14 CFR § 11.47 - May I ask for more time to file my comments?
Yes, if FAA grants your request for more time to file comments, we grant all persons the same amount of time. We will notify the public of the extension by a document in the Federal Register. If FAA denies your request, we will notify you of the denial. To ask for more time, you must file a written or electronic request for extension at least 10 days before the end of the comment period. Your letter or message must -
(a) Show the docket number of the rule at the top of the first page;
(b) State, at the beginning, that you are requesting an extension of the comment period;
(c) Show that you have good cause for the extension and that an extension is in the public interest;
(d) Be sent to the address specified for comments in the rulemaking document on which you are commenting.