AD 77-17-06
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airesearch | Auxiliary Power Units | Airworthiness Directives; AIRESEARCH MANUFACTURING COMPANY of ARIZONA: Applies to AiResearch Model TSCP700-4B and -5 Auxiliary Power Units (APUs) |
Unsafe Condition
High energy release of first stage compressor blades and disc parts due to possible fatigue failure of the disc.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove and inspect the first stage disc blade dove tail slots using specified methods or an approved equivalent. Discs failing inspection must be removed from service. Replacement discs must be inspected before installation unless previously inspected within the last 3000 cycles.
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Compliance Time
Before accumulating more than 3000 cycles on the first stage compressor discs, or within the next 300 cycles after the effective date of this AD, whichever occurs later, unless already accomplished within the last 1700 cycles, and thereafter at intervals not to exceed 2000 cycles since the last inspection.
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Affected Aircraft
AiResearch Model TSCP700-4B and -5 Auxiliary Power Units (APUs) with first stage compressor discs P/Ns 969600-1 or -2 installed.
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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