Comment from Southwest Airlines

Comment #1: SWA requests the addition of a third note to Paragraph (h) for Exceptions to Requirements Bulletin Specifications. Suggested wording is as follows: “(h)(3) Where Boeing Alert Requirements Bulletin 737–53A1421 RB, dated March 20, 2025, specifies contacting Boeing for repair instructions for any corrosion found, minor corrosion repairs or replacement of parts due to corrosion are exempt from the requirements of this AD.” The intent of this additional exception is to account for Minor Repairs and part replacement, specifically those related to corrosion damage discovered during inspections. It would be beneficial to clarify that any corrosion damage repaired in line with the allowable damage limits laid out in the SRM or by Boeing E-UM’s should not require an AMOC to the AD. According to Title 14 CFR 121.379, a certificate holder may perform and approve a repair if it is not classified as a major repair. Additionally, if the aft drain mast fitting shows minor corrosion, replacing the part instead of repairing it should also be considered, this should fit in with the above’s comment regarding “replacement of parts due to corrosion” being exempt from the requirements of this AD. For cases where corrosion damage is more extensive, or if crack damage is found that requires a major reinforcing repair, then obtain an AMOC per paragraph (i). It's likely that some minor corrosion will be discovered and addressed with a non-reinforcing repair—these situations shouldn't disrupt the inspection program or compromise the safety of continued aircraft operations. Comment #2: The addition of the proposed (h)(3) above could cause uncertainty between exceptions (2) and (3). Therefore, SWA suggests (h)(2) be updated with the following verbiage change: “… alternative inspection: Except as specified in (3), this AD….”