AD 91-08-03

final rule

Airworthiness Directives; Sikorsky Aircraft Model S-76A Helicopters

AD Number
91-08-03
Status
final_rule
Effective Date
Product Category
aircraft
Docket
91-ASW-05
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
aircraft Sikorsky Aircraft Corporation S-76A Airworthiness Directives; Sikorsky Aircraft Model S-76A Helicopters

Unsafe Condition

Fatigue failure of the vertical pylon forward spar, which could result in loss of the helicopter.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Determine if forward spar cap angles (part numbers 76201-05001-103 and 76201-05001-104) are installed and if equipped with Sikorsky Modification Kit 76070-20086. If the helicopter has the original unmodified forward spar cap angles with 1,395 or more hours time in service after the AD's effective date, replace the angles with new parts of the same part numbers. For helicopters with less than 1,395 hours time in service, replace the angles prior to accumulating 1,420 hours time in service and thereafter at intervals not exceeding 1,420 hours.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Within the next 25 hours time in service. Thereafter at intervals not to exceed 1,420 hours time in service.

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Sikorsky Aircraft Model S-76A helicopters, certificated in any category.

AI-generated summary from the source AD text. Verify against the official source before acting.

Federal Register Abstract

Forward Spar Cap

Applicability Source Text

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AD Number:
91-08-03
Document Type:
AD Final Rules
Docket Number:
91-ASW-05
Subject Heading:
Airworthiness Directives; Sikorsky Aircraft Model S-76A Helicopters
Subject:
Forward Spar Cap
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
05/03/1991
Make:
Sikorsky Aircraft Corporation
Model:
S-76A
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Superseded AD: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Superseded By: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: 91-08-03
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   91-ASW-05

AMENDMENT:   39-6958

AD NUMBER:   91-08-03

SUBJECT HEADING:   Airworthiness Directives; Sikorsky Aircraft Model S-76A Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective May 3, 1991.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
91-08-03 SIKORSKY AIRCRAFT: Amendment 39-6958. Docket No. 91-ASW-05.

Applicability: All Sikorsky Aircraft Model S-76A helicopters, certificated in any category.

Compliance: Required as indicated, unless already accomplished.

To prevent fatigue failure of the vertical pylon forward spar, which could result in loss of the helicopter, accomplish the following:

(a) Within the next 25 hours time in service determine if forward spar cap angles, part numbers (P/N's) 76201-05001-103 and 76201-05001-104, are installed and if it is equipped with Sikorsky Modification Kit 76070-20086, then--

(1) If the affected helicopter has Sikorsky Modification Kit 76070-20086 installed, no further action is necessary; however

(2) If the affected helicopter has the original unmodified forward spar cap angles with 1,395 or more hours time in service after the effective date of this AD, comply with paragraph (c), unless already accomplished, and thereafter at intervals not to exceed 1,420 hours time in service.

NOTE: Information pertaining to Kit 76070-20086 is contained in Sikorsky Alert Service Bulletin No. 76-55-12.

(b) For those helicopters with the original unmodified forward spar cap angles specified in paragraph (a)(2) with less than 1,395 hours time in service after the effective date of this AD, compliance with paragraph (c) is required prior to accumulation of 1,420 hours time in service, unless already accomplished, and thereafter at intervals not to exceed 1,420 hours time in service.

(c) Remove and replace the forward spar cap angles with new parts of the same part numbers.

(d) In accordance with FAR Sections 21.197 and 21.199, the helicopter may be flown to a base where compliance with the AD may be accomplished.

(e) Upon submission of substantiating data by an owner or operator through an FAA Airworthiness Inspector, an alternate method of compliance or adjustment of the compliance times, which provides an equivalent level of safety, may be used if approved by the Manager, Boston Aircraft Certification Office, Engine and Propeller Directorate, FAA, 12 New England Executive Park, Burlington, Massachusetts 01803.

This Amendment (39-6958, AD 91-08-03) becomes effective on May 3, 1991.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_91-08-03.html
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Print/Save as PDF
Document Versions
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Details
AD Number:
91-08-03
Document Type:
AD Final Rules
Docket Number:
91-ASW-05
Subject Heading:
Airworthiness Directives; Sikorsky Aircraft Model S-76A Helicopters
Subject:
Forward Spar Cap
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
05/03/1991
Make:
Sikorsky Aircraft Corporation
Model:
S-76A
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: 91-08-03
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   91-ASW-05

AMENDMENT:   39-6958

AD NUMBER:   91-08-03

SUBJECT HEADING:   Airworthiness Directives; Sikorsky Aircraft Model S-76A Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective May 3, 1991.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
91-08-03 SIKORSKY AIRCRAFT: Amendment 39-6958. Docket No. 91-ASW-05.

Applicability: All Sikorsky Aircraft Model S-76A helicopters, certificated in any category.

Compliance: Required as indicated, unless already accomplished.

To prevent fatigue failure of the vertical pylon forward spar, which could result in loss of the helicopter, accomplish the following:

(a) Within the next 25 hours time in service determine if forward spar cap angles, part numbers (P/N's) 76201-05001-103 and 76201-05001-104, are installed and if it is equipped with Sikorsky Modification Kit 76070-20086, then--

(1) If the affected helicopter has Sikorsky Modification Kit 76070-20086 installed, no further action is necessary; however

(2) If the affected helicopter has the original unmodified forward spar cap angles with 1,395 or more hours time in service after the effective date of this AD, comply with paragraph (c), unless already accomplished, and thereafter at intervals not to exceed 1,420 hours time in service.

NOTE: Information pertaining to Kit 76070-20086 is contained in Sikorsky Alert Service Bulletin No. 76-55-12.

(b) For those helicopters with the original unmodified forward spar cap angles specified in paragraph (a)(2) with less than 1,395 hours time in service after the effective date of this AD, compliance with paragraph (c) is required prior to accumulation of 1,420 hours time in service, unless already accomplished, and thereafter at intervals not to exceed 1,420 hours time in service.

(c) Remove and replace the forward spar cap angles with new parts of the same part numbers.

(d) In accordance with FAR Sections 21.197 and 21.199, the helicopter may be flown to a base where compliance with the AD may be accomplished.

(e) Upon submission of substantiating data by an owner or operator through an FAA Airworthiness Inspector, an alternate method of compliance or adjustment of the compliance times, which provides an equivalent level of safety, may be used if approved by the Manager, Boston Aircraft Certification Office, Engine and Propeller Directorate, FAA, 12 New England Executive Park, Burlington, Massachusetts 01803.

This Amendment (39-6958, AD 91-08-03) becomes effective on May 3, 1991.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

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