77-04-06: Main Rotor Gearbox
FAA order 77-04-06 is an airworthiness directive in force since August 23, 1979. The FAA's subject line: Main Rotor Gearbox. System: rotorcraft systems.
What it applies to as the FAA lists it
- Kind of product
- Aircraft
- Makes
- Airbus Helicopters Deutschland GmbH
- Models
- BO-105A, BO-105C
Dates and paperwork
- In force since
- August 23, 1979
- Published
- February 17, 1977 (signed February 7, 1977)
- Docket
- Unknown
- Replaced by
- 2022-24-07
- Status
- Historical
- The FAA's document
- Read the order on the FAA's site
The order itself the regulatory text, as published
Show the full text (766 characters)
77-04-06 MESSERSCHMITT-BOLKOW-BLOHM (MBB): Amendment 39-2835 as amended by amendment 39-3528. Applies to all Model BO-105A and BO-105C helicopters, certificated in all categories.
Compliance is required as indicated.
To prevent the possible failure of a main rotor gearbox support, P/Ns 105-10161 and 105-10162, replace the two supports with serviceable supports within the next 10 hours time in service after the effective date of this AD or prior to the accumulation of 6,800 hours time in service on the supports, whichever occurs later, and, thereafter, continue to replace the supports prior to the accumulation of 6,800 hours time in service.
Amendment 39-2835 became effective March 3, 1977.
This amendment 39-3528 becomes effective August 23, 1979.
Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of October 5, 2026. Connections as data: /graph/directive/77-04-06.json · aircraft systems.