14 CFR §145.221

1. (a)A certificated repair station must report to the FAA within 96 hours after it discovers any serious failure, malfunction, or defect of an article. The report must be in a format acceptable to the FAA.
2. (b)The report required under paragraph (a) of this section must include as much of the following information as is available:
   1. (1)Aircraft registration number;
   2. (2)Type, make, and model of the article;
   3. (3)Date of the discovery of the failure, malfunction, or defect;
   4. (4)Nature of the failure, malfunction, or defect;
   5. (5)Time since last overhaul, if applicable;
   6. (6)Apparent cause of the failure, malfunction, or defect; and
   7. (7)Other pertinent information that is necessary for more complete identification, determination of seriousness, or corrective action.
3. (c)The holder of a repair station certificate that is also the holder of a part 121, 125, or 135 certificate; type certificate (including a supplemental type certificate); parts manufacturer approval; or technical standard order authorization, or that is the licensee of a type certificate holder, does not need to report a failure, malfunction, or defect under this section if the failure, malfunction, or defect has been reported under parts 21, 121, 125, or 135 of this chapter.
4. (d)A certificated repair station may submit a service difficulty report for the following:
   1. (1)A part 121 certificate holder, provided the report meets the requirements of part 121 of this chapter, as appropriate.
   2. (2)A part 125 certificate holder, provided the report meets the requirements of part 125 of this chapter, as appropriate.
   3. (3)A part 135 certificate holder, provided the report meets the requirements of part 135 of the chapter, as appropriate.
5. (e)A certificated repair station authorized to report a failure, malfunction, or defect under paragraph (d) of this section must not report the same failure, malfunction, or defect under paragraph (a) of this section. A copy of the report submitted under paragraph (d) of this section must be forwarded to the certificate holder.