- Effective
- April 14, 1983
- Models
- 2T-1A-1, 2T-1A-2
- Data sheet
- TCDSA18EA
- Registered aircraft
- 142 matched by model
- Product
- Aircraft · Small airplane
- Amendment
- 39-4625
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 May 30, 2024.
Copies of the files this page was built from, with their SHA-256. Retrieved October 18, 2026.
| File | Size | SHA-256 | Original |
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| FAA DRS HTML | 22 KB | 053abad6…424c507 | FAA DRS (API key needed) |
On this page
The airworthiness directive
80-21-12 R1 GREAT LAKES AIRCRAFT CORPORATION: Amendment 39-3940 as amended by Amendment 39-4625. Applies to Models 2T-1A-1 and 2T-1A-2 (Serial Numbers 501 through 828) airplanes with Lycoming I0-360 or AEIO-360 engines installed, certificated in any category.
Compliance: Required as indicated, unless already accomplished.
To prevent engine oil inlet temperatures from exceeding acceptable limits within the next 50 hours time- in-service after the effective date of this AD, accomplish either paragraph (a) or (b) below:
(a) Remove Cowl Face P/N 50106-2 and Belly Cowl P/N 50105-2 and modify in accordance with Great Lakes Service Bulletin No. 11, dated September 1, 1980, and incorporate Great Lakes Parts Kit SPK 101. Perform engine run-up and inspect oil system for leaks; or
(b) Fabricate and install a louver plate (P/N 50105-33) and louver backing plate (P/N 50105-32) on the side of the belly cowling in accordance with Great Lakes Drawing Number 50105, Sheet 3 of4, Revision C.
(c) The airplane may be flown in accordance with FAR 21.197 to a location where this AD may be accomplished.
(d) An equivalent method of compliance may be approved by the Manager, Atlanta Aircraft Certification Office, FAA Central Region, 1075 Inner Loop Road, College Park, Georgia 30337.
Drawing 50105, Sheet 3 of 4, Revision C, and Great Lakes Service Bulletin No. 11, dated September 1, 1980, pertinent to this AD, may be obtained from Great Lakes Aircraft Company, Drawer A, Eastman, Georgia 31023; telephone (912) 374-5535.
This Amendment 39-4625 revises Amendment 39-3940 (45 FR 67646), AD 80-21-12 in its entirety.
Amendment 39-3940 became effective October 17, 1980.
This Amendment 39-4625 becomes effective April 14, 1983.
Affected TCDS · 1
The type certificate data sheets for the models this AD names, matched by model and maker.
Registered aircraft · 142
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 | 5 |
| 1975 | 11 |
| 1976 | 24 |
| 1977 | 29 |
| 1978 | 23 |
| 1980 | 6 |
| 1981 | 5 |
| 1982 | 1 |
| 1985 | 2 |
| 1998 | 1 |
| 2013 | 1 |
| 2014 | 3 |
| 2015 | 3 |
| 2016 | 2 |
| 2017 | 1 |
| 2020 | 1 |
| 2021 | 1 |
| 2022 | 4 |
| 2023 | 3 |
15 with no year recorded