- Effective
- August 23, 1979
- Published
- February 17, 1977
- Issued
- February 7, 1977
- Superseded by
- AD2022-24-07
- Models
- BO-105A, BO-105C
- Data sheet
- TCDSH3EU
- Registered aircraft
- 4 matched by model
- Product
- Aircraft · Rotorcraft
- Amendment
- 39-2835
Unofficial copy of the text in the FAA’s Dynamic Regulatory System. The FAA’s own copy is the authoritative one. DRS record last changed November 21, 2025.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
| File | Size | SHA-256 | Original |
|---|---|---|---|
| FAA DRS HTML | 19 KB | 3477f538…25cf197 | FAA DRS (API key needed) |
On this page
The airworthiness directive
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.
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 4
Registered aircraft whose airframe or engine model this AD names. Matched by model only, so check each against the AD’s applicability.
| 1973 | 1 |
|---|---|
| 1974 | 1 |
2 with no year recorded