AD 77-16-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Dowty Propellers | (c) R.209/4-40-4.5 | DOWTY ROTOL Models R245/4-40-4.5/13, R259/4-40-4.5/17 and R209/4-40-4.5/2 Propellers |
| aircraft | Dowty Propellers | (c) R.245/4-40-4.5 | DOWTY ROTOL Models R245/4-40-4.5/13, R259/4-40-4.5/17 and R209/4-40-4.5/2 Propellers |
| aircraft | Dowty Propellers | (c) R.259/4-40-4.5 | DOWTY ROTOL Models R245/4-40-4.5/13, R259/4-40-4.5/17 and R209/4-40-4.5/2 Propellers |
Unsafe Condition
Pitch lock piston cracking and subsequent inability to feather the propeller.
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Required Actions
Inspect pitch lock pistons for cracks around the outside diameter at the 0.025 inch radius per SB 61-873, Rev. 1. Replace cracked pistons with new P/N RA 70089 or redesigned parts per SB 61-875. Comply with paragraphs (c), (d), and (e) after replacement.
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Compliance Time
Before further flight for pistons with 19,000+ flights on effective date. For others: prior to 15,000 flights or within next 100 flights, whichever occurs later, then every 1,000 flights until 19,000 flights.
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Affected Aircraft
Dowty Propellers models R245/4-40-4.5/13, R259/4-40-4.5/17, and R209/4-40-4.5/2 installed on Convair 600 series, Nihon YS-11, and 11A airplanes excluding those with modification VP 2869.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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