AD 94-22-10 R1
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Bombardier Inc. | DHC-8-101 | Airworthiness Directives; de Havilland Model DHC-8-100 and DHC-8-300 Series Airplanes |
| aircraft | Bombardier Inc. | DHC-8-102 | Airworthiness Directives; de Havilland Model DHC-8-100 and DHC-8-300 Series Airplanes |
| aircraft | Bombardier Inc. | DHC-8-103 | Airworthiness Directives; de Havilland Model DHC-8-100 and DHC-8-300 Series Airplanes |
| aircraft | Bombardier Inc. | DHC-8-106 | Airworthiness Directives; de Havilland Model DHC-8-100 and DHC-8-300 Series Airplanes |
| aircraft | Bombardier Inc. | DHC-8-301 | Airworthiness Directives; de Havilland Model DHC-8-100 and DHC-8-300 Series Airplanes |
| aircraft | Bombardier Inc. | DHC-8-311 | Airworthiness Directives; de Havilland Model DHC-8-100 and DHC-8-300 Series Airplanes |
| aircraft | Bombardier Inc. | DHC-8-315 | Airworthiness Directives; de Havilland Model DHC-8-100 and DHC-8-300 Series Airplanes |
Unsafe Condition
Faulty Grimes strobe light systems may develop capacitor failures causing electromagnetic interference that adversely affects the proximity switch electronics unit (PSEU) and its associated systems, leading to abnormal indications such as landing gear advisory light flashing, cabin pressurization rate fluctuations, spoiler retraction/extension, loss of nose landing gear steering, and wheel brake failure.
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Required Actions
Revise the Airplane Flight Manual (AFM) to advise flight crew of abnormal indications caused by faulty strobe lights and procedures to select the A/COL light switch - RED. Install Modification 8/1273 replacing Grimes units with Whelen anti-collision strobe light systems. Maintenance actions per de Havilland Alert Service Bulletin S.B. A8-33-33 and Service Bulletin S/B 8-33-19 Revision A.
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Compliance Time
Before further flight
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Affected Aircraft
Bombardier Inc. models DHC-8-101, DHC-8-102, DHC-8-103, DHC-8-106, DHC-8-301, DHC-8-311, DHC-8-315. Includes serial numbers as specified in the applicability section of AD 94-22-10 R1.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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