AD 80-25-01
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | MD Helicopters, Inc. | 369 | Airworthiness Directives; HUGHES HELICOPTERS Model 369 Series Helicopters |
| aircraft | MD Helicopters, Inc. | 369A | Airworthiness Directives; HUGHES HELICOPTERS Model 369 Series Helicopters |
| aircraft | MD Helicopters, Inc. | 369D | Airworthiness Directives; HUGHES HELICOPTERS Model 369 Series Helicopters |
| aircraft | MD Helicopters, Inc. | 369H | Airworthiness Directives; HUGHES HELICOPTERS Model 369 Series Helicopters |
| aircraft | MD Helicopters, Inc. | 369HE | Airworthiness Directives; HUGHES HELICOPTERS Model 369 Series Helicopters |
| aircraft | MD Helicopters, Inc. | 369HM | Airworthiness Directives; HUGHES HELICOPTERS Model 369 Series Helicopters |
| aircraft | MD Helicopters, Inc. | 369HS | Airworthiness Directives; HUGHES HELICOPTERS Model 369 Series Helicopters |
Unsafe Condition
Fatigue failure of the Hughes couplings in the tail rotor drive shaft and loss of tail rotor power.
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Required Actions
Inspect the fore and aft tail rotor drive shaft couplings to determine their serial numbers. Remove and label as 'Unairworthy' specific couplings with listed serial numbers and replace them with like serviceable parts. Report serial numbers of suspect couplings to the FAA.
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Compliance Time
Within 25 hours' time in service from the effective date of this AD
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Affected Aircraft
MD Helicopters, Inc. Models 369, 369A, 369D, 369H, 369HE, 369HM, 369HS certified in all categories.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Tail Rotor Drive Shaft
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_80-25-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 80-25-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; HUGHES HELICOPTERS Model 369 Series Helicopters Subject: Tail Rotor Drive Shaft Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/04/1980 Make: MD Helicopters, Inc. Model: 369 | 369A | 369D | 369H | 369HE | 369HM | 369HS Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 80-25-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3980 AD NUMBER: 80-25-01 SUBJECT HEADING: Airworthiness Directives; HUGHES HELICOPTERS Model 369 Series Helicopters ACTION: SUMMARY: DATES: Effective December 4, 1980. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 80-25-01 HUGHES HELICOPTERS: Amendment 39-3980. Applies to Model 369 Series Helicopters certified in all categories. Compliance is required as indicated unless already accomplished. To prevent possible fatigue failure of the Hughes couplings in the tail rotor drive shaft and loss of tail rotor power, accomplish the following: (a) Within 25 hours' time in service from the effective date of this AD, inspect the fore and aft tail rotor drive shaft couplings to determine the serial numbers of the installed couplings. The serial number is on the Bendix part number decal. (b) For those helicopters with the following couplings installed, prior to further flight, remove couplings from service and label couplings "Unairworthy." Hughes Part No. 369H92564, serial numbers 0883U, 0932U, 0933U, 0935U, 0940U, 0950U, 0957U, 0961U, 0971U; and for Hughes Part No. 369A5501, serial numbers 10670U and 10672U. Replace removed coupling with like serviceable part. (c) Installation of any coupling listed in paragraph (b) will render the helicopter unairworthy. (d) Report the serial number of each suspect coupling listed in paragraph (b) found as a result of the inspection of paragraph (a) to the Chief, Engineering and Manufacturing Branch, FAA, Western Region, P.O. Box 92007, World Way Postal Center, Los Angeles, California 90009. Negative reports are not necessary. Reporting approved by Office of Management and Budget, OMB No. 04/R0174. (e) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate helicopters to a base for the accomplishment of inspections required by this AD. (f) Alternative inspections, modifications or other actions which provide an equivalent level of safety may be used when approved by the Chief, Engineering and Manufacturing Branch, FAA Western Region. This amendment becomes effective December 4, 1980. FOOTER:
Document Text
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AD Final Rules - DRS_80-25-01.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 80-25-01 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; HUGHES HELICOPTERS Model 369 Series Helicopters Subject: Tail Rotor Drive Shaft Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/04/1980 Make: MD Helicopters, Inc. Model: 369 | 369A | 369D | 369H | 369HE | 369HM | 369HS 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: 80-25-01 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3980 AD NUMBER: 80-25-01 SUBJECT HEADING: Airworthiness Directives; HUGHES HELICOPTERS Model 369 Series Helicopters ACTION: SUMMARY: DATES: Effective December 4, 1980. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 80-25-01 HUGHES HELICOPTERS: Amendment 39-3980. Applies to Model 369 Series Helicopters certified in all categories. Compliance is required as indicated unless already accomplished. To prevent possible fatigue failure of the Hughes couplings in the tail rotor drive shaft and loss of tail rotor power, accomplish the following: (a) Within 25 hours' time in service from the effective date of this AD, inspect the fore and aft tail rotor drive shaft couplings to determine the serial numbers of the installed couplings. The serial number is on the Bendix part number decal. (b) For those helicopters with the following couplings installed, prior to further flight, remove couplings from service and label couplings "Unairworthy." Hughes Part No. 369H92564, serial numbers 0883U, 0932U, 0933U, 0935U, 0940U, 0950U, 0957U, 0961U, 0971U; and for Hughes Part No. 369A5501, serial numbers 10670U and 10672U. Replace removed coupling with like serviceable part. (c) Installation of any coupling listed in paragraph (b) will render the helicopter unairworthy. (d) Report the serial number of each suspect coupling listed in paragraph (b) found as a result of the inspection of paragraph (a) to the Chief, Engineering and Manufacturing Branch, FAA, Western Region, P.O. Box 92007, World Way Postal Center, Los Angeles, California 90009. Negative reports are not necessary. Reporting approved by Office of Management and Budget, OMB No. 04/R0174. (e) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate helicopters to a base for the accomplishment of inspections required by this AD. (f) Alternative inspections, modifications or other actions which provide an equivalent level of safety may be used when approved by the Chief, Engineering and Manufacturing Branch, FAA Western Region. This amendment becomes effective December 4, 1980. FOOTER:
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Retrieved: Apr 8, 2026
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