# Proposed AD FAA-2016-0457: BAE Systems (Operations) Limited Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2016-25-25
- Products: BAE Systems
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: January 21, 2016, 81 FR 3350
- Comments due: March 7, 2016
- Became: [AD 2016-25-25](https://openairdocs.org/ad/2016-25-25)
- Docket: FAA-2016-0457 (https://www.regulations.gov/docket/FAA-2016-0457, where comments are filed)
- Project: 2015-NM-084-AD
- FR document: 2016-01088
- Official PDF: https://openairdocs.org/files/sha256/90/20/9020e7a8e213c206b3879cba623e20da9552e1644f1e7215295f1364732d0c92 (from https://www.govinfo.gov/content/pkg/FR-2016-01-21/pdf/2016-01088.pdf)
- Federal Register: https://www.federalregister.gov/documents/2016/01/21/2016-01088/airworthiness-directives-bae-systems-operations-limited-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D825417C60443EF386257F410081468E.0001
- Page: https://openairdocs.org/proposed/FAA-2016-0457

## Summary

We propose to supersede Airworthiness Directive (AD) 2012-11- 15, for all BAE Systems (Operations) Limited Model 4101 airplanes. AD 2012-11-15 currently requires a one-time detailed inspection for cracks, corrosion, and other defects of the rear face of the wing rear spar, and repair if necessary. Since we issued AD 2012-11-15, we received new reports of cracking found in the wing rear spar and technical analysis results confirmed that the crack initiation and propagation are due to fatigue, with no indication of any other crack initiation mechanism (e.g. stress corrosion). This proposed AD would require repetitive detailed inspections, and repair if necessary. We are proposing this AD to detect and correct cracking in the wing rear spar, which could propagate to a critical length, possibly affecting the structural integrity of the area and resulting in a fuel tank rupture, with consequent damage to the airplane and possible injury to its occupants.

## Notices in this docket

- Jan 21, 2016: Notice of proposed rulemaking (NPRM). (first notice), FR document 2016-01088, comments due Mar 7, 2016 (https://www.federalregister.gov/documents/2016/01/21/2016-01088/airworthiness-directives-bae-systems-operations-limited-airplanes)

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