Ratio-Based Inspections
A ratio-based inspection evaluates multiple individual items as part of a single inspection, rather than a single item. Examples include tool inspections and aircraft forms inspections, where you review a defined number of items.
The acceptable quality limit (AQL) is established based on the standard number of inspection items. If the actual number of items you inspect differs from that standard, EQuAD recalculates the AQL based on the number you actually inspected.
How the AQL is calculated
Example: tool inspection
- Standard number of tools to inspect — 40
- Standard AQL — 2
This gives a base ratio:
2 ÷ 40 = 0.05
During the inspection, you examine 2 drawers containing a total of 50 tools.
The adjusted AQL is calculated using this ratio:
50 × 0.05 = 2.5
Since the AQL must be a whole number, the result rounds up:
Adjusted AQL = 3
So when you inspect 50 tools instead of the standard 40, the allowable AQL becomes 3 rather than the original 2.
When the inspection task you select is configured as ratio based, a Ratio-Based Inspection Details panel appears on the inspection form.
Enter the number of items inspected
- Use the + and − buttons to adjust the number of items inspected, or enter a number directly. Press and hold either button to change the value continuously.
- Review the ratio bar to see how your inspected items are grouped. Each highlighted boundary marks the end of a ratio group.
- Review the Calculated AQL to see the resulting acceptable quality level based on the number of items inspected.
Click How this works to expand an explanation of the ratio calculation.
The number of items inspected is limited to 60.
Where to find the AQL
The acceptable quality level (AQL) for an inspection displays next to the Findings heading on the inspection form, rather than in its own separate section. This applies to all inspections, not just ratio-based ones — for a ratio-based inspection, this value matches the Calculated AQL shown in the panel above.