Condition Inspections vs. FAA Annuals

One of the advantages of owning an experimental amateur-built aircraft like the Rans S-21 is that you're not subject to the FAA's annual inspection requirements that govern certified aircraft. However, your operating limitations — issued with your Experimental Airworthiness Certificate — almost certainly require an annual condition inspection. This is not optional, and failing to complete it keeps your aircraft legally unairworthy.

The good news: as the builder of an E-AB aircraft, you're eligible to act as the repairman for your own aircraft and conduct the condition inspection yourself. If someone else built it, you'll need a licensed A&P mechanic or a person holding a Repairman Certificate for that specific aircraft.

Preparing for the Inspection

Set aside adequate time — a thorough condition inspection shouldn't be rushed. Gather your aircraft records, the original build manual, and any maintenance logs. Review your previous inspection records for any deferred items or noted concerns.

You'll also want the right tools: adequate lighting (an inspection light or headlamp is essential), a torque wrench, basic hand tools, and a clean workspace that allows access to all major aircraft systems.

Airframe Inspection Areas

Fuselage and Structure

  • Inspect all primary structural tubes and skins for cracks, corrosion, or deformation
  • Check all rivet lines for any signs of working (elongated holes, cracked skin near rivets)
  • Inspect all bolts and screws for proper torque and safety wire/cotter pin installation
  • Check all welded joints for cracking (if applicable to your airframe variant)

Control Surfaces and Linkages

  • Check all control cables for fraying, kinking, or corrosion; verify proper tension
  • Inspect all rod-end bearings and clevis pins for wear and proper cotter pin installation
  • Verify full and free movement of all control surfaces (ailerons, elevator, rudder)
  • Check for any binding or excessive play throughout the full range of motion
  • Inspect flap mechanism (if equipped) for proper operation and rigging

Wings and Empennage

  • Inspect wing skins for any signs of impact damage, wrinkles, or oil canning that wasn't there before
  • Check wing attachment hardware — these are primary structural fasteners and deserve careful attention
  • Inspect all fairings and leading edges for impact damage or loose fasteners

Powerplant Inspection (Rotax 912 Series)

The Rotax 912 is a well-proven engine, but it has its own maintenance requirements that differ from traditional Lycoming/Continental powerplants. Key items for the annual condition inspection include:

  • Oil change — Rotax recommends specific oil types and intervals; follow the Rotax maintenance manual, not generic aircraft engine guidance
  • Spark plug inspection — check gap, condition, and torque; Rotax uses automotive-style plugs
  • Gearbox oil check — the Rotax 912 has a separate gearbox (reduction drive) that requires its own oil service
  • Rubber component inspection — Rotax uses rubber mounts and hoses that have calendar-life limits regardless of hours flown
  • Carburetor synchronization — the dual-carb 912 requires periodic sync; check and adjust as needed
  • Airbox and air filter — inspect for condition and security; a contaminated filter affects engine performance significantly

Landing Gear and Brakes

  • Inspect gear legs for cracks, especially at attachment points
  • Check tire pressure and inspect for wear and sidewall condition
  • Inspect brake discs for wear and pad thickness
  • Check all brake hydraulic lines for chafing and leaks
  • Verify nose gear (if tricycle) or tailwheel steering for proper rigging and wear

Avionics and Electrical

  • Check battery condition and charge; load-test if the battery is more than two years old
  • Inspect all wiring for chafing, loose connections, or corrosion at terminals
  • Verify all avionics power up correctly and pitot/static system is unobstructed
  • Confirm ADS-B Out is functioning and squawking correctly

Documenting the Inspection

Log the completed condition inspection in your aircraft maintenance records with the date, aircraft total time, and a statement that the aircraft was inspected and found airworthy (or noting any discrepancies and how they were addressed). This record is required and protects you legally as well as practically.