14 CFR §13.53

1. (a)Filing. Discovery requests and responses are not filed with the FAA Hearing Docket unless in support of a motion, offered for impeachment, or other permissible circumstances as approved by the hearing officer.
2. (b)Scope of discovery. Any party may discover any matter that is not privileged and is relevant to any party's claim or defense.
3. (c)Time for response to written discovery requests.
   1. (1)Written discovery includes interrogatories, requests for admission or stipulations, and requests for production of documents.
   2. (2)Unless otherwise directed by the hearing officer, a party must serve its response to a discovery request no later than 30 days after service of the discovery request.
4. (d)Depositions. After the respondent has filed a request for hearing and an answer, either party may take testimony by deposition.
5. (e)Limits on discovery. The hearing officer may limit the frequency and extent of discovery upon a showing by a party that—
   1. (1)The discovery requested is cumulative or repetitious;
   2. (2)The discovery requested can be obtained from another less burdensome and more convenient source;
   3. (3)The party requesting the information has had ample opportunity to obtain the information through other discovery methods permitted under this section; or
   4. (4)The method or scope of discovery requested by the party is unduly burdensome or expensive.