Sikorsky Aircraft Corporation

6900 Main Street P.O. Box 9729

Stratford, Connecticut 06615-9129

(203) 386-4000

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### ASB 70-06-29A

October 11/11

DRIVE SYSTEM – S-70/H-60 Intermediat e Gearbox (IGB) - One Time Borescope Inspection of

Section 1. Planning Information

A. Effectivity All S-70 and H-60 models and spares with IGB less than 100 hours of

flight time sinc e new or overhaul as of the release date of this ASB.

B. Purpose To perform a one-time inspection to verify output bearing is lubricated for all H60’s and S-70’s.

C. Description An H-60 Intermediate Gearbox (IGB) experienced a fracture of the output shaft

that drives the tail rotor. This ASB provides a method to visually inspect the

lubrication passages from the oil scupper to the input and output housing using a

borescope.

D. Compliance Compliance is essential. The work outlined herein shall be accomplished prior to next

flight.

E. Approval Inspection item.



### Page 1 of 5 ONE-TIME

INSPECTION 

# A LERT

SERVICE BULLETIN

### ALERT

SERVICE BULLETIN

Section 1. Planning Information (Continued)

F. Manpower (Estimated) ASB 70-06-29A

October 11/11

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

Perform Inspection 1 2.0 2.0

Remove/Replace IGB, If Required 1 3.0 3.0

Total Man-Hours 5

. 0

*Estimate does not include time required to prep are helicopter or return it to flight status

.

G. Weight and Balance

Not affected.

H. Electrical Load Data

Not affected.

I. Software Load Data

Not changed.

J. References

None

K. Publications Affected

None

L. Attachment

None

Section 2. Material Information

A. Basis for Material Data

Per helicopter.

B. Bill of Material

None

C. Consumable Material

None



### Page 2

ONE-TIME

INSPECTIONASB 70-06-29A

October 11/11 

### ALERT

SERVICE BULLETIN

Section 2. Material Information (Continued)

D. Tools Required

See Appendix I for borescope requirements

Section 3. Accomplishment Instructions

A. Perform inspection of intermediate gearbox (IGB) output seal as follows:

(1) Drain oil from IGB per drive system maintenance procedures.

(2) Remove sight glass per drive system maintenance procedures.

NOTE: The borescope inspection may be waived if the maintainer elects to

disassemble the IGB for inspection of t he lubrication passages noted in Figure 1.

(3) Using borescope inspect lubrication passages from the oil scupper to input and

output housings (see Figure 1 and Figure 2) as follows:

(a) If there are no obstructions in the oil passages, gearbox is acceptable and

inspection is complete. Reinstall all parts and service in accordance with

maintenance procedures.

(b) If obstructions are observed remove IGB and return to Depot for teardown

evaluation and disposition. Replace with IGB from spares and service in

accordance with maintenance procedures (NOTE: Replacement IGB should be

inspected per this ASB unless the su ffix “A” has been adde d to the S/N).

(4) Return helicopter to service.

B. Record of compliance:

(1) Make an appropriate lo gbook entry to show compliance with this ASB.

(2) Upon compliance with this ASB, notify Si korsky by completing the attached ALERT

SERVICE BULLETIN COMPLIANCE RECORD and returning it to Sikorsky Aircraft

Corporation.

(3) Add an “A” suffix to the S/N of all IGB’ s that have been inspected and complied with

this ASB.



### Page 3

ONE-TIME

INSPECTION

### ALERT

SERVICE BULLETIN ASB 70-06-29A

October 11/11



### IGB Oil Passages To Be Inspected

FIGURE 1



### Page 4 ONE-TIME

INSPECTIONASB 70-06-29A

October 11/11 

### ALERT

SERVICE BULLETIN

Borescope Inspection Through Sight Glass Port

FIGURE 2

Page 5 ONE-TIME

INSPECTION

# (860) 998-7565

EMAIL ADDRESS: GPSIKSASProductSafet@utc.com

ATTENTION: SAS PRODUCT SAFETY MANAGER

SIKORSKY AEROSPACE SERVICES

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

completing and returning this ENTIRE PAGE by MAIL

, FAX , or scan & EMAIL

.

No. 70-06-29A

: DRIVE SYSTEM – S-70/H-60 Intermediate G earbox (IGB) - One Time Borescope

Inspection of

### BUSINESS REPLY MAIL

MAILSTOP: S328A

ATTENTION: SAS PRODUCT SAFETY MANAGER

SIKORSKY AEROSPACE SERVICES



## Or scan and email to:

GPSIKSASProductSafet@utc.co

m

## Appendix I Pa g e 1

ULTRASONIC 

## NONDESTRUCTIVE TESTING/ INSPECTION TECHNIQUE

Technique Number: VT 8000 Rev Number: 0 Part Number:

70357-06300-044 Part Name: Intermediate Gearbox Material:

Magnesium Rev Date: N/A

Approved: 10/08/2011

Part Preparation: Remove sight glass. Personnel performing th is inspection should be thoroughly familiar with the operation of bore

scopes/video probes.

Equipment and Materials

Video probe/bore scope: The inspection probe must have at least two way articulation and a length of 20 inches or more. The pr obe

should have removable tips in order to view the area of inte rest from both 0 degrees and 90 degrees. The shaft of the probe mus t be

flexible and the focal length of the tip optics should be betw een 1-5mm near to 20-50 mm far. The diameter of the probe should be

5mm or less.

Note: If the proper bore scope equipment is not availa ble, return the gearbox to depot for evaluation.

Inspection

• Place the 90 degree tip on the probe the first few ins pections for familiarization. See Figure 2.

• Evaluate the condition of the passages using the 0 degree opt ical tip on the bore scope or any combination the inspector

finds necessary. Insert the scope through the sight glass hole into the IGB. See fig 1.

• Push the scope into the hole in a downward direction after getting past the floor to wall corner and with a slight twist towar d

the input side housing to assist the probe as it follows the designed flow path into the scupper. See Figure 2.

• If inserted correctly, the probe will bottom out in t he scupper at a depth of 20 inches. See Figure 3.

• The holes are readilly apparent when using th e 90 degree optical tip. See figure 4.

• If the passages are blocked by a plug they will appear as illustrated in figures 5 and 6 when using a 90 degree optical tip.

• Passages are blocked by a plug they will also appear as illustrated in figures 7 and 8 when using a 0 degree optical tip.

• Passages that are clear of plugs will appear as illustrated in figures 9 and 10 when using a 0 degree optical tip.

Reporting

Note: The plugs are white and difficult to see. If there is an y doubt as to the condition of the oil passages route the IGB to the Depot

for evaluation. If a plugged passage is detected during th is inspection red tag the aircraft and R&R the IGB.

## Appendix I

Figure 1

Insert the bore scope into the sight glass hole

Figure 2

Allow the bore scope to follow the natural path into the scupper Note: Gearbox

shown open

for clarification

purposes Pa g e 2

## Appendix I

Figure 3

If inserted correctly, the probe will stop inside the scupper at a depth of 20 inches.

Figure 4

Both passages in view using 90 degree tip Note: Gearbox

shown open

for clarification

purposes Pa g e 3

## Appendix I

Figure 5

Plugged input side hole 90 degree tip

Figure 6

Plugged output side hole 90 degree tip Pa g e 4

## Appendix I

Figure 7

Plugged output side hole 0 degree tip

Figure 8

Plugged Input side hole 0 degree tip Pa g e 5

## Appendix I

Figure 9

Input hole clear 0 degree

Figure 10

Output hole clear 0 degree Pa g e 6