AD 68-20-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Dowty Propellers | (c) R184/4-30-4/ | DOWTY ROTOL Models (c) R.193/4-30-4/50, (c) R.257/4-30-4/60, and (c) R.184/4-30-4/50 Propellers |
| aircraft | Dowty Propellers | (c) R193/4-30-4/ | DOWTY ROTOL Models (c) R.193/4-30-4/50, (c) R.257/4-30-4/60, and (c) R.184/4-30-4/50 Propellers |
| aircraft | Dowty Propellers | (c) R257/4-30-4/ | DOWTY ROTOL Models (c) R.193/4-30-4/50, (c) R.257/4-30-4/60, and (c) R.184/4-30-4/50 Propellers |
Unsafe Condition
Failure of the propeller hub driving center, part number RA 57500, due to cracks.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Incorporate Dowty Rotol Modification (c) VP.2486 per Service Bulletin 61.573B or equivalent. Inspect hubs with magnifying glass and magnetic particle fluid method per SB 61-633. Replace cracked driving centers before flight. For R.184/4-30-4/50 propellers, inspections and modifications depend on hours time in service as specified.
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Compliance Time
Within the next 4500 hours time in service after the effective date for most propellers, or as specified for R.184/4-30-4/50 based on their time in service on the effective date.
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Affected Aircraft
Dowty Rotol propellers models (c) R.193/4-30-4/50, (c) R.257/4-30-4/60, and (c) R.184/4-30-4/50 installed on specific aircraft models as listed.
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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