AD 84-03-51
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Columbia Helicopters, Inc. | 234 | Airworthiness Directives; BOEING VERTOL COMPANY Model 234 Series Helicopters |
Unsafe Condition
Cracking of the main rotor head tie bars, specifically forward and aft tie bars P/N 114R21551 with serial numbers A13207 and below (excluding those with a 'B' suffix), could cause possible hazards in flight.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Visually inspect forward tie bars (P/N 114R21551, serial numbers A13207 and below) for cracks within 25 hours time in service from the AD effective date or before 450 hours time in service, whichever is later. Similarly inspect aft tie bars (same part and serial numbers) within 25 hours or before 550 hours. Repeat inspections at intervals not exceeding 450 hours (forward) or 550 hours (aft). Remove and replace cracked tie bars before further flight.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within the next 25 hours time in service from the effective date of this AD or before the accumulation of 450 hours time in service (for forward tie bars) and 550 hours time in service (for aft tie bars), whichever comes later
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Boeing Vertol Model 234 series helicopters with forward and aft main rotor tie bars P/N 114R21551, serial numbers A13207 and below (excluding those with a 'B' suffix)
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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