The tiers
Every article carries a tier: Private, Instrument, Commercial, or CFI. The first three are depth — the same subject, explained for a reader one certificate or rating further along. The names are chosen carefully: Private and Commercial are certificates, Instrument is a rating, and CFI is a separate instructor certificate — so the axis is a reading level, not a "certificate level."
Tier 4 is CFI, not ATP, on purpose. Under 14 CFR §61.183(c), a flight instructor applicant (sport-pilot instructors, a separate subpart, excepted) needs a commercial pilot or ATP certificate — so instructing branches off at Commercial: the commercial certificate is the minimum ticket, and the typical route into instructing runs through it. CFI articles are a mode, not a fourth notch of difficulty: they cover how a thing is taught and where learners go wrong, and each one names the article it teaches.
The edges
Articles declare four kinds of connection, and every connection is rendered from both ends automatically — no hand-written cross-links, so nothing dangles:
- Read first — a prerequisite. The build fails if these ever form a cycle.
- Deepens — the same topic, exactly one tier up. Direction is enforced.
- Teaches — a CFI article pointing at the item it teaches.
- Related — lateral connections, including across domains.
The boarding pass
Every article wears one. The seat row encodes the tier — rows 28–32 ride in the back with the Private reader, 18–22 are Instrument, 7–11 Commercial, and rows 1–3 are reserved for CFI. It's a small joke, but it's a consistent one.
Corrections
Every article is fact-checked adversarially before it ships — an independent pass whose job is to flag, not to confirm. When a claim has no documented source, the article says so rather than inventing a tidier story. Spot an error anyway? It will be corrected, and noted.