AD 86-23-51
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Columbia Helicopters, Inc. | 234 | Airworthiness Directives; BOEING VERTOL Model 234 Series Helicopters |
Unsafe Condition
Failure of the spiral bevel ring gear/sun gear bolted joint.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove all spiral bevel ring gears, first stage sun gears, and spacer shims with more than zero hours time in service. Install new spiral bevel ring gear, first stage sun gear (serviceable), spacer shim, and associated hardware (bolt, washer, nut).
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Compliance Time
before further flight
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Affected Aircraft
Boeing Vertol Model 234 series helicopters with forward rotor transmission P/N's 234D1200-2, -3, -4, -5, -6 and/or aft rotor transmission P/N's 234D2200-3, -4, -5.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Transmissions
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_86-23-51.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 86-23-51 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; BOEING VERTOL Model 234 Series Helicopters Subject: Transmissions Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 07/20/1987 Make: Columbia Helicopters, Inc. Model: 234 Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 86-23-51 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-5659 AD NUMBER: 86-23-51 SUBJECT HEADING: Airworthiness Directives; BOEING VERTOL Model 234 Series Helicopters ACTION: SUMMARY: DATES: Effective July 20, 1987. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 86-23-51 BOEING VERTOL: Amendment 39-5659. Applies to Boeing Vertol Model 234 series helicopters certificated in any category, equipped with forward rotor transmission P/N's 234D1200-2, -3, -4, -5, and -6 and/or aft rotor transmission P/N's 234D2200-3, -4, and -5. Compliance is required as indicated, unless already accomplished. To prevent failure of the spiral bevel ring gear/sun gear bolted joint, accomplish the following before further flight. (a) For both forward and aft transmissions, remove all spiral bevel ring gears, P/N's 114D1244-5 and -6 and 114D2254-5 and -6; first stage sun gears, P/N's 234D1243-1 and -2 and 234D2250-1 and -2; and spacer shim, P/N's 114D2257-1 and -2, with more than zero hours time in service. Spiral bevel ring gears, P/N's 114D1244-6 and 114D2254-6; first stage sun gears, P/N's 234D1243-2 and 234D2250-2; and spacer shim, P/N 114D2257-2, are not eligible for further service. (b) Install the following parts, which must be new, except for the first stage sun gear, (item (b)(2) below), which must be serviceable: (1) Spiral bevel ring gear, P/N 114D1244-5 or 114D2254-5; (2) First stage sun gear, P/N 234D1243-1 or 234D2250-1; (3) Spacer shim, P/N 114D2257-1; and (4) Associated hardware as follows: (i) Bolt, P/N BACB30MT6T12; (ii) Washer, P/N BACW10BP6P; and (iii) Nut, P/N BACN10TW6. (c) An alternate method of compliance which provides an equivalent level of safety with this AD may be used when approved by the Manager, New York Aircraft Certification Office, 181 South Franklin Avenue, Rm. 202, Valley Stream, NY 11581. This amendment, 39-5659, becomes effective July 20, 1987, as to all persons except those persons to whom it was made immediately effective by individual telegrams issued November 14, 1986, which contained this amendment. FOOTER:
Document Text
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AD Final Rules - DRS_86-23-51.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 86-23-51 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; BOEING VERTOL Model 234 Series Helicopters Subject: Transmissions Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 07/20/1987 Make: Columbia Helicopters, Inc. Model: 234 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: 86-23-51 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-5659 AD NUMBER: 86-23-51 SUBJECT HEADING: Airworthiness Directives; BOEING VERTOL Model 234 Series Helicopters ACTION: SUMMARY: DATES: Effective July 20, 1987. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 86-23-51 BOEING VERTOL: Amendment 39-5659. Applies to Boeing Vertol Model 234 series helicopters certificated in any category, equipped with forward rotor transmission P/N's 234D1200-2, -3, -4, -5, and -6 and/or aft rotor transmission P/N's 234D2200-3, -4, and -5. Compliance is required as indicated, unless already accomplished. To prevent failure of the spiral bevel ring gear/sun gear bolted joint, accomplish the following before further flight. (a) For both forward and aft transmissions, remove all spiral bevel ring gears, P/N's 114D1244-5 and -6 and 114D2254-5 and -6; first stage sun gears, P/N's 234D1243-1 and -2 and 234D2250-1 and -2; and spacer shim, P/N's 114D2257-1 and -2, with more than zero hours time in service. Spiral bevel ring gears, P/N's 114D1244-6 and 114D2254-6; first stage sun gears, P/N's 234D1243-2 and 234D2250-2; and spacer shim, P/N 114D2257-2, are not eligible for further service. (b) Install the following parts, which must be new, except for the first stage sun gear, (item (b)(2) below), which must be serviceable: (1) Spiral bevel ring gear, P/N 114D1244-5 or 114D2254-5; (2) First stage sun gear, P/N 234D1243-1 or 234D2250-1; (3) Spacer shim, P/N 114D2257-1; and (4) Associated hardware as follows: (i) Bolt, P/N BACB30MT6T12; (ii) Washer, P/N BACW10BP6P; and (iii) Nut, P/N BACN10TW6. (c) An alternate method of compliance which provides an equivalent level of safety with this AD may be used when approved by the Manager, New York Aircraft Certification Office, 181 South Franklin Avenue, Rm. 202, Valley Stream, NY 11581. This amendment, 39-5659, becomes effective July 20, 1987, as to all persons except those persons to whom it was made immediately effective by individual telegrams issued November 14, 1986, which contained this amendment. FOOTER:
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Retrieved: Apr 8, 2026
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