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S-92 ALERT 

SERVICE BULLETIN 

WARNING: THIS DOCUMENT, OR AN EMBODIMENT OF IT IN ANY MEDIA, DISCLOSES INFORMATION WHICH IS PROPRIETARY, IS THE PROPERTY OF SIKORSKY AIRCRAFT 

CORPORATION AND/OR ITS SUBSIDIARIES, IS AN UNPUBLISHED WORK PROTECTED UNDER APPLICABLE COPYRIGHT LAWS, AND IS DELIVERED ON THE EXPRESS CONDITION 

THAT IT IS NOT TO BE USED, DISCLOSED, REPRODUCED, IN WHOLE OR IN PART (INCLUDING REPRODUCTION AS A DERIVATIVE WORK), OR USED FOR MANUFACTURE FOR 

ANYONE OTHER THAN SIKORSKY AIRCRAFT CORPORATION AND/OR ITS SUBSIDIARIES WITHOUT ITS WRITTEN CONSENT, AND THAT NO RIGHT IS GRANTED TO DISCLOSE OR 

SO USE ANY INFORMATION CONTAINED HEREIN. ALL RIGHTS RESERVED. ANY ACT IN VIOLATION OF APPLICABLE LAW MAY RESULT IN CIVIL AND CRIMINAL PENALTIES. 

EXPORT WARNING: THESE COMMODITIES, TECHNICAL DATA OR SOFTWARE ARE SUBJECT TO THE EXPORT CONTROL OF EITHER THE INTERNATIONAL TRAFFIC IN ARMS 

REGULATIONS (ITAR) OR THE EXPORT ADMINISTRATION REGULATIONS (EAR) AND CANNOT BE EXPORTED WITHOUT THE AUTHORIZATION OF EITHER THE DEPARTMENT OF 

STATE OR THE DEPARTMENT OF COMMERCE PRIOR TO EXPORT. EXPORT INCLUDES DISCLOSURE AND OR ACCESS TO COMMODITIES, TECHNICAL DATA OR SOFTWARE BY 

FOREIGN NATIONALS WHETHER LOCATED IN THE UNITED STATES OR ABROAD. THIS REQUIREMENT APPLIES EQUALLY TO FOREIGN NATIONAL EMPLOYEES OF U.S. 

COMPANIES AND THEIR FOREIGN SUBSIDIARIES. 

ASB 92-63-034 

Basic Issue ▪ March 08/12 

SUBJECT: ROTOR DRIVES – Main Gear Box – Main Module Assembly – Perform One-Time Eddy 

Current Inspection of Main Module Assembly for Cracks 

Section 1. PLANNING INFORMATION 

A. Effectivity All S-92A model helicopters with serial numbers 920006 through 920157 with: 

Upper housing assembly part numbers 92351-15110-041 through -046 all serial 

numbers. 

Upper housing assembly part number 92351-15310-041 with serial numbers 

A1713-00001 through -00144 excluding -00143 through -00142, -00140, -00138, -

00127, -00111, -00109, -00103 through -00102, -00095, -00083, -00073 through -

00072, -00062, -00051, -00032, -00023 through -00015, -00013 and -00010. 

All main module assemblies (including spares). 

B. Purpose To perform an eddy current inspection of the main module assembly for cracks. 

To notify all operators that upon compliance with the inspection described herein, 

the current daily visual inspection implemented by ASB 92-63-032 is waived. 

C. Description The main module assembly is inspected for cracks using the eddy current method. 

If suspect indications are found, a follow-on fluorescent penetrant inspection (FPI) 

is performed. If a suspect indication is confirmed, the main module assembly is 

removed from service. If no suspect indications are found, or if suspect indications 

are not confirmed by FPI, the helicopter is returned to service. 

D. Compliance Compliance is essential. The inspection outlined herein shall be accomplished 

within 200 flight hours or 90 days from the issue date of this Alert Service Bulletin 

(ASB), whichever occurs first. 

Sikorsky Aircraft Corporation

6900 Main Street P.O. Box 9729 

Stratford, Connecticut 06615-9129 

(203) 386-4000
S-92 ALERT ASB 92-63-034 

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Section 1. PLANNING lNFORMATION (Continued) 

E. Approval Inspection item. 

F. Manpower (Estimated) 

Task No. of Men No. of Hours Man-Hours* 

Remove cowling and covers 1 1.0 1.0 

Perform inspection 1 1.0 1.0

Total Man-Hours 2.0 

*Estimate does not include time required to prepare helicopter or return it to flight status. 

G. Material 

(1) Phasec 3d flaw detector (or equivalent). 

(2) VM Products 2502RAFX-1/8 x 8 probe (or equivalent). 

H. Tooling 

(1) Permanent marker (or equivalent). 

(2) Nonmetallic scraper (or equivalent). 

(3) Soft bristled brush (or equivalent). 

I. Weight and Balance 

Not affected. 

J. Electrical Load Data 

Not affected. 

K. Software Load Data 

Not changed. 

L. References 

(1) Maintenance Manual SA S92A-AMM-000, Chapter/Section 54-40-01-900-001/-002. 

(2) Maintenance Manual SA S92A-AMM-000, Chapter/Section 63-20-01-900-001/-002. 

M. Publications Affected 

None. 
ASB 92-63-034 S-92 ALERT

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Section 1. PLANNING lNFORMATION (Continued) 

N. Attachment 

None. 

Section 2. MATERIAL INFORMATION 

A. Basis for Material Data 

Per helicopter. 

B. Bill of Material 

Qty Nomenclature Part No. Source

1 Magnesium Reference Block EWR213573-101, or equivalent (1) 

(1) For part availability and lead time requirements contact your Customer Service 

Representative at Helicopter Support Inc. (HSI). Submit a purchase order referencing this 

ASB number and the helicopter serial number(s) on which these parts will be used. This will 

allow HSI and the operator to track shipment and receipt of parts. Orders will be accepted 

by letter, telephone, facsimile (FAX) or through the HSI website: www.HSIUS.com. For 

prompt shipment, reference address of each shipping destination. Direct your order to: 

HELICOPTER SUPPORT INC. 

124 Quarry Road 

P.O. Box 11068 

Trumbull, Connecticut 06611 U.S.A. 

Attn: Customer Service 

FAX: (203) 416-4291 Telephone: (203) 416-4000 

HSI website: www.HSIUS.com
S-92 ALERT ASB 92-63-034 

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Section 2. MATERIAL INFORMATION (Continued) 

C. Consumable Material 

Qty Nomenclature Part No. Source

As Req’d Teflon Tape OML 1005 or equivalent (1) 

As Req’d Low Lint Cloth A-A-59323 Type II or equivalent (1) 

As Req’d Acetone O-A-51 or equivalent (1) 

As Req’d Paint Stripper MIL-R-81294 or equivalent (2) 

As Req’d Epoxy Primer MIL-PRF-85582D or equivalent 

Alternate MIL-P-23377 or equivalent 

(3) 

As Req’d Polyurethane Coating 36231 MIL-PRF-85285E or equivalent (3) 

(1) Procure from local supply. 

(2) Available from Chemsol. Website: www.chemsol.com. 

(3) Available from Trans Chem. Website: www.trans-chem.com. 

Section 3. ACCOMPLISHMENT INSTRUCTIONS 

A. Prepare helicopter for inspection: 

(1) Turn off all helicopter electrical and hydraulic power. 

(2) Engage rotor brake. 

(3) Remove center cover, if required. Refer to Maintenance Manual SA S92A-AMM-000, 

Chapter/Section 54-40-01-900-001. 

OBSERVE ALL CAUTIONS AND WARNINGS ON CONTAINERS 

WHEN USING CONSUMABLES. WHEN APPLICABLE, WEAR 

NECESSARY PROTECTIVE GEAR DURING HANDLING AND USE. IF 

A CONSUMABLE IS FLAMMABLE OR EXPLOSIVE, MAKE CERTAIN 

CONSUMABLE AND ITS VAPORS ARE KEPT AWAY FROM HEAT, 

SPARK AND FLAME. MAKE CERTAIN FIREFIGHTING EQUIPMENT 

IS READILY AVAILABLE PRIOR TO USE. FOR ADDITIONAL 

INFORMATION ON TOXICITY, FLASHPOINT AND FLAMMABILITY 

OF CHEMICALS, CONSULT YOUR MEDICAL PEOPLE OR THE 

MANUFACTURER OF THE CONSUMABLE. 
ASB 92-63-034 S-92 ALERT

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Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) 

B. Calibrate eddy current flaw detector (Phasec 3d, or equivalent): 

NOTE: The person performing eddy current inspection must be certified to Level 2 in the 

method for the purpose of conducting the input gear box inspection. If inspectors of 

other certification levels are utilized as permitted by NAS 410 or equivalent, this decision 

is the responsibility of the operator and their responsible Level 3 supervisor. 

Parameter Settings for Main Module

Probe drive Low 

Phase 88 deg/as required 

Differential gain - 

Filter DC/100 

Low Pass - 

Gain 33/43 

Frequency 100KHz 

Probe Bridge 

(1) Place 0.2 mm Teflon tape (OML 1005, or equivalent) over notches in magnesium reference 

block (EWR213573-101, or equivalent) to simulate lift-off from paint or Rockhard coating. 

Estimate amount of tape required by comparing lift-off from magnesium reference block to 

lift-off over the area of interest. 

(2) Hold probe end (2502RAFX-1/8 x 8, or equivalent) perpendicular to surface of magnesium 

reference block (EWR213573-101, or equivalent) in a flat area away from calibration 

notches. Balance (null) the instrument, placing “dot” approximately one screen division 

vertically from bottom of screen and two screen divisions horizontally from right side of 

screen. See Figure 1. 

(3) Raise probe (2502RAFX-1/8 x 8, or equivalent) slightly from surface of magnesium 

reference block (EWR213573-101, or equivalent) and observe direction of lift-off signal. 

(4) Adjust phase control until lift-off signal moves to the left of screen as probe (2502RAFX-1/8 

x 8, or equivalent) is raised from surface. 

(5) Maintaining probe (2502RAFX-1/8 x 8, or equivalent) perpendicular to surface of 

magnesium reference block (EWR213573-101, or equivalent), scan probe tip across 

0.008-inch (0.2 mm), 0.020-inch (0.5 mm) and 0.040-inch (1 mm) deep EDM notches, and 

observe amplitude of indications on screen. 

(6) Adjust gain until amplitude of signal from 0.040-inch (1 mm) EDM notch is at least two 

vertical screen divisions on CRT screen. See Figure 1. 
S-92 ALERT ASB 92-63-034 

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Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) 

C. Perform eddy current inspection: 

(1) Observe following common techniques: 

(a) Place probe at inspection location and balance (null) the instrument. Re-adjust 

phase as necessary. 

(b) Maintain probe perpendicular to surface and scan inspection location. Do not 

exceed two inches per second scan speed, and move probe in 1/8 (0.125) inch 

increments, taking care to avoid edges. 

(c) When scan of inspection location is complete, repeat scan in a direction 

approximately 90 degrees from first scan. 

(d) Any repeatable linear eddy current response equal to or greater than that of the 

0.020-inch (0.5 mm) deep notch response from the magnesium reference block is a 

suspect linear indication. 

(e) Do not inspect nuts or other attaching hardware. 

(f) Re-verify calibration of eddy current flaw detector (Phasec 3d, or equivalent) 

following completion of inspection. 

(2) Inspect main module assembly: 

(a) Inspect surfaces adjacent to Lee plug. See Figure 2. 

(b) If no suspect linear indication is found no further action is required. Proceed to 

Paragraph E. 

(c) If any suspect linear indication is found, proceed as follows: 

1. Map suspect area on part surface with a permanent marker. 

2. Fill out data sheet and return data sheet to Sikorsky Aircraft Corporation. 
ASB 92-63-034 S-92 ALERT

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Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) 

3. Strip paint from mapped area (mapped by permanent marker) as follows: 

a Apply a heavy coating of paint stripper (MIL-R-81294, or equivalent) to 

mapped area using a soft bristled brush. 

b Allow paint stripper to remain on surface until paint film has been softened 

or lifted. Gently scrub surface with a small cleaning brush to loosen paint 

in stubborn areas. 

c Remove softened paint and paint stripper with a nonmetallic scraper. 

d Repeat steps a through c until all paint has been removed from suspect 

crack area. 

e Rinse thoroughly with clean, fresh water and wipe dry with clean low lint 

cloth (A-A-59323 Type II, or equivalent). 

4. Perform FPI of mapped area: 

a If FPI confirms a linear indication (crack) in main module assembly, 

remove main module assembly from service. Refer to Maintenance 

Manual SA S92A-AMM-000, Chapter/Section 63-20-01-900-001/-002. 

Proceed to Paragraph D. 

b If FPI does not confirm any linear indications, reapply protective finish to 

stripped paint area. Proceed to paragraph D. 

D. Following FPI, reapply protective finish as follows: 

(1) Clean stripped area with acetone (O-A-51, or equivalent) and a clean low lint cloth (A-A59323 Type II, or equivalent). 

(2) Apply two coats of activated epoxy primer (MIL-PRF-85582D or equivalent, alternate MILP-23377 or equivalent). 

(a) Each coat of activated epoxy primer (MIL-PRF-85582D or equivalent, alternate MILP-23377 or equivalent) shall have a film thickness of 0.3 – 0.6 mils (0.0003 – 0.0006 

inch). 

(b) Allow each coat of activated epoxy primer (MIL-PRF-85582D or equivalent, alternate 

MIL-P-23377 or equivalent) to dry for a minimum of one hour. 
S-92 ALERT ASB 92-63-034 

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Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) 

NOTE: Topcoat should not exceed 4.5 mils (0.0045 inch) thickness. 

(3) Apply three coats of gray high solids polyurethane coating 36231 (MIL-PRF-85285E, or 

equivalent). 

(a) Each coat of gray high solids polyurethane coating 36231 (MIL-PRF-85285E, or 

equivalent) should have a dry film thickness of 0.9 – 1.5 mils (0.0009 – 0.0015 inch). 

(b) Allow each coat of gray high solids polyurethane coating 36231 (MIL-PRF-85285E, 

or equivalent) to dry for a minimum of two hours. 

E. Return helicopter to flight status: 

(1) Install center cover, if required. Refer to Maintenance Manual SA S92A-AMM-000, 

Chapter/Section 54-40-01-900-002. 

(2) Return helicopter to service. 

F. Record of compliance: 

(1) Make helicopter logbook entries to show compliance with this ASB as follows: 

(a) Make helicopter level logbook entry on form SA7343-15. 

(b) When ASB modifies a component that can be removed from this helicopter: 

1. Make component log card entries on forms SA7343-22 & SA7343-21 as 

applicable. 

2. If a component modified by this ASB does not have a log card and the ASB 

does not create one, then annotate compliance on the next higher assembly 

that the component belongs to which does have a log card. 

NOTE: If access to www.Sikorsky360.com is unavailable, complete attached ALERT 

SERVICE BULLETIN COMPLIANCE RECORD CARD and return it to Sikorsky 

Aircraft Corporation. 

(2) Make an appropriate electronic compliance entry in the E-Notification section at 

www.Sikorsky360.com. Refer to User Guide located on the www.Sikorsky360.com/ENotification Search page. 

 
ASB 92-63-034 S-92 ALERT

Basic Issue ▪ March 08/12 SERVICE BULLETIN

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Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) 

EDDY CURRENT INDICATIONS FOR MAGNESIUM REFERENCE BLOCK 

FIGURE 1 

SA

TD2637
S-92 ALERT ASB 92-63-034 

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Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) 

MAIN MODULE ASSEMBLY INSPECTION 

FIGURE 2 

SA

TD2664

STATIONARY

SCISSORS (REF)

DETAIL A

MAIN MODULE 

ASSEMBLY (REF)

INSPECT LEE PLUG BOSS,

CORED PASSAGES AND 

ADJACENT SURFACES.

DETAIL A

(SOME PARTS OMITTED FOR CLARITY)
ASB 92-63-034 S-92 ALERT

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Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) 

Eddy Current Inspection Data Sheet. 

Record following information for each helicopter. Return this data sheet to Sikorsky Aircraft Corporation. 

1. Customer/Operator Name: 

2. Helicopter Serial Number: 

3. Date Eddy Current Inspection is Performed: 

4. Helicopter Total Time Since New: 

5. Main Module Assembly Serial Number: 

6. Main Module Assembly Flight Hours: 

7. Please use the following Table to record eddy current inspection results. 

Inspection Area Linear Indication Found? Linear Indication Confirmed by FPI? 

Main Module Assembly 
(Fold over and tape closed) 

SIKORSKY AIRCRAFT CORPORATION 

FACSIMILE NUMBER (860) 998-7565 

EMAIL ADDRESS: GPSIKSASProductSafet@utc.com 

ATTENTION: SAS PRODUCT SAFETY MANAGER 

SIKORSKY AEROSPACE SERVICES 

(Fold Up to Arrows)

IMPORTANT NOTICE 

Upon COMPLIANCE with the attached ASB, Sikorsky requests your cooperation in completing and 

returning this ENTIRE PAGE by MAIL, FAX, or scan & EMAIL. 

If you have internet access, you may go to www.sikorsky.com to record your compliance. 

Please fill in the requested information at the bottom of the page, so we may maintain 

proper records documenting the configuration of your aircraft. This information is useful 

when determining configuration and effectivity of issues affecting fielded aircraft. 

This request is in keeping with our policy to assure that our customers receive the latest 

information applicable for the maintenance of your aircraft. Thank you. 

ALERT SERVICE BULLETIN: ________________ Compliance Record Card 

TITLE: ___________________________________________________________________ 

 ___________________________________________________________________ 

 ___________________________________________________________________ 

OWNER/OPERATOR: _____________________________________________________ 

SUBMITTED BY: ___________________________ DATE: ____________________ 

FOLLOWING SERIAL NUMBERS ARE NOT AFFECTED BY THIS ASB 

ASB HAS BEEN COMPLIED WITH ON THE FOLLOWING SERIAL NUMBERS 

 ___________ ___________ ___________ ___________ ___________ ___________ 

 ___________ ___________ ___________ ___________ ___________ ___________ 

No. 92-63-034 

ROTOR DRIVES – Main Gear Box – Main Module Assembly – Perform OneTime Eddy Current Inspection of Main Module Assembly for Cracks 
No Postage 

Necessary 

BUSINESS REPLY MAIL 

FIRST-CLASS MAIL PERMIT NO. 432 BRIDGEPORT CT 

POSTAGE WILL BE PAID BY ADDRESSEE 

SIKORSKY AIRCRAFT CORPORATION

P.O. BOX 9729 

6900 MAIN STREET 

STRATFORD, CONNECTICUT 06615-9129 U.S.A.

MAILSTOP: S328A

ATTENTION: SAS PRODUCT SAFETY MANAGER 

 SIKORSKY AEROSPACE SERVICES 

Please complete the form on the reverse side and FAX to 

FACSIMILE NUMBER (860) 998-7565 

Or scan and email to: 

EMAIL ADDRESS: GPSIKSASProductSafet@utc.com 

or fold and return ENTIRE form to Sikorsky Aircraft Corporation