Airworthiness Requirements and Aircraft Systems
Airworthiness questions confirm that you know what keeps a glider legal: inspections, documents, placards, and the systems you preflight.
Inspections and documents
- An annual inspection within the preceding 12 calendar months (91.409); a 100-hour inspection is not required because gliders are not operated for hire.
- An experimental amateur-built glider needs an annual condition inspection by the holder of the repairman certificate or an appropriately rated mechanic.
- Airworthiness directives apply to gliders and their components, including tow releases and oxygen cylinders.
- Preventive maintenance by an owner-pilot covers the items in Part 43 Appendix A, which includes fabric work on a glider.
- Required aboard: airworthiness certificate, registration, operating limitations, and weight and balance data.
- Gliders are excepted from the ELT requirement (91.207) and from transponder/ADS-B rules when there is no engine-driven electrical system.
Systems you must know
- Flight controls, trim, and spoilers or dive brakes; the spoiler handle must be checked for full travel and freedom before launch.
- Tow release: check that it operates and that the ring or weak link is correct for the glider.
- Instruments: airspeed, altimeter with a current setting, variometer, and yaw string.
- Ballast tanks, canopy latch and jettison, wheel brake, oxygen system, and radio.
Worked example
The annual inspection in the logbook is signed 3 September 2024 and today is 15 October 2025. The inspection is valid through the last day of the 12th month, 30 September 2025, so the glider is not airworthy for flight today until the inspection is completed and endorsed. A preflight that finds everything else serviceable does not fix this.
Traps that cost marks
Assuming gliders need an ELT or a transponder; confusing the annual inspection with a condition inspection; skipping the tow release check because the launch "felt fine last time"; and flying with a placarded limitation the pilot has never read.