AD 78-25-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Learjet Inc. | 35 | Airworthiness Directives; Gates Learjet Model 35 and 36 Airplanes |
| aircraft | Learjet Inc. | 36 | Airworthiness Directives; Gates Learjet Model 35 and 36 Airplanes |
Unsafe Condition
Cracked, bent, broken, or worn bolt 5 in the cabin door mechanism could prevent proper locking of the upper door, leading to possible unwanted door openings.
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Required Actions
Inspect and replace bolt 5 for cracks, breaks, bends, or wear; inspect door locking mechanism for wear and defects, including hole diameter not exceeding 0.201 inches; submit reports on defective bolts to FAA. Replace bolts with specified parts and ensure door mechanism functions without binding.
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Compliance Time
Initial inspections/replacements based on total time in service: prior to 3,075 hours or within 75 hours after AD effective date for certain ranges, with repetitive intervals of 3,000 hours. Locking mechanism inspections must occur first if bolt defects are found, with intervals tied to bolt inspection schedules.
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Affected Aircraft
Gates Learjet Model 35 (serial numbers 35-001 through 35-167) and Model 36 (serial numbers 36-001 through 36-038) with 36-inch wide cabin doors.
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Federal Register Abstract
Door Mechanism
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_78-25-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 78-25-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Gates Learjet Model 35 and 36 Airplanes Subject: Door Mechanism Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/14/1978 Make: Learjet Inc. Model: 35 | 36 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 78-25-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3362 AD NUMBER: 78-25-02 SUBJECT HEADING: Airworthiness Directives; Gates Learjet Model 35 and 36 Airplanes ACTION: SUMMARY: DATES: Effective December 14, 1978. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 78-25-02 GATES LEARJET: Amendment 39-3362. Applies to those Model 35 (Serial Numbers 35-001 through 35-167) and 36 (Serial Numbers 36-001 through 36-038) airplanes, certificated in all categories, which have a 36-inch wide (as opposed to 24-inch wide) cabin door. Compliance: Required as indicated in accordance with Compliance Table I set forth in this AD, unless already accomplished. To assure proper locking of the cabin upper door when the inside handle is in the locked position and to prevent possible unwanted door openings that may occur, accomplish the following at the time intervals noted in Table I of this AD: TABLE I COMPLIANCE TIMES AD 78-25-02 INSPECTION TIMES Airplane Total Time In Service (Hours) Paragraph "A" Bolt Inspection & Replacement Paragraph "B" Locking Mechanism Inspection Initial Inspection/ Replacement Interval for Repetitive Inspections/ Replacement Initial Inspection Interval for Repetitive Inspections 0 - 2,999 Prior to or upon the accumulation of 3,075 hours’ time in service Each 3,000 hours' time in service there- after In accordance with asterisk (*) paragraph below or upon accumulation of 6,075 hours’ time in service, whichever occurs first In accordance with asterisk (*) paragraph below or upon accumulation of each 6,000 hours’ time in service after initial inspection 3,000 - 5,999 Within 75 hours' time in service after the effective date of this AD Each 3,000 Hours’ time in service thereafter In accordance with asterisk (*) paragraph below or upon accumulation of 6,075 hours’ time in service, whichever occurs first In accordance with asterisk (*) paragraph below or upon accumulation of each 6,000 hours’ time in service after initial inspection 6,000 - up Within 75 hours' time in service after the effective date of this AD Each 3,000 hours’ time in service there-after Within 5 hours’ time in service after the effective date of this AD In accordance with asterisk (*) paragraph below or upon accumulation of each 6,000 hours; time in service after initial inspection * The door locking mechanism inspection must be accomplished any time the bolt inspection required by Paragraph "A" of this AD reveals a cracked, bent, broken or worn bolt. A) Inspect and replace, at the time intervals noted in Table I above, the bolt identified as 5 in Figure I of this AD in accordance with Gates Learjet 35/36/35A/36A Maintenance Manual Temporary Revisions No. 5-52 and 5-55 or later revisions and as summarized below: 1) Remove the bolt from the upper door rod control assembly and visually inspect it for cracks, breaks, bends, or wear. If any of the aforementioned defects are found, accomplish the door locking mechanism inspection required by Paragraph "B" of this AD prior to the next flight; and 2) Replace the bolt removed in Paragraph A)1) of this AD with a new Gates Learjet Part Number 2311490-8 Bolt, or a new AN3-21 Bolt modified in accordance with Detail "A" in Figure I of this AD, and secure using an AN960D10 Washer and either a new MS20365- 1032 Nut or AN310-3 Nut and MS24665-132 Cotter Pin. B) Inspect, at the time intervals noted in Table I above, the cabin door locking mechanism in accordance with Gates Learjet 35/36/35A/36A Maintenance Manual Temporary Revision No. 5-54 or later revisions, and as summarized below: 1) Drill out rivets and remove cabin upper door inner panel. 2) Remove and inspect door locking mechanism for wear and defects in accordance with Learjet Service Manual Inspection Requirements. The maximum allowable diameter (measured in any direction) of the hole in which the 5 bolt is installed is .201 inches. Replace any excessively worn or defective parts prior to the next flight. 3) Reinstall door locking mechanism and using rivets, reinstall the inner panel. 4) Check door locking mechanism for free movement with no binding thru entire operating travel. Correct any binding prior to the next flight. 5) Energize door warning system and check its operation for proper functioning. C) Submit a written report on any cracked, broken, bent or worn 5 (See Figure I of this AD) bolts discovered during inspections required by this AD to the FAA via a letter to FAA, Chief, Engineering and Manufacturing Branch (ACE-210), 601 East 12th Street, Kansas City, Missouri 64106 or an FAA M or D report (FAA Form 8330-2). The report must include airplane model, serial number, airplane total time-in-service, bolt or pin total time-in-service and statements describing the condition of the bolt and the hole including dimensions of the hole determined in accordance with Paragraph B)2) of this AD. (Reporting approved by the Office of Management and Budget under OMB No. 04-R0174.) D) The actions made mandatory by Paragraphs A, B and C of this AD are no longer required when Gates Learjet Door Modification Kit AMK78-2 is installed. E) Airplanes may be flown in accordance with FAR 21.197 to a base where this AD can be accomplished. F) Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region. This amendment becomes effective December 14, 1978. FOOTER:
Document Text
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AD Final Rules - DRS_78-25-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 78-25-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Gates Learjet Model 35 and 36 Airplanes Subject: Door Mechanism Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/14/1978 Make: Learjet Inc. Model: 35 | 36 Product Type: Aircraft Product Subtype: 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: 78-25-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3362 AD NUMBER: 78-25-02 SUBJECT HEADING: Airworthiness Directives; Gates Learjet Model 35 and 36 Airplanes ACTION: SUMMARY: DATES: Effective December 14, 1978. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 78-25-02 GATES LEARJET: Amendment 39-3362. Applies to those Model 35 (Serial Numbers 35-001 through 35-167) and 36 (Serial Numbers 36-001 through 36-038) airplanes, certificated in all categories, which have a 36-inch wide (as opposed to 24-inch wide) cabin door. Compliance: Required as indicated in accordance with Compliance Table I set forth in this AD, unless already accomplished. To assure proper locking of the cabin upper door when the inside handle is in the locked position and to prevent possible unwanted door openings that may occur, accomplish the following at the time intervals noted in Table I of this AD: TABLE I COMPLIANCE TIMES AD 78-25-02 INSPECTION TIMES Airplane Total Time In Service (Hours) Paragraph "A" Bolt Inspection & Replacement Paragraph "B" Locking Mechanism Inspection Initial Inspection/ Replacement Interval for Repetitive Inspections/ Replacement Initial Inspection Interval for Repetitive Inspections 0 - 2,999 Prior to or upon the accumulation of 3,075 hours’ time in service Each 3,000 hours' time in service there- after In accordance with asterisk (*) paragraph below or upon accumulation of 6,075 hours’ time in service, whichever occurs first In accordance with asterisk (*) paragraph below or upon accumulation of each 6,000 hours’ time in service after initial inspection 3,000 - 5,999 Within 75 hours' time in service after the effective date of this AD Each 3,000 Hours’ time in service thereafter In accordance with asterisk (*) paragraph below or upon accumulation of 6,075 hours’ time in service, whichever occurs first In accordance with asterisk (*) paragraph below or upon accumulation of each 6,000 hours’ time in service after initial inspection 6,000 - up Within 75 hours' time in service after the effective date of this AD Each 3,000 hours’ time in service there-after Within 5 hours’ time in service after the effective date of this AD In accordance with asterisk (*) paragraph below or upon accumulation of each 6,000 hours; time in service after initial inspection * The door locking mechanism inspection must be accomplished any time the bolt inspection required by Paragraph "A" of this AD reveals a cracked, bent, broken or worn bolt. A) Inspect and replace, at the time intervals noted in Table I above, the bolt identified as 5 in Figure I of this AD in accordance with Gates Learjet 35/36/35A/36A Maintenance Manual Temporary Revisions No. 5-52 and 5-55 or later revisions and as summarized below: 1) Remove the bolt from the upper door rod control assembly and visually inspect it for cracks, breaks, bends, or wear. If any of the aforementioned defects are found, accomplish the door locking mechanism inspection required by Paragraph "B" of this AD prior to the next flight; and 2) Replace the bolt removed in Paragraph A)1) of this AD with a new Gates Learjet Part Number 2311490-8 Bolt, or a new AN3-21 Bolt modified in accordance with Detail "A" in Figure I of this AD, and secure using an AN960D10 Washer and either a new MS20365- 1032 Nut or AN310-3 Nut and MS24665-132 Cotter Pin. B) Inspect, at the time intervals noted in Table I above, the cabin door locking mechanism in accordance with Gates Learjet 35/36/35A/36A Maintenance Manual Temporary Revision No. 5-54 or later revisions, and as summarized below: 1) Drill out rivets and remove cabin upper door inner panel. 2) Remove and inspect door locking mechanism for wear and defects in accordance with Learjet Service Manual Inspection Requirements. The maximum allowable diameter (measured in any direction) of the hole in which the 5 bolt is installed is .201 inches. Replace any excessively worn or defective parts prior to the next flight. 3) Reinstall door locking mechanism and using rivets, reinstall the inner panel. 4) Check door locking mechanism for free movement with no binding thru entire operating travel. Correct any binding prior to the next flight. 5) Energize door warning system and check its operation for proper functioning. C) Submit a written report on any cracked, broken, bent or worn 5 (See Figure I of this AD) bolts discovered during inspections required by this AD to the FAA via a letter to FAA, Chief, Engineering and Manufacturing Branch (ACE-210), 601 East 12th Street, Kansas City, Missouri 64106 or an FAA M or D report (FAA Form 8330-2). The report must include airplane model, serial number, airplane total time-in-service, bolt or pin total time-in-service and statements describing the condition of the bolt and the hole including dimensions of the hole determined in accordance with Paragraph B)2) of this AD. (Reporting approved by the Office of Management and Budget under OMB No. 04-R0174.) D) The actions made mandatory by Paragraphs A, B and C of this AD are no longer required when Gates Learjet Door Modification Kit AMK78-2 is installed. E) Airplanes may be flown in accordance with FAR 21.197 to a base where this AD can be accomplished. F) Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region. This amendment becomes effective December 14, 1978. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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