# 14 CFR Part 39: Airworthiness Directives

> What an AD is, the legal effect of one, and how to comply another way.

Source: https://www.aerscheduler.com/regulations/part-39
Full text of Part 39: https://www.ecfr.gov/current/title-14/part-39

- [14 CFR 39.3: What an Airworthiness Directive is](https://www.aerscheduler.com/regulations/39-3.md): An Airworthiness Directive is a legally enforceable FAA rule, not a recommendation. ADs apply to four kinds of product: aircraft, aircraft engines, propellers and appliances.
- [14 CFR 39.7: Flying without complying with an AD](https://www.aerscheduler.com/regulations/39-7.md): Anyone who operates a product that does not meet the requirements of an applicable Airworthiness Directive is in violation of 39.7. That makes an overdue AD a reason not to fly, and the pilot and the owner can both be held responsible.
- [14 CFR 39.11: What an AD can require](https://www.aerscheduler.com/regulations/39-11.md): An AD can require three kinds of thing: inspections you must carry out, conditions and limitations you must comply with, and actions you must take to resolve the unsafe condition.
- [14 CFR 39.15: ADs on a modified aircraft or part](https://www.aerscheduler.com/regulations/39-15.md): Yes, an AD still applies after the product has been changed. Modifying, altering or repairing the affected area does not take an aircraft or part out of an AD that names it.
- [14 CFR 39.19: Alternative methods of compliance (AMOC)](https://www.aerscheduler.com/regulations/39-19.md): Anyone may propose an alternative method of compliance (AMOC), or a change in compliance time, that gives an acceptable level of safety. You may use it only after the manager of the FAA office named in the AD approves it.
- [14 CFR 39.23: Ferrying an aircraft with an open AD](https://www.aerscheduler.com/regulations/39-23.md): You can usually fly an aircraft with an open AD to a place where the work can be done, but you need a special flight permit (a ferry permit) from the FAA unless your operations specifications already allow it. The AD itself can rule the flight out.