Air Conditioning - Cabin Altitude Pressure Switches - Functional Test
- Published
- Effective
- Deadline
- Replaces
- 2021-14-20
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators must perform repetitive functional tests of the cabin altitude pressure switches using specified adapters and adhere to the Boeing 737 AMM procedures. Any necessary on-condition actions, such as switch replacements, must be completed based on test results. Compliance with this AD is mandatory by January 26, 2023.
Summary
Airworthiness Directive 2022-24-09 is a final rule issued by the FAA addressing all Boeing Company Model 737 series airplanes. It mandates repetitive functional tests of the cabin altitude pressure switches with specified adapter requirements to prevent false test failures. This directive supersedes the previous AD 2021-14-20 and aims to ensure the cabin altitude warning system activates correctly to prevent hypoxia risks to flightcrew.
What changed
This AD supersedes AD 2021-14-20 by retaining the repetitive functional tests and on-condition actions but adds specific requirements for test adapters to avoid false failures. It clarifies maintenance procedures by including references to Boeing 737 Aircraft Maintenance Manual procedures and maintains hose length restrictions for testing. The AD does not reduce the testing interval despite requests from operators.
Why it matters
This directive is critical for aviation professionals as it addresses latent failures in cabin altitude pressure switches that could prevent the cabin altitude warning system from activating above 10,000 feet. Ensuring accurate functional testing with proper adapters reduces false failures and enhances flight safety by preventing potential hypoxia and loss of airplane control. Operators and maintenance teams must comply to maintain airworthiness and regulatory compliance.
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