AD 77-21-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airbus Helicopters Deutschland GmbH | BO-105A | Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Model BO-105A and BO-105C Helicopters |
| aircraft | Airbus Helicopters Deutschland GmbH | BO-105C | Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Model BO-105A and BO-105C Helicopters |
Unsafe Condition
The unsafe condition involves improper socket connections (1 VED and 1 VEE) and plugs (110 VVa and 210 VVa) in the main relay box, which could lead to electrical system failure or fire due to arcing or short circuits.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove socket connections 1 VED and 1 VEE from the main relay box, remove plugs 110 VVa and 210 VVa along with their associated receptacles and wiring bundles, and install the generator wiring assembly per MBB Service Bulletin No. 90-11 dated April 17, 1975, or an FAA-approved equivalent.
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Compliance Time
within the next 600 hours time in service after the effective date of this AD
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Affected Aircraft
Messerschmitt-Bolkow-Blohm (MBB) Model BO-105A and BO-105C helicopters, Serial Number V4 through V10, and S1 through S160
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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