Are FAA Airworthiness Directives Especially Weird?

FAA Airworthiness Directives (ADs) are one of the clearest examples of Incorporation by Reference (IBR) as a regulatory technique taken to its logical extreme.

What that means in practice

In many modern FAA ADs:

• The binding legal obligation is: "You must comply with the actions specified in [external document]."
• The actual maintenance steps (replace X, inspect Y, torque Z) live in:
  • manufacturer service bulletins
  • EASA (European) ADs
  • OEM manuals
  • other proprietary documents

What you see in REGTEXT

When you look at the regulatory text of a typical FAA AD, you often see:

• Compliance wrappers — "Comply with this AD within the compliance times specified"
• Cross-references to paragraphs — "as specified in paragraph (g)"
• IBR pointers — "This AD requires accomplishing the actions specified in Boeing Service Bulletin 737-57-1234"

…but not the actual maintenance actions themselves.

Why this matters for requirement extraction

FRTracker's requirement extraction is deterministic and rule-based. We only extract requirements that:

1. Appear in REGTEXT sections (the actual binding regulatory text)
2. Contain concrete action verbs (replace, inspect, install, remove, etc.)
3. Are not compliance wrappers (which are tautological meta-instructions)

For FAA ADs that heavily use IBR, the REGTEXT may contain zero extractable requirements because all the concrete obligations are in the external documents.

This is intentional, not a bug

We could artificially inflate extraction rates by treating "Comply with this AD" as a requirement—but that would be misleading. A compliance wrapper tells you that you must comply, not what you must do.

The extraction algorithm is documented in detail at REQUIREMENT_EXTRACTION.md and is designed to be iterable by future developers without AI assistance.