AD 79-11-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | FH1100 Manufacturing Corporation | 1100 | Airworthiness Directives; Fairchild (Hiller) Model 1100 and FH-1100 Helicopters |
| aircraft | FH1100 Manufacturing Corporation | FH-1100 | Airworthiness Directives; Fairchild (Hiller) Model 1100 and FH-1100 Helicopters |
Unsafe Condition
Cracking of the transmission lower housing gimbal ring support.
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Required Actions
Inspect and repair P/N 24-23030-7 transmission lower housings with 500+ hours since new/overhauled within 50 hours after AD effective date or last 500 hours, repeating every 500 hours. Ream gimbal ring mounting holes to next size for housings with 1200+ hours within 100 hours after AD effective date or last 1100 hours, repeating every 1200 hours. Retire housings if hole diameter exceeds 0.8755 inch or total time reaches 3600 hours. Install P/N 24-23030-11 to exempt from AD.
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Compliance Time
within 50 hours after the effective date of this AD, unless already accomplished within the last 500 hours... within 100 hours after the effective date of this AD and at each 1200-hour interval thereafter... upon installation of P/N 24-23030-11
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Affected Aircraft
Fairchild (Hiller) Model 1100 and FH-1100 helicopters with P/N 24-23030-7 transmission lower housings installed in P/N 24-23000-11, -31, and -41 transmission assemblies
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Federal Register Abstract
Lower Housing Transmissions
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_79-11-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 79-11-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Fairchild (Hiller) Model 1100 and FH-1100 Helicopters Subject: Lower Housing Transmissions Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 06/04/1979 Make: FH1100 Manufacturing Corporation Model: 1100 | FH-1100 Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 79-11-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3479 AD NUMBER: 79-11-04 SUBJECT HEADING: Airworthiness Directives; Fairchild (Hiller) Model 1100 and FH-1100 Helicopters ACTION: SUMMARY: DATES: Effective June 4, 1979. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 79-11-04 FAIRCHILD (HILLER): Amendment 39-3479. Applies to Model 1100 and FH-1100 type helicopters certificated in all categories. Compliance required as indicated unless already accomplished. In order to prevent cracking of the transmission lower housing gimbal ring support, accomplish the following: a. For P/N 24-23030-7 transmission lower housings (installed in P/N 24-23000-11, -31, and -41 transmission assemblies) which have accumulated 500 or more hours since new or overhauled, inspect and repair as necessary within 50 hours after the effective date of this AD, unless already accomplished within the last 500 hours, in accordance with Fairchild Service Bulletin No. FH-1100-23-10 dated September 25, 1974, revised April 24, 1979. This inspection shall be repeated at each 500-hour interval thereafter. b. For P/N 24-23030-7 transmission lower housings which have accumulated 1200 or more hours, unless already accomplished within the last 1100 hours, ream the gimbal ring mounting holes to the next larger size in accordance with Fairchild Service Bulletin No. FH-1100-23-10 dated September 25, 1974, revised April 24, 1979, within 100 hours after the effective date of this AD and at each 1200-hour interval thereafter. c. As a result of the inspection and repair required under paragraphs a and b herein, if the gimbal ring mounting hole diameter exceeds 0.8755 inch or a total time of 3600 hours is attained on the P/N 24-23030-7 lower housing assembly the housing shall be retired from further service. d. Upon installation of transmission lower housing assembly P/N 24-23030-11, the requirements of this AD are no longer applicable. e. Equivalent inspections or parts must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. Upon submission of substantiating data by an owner or operator through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, may adjust the inspection interval specified in this airworthiness directive. f. Rotorcraft may be flown to a base where the maintenance required by this airworthiness directive is to be performed per FARs 21.197 and 21.199. This amendment is effective June 4, 1979. FOOTER:
Document Text
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AD Final Rules - DRS_79-11-04.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 79-11-04 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Fairchild (Hiller) Model 1100 and FH-1100 Helicopters Subject: Lower Housing Transmissions Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 06/04/1979 Make: FH1100 Manufacturing Corporation Model: 1100 | FH-1100 Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 79-11-04 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3479 AD NUMBER: 79-11-04 SUBJECT HEADING: Airworthiness Directives; Fairchild (Hiller) Model 1100 and FH-1100 Helicopters ACTION: SUMMARY: DATES: Effective June 4, 1979. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 79-11-04 FAIRCHILD (HILLER): Amendment 39-3479. Applies to Model 1100 and FH-1100 type helicopters certificated in all categories. Compliance required as indicated unless already accomplished. In order to prevent cracking of the transmission lower housing gimbal ring support, accomplish the following: a. For P/N 24-23030-7 transmission lower housings (installed in P/N 24-23000-11, -31, and -41 transmission assemblies) which have accumulated 500 or more hours since new or overhauled, inspect and repair as necessary within 50 hours after the effective date of this AD, unless already accomplished within the last 500 hours, in accordance with Fairchild Service Bulletin No. FH-1100-23-10 dated September 25, 1974, revised April 24, 1979. This inspection shall be repeated at each 500-hour interval thereafter. b. For P/N 24-23030-7 transmission lower housings which have accumulated 1200 or more hours, unless already accomplished within the last 1100 hours, ream the gimbal ring mounting holes to the next larger size in accordance with Fairchild Service Bulletin No. FH-1100-23-10 dated September 25, 1974, revised April 24, 1979, within 100 hours after the effective date of this AD and at each 1200-hour interval thereafter. c. As a result of the inspection and repair required under paragraphs a and b herein, if the gimbal ring mounting hole diameter exceeds 0.8755 inch or a total time of 3600 hours is attained on the P/N 24-23030-7 lower housing assembly the housing shall be retired from further service. d. Upon installation of transmission lower housing assembly P/N 24-23030-11, the requirements of this AD are no longer applicable. e. Equivalent inspections or parts must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. Upon submission of substantiating data by an owner or operator through an FAA Maintenance Inspector, the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, may adjust the inspection interval specified in this airworthiness directive. f. Rotorcraft may be flown to a base where the maintenance required by this airworthiness directive is to be performed per FARs 21.197 and 21.199. This amendment is effective June 4, 1979. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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