# AIRS Troubleshoot
## Failure Modes and Non-Convergence Examples

**Status:** Informative (Non-Normative)  
**Applies to:** Acoustic Incident Reconstruction Standard (AIRS) v1.0

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## A.1 Purpose of This Appendix

This appendix provides concrete examples of scenarios in which
AIRS either:
- rejects candidate reconstructions, or
- reports non-convergence.

These examples are provided to demonstrate transparency,
not to extend or modify the AIRS standard.

Failure is treated as a valid analytical outcome when
physical or evidentiary constraints cannot be satisfied.

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## A.2 General Failure Taxonomy

AIRS failures fall into four broad categories:

1. Measurement Ambiguity  
2. Clock Model Breakdown  
3. Geometric Underdetermination  
4. Data Integrity Violations

Each category is illustrated below.

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## A.3 Scenario 1 — Phase Ambiguity Without Closure

### Description
Multiple observers record an impulsive event.
Phase-based measurements are internally consistent per device,
but admit multiple integer cycle assignments globally.

### Observed Conditions
- Clean transients on all devices
- Stable phase measurements
- Multiple cycle-count solutions satisfy individual observers

### Why AIRS Rejects
No single integer cycle assignment satisfies all observers
under a shared geometry and bounded speed of sound.

### Outcome
- All candidate solutions rejected
- Event marked **non-resolvable**
- Logged reason: cycle ambiguity without closure

### Key Principle Demonstrated
Local precision does not imply global truth.

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## A.4 Scenario 2 — Clock Drift Beyond Model Bounds

### Description
Two recordings appear aligned early in the incident window
but diverge progressively over time.

### Observed Conditions
- Apparent linear drift exceeding plausible oscillator error
- Required drift parameter deviates significantly from 1.0

### Why AIRS Rejects
The clock model would require implausible drift
to force alignment.

### Outcome
- Drift-bounded hypothesis rejected
- Non-convergence reported unless additional observers exist

### Key Principle Demonstrated
Alignment must remain physically plausible,
not merely numerically achievable.

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## A.5 Scenario 3 — Insufficient Observer Geometry

### Description
Two observers record an event from similar locations
or along nearly collinear lines of sight.

### Observed Conditions
- Arrival time differences within uncertainty
- Large family of geometries satisfy constraints

### Why AIRS Rejects
Geometry is underdetermined.
Multiple event locations remain admissible.

### Outcome
- Timing order may be reported
- Spatial inference withheld
- Geometry flagged as non-unique

### Key Principle Demonstrated
AIRS does not invent geometry where physics does not constrain it.

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## A.6 Scenario 4 — Reverberation-Dominated Signals

### Description
An indoor event is recorded where reflections dominate
and no clear direct arrival can be isolated.

### Observed Conditions
- Multiple strong onsets
- Arrival timing unstable across bandpass filters

### Why AIRS Rejects
No Direct Arrival Candidate (DAC) can be established.

### Outcome
- Event excluded from reconstruction
- Logged as DAC failure

### Key Principle Demonstrated
AIRS prioritizes physical validity over signal richness.

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## A.7 Scenario 5 — Edited or Time-Warped Recordings

### Description
A recording has been edited or processed such that
time is non-linearly distorted.

### Observed Conditions
- Sudden timing discontinuities
- Inconsistent offset or drift estimates across segments

### Why AIRS Rejects
The observer clock model is violated.

### Outcome
- Recording excluded
- Remaining observers re-evaluated
- Possible non-convergence

### Key Principle Demonstrated
AIRS requires temporal integrity to make claims.

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## A.8 Scenario 6 — Competing Solutions Within Tolerance

### Description
Two distinct reconstructions satisfy all constraints
within declared uncertainty bounds.

### Observed Conditions
- Comparable residuals
- No physical constraint favors one solution

### Why AIRS Rejects
AIRS does not select between indistinguishable explanations.

### Outcome
- Multiple solutions reported
- Marked non-unique
- No preferred narrative selected

### Key Principle Demonstrated
Ambiguity is reported, not resolved arbitrarily.

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## A.9 Summary

These scenarios illustrate that AIRS is designed to:
- reject attractive but unsupported solutions,
- halt when physical closure is not achievable,
- and surface ambiguity rather than conceal it.

Failure modes are an expected and documented part
of responsible incident reconstruction.

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## A.10 Relationship to the Standard

This appendix:
- does not alter AIRS requirements,
- does not introduce new constraints,
- and is provided solely for explanatory purposes.

Normative requirements remain exclusively within
the AIRS standard document.
