# Airworthiness Directives; The Boeing Company Airplanes
> **Rule** · Final rule; request for comments. · Published 2018-05-23 · Effective 2018-06-07 · 83 FR 23775
## Document
- **Document number:** 2018-10920
- **Category:** airworthiness
- **Manufacturer:** The Boeing Company
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 83 FR 23775
- **Publication date:** 2018-05-23
- **Effective date:** 2018-06-07
- **FAA docket:** Docket No. FAA-2018-0446
## Abstract

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD requires repetitive high frequency eddy current (HFEC) and detailed inspections, as applicable, for cracking of certain aft vertical stiffeners; repetitive detailed inspections for cracking of time-limited repairs, as applicable; a one-time HFEC inspection for cracking of the keel beam upper chord inboard flanges; a one-time general visual inspection for cracking of a certain angle; and applicable on-condition actions. This AD was prompted by a report of cracks in the left-side and right-side keel beam upper chords and aft vertical stiffeners. We are issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2018/05/23/2018-10920/airworthiness-directives-the-boeing-company-airplanes)
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