AD 67-29-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Maryland Air Industries, Inc. | F-27J | Airworthiness Directives; Fairchild-Hiller Models F-27J and FH-227 Aircraft |
| aircraft | Maryland Air Industries, Inc. | FH-227 | Airworthiness Directives; Fairchild-Hiller Models F-27J and FH-227 Aircraft |
| aircraft | Maryland Air Industries, Inc. | FH-227B | Airworthiness Directives; Fairchild-Hiller Models F-27J and FH-227 Aircraft |
| aircraft | Maryland Air Industries, Inc. | FH-227C | Airworthiness Directives; Fairchild-Hiller Models F-27J and FH-227 Aircraft |
| aircraft | Maryland Air Industries, Inc. | FH-227D | Airworthiness Directives; Fairchild-Hiller Models F-27J and FH-227 Aircraft |
| aircraft | Maryland Air Industries, Inc. | FH-227E | Airworthiness Directives; Fairchild-Hiller Models F-27J and FH-227 Aircraft |
Unsafe Condition
The APU fire detection system may have inadequate reliability and sensitivity due to insufficient fire detectors and non-fire resistant wiring in the fire detection circuit.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Install an additional fire detector (Solar P/N 7447-2) within 100 operational APU hours. Install MIL-W-25038B fire resistant wire in the fire detection circuit within 100 operational APU hours. Replace existing 700 degree fire detectors (Solar P/N 7447-1) with 400+25 degree F detectors (Solar P/N 7447-2) within 200 operational APU hours.
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Compliance Time
Within the next 100 operational APU hours following the effective date of this AD (for paragraphs (a) and (b)), and within the next 200 operational APU hours for paragraph (c).
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Affected Aircraft
Fairchild-Hiller Models F-27J and FH-227 aircraft with installed Solar Auxiliary Power Unit Model T-62T-25, Serial Nos. S-408000 to S-408099 inclusive.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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