What Supplements Apply to DAFI 21-101? (And Does Your MAJCOM Have One?)
DAFI 21-101 carries MAJCOM supplements from ACC, AMC, PACAF, AFGSC, AFMC and more — but several were certified before the base instruction's latest update, so the local rule may lag. Here's the full tree.
MAJCOM supplements layer onto DAFI 21-101 — and some predate the base's latest change.
The DAFI 21-101 supplement tree
Does my MAJCOM have a supplement?
The lag trap: when a supplement predates its base
How to read a supplement against the base
FAQ
The DAFI 21-101 supplement tree
DAFI 21-101, Aircraft and Equipment Maintenance Management, is the base instruction. Most MAJCOMs publish a supplement that tightens or extends it for their aircraft and operating environment.
The live, always-current tree — every supplement, its command, certification date, and currency flag — is on the DAFI 21-101 page. Start there before you inspect.
Does my MAJCOM have a supplement?
If you fly for ACC, AMC, PACAF, AFGSC, or AFMC, there's a good chance the answer is yes. The supplement controls the local rule wherever it's stricter than the base.
The lag trap: when a supplement predates its base
Here's the finding most inspectors miss. Across the supplements we index, 75% were last updated before the base instruction they modify. A supplement certified in 2022 can't reflect a 2024 change to the base.
of indexed MAJCOM/unit supplements lag the base instruction they modify.
We flag every lagging supplement on the base-pub page with an amber badge, so you can see at a glance whether the local guidance you're inspecting to is behind the base.
How to read a supplement against the base
A supplement only states what it changes. Read it side-by-side with the base: paragraphs the supplement doesn't touch still come from the base instruction.
Frequently asked questions
- Where do MAJCOM supplements to DAFI 21-101 live?
- On the public e-Publishing catalog under each command. CheckMyAFI gathers them into one supplement tree under the base pub so you don't have to hunt command by command.
- If my MAJCOM has no supplement, what controls?
- The base DAFI 21-101 is the controlling document. Absence of a supplement means no command-level additions — not an exemption.
- How do I know if a supplement is out of date?
- Compare its last-updated date to the base instruction's. If the supplement is older, it can't reflect the base's latest changes — we badge these as lagging.
- Does a unit supplement override a MAJCOM supplement?
- Layering runs base → MAJCOM → unit, each adding or tightening. The most specific, most protective applicable requirement controls.