# Boeing Alert Service Bulletin 747-21A2577

Copy: Revision 1 ("SB 747-21A2577 R1"), 66 pages: PDF https://openairdocs.org/files/sha256/47/42/47426d6742e11fb152ec64b10fbd71c9a9182557f4d2f6cf81693dcb2207e690; text https://openairdocs.org/service-documents/boeing/747-21a2577/file/47426d6742e1.md. Rights: © The Boeing Company. Filed by the FAA in regulations.gov docket FAA-2022-1058, the docket of AD 2023-03-15. Not covered by OpenAirDocs’ CC0 dedication.

## Details

- Manufacturer: [Boeing](https://openairdocs.org/service-documents/boeing.md)
- Type: Service bulletin (Alert Service Bulletin)
- Number: 747-21A2577
- Latest revision known: 747-21A2577, Revision 2, dated February 10, 2023 (OpenAirDocs)
- Page: https://openairdocs.org/service-documents/boeing/747-21a2577

## ADs that cite it (2) (OpenAirDocs)

Newest first, with the revision each names, as OpenAirDocs read it from the AD's text.

- [AD 2023-03-15](https://openairdocs.org/ad/2023-03-15.md), effective Apr 14, 2023: Revision 2
- [AD 2021-07-09](https://openairdocs.org/ad/2021-07-09.md), effective May 12, 2021: No revision named

Also cited in [2 proposed ADs](https://openairdocs.org/service-documents/boeing/747-21a2577/proposed.md).

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