AD 89-08-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Bell Helicopter Textron, Inc. | 204B | Airworthiness Directives; BELL HELICOPTER TEXTRON, INC. Model 204B, 205A, 205A-1, 212, and 412 Helicopters |
| aircraft | Bell Helicopter Textron, Inc. | 205A | Airworthiness Directives; BELL HELICOPTER TEXTRON, INC. Model 204B, 205A, 205A-1, 212, and 412 Helicopters |
| aircraft | Bell Helicopter Textron, Inc. | 205A-1 | Airworthiness Directives; BELL HELICOPTER TEXTRON, INC. Model 204B, 205A, 205A-1, 212, and 412 Helicopters |
| aircraft | Bell Helicopter Textron, Inc. | 212 | Airworthiness Directives; BELL HELICOPTER TEXTRON, INC. Model 204B, 205A, 205A-1, 212, and 412 Helicopters |
| aircraft | Bell Helicopter Textron, Inc. | 412 | Airworthiness Directives; BELL HELICOPTER TEXTRON, INC. Model 204B, 205A, 205A-1, 212, and 412 Helicopters |
Unsafe Condition
Failure of the main transmission spiral bevel gear (P/N 204-040-701-103) could result in possible loss of the helicopter due to metal contamination, cracks, chipping, or metal deformation.
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Required Actions
Within 10 hours' time in service after the effective date, inspect the transmission internal sump oil filter daily for metal contamination. If contamination is found, disassemble the main transmission, replace unserviceable parts, and perform subsequent inspections every 50 hours' time in service. Inspect spiral bevel gear teeth for cracks, chipping, or deformation using a light and dental mirror; replace unserviceable parts. Compliance ceases when gear reaches 250 hours' time in service.
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Compliance Time
Within the next 10 hours' time in service upon effective date of this AD and thereafter, before the first flight of each day, and at intervals not to exceed 50 hours' time in service from the last inspection.
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Affected Aircraft
Bell Helicopter Textron, Inc. Models 204B, 205A, 205A-1, 212 (S/N 31304, 31305, 31307), and 412 (S/N 33175, 33177-33182, 33185-33195, 33190, 33192, 33194, 33195) helicopters with main transmission spiral bevel gear P/N 204-040-701-103, serial numbers listed in the AD, delivered between January 1, 1988, and April 4, 1989, and having less than 250 hours' time in service as of the effective date.
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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