AD 99-11-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Division | Military R-1340 Series | Airworthiness Directives; Pratt & Whitney R-1340 Series Reciprocating Engines |
| engine | Pratt & Whitney Division | Wasp R-1340-59 | Airworthiness Directives; Pratt & Whitney R-1340 Series Reciprocating Engines |
| engine | Pratt & Whitney Division | Wasp R-1340-61 | Airworthiness Directives; Pratt & Whitney R-1340 Series Reciprocating Engines |
| engine | Pratt & Whitney Division | Wasp S1H1 | Airworthiness Directives; Pratt & Whitney R-1340 Series Reciprocating Engines |
| engine | Pratt & Whitney Division | Wasp S1H1-G | Airworthiness Directives; Pratt & Whitney R-1340 Series Reciprocating Engines |
| engine | Pratt & Whitney Division | Wasp S1H2 | Airworthiness Directives; Pratt & Whitney R-1340 Series Reciprocating Engines |
| engine | Pratt & Whitney Division | Wasp S1H4 | Airworthiness Directives; Pratt & Whitney R-1340 Series Reciprocating Engines |
| engine | Pratt & Whitney Division | Wasp S3H1 | Airworthiness Directives; Pratt & Whitney R-1340 Series Reciprocating Engines |
| engine | Pratt & Whitney Division | Wasp S3H1-G | Airworthiness Directives; Pratt & Whitney R-1340 Series Reciprocating Engines |
| engine | Pratt & Whitney Division | Wasp S3H2 | Airworthiness Directives; Pratt & Whitney R-1340 Series Reciprocating Engines |
Unsafe Condition
Cylinder head cracking can result in engine power loss, forced landing, and damage to the aircraft.
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Required Actions
Perform initial and repetitive visual inspections of cylinders for head cracking in accordance with PW Service Bulletin No. 1787. Replace cracked cylinders with serviceable parts. At the next overhaul, perform fluorescent penetrant inspection (FPI) of each cylinder.
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Compliance Time
Initial inspections within 50 or 125 flight hours TIS after effective date depending on installation type; repetitive inspections at intervals not to exceed 100 or 250 flight hours TIS.
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Affected Aircraft
Pratt & Whitney R-1340 series reciprocating engines including specified models installed on de Havilland DHC-3, Air Tractor AT-301, and Ag Cat Corporation G-164A aircraft.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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