# Airworthiness Directives; The Boeing Company Airplanes
> **Rule** · Final rule. · Published 2015-08-11 · Effective 2015-09-15 · 80 FR 48013
## Document
- **Document number:** 2015-19316
- **Category:** airworthiness
- **Manufacturer:** The Boeing Company
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 80 FR 48013
- **Publication date:** 2015-08-11
- **Effective date:** 2015-09-15
- **FAA docket:** Docket No. FAA-2014-0487
## Abstract

We are superseding Airworthiness Directive (AD) 2012-19-11 for certain The Boeing Company Model 737 airplanes. AD 2012-19-11 required incorporating design changes to improve the reliability of the cabin altitude warning system by installing a redundant cabin altitude pressure switch, replacing the aural warning module (AWM) with a new or reworked AWM, and changing certain wire bundles or connecting certain previously capped and stowed wires as necessary. For certain airplanes, AD 2012-19-11 also required prior or concurrent incorporation of related design changes by modifying the instrument panels, installing light assemblies, modifying the wire bundles, and installing a new circuit breaker, as necessary. This AD was prompted by the report of a flightcrew not receiving an aural warning during a lack-of-cabin pressurization event. We are issuing this AD to prevent the loss of cabin altitude warning, which could delay flightcrew recognition of a lack of cabin pressurization, and could result in incapacitation of the flightcrew due to hypoxia (a lack of oxygen in the body), and consequent loss of control of the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2015/08/11/2015-19316/airworthiness-directives-the-boeing-company-airplanes)
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