critical remaining life
Split
60 / 20 / 20 by unitNo engine appears in two splits
Baseline accuracy
80.33%Held-out test, honest split
AI-1
Leakage caught
A leaky split inflates measured accuracy
+2.72 pp test accuracy when engines are allowed to bleed across train and test, versus a clean unit-level split

Splitting the data by row instead of by engine lets the same asset appear in both training and test. Measured accuracy rises from 80.33% to 83.05%. The gain is not skill. It is memorization the evaluation failed to prevent. A pass threshold set on the leaky number would certify a system that the honest split does not support.

This is the failure mode AI-1 targets: train, validation, and test separation with documented provenance.
AI-4
Monitor qualified
A drift monitor earned through four failed designs
0.58σ / 1.17σ injected bias at first alert and at inhibit, once the monitor was designed against a measured no-drift floor

Naive drift designs fired false alarms on healthy data, population indices past 7.8 where the real signal was noise. Only after declaring regime, per-asset baseline, and window and bin design did the monitor become trustworthy: it alerts at 0.58σ of injected bias and inhibits at 1.17σ. Left unmonitored, the classifier's false-fault rate climbs to 0.70 under full bias.

This is the failure mode AI-4 targets: post-deployment drift monitoring with thresholds meaningful against a sampling floor.
AI-6AI-12
Denial finding
Softmax confidence detects OOD worse than chance
AUROC 0.117 for max-softmax OOD scoring: below 0.5 means the model is most confident exactly when it is most wrong

The popular softmax-confidence detector scores out-of-distribution inputs worse than a coin flip. A Mahalanobis detector recovers gross regime shift perfectly (AUROC 1.0) but catches the subtle near-boundary fan fault only 44% of the time at a 2% false-positive budget. No single OOD method passed every regime. That result is reported as a denial, not smoothed over.

This is the failure mode AI-6 and AI-12 target: a characterized OOD response, not a confidence threshold assumed to work.
AI-8AI-12
Fail → pass
Confidence miscalibrated, then corrected and re-checked
0.160 → 0.030 expected calibration error before and after temperature scaling, against a 0.05 pass criterion

Out of the box the model's stated confidence was off by 0.16 expected calibration error, a clear fail. A single temperature parameter fitted on validation data brought it to 0.030, a pass. The requirement is not that the model is born calibrated. It is that calibration is measured, corrected, and verified before the confidence is trusted.

This is the failure mode AI-8 and AI-12 target: confidence that means what it says, demonstrated by measurement.
[ Why the Failures Stay In ]

A bench that cannot fail its subject is not evidence.

Two of the four results above are failures. The softmax detector performs worse than chance. The out-of-the-box calibration does not pass. They are kept because they are the point. A verification method that certifies whatever it is pointed at proves nothing. These are held to the same pass and fail criteria a real assessment would apply, and they are allowed to fail.

[ Reproduce It ]

Open pipeline. Open data.

The full pipeline, configuration, seeds, and result files are public. Every figure on this page traces to a JSON artifact in the repository, produced under a pre-declared configuration. The framework these methods verify against is openly published under a citable DOI.

Repository github.com/safetycriticallabs/cmapss-verification-demo
Data NASA C-MAPSS FD001. Public, no license restriction on use.
Framework 10.5281/zenodo.19024420 (cite this)

This is a demonstration of SCL verification methods on a public dataset. It is not an issued certification, and it makes no safety claim about any real turbofan engine. It exists to show that the framework's requirements resolve to measurements that can pass, and can fail.