AD 80-17-11
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Learjet Inc. | 35 | Airworthiness Directives; Gates Learjet Model 35 and 36 Series Airplanes |
| aircraft | Learjet Inc. | 35A (C-21A) | Airworthiness Directives; Gates Learjet Model 35 and 36 Series Airplanes |
| aircraft | Learjet Inc. | 36 | Airworthiness Directives; Gates Learjet Model 35 and 36 Series Airplanes |
| aircraft | Learjet Inc. | 36A | Airworthiness Directives; Gates Learjet Model 35 and 36 Series Airplanes |
Unsafe Condition
Encountering a possible overload flight condition that could fail the forward engine mount.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Install airspeed warning placards and modify the Mach/overspeed switch circuit to reduce VMO to 307 KIAS. Insert a temporary AFM supplement from SB 35/36-11-3. Replace or re-age both forward engine mounts within 600 hours' time-in-service using AMK 80-6 at authorized facilities. Obtain Special Flight Permits under FAR 21.197 if needed for relocation.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 75 hours time-in-service after the effective date of this AD for Paragraph A; within the next 600 hours' time-in-service after the effective date for Paragraph B.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Gates Learjet Model 35 (serial 35-050 through 35-339 except 35-054 and 35-065) and Model 36 (serial 36-017 through 36-045).
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Airspeed Warning Placard
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_80-17-11.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 80-17-11 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Gates Learjet Model 35 and 36 Series Airplanes Subject: Airspeed Warning Placard Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 08/28/1980 Make: Learjet Inc. Model: 35 | 35A (C-21A) | 36 | 36A Product Type: Aircraft Product Subtype: Small/Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 80-17-11 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3888 AD NUMBER: 80-17-11 SUBJECT HEADING: Airworthiness Directives; Gates Learjet Model 35 and 36 Series Airplanes ACTION: SUMMARY: DATES: Effective August 28, 1980. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 80-17-11 GATES LEARJET: Amendment 39-3888. Applies to the following model and serial number airplanes: Model 35 Series Serial Number 35-050 through 35-339 except 35-054 and 35-065 Model 36 Series Serial Number 36-017 through 36-045 COMPLIANCE: Required as indicated unless already accomplished. To prevent encountering a possible overload flight condition that could fail the forward engine mount, accomplish the following: A) Within the next 75 hours time-in-service after the effective date of this AD, in accordance with Gates Learjet Corporation Service Bulletin 35/36-11-3, dated July 28, 1980: 1. Install airspeed warning placards and modify the Mach/overspeed switch circuit to effect a reduced maximum operating airspeed (VMO) of 307 KIAS, from sea level to 31,100 feet altitude. 2. Insert in the existing Airplane Flight Manual the temporary Airplane Flight Manual Supplement included in Service Bulletin 35/36-11-3. B) Within the next 600 hours' time-in-service after the effective date of this AD, replace or re-age both forward engine mounts in accordance with Gates Learjet Corporation Airplane Modification Kit AMK 80-6. Accomplish the removal and installation of the engine mounts at authorized Gates Learjet Service Centers and the nondestructive testing and heat treating at appropriately rated FAA certified repair stations. C) Upon compliance with Paragraph B above, the requirements of Paragraph A of this AD are no longer applicable. D) Issuance of a Special Flight Permit in accordance with FAR 21.197 is permitted for the purpose of moving the affected airplanes to a location where the modifications required by this AD can be accomplished. E) Any equivalent means of compliance with this AD must be approved by the Chief, Aircraft Certification Program, Federal Aviation Administration, Room 238, Terminal Building No. 2299, Mid-Continent Airport, Wichita, Kansas 67209. This amendment becomes effective August 28, 1980. FOOTER:
Document Text
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AD Final Rules - DRS_80-17-11.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 80-17-11 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Gates Learjet Model 35 and 36 Series Airplanes Subject: Airspeed Warning Placard Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 08/28/1980 Make: Learjet Inc. Model: 35 | 35A (C-21A) | 36 | 36A Product Type: Aircraft Product Subtype: Small/Large 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: 80-17-11 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3888 AD NUMBER: 80-17-11 SUBJECT HEADING: Airworthiness Directives; Gates Learjet Model 35 and 36 Series Airplanes ACTION: SUMMARY: DATES: Effective August 28, 1980. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 80-17-11 GATES LEARJET: Amendment 39-3888. Applies to the following model and serial number airplanes: Model 35 Series Serial Number 35-050 through 35-339 except 35-054 and 35-065 Model 36 Series Serial Number 36-017 through 36-045 COMPLIANCE: Required as indicated unless already accomplished. To prevent encountering a possible overload flight condition that could fail the forward engine mount, accomplish the following: A) Within the next 75 hours time-in-service after the effective date of this AD, in accordance with Gates Learjet Corporation Service Bulletin 35/36-11-3, dated July 28, 1980: 1. Install airspeed warning placards and modify the Mach/overspeed switch circuit to effect a reduced maximum operating airspeed (VMO) of 307 KIAS, from sea level to 31,100 feet altitude. 2. Insert in the existing Airplane Flight Manual the temporary Airplane Flight Manual Supplement included in Service Bulletin 35/36-11-3. B) Within the next 600 hours' time-in-service after the effective date of this AD, replace or re-age both forward engine mounts in accordance with Gates Learjet Corporation Airplane Modification Kit AMK 80-6. Accomplish the removal and installation of the engine mounts at authorized Gates Learjet Service Centers and the nondestructive testing and heat treating at appropriately rated FAA certified repair stations. C) Upon compliance with Paragraph B above, the requirements of Paragraph A of this AD are no longer applicable. D) Issuance of a Special Flight Permit in accordance with FAR 21.197 is permitted for the purpose of moving the affected airplanes to a location where the modifications required by this AD can be accomplished. E) Any equivalent means of compliance with this AD must be approved by the Chief, Aircraft Certification Program, Federal Aviation Administration, Room 238, Terminal Building No. 2299, Mid-Continent Airport, Wichita, Kansas 67209. This amendment becomes effective August 28, 1980. FOOTER:
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Retrieved: Apr 8, 2026
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