# Proposed AD FAA-2011-0991: the Boeing Company Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2012-13-08
- Products: Boeing
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: September 22, 2011, 76 FR 58722
- Comments due: November 7, 2011
- Became: [AD 2012-13-08](https://openairdocs.org/ad/2012-13-08)
- Docket: FAA-2011-0991 (https://www.regulations.gov/docket/FAA-2011-0991, where comments are filed)
- Project: 2010-NM-134-AD
- FR document: 2011-24356
- Official PDF: https://openairdocs.org/files/sha256/72/c9/72c9336f6082c7f527b6e6c0837d8ef8d91a428736c6820ae7aa74f7062a7b57 (from https://www.govinfo.gov/content/pkg/FR-2011-09-22/pdf/2011-24356.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/09/22/2011-24356/airworthiness-directives-the-boeing-company-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/56B010A77DA8150586257913004A08E1.0001
- Page: https://openairdocs.org/proposed/FAA-2011-0991

## Summary

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain Model 747-100, 747-100B, 747- 200B, 747-200C, 747-200F, 747-400F, 747SR, and 747SP series airplanes, without a stretched upper deck or stretched upper deck modification. The existing AD currently requires repetitive inspections for cracks of each affected tension tie and of the surrounding structure, and related investigative and corrective actions if necessary. This proposed AD would also require, for certain airplanes, modifying the tension tie structure or tension tie and frame structure at certain stations; and a post-modification inspection of the modified area and post-modification repetitive inspections of the unmodified area, and repair if necessary. Doing the modification would terminate the repetitive inspection requirements in the existing AD. This proposed AD would reduce the compliance time and add inspections for certain airplanes. This proposed AD results from reportsthat certain airplanes have tension ties that are susceptible to widespread fatigue damage. This proposed AD also results from reports of cracks on the forward and aft tension tie channels at station (STA) 740 and STA 760, and a determination that initial inspection intervals need to be reduced. We are proposing this AD to prevent tension ties from becoming severed or disconnected from the frames, which could lead to rapid in-flight decompression.

## Notices in this docket

- Sep 22, 2011: Notice of proposed rulemaking (NPRM). (first notice), FR document 2011-24356, comments due Nov 7, 2011 (https://www.federalregister.gov/documents/2011/09/22/2011-24356/airworthiness-directives-the-boeing-company-airplanes)

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