AD 59-12-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Maryland Air Industries, Inc. | F-27 | Airworthiness Directives; Fairchild All Model F-27 Series Aircraft |
| aircraft | Maryland Air Industries, Inc. | F-27A | Airworthiness Directives; Fairchild All Model F-27 Series Aircraft |
| aircraft | Maryland Air Industries, Inc. | F-27B | Airworthiness Directives; Fairchild All Model F-27 Series Aircraft |
| aircraft | Maryland Air Industries, Inc. | F-27F | Airworthiness Directives; Fairchild All Model F-27 Series Aircraft |
| aircraft | Maryland Air Industries, Inc. | F-27G | Airworthiness Directives; Fairchild All Model F-27 Series Aircraft |
| aircraft | Maryland Air Industries, Inc. | F-27J | Airworthiness Directives; Fairchild All Model F-27 Series Aircraft |
| aircraft | Maryland Air Industries, Inc. | F-27M | Airworthiness Directives; Fairchild All Model F-27 Series Aircraft |
Unsafe Condition
A loose 'B' nut on the fuel line connection to the combustion heater fuel control unit caused fuel leakage around the shroud.
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Required Actions
Remove and retain shroud assemblies P/N 27-774575-1 attached to specified tube assemblies. Inspect and torque fittings to specified values (135-150 in-lbs for P/N 27-774512-11 and 40-65 in-lbs for P/N 27-683051-151/-251). Reinstall shrouds after verifying no fuel leakage during heater operation.
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Compliance Time
July 15, 1959, and every 100 hours thereafter until the permanent fix is incorporated.
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Affected Aircraft
Fairchild F-27 Series aircraft equipped with the heater system, including models F-27, F-27A, F-27B, F-27F, F-27G, F-27J, F-27M.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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