AD 2021-14-20
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Boeing | Company | Airworthiness Directives; The Boeing Company Airplanes |
Unsafe Condition
latent failures of the cabin altitude pressure switches, which could result in the loss of cabin altitude warning, delay flightcrew recognition of a lack of cabin pressurization, and result in incapacitation of the flightcrew due to hypoxia, and consequent loss of control of the airplane.
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Required Actions
accomplish the actions specified in the service information, including repetitive functional tests of the cabin altitude pressure switches, on-condition actions including follow-on functional testing and replacement of failed switches, sending a report to Boeing about any pressure switches that fail the initial functional test, and reporting to Boeing the airplanes in the operator's fleet that have been tested.
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Compliance Time
Before further flight
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Affected Aircraft
all The Boeing Company Model 737 airplanes
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Source: Official FAA Source ↗
Retrieved: Apr 4, 2026
Rights: U.S. Government Public Domain
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