AD 72-07-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Dowty Propellers | (c) R.284/3-20-3/ | DOWTY ROTOL applies to all propellers with blade root sizes Nos. 20 and 30 |
| aircraft | Dowty Propellers | (c) R130/4-20-4/ | DOWTY ROTOL applies to all propellers with blade root sizes Nos. 20 and 30 |
| aircraft | Dowty Propellers | (c) R141/4-20-4/ | DOWTY ROTOL applies to all propellers with blade root sizes Nos. 20 and 30 |
| aircraft | Dowty Propellers | (c) R147/4-20-4/ | DOWTY ROTOL applies to all propellers with blade root sizes Nos. 20 and 30 |
| aircraft | Dowty Propellers | (c) R148/4-20-4/ | DOWTY ROTOL applies to all propellers with blade root sizes Nos. 20 and 30 |
| aircraft | Dowty Propellers | (c) R175/4-30-4/ | DOWTY ROTOL applies to all propellers with blade root sizes Nos. 20 and 30 |
| aircraft | Dowty Propellers | (c) R179/4-20-4/ | DOWTY ROTOL applies to all propellers with blade root sizes Nos. 20 and 30 |
| aircraft | Dowty Propellers | (c) R184/4-30-4/ | DOWTY ROTOL applies to all propellers with blade root sizes Nos. 20 and 30 |
| aircraft | Dowty Propellers | (c) R186/4-30-4/ | DOWTY ROTOL applies to all propellers with blade root sizes Nos. 20 and 30 |
| aircraft | Dowty Propellers | (c) R187/4-30 | DOWTY ROTOL applies to all propellers with blade root sizes Nos. 20 and 30 |
Unsafe Condition
Fatigue failure of propeller blades or blade bearings due to loss of bearing pre-load from discrepancies in ground tracks or improper assembly.
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Required Actions
Inspect blade bearings by measuring and recording bearing torque and center race spigot mean diameter before and after removal of pre-load, following Dowty Rotol Service Letter No. SER/SSL/1. Determine serviceability based on expansion values and either return to service, remove from service, or send for load-expansion torque test.
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Compliance Time
Within the next 400 hours' time in service after the effective date (March 29, 1972) or at the next disassembly of a bearing from a blade for cause, whichever occurs sooner. Thereafter, at intervals not exceeding 5,000 hours' time in service or at each disassembly for cause.
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Affected Aircraft
Dowty Propellers models R.284/3-20-3/, R130/4-20-4/, R141/4-20-4/, R147/4-20-4/, R148/4-20-4/, and others with blade root sizes Nos. 20 and 30, installed on Fairchild F-27, Fairchild Hiller F-227, Armstrong Whitworth AW 650, Vickers Viscount 745/810, and Grumman G-159 series airplanes.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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