AD 80-21-12 R1
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Great Lakes Aircraft Company, LLC (John Duncan) | 2T-1A-1 | Airworthiness Directives; Great Lakes Models 2T-1A-1 and 2T-1A-2 Series Airplanes |
| aircraft | Great Lakes Aircraft Company, LLC (John Duncan) | 2T-1A-2 | Airworthiness Directives; Great Lakes Models 2T-1A-1 and 2T-1A-2 Series Airplanes |
Unsafe Condition
Engine oil inlet temperatures exceeding acceptable limits due to inadequate cooling airflow.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove and modify cowl face and belly cowl parts per Service Bulletin 11 and install parts kit SPK 101, or install louver plates per Drawing 50105, Sheet 3 of 4, Revision C. Perform engine run-up and inspect for oil leaks.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within the next 50 hours time-in-service after the effective date of this AD
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Great Lakes Models 2T-1A-1 and 2T-1A-2 (Serial Numbers 501 through 828) with Lycoming IO-360 or AEIO-360 engines installed.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Engine Oil System
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_80-21-12_R.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 80-21-12 R1 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Great Lakes Models 2T-1A-1 and 2T-1A-2 Series Airplanes Subject: Engine Oil System Status: Current Citation: This information is not available Citation Publish Date: Effective Date: 04/14/1983 Make: Great Lakes Aircraft Company, LLC (John Duncan) Model: 2T-1A-1 | 2T-1A-2 Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 80-21-12 R1 CITATION: This information is not available PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-4625 AD NUMBER: 80-21-12 R1 SUBJECT HEADING: Airworthiness Directives; Great Lakes Models 2T-1A-1 and 2T-1A-2 Series Airplanes ACTION: SUMMARY: DATES: Effective April 14, 1983. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 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 of 4, 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. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_80-21-12_R.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 80-21-12 R1 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Great Lakes Models 2T-1A-1 and 2T-1A-2 Series Airplanes Subject: Engine Oil System Status: Current Citation: This information is not available Citation Publish Date: Effective Date: 04/14/1983 Make: Great Lakes Aircraft Company, LLC (John Duncan) Model: 2T-1A-1 | 2T-1A-2 Product Type: Aircraft Product Subtype: Small Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 80-21-12 R1 CITATION: This information is not available PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-4625 AD NUMBER: 80-21-12 R1 SUBJECT HEADING: Airworthiness Directives; Great Lakes Models 2T-1A-1 and 2T-1A-2 Series Airplanes ACTION: SUMMARY: DATES: Effective April 14, 1983. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 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 of 4, 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. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.
Related Airworthiness Directives
2004-25-22
final ruleAirworthiness Directives; Great Lakes Aircraft Company, LLC, Models 2T-1A-1 and 2T-1A-2 Airplanes
Unsafe Condition: Heat distortion, damage, and cracks in the alternate air door could cause pieces to break off and get sucked into the induction system, blocking the airflow to the engine. Additionally, the absence...
78-26-10 R1
final ruleAirworthiness Directives; Great Lakes Model 2T-1A-1 and 2T-1A-2 Airplanes
Unsafe Condition: Contamination of cockpit heater air with carbon monoxide due to cracks in the support plates of the heat exchanger at both ends between the five tube cluster.