1. PLANNING INFORMATION A. Effectivity All S-70A/C (BlackHawkderivatives), and S-70B and S-70C(M) (SeaHawkand Naval Hawk derivatives) as identified in Section 3.,A. Components: Tail Gearbox Output Bevel Gear, Part Number: 70358-06620. B. Purpose To perform a initial UT inspection in accordance with Special Service Instructions (SSI) No. 70-121A or, latest revision. The inspection process shall be completed by personnel certified as Level II UT Technicians or equivalent, with Sikorsky Aircraft Corporation administered training specific to use this procedure. Background A TGB experienced a fracture of the output shaft spline that drives the tail rotor blades. The investigation has revealed that spline geometry and/or fretting found may be a contributor. It also revealed that potential cracks can be identified using a UT inspection probe without additional TGB disassembly. The UT inspection can be performed during the phase maintenance inspections when the tail rotor servo and pitch beam shaft are removed. C. Description All customers are requested to immediately contact Sikorsky Aircraft Corporation, at telephone number (203) 416-4299, or e-mail: (www.sikorskywcs@sikorsky.com) to schedule the required administered training. The administered training will be performed at Sikorsky Aircraft production facility in Stratford, CT USA. We recommend that all required administered training be completed within the compliance time of this Alert Service Bulletin THIS ALERT SERVICE BULLETIN IS THE PROPERTY OF SIKORSKY AIRCRAFT CORPORATION AND IS PROTECTED UNDER THE COPYRIGHT LAWS OF THE UNITED STATES AND OTHER COUNTRIES. THIS ALERT SERVICE BULLETIN IS DISTRIBUTED ONLY TO OWNERS/OPERATORS OF COMMERCIALLY-CERTIFIED SIKORSKY HELICOPTERS AND SIKORSKY-AUTHORIZED LOGISTIC AND SERVICE CENTERS FOR THE PURPOSE OF FOSTERING THE SAFE AND EFFICIENT OPERATION OF SUCH HELICOPTERS AND UNDER THE EXPRESS CONDITION THAT THE CONTENTS OF THIS ALERT SERVICE BULLETIN ARE NOT TO BE DISCLOSED, REPRODUCED, OR DISTRIBUTED, IN WHOLE OR IN PART, TO ANY THIRD PARTY, OR ADAPTED AS A DERIVATIVE WORK, WITHOUT THE EXPRESS DOCUMENTED CONSENT OF SIKORSKY AIRCRAFT CORPORATION. ANY ACT IN VIOLATION OF APPLICABLE LAW MAY RESULT IN CIVIL AND/OR CRIMINAL PENALTIES. LIMITED DISTRIBUTION R SIKORSKY AIRCRAFT CORPORATION 1999 ALL RIGHTS RESERVED No. 70-06-28A Subject: DRIVE SYSTEM - Tail Rotor Gearbox (TGB) - Output Shaft - Initial Ultrasonic Test (UT) Inspection of

March 27/08 Page 1 of 5 Revisio n A - May 21/09(ASB), but no later than three (3) months from the issue date of this ASB. Helicopter is prepared for maintenance. The tail rotor box fairing is removed. The tail rotor servo and pitch beam shaft are removed. A UT inspection is performed and data is analyzed. If tail gearbox output bevel gear fails the UT inspection, contact Sikorsky Aircraft Corporation for further instructions. If tail gearbox output bevel gear passes UT inspection, the tail rotor servo and pitch beam are installed. Tail rotor box fairing is installed. Helicopter is returned to service. D. Compliance Compliance is essential. The UT inspection outlined herein is to be accomplished as follows: (1) For S-70A and S-70C Derivatives, perform initial UT inspection at next scheduled phase maintenance inspection when the tail rotor servo is scheduled to be removed. (a) Recurring UT inspection for S-70A and S-70C derivatives shall be performed at the next phase PMS-2 special inspection. (2) For SH-60F Derivatives S-70B, S-70B-6, S-70C(M)-1, S-70C(M2), perform initial UT inspection at next scheduled phase maintenance inspection regardless if tail rotor servo is scheduled to be removed or not. (a) Recurring UT inspection shall be performed at the next scheduled phase inspection when the tail rotor servo is scheduled to be removed. (3) For SH-60B Derivatives S-70B-2, S-70B-3, S-70B-7 tail gearbox assemblies, perform initial UT inspection at next scheduled phase maintenance inspection regardless if tail rotor servo is scheduled to be removed or not. (a) Recurring UT inspection shall be performed at the next scheduled phase inspection when the tail rotor servo is scheduled to be removed. E. Approval Inspection Item. F. Manpower (Estimated) No. of Men No. of Hours Man-Hours Remove Details 2 2.0 4.0

Install Details 2 2.0 4.0 NOTE: Does not include time required to prepare helicopter for maintenance, or return helicopter to flight status. No. 70-06-28A DRIVE SYSTEM - Tail Rotor Gearbox (TGB) - Output Shaft - Initial Ultrasonic Test (UT) Inspection of

1. PLANNING INFORMATION (Continued)

March 27/08 Page 2 Revisio n A - May 21/09G. Tooling Refer to SSI No. 70-121A, or latest revision. H. Weight and Balance None. I. Electrical Load Data Not Changed. J. References Applicable Maintenance Manual for Removal and Installation procedures. K. Publications Affected (1) Applicable Preventive Maintenance Services, PMS-2 (2) Applicable Preventive Maintenance Information Cards, Phase A/B/C/D (3) Applicable Preventive Maintenance Information Cards, Phase A/B (4) Ultrasonic Testing inspection requirement will be added to the Applicable Special/Conditional/Preservation Maintenance Requirement Cards at a later date. L. Attachment Special Service Instructions No. 70-121A for UT inspection of tail gearbox output bevel gear. 2 MATERIAL INFORMATION A. Consumable Material None. B. Bill of Material None. 3. ACCOMPLISHMENT INSTRUCTIONS A. Determine inspection requirements as follows: No. 70-06-28A DRIVE SYSTEM - Tail Rotor Gearbox (TGB) - Output Shaft - Initial Ultrasonic Test (UT) Inspection of

1. PLANNING INFORMATION (Continued)

March 27/08 Page 3 Revisio n A - May 21/09(1) For BlackHawkand S-70 Derivatives: If the helicopter has not been through a Preventive Maintenance Services, PMS-2 inspection, then perform the one-time UT inspection at the next scheduled PMS-2 inspection. (2) For Naval Hawkderivatives which follow the Preventive Maintenance Information Cards, Phase A/B/C/D, perform the one-time UT inspection at the next scheduled 175 hr phase inspection. (3) For SeaHawkderivatives which follow the Preventive Maintenance Information Cards, Phase A/B schedule, perform the one-time UT inspection at the next scheduled 250 hr phase inspection. B. Perform an initial UT inspection as follows: (1) Prepare helicopter for maintenance. (2) Remove tail rotor servo and pitch beam shaft, refer to applicable Maintenance Manual.
NOTE: The inspection process shall be completed by personnel certified as Level II UT Technicians, or equivalent with Sikorsky Aircraft administered training specific to use this procedure. (3) Perform an initial UT inspection in accordance with SSI No. 70-121A or, latest revision. (4) Record information on attached Tail Gearbox Output Bevel Gear Data Sheet. (5) Install tail rotor servo and pitch beam shaft. Refer to applicable Maintenance Manual. (6) Install tail rotor box fairing. Refer to applicable Maintenance Manual. (7) Return helicopter to service. C. Record of Compliance (1) Make an appropriate logbook/log card entry to show compliance with this ASB. (2) Upon compliance with this Alert Service Bulletin, complete attached ALERT SERVICE BULLETIN COMPLIANCE RECORD CARD and return it to Sikorsky Aircraft Corporation. No. 70-06-28A DRIVE SYSTEM - Tail Rotor Gearbox (TGB) - Output Shaft - Initial Ultrasonic Test (UT) Inspection of

3. ACCOMPLISHMENT INSTRUCTIONS (Continued)

March 27/08 Page 4 Revisio n A - May 21/09D. Tail Gearbox Output Bevel Gear Data Sheet. Record following information for all Tail Gearbox Assembly Output Bevel Gear and FAX to Sikorsky Aircraft Corporation, WCS at (860) 998-7565. Make copy of Tail Gearbox Output Bevel Gear Data Sheet for each helicopter recorded. Customer/Operator Name: _____________________________________________________ Inspection Performed by:________________________________Date:___________________ Installed on Helicopter Serial Number:_____________________________________________ Tail Gearbox Assembly Serial No. ________________________________________________ Part Removed at Phase X________________________________________________________ UT Inspection Performed: Yes___________________No_______________________________ Part Accepted: Yes____________________________No______________________________ Part Failed: Yes____________________________No_________________________________ Signal Percent:_______________________________________________________________ FSH Attach a Screen Image No. 70-06-28A DRIVE SYSTEM - Tail Rotor Gearbox (TGB) - Output Shaft - Initial Ultrasonic Test (UT) Inspection of

3. ACCOMPLISHMENT INSTRUCTIONS (Continued)

March 27/08 Page 5 Revisio n A - May 21/09

### WCS PRODUCT SAFETY MANAGER WORLDWIDE CUSTOMER SERVICE

,

No. 70-06-28A DRIVE SYSTEM - Tail Rotor Gearbox (TGB) - Output Shaft - Initial Ultrasonic Test (UT) Inspection of

### BUSINESS REPLY MAIL

MAILSTOP: K100A WCS PRODUCT SAFETY MANAGER WORLDWIDE CUSTOMER SERVICEMay 21, 2009 TRANSMITTAL SHEET Subject: SPECIAL SERVICE INSTRUCTIONS NO. 70-121 -TAIL GEAR BOX ASSEMBLY -Ultrasonic Testing of Ultrasonic Inspection of This page transmits Revision A to Special Service Instructions No. 70-121 dated March 27, 2008. Special Service Instructions No. 70-121A supersedes Special Service Instructions No. 70-121 dated March 27, 2008. The text changed by this Revision is indicated by a vertical line in the outer margin of the page. Revision Feature: The Instructions section, paragraph (5), has been revised to reflect new blade disposition procedures. Paragraph (6), and Reference (a) have been deleted. In Description section, revised 25% full screen height to allowable full screen height. In References Section, changed ASB to reflect revison A. In Instructions Section, step A. (1) a., added; including appropriate cable. In Instructions Section, step A. (1) e., added: The 20.0-inch Non-metallic Rod (to be used when cleaning shaft bore). In Instructions Section, step A. (2) g., added: Mode: In Instructions Section, step A. (2) h., added: Add six dB when scanning. In Instructions Section, step A. (4), added: Point of contact for any questions information. Renumbered remaining steps. In Instructions Section, added steps (5) and revise existing procedures. In Consumable Materials Section, added Lint-free Cleaning Cloth or Wipes information. In Tools Required Section, added Feeler Gage and added steps (2) and (3) for Source. Added new Figure 1 and renumbered remaining Figures. Revised Figure 5. Revised Figure 7. SIKORSKY AIRCRAFT Technical Directives Section

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# Sikorsky A United Technologies Company Sikorsky Aircraft Corporation 6900 Main Street P.O. Box 9729 Stratford, Connecticut 06497-9129 (203) 386-4000

March 27, 2008 Revision A – May 21/09 Page 1 of 15 

### SPECIAL SERVICE INSTRUCTIONS No. 70-121A Subject : TAIL GEAR BOX ASSEMBLY – Ultrasonic Testing of Purpose : To perform an inspection using ultrasonic testing process. Model : All S-70A/C (Blackhawk derivatives), and S-70B and S-70C(M) (Seahawk and Naval Hawk derivatives). Description : Helicopter is prepared for maintenance. Tail rotor fairing is removed. Tail rotor servo and pitch beam shaft are removed. Ultrasonic test (UT) inspection is performed on tail gear box output bevel gear. Any UT signals in the insp ection area that exceed allowable full screen height (FSH) UT are to be reported to Sikorsky Ai rcraft Corporation. If the UT signals appear to be near allowable FSH, re-oil the bore and reinspect the area in question. If on second inspection the same result is noted, clean t he bore and reinstall the tail rotor servo, pitch beam shaft, and tail rotor fairing. Heli copter is return ed to service. References: (a) Applicable Maintenance Manual. (b) Alert Service Bulletin 70-06-28A or latest revision. Effectivity : All S-70 A/C helicopters (Blackhawk deriv atives), and S-70B and S-70C(M) helicopters (Seahawk and Naval Hawk derivatives). Component: Tail Gear box Output Bevel Gear p/n 70358-06620. Instructions : A. UT Inspection Procedure: (1) The following equipment shall be used: a. Ultrasonic Instrument: Sonatest, Panametrics (or equivalent) including appropriate cable. b. Ultrasonic Inspection Tool: Olympus HB 2344 (or equivalent as approved by Sikorsky Aircraft Corporation). c. Ultrasonic Couplant: Tail Gear box Oil (D OD-PRF-85734 preferred or MIL-PRF 23699). d. Calibration Standard: Ring - EWR203026. e. The 20.0 inch Non-metallic Rod (t o be used when cleaning shaft bore). f. Reference Document: Tech Sheet 5047, latest revision. (2) Set ultrasonic test equipm ent for calibration as follows: a. Frequency: 10 MHZ. b. Range: 1.0 inch. c. Dampening: 50 Ohms.

### SPECIAL SERVICE INSTRUCTION NO. 70-121A
d. Velocity: 0.1254”/microsecond. e. Delay/Zero: Exit point at “0” graticule (0.266”) or 3.998 

### μ Sec. f. Reject: Off. g. Mode: Pulse-Echo. h. Sensitivity Level: Set signal amplitude from Ca libration Notch to 80% FSH (Figure 1). Add six dB when scanning. (3) Inspection: a. 80% FSH from ID Notch (10% baseline material signal in shaft). b. Scan Index: 1/16”. Refer to instructions in Section (4). c. Discontinuity Evaluation: Any positive signal appearing in output bevel gear spline area shall be evaluated. Signals allowable FSH or greater are cause for rejection. Remove retention plate to expose spline for evaluation. (4) Point of contact for any questions: a. Andy Voor: Telephone No. 1-(203) 383-7539. b. Mike Shakinovsky: Telephone No. 1-(203) 386-4935. (5) Perform ultrasonic test on tail gear box output bevel gear as follows: a. Calibrate instrument using calibration standard noted in Section (2.) (Figure 1). b. Adjust signal amplitude to 80% FSH from OD notch. Add 6dB to this reference for scanning (approximately 10% baseline material noise in shaft is acceptable). c. Clean tail gear box shaft bore as follows: 1 Using dry lint free wipes clean the tail gear box shaft bore prior to inspection. Refrain from using any solvents or cleaners that c ould possibly contaminate the tail gear box. NOTE Count number of wipes used and make sure they are all removed upon completion. 2 Push wipes in from servo side out through rotor side of bore to avoid pushing dirt into tail gear box. NOTE Make sure there is adequate oil coverage prior to performing inspection. d. Lubricate spline end bore with tail gear box oil as follows:

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

NOTE

• Make sure the Transducer Wedge is tipped forward to allow insertion into the bore.

• Make sure search unit is adequately co upled throughout inspection. A dry bore is usually indicated by increase friction of pr obe; reduction in amplitude of the front spline signal and/or baseline noise . If this condition is detected, recouple/lube and reinspect.

• After ultrasonic tool is inserted, rotate it 360 degrees to spread the oil. e. Insert ultrasonic tool into rear bore from servo end of tail gear box and rotate to spread oil (Figure 2). f. Using a standard feeler gage, make sure there is a gap of 0.010 inches between probe head and shaft flange. If gap is less than 0.010 inches loosen screws 3/8 (0.375) inches apply Loctite 420 (or equivalent) to threads, then tighten screws to set shaft flange against feeler gage (Figure 6). g. Fully insert tool and locate large plug in rear bore. Maintain its position in rear bore while scanning at approximately 1.00 inch per second (Figure 3). NOTE

• Make sure all surfaces of probe are visually clean prior to inserting device into bore.

• Check all screws, fasteners, and other components of probe prior to and after inspection. h. Scan toward front of spline until signals fr om spline end shoulder are visible and probe reaches forward stop ring. (Figure 4). i. Rotate tool clockwise approximately 1/16 (0. 0625) inch. Scan spline area as tool is withdrawn to aft stop ring. j. Any positive signal appearing in output bevel gear spline area shall be evaluated as follows: k. Repeat this procedure until entire spline area has been scanned. l. Repeat scan, by rotating tool one full revolution, then index forward and repeat until full spline area has been scanned. m. Clean tail gear box shaft bore as follows: 1 Using dry lint free wipes clean the tail gear box shaft bore prior to inspection. Refrain from using any solvents or cleaners that c ould possibly contaminate the tail gear box. NOTE Count number of wipes used and make sure they are all removed upon completion.
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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

2 Push wipes in from servo side out through rotor side of bore to avoid pushing dirt into tail gear box. n. Check calibration sensitivity with calibra tion ring after each output bevel gear shaft has been inspected. Recalibrate and reinspect if calibration is off by more than 5%. NOTE Evaluate at Calibration Sensitivit y (scan sensitivity minus 6 dB). 1 In areas within two adjacent splines on either side of missing spline as shown in Figure 1, Zone 1, signals 25% FSH or great er at calibration sensitivity (not scan sensitivity) are cause for investigation/rejection. 2 In tip of spline as shown in Figure 1, Zone 2, signals 35% FSH or greater at calibration sensitivity (not sc an sensitivity) are cause for investigation/rejection. Verification of indications from tip of spline (Zone 2) can be conducted by damping using an oil soaked Q-tip. This does not require re-verification after subsequent assembly. 3 In all remaining splines, signals 35% FSH or greater at calibration sensitivity (not scan sensitivity) are cause fo r investigation/rejection. 4 Check calibration sensitivity with calibration ring after each output bevel gear shaft has been inspected. 5 Screen view in Figure 5 is signal response from spline end with probe position towards front stop. Note the two typical low amplitude signals from spline end that follow main spline end signal. 6 An indication from a spline crown anomaly will be further out in time than one from a spline root anomaly (Figure 6). 7 An example of signals from a simulated crack (EDM notches) is shown in Figure 5. Remove retention plate if further investigation is necessary. NOTE

• Crack indications shall be recorded on the data sheet attached and reported to Sikorsky Aircraft Corporation. 8 If a tail gear box is rejected for this inspection, tag rejected tail gear box with the following note: “THIS TAIL GEAR BOX HAS BEEN RE JECTED AND BEING RETURNED FOR OUTPUT SHAFT SPLINE CRACK INDICA TION DURING PHASE UT INSPECTION.”

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

B. Record of Compliance: Make an appropriate logbook/log card entr y to show compliance with this SSI. Weight and Balance Data: None. Manpower (Estimated):

No. of Men No. of Hours Man-Hours Mechanic 1 1.5 *1.5 UT Technician 1 1.5 *1.5 Total Man/Hours 4.0 *Does not include time required to prepare helicopter for maintenance or return it to flight status. Parts Required: Not Applicable Consumable Material: WARNING OBSERVE ALL CAUTIONS AND WARNINGS ON CONTAINERS WHEN USING CONSUMABLES. WHEN APPLICABLE, WEAR ALL NECESSARY PROTECTIVE GEAR DURING HANDLING AND USE. IF A CO NSUMABLE IS FLAMMABLE OR EXPLOSIVE, MAKE CERTAIN CONSUMABLE AND ITS VAPORS ARE KEPT AWAY FROM HEAT, SPARK, AND FLAME. MAKE CERTAIN EQUIPMENT IS PROPERLY GROUNDED AND FIREFIGHTING EQUIPMENT IS READILY AVAI LABLE PRIOR TO USE. FOR ADDITIONAL INFORMATION ON TOXICITY, FLASHPOINT, AND FLAMMABILITY OF CHEMICALS, CONSULT YOUR MEDICAL PEOPLE, OR MANUFACTURER OF THE CONSUMABLE.

Qty Nomenclature Part Number Source A/R Oil, Tail Gear box DOD-PRF-85734 (or MIL-PRF-23699), or equivalent (1)

A/R Lint-free Cleaning Cloth or Wipes MIL-C-85043 or equivalent (2)

A/R Loctite 420 MIL-A-46050C Ty pe II, Class I, or equivalent (3)

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

A. Tools Required: Qty Nomenclature Part Number Source 1 Calibration Ring EWR 203026 (1)

1 Feeler Gage Standard Feeler Gage with 0.010 inch gage (2)

1 Ultrasonic Inspection Tool Olympus, HB 2344 or equivalent (as approved by Sikorsky Aircraft Corporation) (1)

1 Ultrasonic Inspection Tech Sheet Reference Document: Tech Sheet 5047 (latest revision) (1)

Source: (1) Supplied by Sikorsky Aircraft Corporation. (2) Procure from local supply. (3) Ellsworth Adhesives, Web site: http://www.ellsworth.com/display/ productdetail.html?productid=981

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

TAIL GEAR BOX DATA SHEET Table 1: Tail Gear box (TGB) P/N 70358-_____-___ S/N Time Since New (TSN) Time Since Overhaul (TSO)

Table 2: Retention Plate P/N 70358-06612-____ S/N TSN TSO

Table 3: Output Bevel Gear (only for helicopter models where P/N is recorded on TGB log card P/N 70358-06620-____ S/N TSN TSO

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

Table 4: Torque Check (torque sequence is 1, 9, 13, 5, 11, 3, 15, 7, 2, 10, 14, 6, 16, 8, 12, and 4) Note: Torque Check is only required if output shaft spline does not pass UT inspection.

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

Zone 1

Zone 2: Applies to all splines including those in Zone 1.



### FIGURE 1 : Inspection Zones

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

FIGURE 2: Signal Response of an EDM Notch

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

FIGURE 3: Spline Scan Area

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

FIGURE 4: Fully Insert Tool to Locate Large Plug in Rear Bore

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

FIGURE 5: Signal Response of Spline End

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

FIGURE 6: Signal Responses of Crown Notch and Root Notch

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### SPECIAL SERVICE INSTRUCTION NO. 70-121A

FIGURE 7: Scan Positioning and Length of Scan Stops

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