The short answer
Inspection Authorization (IA) is an additional FAA authorization held by experienced A&P mechanics that permits them to approve annual inspections and sign off major repairs and alterations on FAA Form 337. Every annual inspection must be approved by an IA or an authorized repair station.
Why IAs matter to owners
The IA is the gatekeeper of the annual cycle: no matter who does the wrench work, the annual's approval for return to service requires an IA's signature. IAs must meet experience requirements, maintain currency through activity and renewal requirements, and are typically the most experienced maintenance professionals an owner deals with.
A long-term relationship with an IA who knows a specific airframe pays off — familiarity with an aircraft's history makes inspections both more efficient and more meaningful.
Related terms and reading
Keep every hour and inspection straight
Maggneto tracks engine times, inspections, and ADs from your actual logbooks — so terms like these become numbers you can act on. Browse the full maintenance glossary.