FAA enforcement actions typically begin with either an FAA inspector witnessing or learning of an FAR violation. If the FAA finds basis for enforcement action, they will issue a Letter of Investigation which gives an airman an option to respond or not, within ten days. It is at this point that the airman should seek the help of an aviation attorney, if (s)he hasn't already done so. In some instances a carefully drafted explanation with facts and argument may convince the FAA to drop the case. If the FAA continues its efforts against the airman, they will usually issue a Notice of Proposed Certificate Action (or civil penalty) if they do not consider the matter an emergency. At this point the airman has three choices: surrender his or her certificate, ask for an informal conference probably to be conducted with an FAA attorney at an FAA regional office, or formally appeal the case before an NTSB administrative law judge. If the airman or the FAA is not content with the judges findings, the case can be appealed to the full NTSB board. Appeal thereafter may be taken to the U.S. Court of Appeals.
If for some reason after learning of an FAR violation the FAA believes an emergency response is required, they may issue an Emergency Revocation Order, after which the airman must surrender all certificates immediately. Failure to surrender all certificates results in a possible $1100.00 per-day penalty. An airman may appeal the emergency aspect of the order, but this must be done within two days of receipt of the order. If an airman doesn't use the two-day appeal, an airman must surrender all certificates but then can still file an appeal as described in the paragraph above. FAA discovery of certain acts, like falsifying airman logbooks and certificate applications, certainly result in emergency revocation of all certificates, and successful appeals are extremely rare.
Typically non-emergency sanctions may be avoided if the airman had filed a NASA report within ten days of the event that give rise to the FAA's action. It is probably always a good idea to file a timely NASA report when an airman believes (s)he may have violated an FAR. Having filed a report doesn't mean it will necessarily need to be used, but if so, under most circumstances it can prevent sanctions from being brought against the airman. However, the NASA report is not exculpatory in cases of intentional FAR violations, and probably not in the case of an accident. The form is “NASA ARC Form 277, Aviation Safety Report” and can be found on the Internet under “NASA Form” or on the FAA's web site www.faa.gov.
Among the greater authorities granted to the FAA is 49 U.S.C. Sec. 44709, which FAA inspectors refer to as a “709 ride.” It is an evaluation the FAA can impose upon any airman the FAA believes my not be competent. Usually the evaluation includes a flight with an FAA inspector, but may in some instances require only a ground evaluation.