AD 51-04-02

final rule

WARNER Model All Engines Except Those With the Letter "A"

AD Number
51-04-02
Status
final_rule
Effective Date
Product Category
engine
Docket
Unknown
FR Citation
This information is not available.

Applicability

TypeManufacturerModelDetails
engine Warner Engine Company, LLC Scarab Jr. Series 40 WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Scarab Jr. Series 50 WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Scarab Series 28 WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Scarab Series 29 WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Scarab Series 30 WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Scarab Series 40 WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Scarab Series 50 WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Super Scarab Series 165 WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Super Scarab Series 165-B WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Super Scarab Series 165-D WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Super Scarab Series 185 WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Super Scarab Series 185J WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Super Scarab Series 185K WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Super Scarab Series 40 WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Super Scarab Series 50 WARNER Model All Engines Except Those With the Letter "A"
engine Warner Engine Company, LLC Super Scarab Series 50A WARNER Model All Engines Except Those With the Letter "A"

Unsafe Condition

Failure of the 5/16-inch cylinder holddown studs P/N S506, which can result from stretching due to loose nuts leading to fatigue failure.

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

Required Actions

Inspect cylinder holddown nuts for torque between 180 and 200 inch-pounds, replace broken studs for the affected cylinder, and replace all studs if nuts are loose. Alternatively, replace 5/16-inch studs S506 and nuts N-511 with 3/8-inch stud S-911 and nut N-910, install an 'O' type ring gasket, and stamp 'A' on the engine nameplate.

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

Compliance Time

As soon as possible but not later than April 1, 1951 and at each 100 hours of operation thereafter.

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

Affected Aircraft

Warner Engine Company, LLC engines: Scarab Jr. Series 40, Scarab Jr. Series 50, Scarab Series 28, Scarab Series 29, Scarab Series 30, and others except those with the letter 'A' stamped after the serial number on the engine nameplate.

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

Federal Register Abstract

Cylinder Holddown Studs

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_51-04-02.html
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AD Number:
51-04-02
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
WARNER Model All Engines Except Those With the Letter "A"
Subject:
Cylinder Holddown Studs
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Warner Engine Company, LLC
Model:
Scarab Jr. Series 40 | Scarab Jr. Series 50 | Scarab Series 28 | Scarab Series 29 | Scarab Series 30...Show more
Product Type:
Engine
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
Updated RGL applicability to match AD applicability; CAR C-11-185
AIRWORTHINESS DIRECTIVES FINAL RULES: 51-04-02
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   51-04-02

SUBJECT HEADING:   WARNER Model All Engines Except Those With the Letter "A"

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   51-04-02 WARNER: Applies to All Engines Except Those With the Letter "A" Stamped After the Serial Number on the Engine Nameplate. The Letter "A" Indicates That the Modifications Hereinafter Discussed Have Already Been Accomplished.
Compliance required as indicated.
As a precautionary measure to preclude serious flight hazards resulting from failure of the 5/16-inch cylinder holddown studs P/N S506, the following inspections or replacements should be accomplished.
A. Compliance required as soon as possible but not later than April 1, 1951 and at each 100 hours of operation thereafter.
1. Check the cylinder holddown nuts to determine that they are tightened to a torque of 180 inch- pounds desired to a 200 inch-pounds maximum.
(a) If one or more of the studs is found to be broken, replace all of the studs for the particular cylinder.
(b) Loose cylinder holddown nuts are a good indication that the stud may have stretched to the extent that fatigue failure may soon result. If one or more of the nuts is found loose, it is recommended that all of the studs in the cylinder be replaced.
(c) When installing a cylinder with oil on the stud threads, tighten nuts to 200 inch-pounds desired to 225 inch-pounds maximum.
(Warner Service Letter No. A-15 discusses procedures for inspecting and replacing 5/16-inch studs and nuts.)
B. Compliance not required, but will eliminate foregoing mandatory inspections.
1. Replace cylinder stud P/N S506 and nut N-511 with 3/8-inch stud S-911 and nut N-910.
2. Replace gasket between cylinder barrel and crankcase with an "O" type ring.
3. Stamp letter "A" after serial number on engine nameplate when this modification has been completed.
(Warner Service Letter No. A-17 explains the details connected with the replacement of these parts.)
The Warner Aircraft Co., P. O. Box 229, Niles, Mich., which purchased the assets of the Warner Division of the Clinton Machine Co., Detroit, Mich., have a large supply of replacement part stocks that will be held in their inventory for an indefinite period. Warner Service Letter No. A-17 should be consulted before ordering these replacement parts. If either Letter A-17 or Letter A-15 is not available, copies may be obtained from the Warner Aircraft Co., Box 229, Niles, Mich.

FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_51-04-02.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
51-04-02
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
WARNER Model All Engines Except Those With the Letter "A"
Subject:
Cylinder Holddown Studs
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Warner Engine Company, LLC
Model:
Scarab Jr. Series 40 | Scarab Jr. Series 50 | Scarab Series 28 | Scarab Series 29 | Scarab Series 30...Show more
Product Type:
Engine
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
Updated RGL applicability to match AD applicability; CAR C-11-185
AIRWORTHINESS DIRECTIVES FINAL RULES: 51-04-02
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:  

AD NUMBER:   51-04-02

SUBJECT HEADING:   WARNER Model All Engines Except Those With the Letter "A"

ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:   51-04-02 WARNER: Applies to All Engines Except Those With the Letter "A" Stamped After the Serial Number on the Engine Nameplate. The Letter "A" Indicates That the Modifications Hereinafter Discussed Have Already Been Accomplished.
Compliance required as indicated.
As a precautionary measure to preclude serious flight hazards resulting from failure of the 5/16-inch cylinder holddown studs P/N S506, the following inspections or replacements should be accomplished.
A. Compliance required as soon as possible but not later than April 1, 1951 and at each 100 hours of operation thereafter.
1. Check the cylinder holddown nuts to determine that they are tightened to a torque of 180 inch- pounds desired to a 200 inch-pounds maximum.
(a) If one or more of the studs is found to be broken, replace all of the studs for the particular cylinder.
(b) Loose cylinder holddown nuts are a good indication that the stud may have stretched to the extent that fatigue failure may soon result. If one or more of the nuts is found loose, it is recommended that all of the studs in the cylinder be replaced.
(c) When installing a cylinder with oil on the stud threads, tighten nuts to 200 inch-pounds desired to 225 inch-pounds maximum.
(Warner Service Letter No. A-15 discusses procedures for inspecting and replacing 5/16-inch studs and nuts.)
B. Compliance not required, but will eliminate foregoing mandatory inspections.
1. Replace cylinder stud P/N S506 and nut N-511 with 3/8-inch stud S-911 and nut N-910.
2. Replace gasket between cylinder barrel and crankcase with an "O" type ring.
3. Stamp letter "A" after serial number on engine nameplate when this modification has been completed.
(Warner Service Letter No. A-17 explains the details connected with the replacement of these parts.)
The Warner Aircraft Co., P. O. Box 229, Niles, Mich., which purchased the assets of the Warner Division of the Clinton Machine Co., Detroit, Mich., have a large supply of replacement part stocks that will be held in their inventory for an indefinite period. Warner Service Letter No. A-17 should be consulted before ordering these replacement parts. If either Letter A-17 or Letter A-15 is not available, copies may be obtained from the Warner Aircraft Co., Box 229, Niles, Mich.

FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

This site is not affiliated with or endorsed by the FAA. Always verify with official sources.