AD 90-20-21
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Bombardier Inc. | DHC-8-101 | Airworthiness Directives; Boeing Of Canada, Ltd., De Havilland Division Model DHC-8-100 Series Airplanes |
| aircraft | Bombardier Inc. | DHC-8-102 | Airworthiness Directives; Boeing Of Canada, Ltd., De Havilland Division Model DHC-8-100 Series Airplanes |
| aircraft | Bombardier Inc. | DHC-8-103 | Airworthiness Directives; Boeing Of Canada, Ltd., De Havilland Division Model DHC-8-100 Series Airplanes |
| aircraft | Bombardier Inc. | DHC-8-106 | Airworthiness Directives; Boeing Of Canada, Ltd., De Havilland Division Model DHC-8-100 Series Airplanes |
Unsafe Condition
Deformation or loss of the engine forward side cowl doors due to compartment overpressurization, leading to loss of fire extinguishing capability.
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Required Actions
Modify the cowl door retention latch arrangement and install pressure relief features on both engine cowlings in accordance with de Havilland Service Bulletin No. 8-71-13, Revision C. An alternate means of compliance or adjustment of compliance time may be approved by the Manager, New York Aircraft Certification Office.
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Compliance Time
within 300 days after the effective date of this AD
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Affected Aircraft
De Havilland Model DHC-8-100 series airplanes, Serial Numbers 1 through 156 and 158 through 193
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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