AD 66-13-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Maryland Air Industries, Inc. | F-27 | Airworthiness Directives; Fairchild Model F-27 Series Airplanes |
| aircraft | Maryland Air Industries, Inc. | F-27A | Airworthiness Directives; Fairchild Model F-27 Series Airplanes |
| aircraft | Maryland Air Industries, Inc. | F-27B | Airworthiness Directives; Fairchild Model F-27 Series Airplanes |
| aircraft | Maryland Air Industries, Inc. | F-27F | Airworthiness Directives; Fairchild Model F-27 Series Airplanes |
| aircraft | Maryland Air Industries, Inc. | F-27G | Airworthiness Directives; Fairchild Model F-27 Series Airplanes |
| aircraft | Maryland Air Industries, Inc. | F-27J | Airworthiness Directives; Fairchild Model F-27 Series Airplanes |
| aircraft | Maryland Air Industries, Inc. | F-27M | Airworthiness Directives; Fairchild Model F-27 Series Airplanes |
Unsafe Condition
Failure of both inverters and resulting loss of essential load circuits due to a failure of a common ground.
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Required Actions
Modify the inverter ground circuit in accordance with Fairchild Service Bulletin 34-9 (dated December 16, 1965) or an FAA-approved equivalent for airplanes with specific conforming drawings and modifications. For others, use Service Bulletins 34-4 or 34-9. Compliance may be adjusted upon FAA approval based on operator's inspection schedule.
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Compliance Time
within the next 350 hours' time in service after the effective date of this AD
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Affected Aircraft
Maryland Air Industries, Inc. Model F-27 Series Airplanes (F-27, F-27A, F-27B, F-27F, F-27G, F-27J, F-27M)
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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