# Sikorsky Alert Service Bulletin 76-73-8 Copy: Revision A ("Sikorsky ASB 76-73-8 Rev A (IBR)"), 18 pages: PDF https://openairdocs.org/files/sha256/31/f9/31f9500c2e14a390e5a3ff90dfe8d318522cc551dfd6a04e315512bc65850b78; text https://openairdocs.org/service-documents/sikorsky/sb-76-73-8/file/31f9500c2e14.md. Rights: © Sikorsky. Filed by the FAA in regulations.gov docket FAA-2017-0874, the docket of AD 2018-10-07. Not covered by OpenAirDocs’ CC0 dedication. ## Details - Manufacturer: [Sikorsky](https://openairdocs.org/service-documents/sikorsky.md) - Type: Service bulletin (Alert Service Bulletin) - Number: 76-73-8 - Latest revision known: 76-73-8, Revision A (OpenAirDocs) - Page: https://openairdocs.org/service-documents/sikorsky/sb-76-73-8 ## Text (18 pages) Rights: © Sikorsky. Filed by the FAA in regulations.gov docket FAA-2017-0874, the docket of AD 2018-10-07. Not covered by OpenAirDocs’ CC0 dedication. Some pages are OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 S-76® HELICOPTER ALERT SERVICE BULLETIN NOTICE TO ALL PERSONS RECEIVING THIS DOCUMENT: 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INFORMATION WHICH IS PROPRIETARY, IS THE PROPERTY OF SIKORSKY AIRCRAFT CORPORATION AND/OR ITS SUBSIDIARIES, IS AN UNPUBLISHED WORK PROTECTED UNDER APPLICABLE COPYRIGHT LAWS, AND IS DELIVERED ON THE EXPRESS CONDITION THAT IT IS NOT TO BE USED, DISCLOSED, REPRODUCED, IN WHOLE OR IN PART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. S-76® IS A REGISTERED TRADEMARK OF SIKORSKY AIRCRAFT CORPORATION. ASB 76-73-8 August 21/15 Revision A ▪ December 4/15 SUBJECT: ENGINE AND FUEL CONTROL – 2S1 and 2S2 Engine Digital Engine Control System Collective Position Transducer (CPT) – One-Time Inspection and Differential Voltage Test of CPT Section 1. P LANNING INFORMATION A. Effectivity All S-76C+ and C++ model helicopters equipped with Arriel 2S1 or 2S2 engines. B. Purpose To perform a one-time inspection and differential voltage test of CPT. Several events have occurred where CPTs have faulted internally. C. Description Helicopter is prepared for maintenance. Access to CPT is gained. One-time differential voltage test of CPT is performed. If CPT fails test, CPT is replaced. If CPT passes test, helicopter is returned to service. D. Compliance Compliance is essential. The inspection outlined herein shall be accomplished no later than December 31, 2015. If SSI 76-87, One-Time Differential Voltage Test of CPT, basic issue or later revision, is complied with, no further action is required. E. Approval Inspection Item. Sikorsky Aircraft Corporation 6900 Main Street P.O. Box 9729 Stratford, Connecticut 06615-9129 (203) 386-4000 Page 1 of 16 ATA 73-22-04 ONE-TIME INSPECTION WARNING – This information contains technical data subject to the EAR. Diversion contrary to US Law is prohibited. ECCN: 9E991 ### Page 2 S-76 ALERT ASB 76-73-8 SERVICE BULLETIN Revision A ▪ December 4/15 Section 1. P LANNING lNFORMATION (Continued) F. Manpower (Estimated) Task No. of Men No. of Hours Man-Hours* Remove FWD Fairing 1 0.50 0.50 Install CPT Differential Voltage Test Box 1 0.25 0.25 Perform Total Resistance Checks 1 0.50 0.50 Perform Linearity Resistance Test 1 1.00 1.00 Measure Excitation Voltage 1 0.50 0.50 Differential Voltage Test 1 0.50 0.50 Remove CPT Differential Voltage Test Box, Final Checks 1 0.25 0.25 Install FWD Fairing 1 0.50 0.50 Total Man-Hours 4.00 *Estimate does not include time required to prepare helicopter or return it to flight status. G. Tooling Qty Nomenclature Part Number Source 1 CPT Differential Voltage Test Box 76700-40009-042 (2) 1 Multimeter Fluke 179 or equivalent (1) (1) Available through normal supply channels. (2) For parts availability and lead time requirements contact your Account Service Manager or Customer Service Representative at Sikorsky Aircraft Corporation, Commercial Systems and Services. Submit a purchase order referencing this ASB number and the helicopter serial number(s) on which these parts will be used. This will allow Sikorsky Aircraft Corporation, Commercial Systems and Services and the operator to track shipment and receipt of parts. Orders will be accepted by letter, telephone, facsimile (FAX) or through the Sikorsky Aircraft Corporation, Commercial Systems and Services website: https://customerportal.sikorsky.com. For prompt shipment, reference address of each shipping destination. Direct your order to: Sikorsky Aircraft Corporation Commercial Systems and Services Mailstop K100 124 Quarry Road Trumbull, CT 06611 U.S.A. Attn: Account Service Manager FAX: (203) 416-4291, Telephone: (203) 416-4000 https://customerportal.sikorsky.com Page 2 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 3 ASB 76-73-8 S-76 ALERT Revision A ▪ December 4/15 SERVICE BULLETIN Section 1. P LANNING lNFORMATION (Continued) H. Weight and Balance Not affected. I. Electrical Load Data Not affected. J. Software Load Data Not changed. K. References (1) Maintenance Manual, SA 4047-76C-2, Flight Controls – Inspection/Check, Task 67-00-00. (2) Maintenance Manual, SA 4047-76C-2, 2S1 and 2S2 Engine Digital Engine Control System Collective Position Transducer – Maintenance Practices, Task 73-22-04. L. Publications Affected (1) Temporary Revision No. 5-181 against Maintenance Manual, SA 4047-76C-2-1, Chapter/Section 5-20-00, is issued concurrently with this ASB. (2) Temporary Revision No. 73-05 against Maintenance Manual, SA 4047-76C-2, Chapter/Section 73-22-04, is issued concurrently with this ASB. M. Attachment None. Section 2. M ATERIAL INFORMATION A. Basis for Material Data Per helicopter. B. Bill of Material None. C. Consumable Material Page 3 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 4 S-76 ALERT ASB 76-73-8 SERVICE BULLETIN Revision A ▪ December 4/15 Section 2. MATERIAL INFORMATION (Continued) Qty Nomenclature Part No. Source 1 9 Volt Battery Commercially available or equivalent (1) (1) Available through normal supply channels. Section 3. A CCOMPLISHMENT INSTRUCTIONS A. Prepare helicopter for inspection as follows: (1) Connect external power cart to helicopter. (2) Connect hydraulic power unit to No. 2 side. (3) Engage rotor brake. (4) Push in the following DC ESSENTIAL bus circuit breakers located on the lower circuit breaker panel: (a) For S-76C+ helicopters with IIDS: 1. NO. 1 DECU PWR 2. NO. 2 DECU PWR (b) For S-76C+ helicopters with DDR: 1. NO. 1 ENG-DECU PWR 2. NO. 2 ENG-DECU PWR (c) For S-76C++ helicopters with IIDS: 1. NO. 1 ENG CHA 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. Page 4 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 5 ASB 76-73-8 S-76 ALERT Revision A ▪ December 4/15 SERVICE BULLETIN Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) 2. NO. 1 ENG CHB 3. NO. 2 ENG CHA 4. NO. 2 ENG CHB NOTE: Do not cycle DECU circuit breakers during test as the IIDS maintenance pages will display dashes for engine collective position. If IIDS maintenance page displays dashes for CPT position, turn OFF helicopter power, wait a few seconds, and then turn helicopter power back ON. (5) Remove forward fairing and flight controls enclosure to access CPT. B. Install CPT differential voltage test box (76700-40009-042) as follows (Refer to Figure 1): NOTE: CPT differential voltage test box (76700-40009-042) will be referred to as test box, hereafter. (1) Disconnect transducer connector P1 from J1030 receptacle. (2) C onnect P1 to TJ1030 of test box. (3) Connect TP1030A of test box to J1030 receptacle. C. Perform total resistance checks as follows (Refer to Figures 1, 2, and 3): (1) Verify DECU #1 EXCITATION SELECT SWITCH is OFF on test box. (2) Verify DECU #2 EXCITATION SELECT SWITCH is OFF on test box. (3) Connect positive terminal of multimeter to TP-3 of test box. (4) Connect negative terminal of multimeter to TP-1 of test box. (5) Measure total resistance of DECU #1 POT. Record measurements on CPT Data Sheet and here (Refer to step O.): __________ ohms. (a) Resistance must be 4500 ohms to 5500 ohms. (b) If resistance is not within tolerance, record findings on CPT Data Sheet, and replace CPT. (Refer to Section 3. O. and Maintenance Manual, SA 4047-76C-2, Task 73-22- 04.) (6) Connect positive terminal of multimeter to TP-6 of test box. (7) Connect negative terminal of multimeter to TP-4 of test box. (8) Measure total resistance of DECU #2 POT. Record measurements on CPT Data Sheet and here (Refer to step O.): ___________ohms. Page 5 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 6 S-76 ALERT ASB 76-73-8 SERVICE BULLETIN Revision A ▪ December 4/15 Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) (a) Resistance must be 4500 ohms to 5500 ohms. (b) If resistance is not within tolerance, record findings on CPT Data Sheet, and replace CPT. (Refer to Section 3. O. and Maintenance Manual, SA 4047-76C-2, Task 73-22- 04.) D. Perform CPT linearity resistance movement test for No. 1 and No. 2 DECUs as follows (Refer to Figures 1 and 2): (1) Connect positive terminal of multimeter to TP-2 of test box. (2) Connect negative terminal of multimeter to TP-1 of test box. (3) Set multimeter to read between 2000 ohms and 3000 ohms. (4) Move CPT to test position as follows: (a) Turn on helicopter electrical power. (b) Apply external hydraulics to No. 2 side. (c) While pressing the collective trim release trigger, raise the collective arm up until the multimeter reads approximately 2000 ohms. (5) While monitoring multimeter, press collective trim release trigger, and raise the collective arm slowly and smoothly at a rate of approximately 0.25 inches per second until multimeter reads approximately 3000 ohms. (6) While pressing collective trim release trigger, lower the collective arm until multimeter reads approximately 2000 ohms. (7) Check multimeter and note if there are any linear abnormalities or large jumps of resistance typically greater than 200 ohms during travel. NOTE: An example of abnormality: resistance reads 2300 ohms and jumps to 2600 ohms then back down to 2450 ohms. (Refer to Figure 3). (a) Record any nonlinear movement relative to a smooth collective arm movement on CPT Data Sheet (Briefly, describe in your own words what you saw and the range of resistance where anomaly occurred) and here (Refer to step O.): __________________________________________________________. (b) If travel shows a change in resistance greater than 200 ohms, record findings on CPT Data Sheet, and replace CPT. (Refer to Section 3. O. and Maintenance Manual, SA 4047-76C-2, Task 73-22-04.) (8) Connect positive terminal of multimeter to TP-5 of test box. (9) Connect negative terminal of multimeter to TP-4 of test box. Page 6 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 7 ASB 76-73-8 S-76 ALERT Revision A ▪ December 4/15 SERVICE BULLETIN Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) (10) Set multimeter to read between 2000 ohms and 3000 ohms. (11) Move CPT to test position as follows: (a) While pressing the collective trim release trigger, raise the collective arm up until the multimeter reads approximately 2000 ohms. (12) While monitoring multimeter, press collective trim release trigger, and raise the collective arm slowly and smoothly at a rate of approximately 0.25 inches per second until multimeter reads approximately 3000 ohms. (13) While pressing collective trim release trigger, lower the collective arm until multimeter reads approximately 2000 ohms. (14) Check multimeter and note if there are any linear abnormalities or large jumps of resistance typically greater than 200 ohms during travel. NOTE: An example of abnormality: resistance reads 2300 ohms and jumps to 2600 ohms then back down to 2450 ohms. (Refer to Figure 3). (a) Record any nonlinear movement relative to a smooth collective arm movement on Collective Position Transducer (CPT) Data Sheet (Briefly, describe in your own words what you saw and the range of resistance where anomaly occurred) and here: __________________________________________________________. (b) If travel shows a change in resistance greater than 200 ohms, record findings on Collective Position Transducer (CPT) Data Sheet, and replace CPT. (Refer to Section 3. O. and Maintenance Manual, SA 4047-76C-2, Task 73-22-04.) (c) Turn off helicopter hydraulic and electrical power. E. Determine DECU excitation voltage as follows (Refer to Figure 1 and 2): (1) Toggle DECU #1 EXCITATION SELECT SWITCH to DECU #1 EXCITATION on test box. (2) Toggle DECU #2 EXCITATION SELECT SWITCH to DECU #2 EXCITATION on test box. NOTE: The engine DECUs each provide an excitation voltage in the range of 9.5 to 10.5 VDC (reference). The engine manufacturer does not specify a field inspection check of this voltage, nor specify field inspection criterion since the excitation is automatically and internally self-checked by the DECU, which will declare a fault if the accuracy is not acceptable for engine operation. The purpose of this step to check that helicopter wiring is not causing any excitation voltage discrepancy, and to determine if two DECUs are close enough in tolerances to serve as a voltage source for the CPT differential signal check in step F. Otherwise an alternate means of test using a battery source is specified in step E.(6). (3) Turn on helicopter hydraulic and electrical power. Page 7 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 8 S-76 ALERT ASB 76-73-8 SERVICE BULLETIN Revision A ▪ December 4/15 Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) (4) Measure excitation voltage from TP-3 to TP-1 of test box. Record measurements on CPT Data Sheet and here (Refer to step O.): ______________ VDC. (a) If voltage is outside the 9.5 VDC to 10.5 VDC tolerance range, verify integrity of helicopter wiring as follows: 1. Verify continuity of No. 1 DECU excitation wiring. 2. Verify pins are seated properly in all associated connectors. (5) Measure excitation voltage from TP-6 to TP-4 of test box, recording measurements on CPT Data Sheet and here: ______________ volts. (a) If voltage is outside the 9.5 VDC to 10.5 VDC range, verify integrity of helicopter wiring as follows: 1. Verify continuity of No. 2 DECU excitation wiring. 2. Verify pins are seated properly in all associated connectors. (6) If difference of voltages recorded in steps E. (4) and E. (5) are within 10 mV, proceed to step F. and continue testing; otherwise perform the following steps to use the common 9 volt battery excitation source: (a) Toggle DECU #1 EXCITATION SELECT SWITCH to 9 VOLT EXCITATION on test box. (b) Toggle DECU #2 EXCITATION SELECT SWITCH to 9 VOLT EXCITATION on test box. (c) Measure excitation voltage from TP-3 to TP-1 of test box. Record measurements on CPT Data Sheet and here: _________________volts. (d) Measure excitation voltage from TP-6 to TP-4 of test box. Record measurements on CPT Data Sheet and here: _________________volts. (e) Verify voltages in steps E. (6) (c) and E. (6) (d) are within ± 10 mV and also greater than or equal to 9 volts. (f) If excitation is less than 9 volts, replace battery with fresh 9 volt battery (commercially available or equivalent). NOTE: If using 9 volt excitation, switch positions are to be kept at 9 VOLT EXCITATION, and helicopter power is to be cycled prior to performing differential voltage test step F. This will make the collective positions available on the IIDS for collective movement. F. Run differential voltage test as follows (Refer to Figures 1 and 2): (1) Connect positive terminal of multimeter to TP-2 of test box. Page 8 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 9 ASB 76-73-8 S-76 ALERT Revision A ▪ December 4/15 SERVICE BULLETIN Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) (2) Connect negative terminal of multimeter to TP-5 of test box. (3) Push collective all the way to down stop. (4) Set multimeter to record maximum and minimum voltages. (5) Monitor the left and right DDR/IIDS (as equipped) on maintenance page to read collective position. (6) While pressing collective trim release trigger, slowly and smoothly raise the collective arm to full up position at a rate of approximately 1% per second (using the DDR/IIDS % collective readout) or approximately 0.25 inches per second, if DDR/IIDS is not available. (7) While pressing collective trim release trigger, slowly and smoothly lower the collective arm to full down position at a rate of approximately 1% per second (using the DDR/IIDS % collective readout) or approximately 0.25 inches per second, if DDR/IIDS is not available. (8) Record maximum and minimum values from multimeter on CPT Data Sheet and here (Refer to step O.): (a) Maximum value: _________ millivolts. (b) Minimum value: _________ millivolts. G. Verify test results as follows: (1) If the maximum voltage recorded in step F.(8) is greater than 100 millivolts, or if the minimum voltage is less than -100 millivolts, replace CPT. (2) If voltages are within specifications, proceed to next step. H. Power down helicopter and remove test box as follows (Refer to Figures 1 and 2): (1) Turn off all hydraulic and electrical power. (2) Disconnect multimeter from test box. (3) Disconnect test connectors TJ1030 and TP1030A from test box. Remove test box from helicopter. (4) Connect electrical connector P1 of CPT to electrical connector J1030. I. Perform final checks as follows: (1) Turn helicopter power on. (2) Apply external hydraulics to No. 2 side of helicopter. Page 9 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 10 S-76 ALERT ASB 76-73-8 SERVICE BULLETIN Revision A ▪ December 4/15 Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) (3) While monitoring DDR/IIDS and moving the collective stick through its entire up and down range, verify No. 1 Eng Collective and No. 2 Eng Collective are greater than or equal to 10% at Low Collective and less than or equal to 90% at High Collective. (a) If collective values are outside of the 10% to 90% range, verify the CPT rigging is correct. (Refer to Maintenance Manual, SA 4047-76C-2, Removal/Installation Collective Position Transducer, Task 73-22-04). (b) If CPT rigging is correct, perform quick rigging checks. (Refer to Maintenance Manual, SA 4047-76C-2, Quick Rigging Checks, Task 67-00-00). (c) If DECU faults occur during final check, and cannot be alleviated by correcting the range to within 10%-90% by normal potentiometer adjustment procedures or rigging adjustment procedures, refer to engine manufacturer manual for DECU fault troubleshooting. (d) If no DECU faults exist but significant collective signal abnormality is evident in side to side engine comparison after all helicopter checks otherwise correct, consult engine manufacturer. J. Re-install flight controls enclosure and forward fairing. K. Disengage rotor brake. L. Turn off and disconnect hydraulic and electrical power. M. Refer to Temporary Revisions listed in the Publications Affected Section of this ASB for recurring inspections of CPT. N. Return helicopter to service. Page 10 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 11 ASB 76-73-8 S-76 ALERT Revision A ▪ December 4/15 SERVICE BULLETIN Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) O. Collective Position Transducer (CPT) Data Sheet. (CPT Data Sheet can be downloaded and returned via email by double clicking this link). (1) Record the following information for each CPT tested. (2) Report the following data back to Sikorsky Aircraft Product Safety Manager with your Compliance Card (Facsimile Number: (860) 998-7565, or E-Mail address: GPSIKSASProductSafet@utc.com): (3) The CPT Data Sheet is completed and submitted at the first or initial inspection and every 300 hours. Customer/Operator Name: Helicopter Serial Number: Helicopter Total Time Since New: CPT Part Number: CPT Serial Number: NOTE: Visual inspection. Do not remove CPT. CPT Time in Service or Date Installed on Helicopter: Describe CPT Failure and Circle either “PASS” or “FAIL” for each test: (1) Total Resistance Checks: (a) No. 1 DECU CPT: ohms PASS / FAIL (b) No. 2 DECU CPT: ohms PASS / FAIL (2) Linearity Resistance Movement for No. 1 DECU: (a) Describe CPT non-linearity movement for No. 1 DECU: PASS / FAIL __________________________________________________________ 1. Area of non-linearity resistance: a ___________ohms to ____________ohms (b) Describe CPT non-linearity movement for No. 2 DECU: PASS / FAIL __________________________________________________________ 1. Area of non-linearity resistance: a ___________ohms to ____________ohms Page 11 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 12 S-76 ALERT ASB 76-73-8 SERVICE BULLETIN Revision A ▪ December 4/15 Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) (3) Excitation Voltage Test: (a) DECU No. 1 Excitation: __________________volts (b) DECU No. 2 Excitation: __________________volts (4) Differential Voltage Test: (a) Maximum value: __________________millivolts PASS / FAIL (b) Minimum value: __________________millivolts PASS / FAIL Name: Date: ____________________________ Page 12 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 13 (OCR) ASB 76-73-8 S-76 ALERT Revision A • December 4/15 SERVICE BULLETIN Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) EXC GND EXC +10 VDC • EXC GND WIPER OUTPUT EXC +10 VDC TEST BOX, CPT DIFFERENTIAL VOLTAGE 76700-40009-042 TD3474 CPT DIFFERENTIAL VOLTAGE TEST BOX INSTALLATION FIGURE 1 ONE-TIME ATA INSPECTION 73-22-04 Page 13 This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 14 (OCR) S-76 ALERT ASB 76-73-8 SERVICE BULLETIN Revision A • December 4/15 Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) OFF OFF 9 VOLT DECU #1 9 VOLT DECU #2 EXCITATION EXCITATION EXCITATION EXCITATION DECU #1 EXCITATION SELECT SWITCH DECU #2 EXCITATION SELECT SWITCH - DECU #1 POT 7 - DECU #2 POT TP-1 TP-2 TP-3 TP-4 TP-5 TP-6 EXCITATION WIPER EXCITATION EXCITATION WIPER EXCITATION GND OUTPUT VOLTAGE GND OUTPUT VOLTAGE TD3475 CPT DIFFERENTIAL VOLTAGE TEST BOX FIGURE 2 ATA ONE-TIME 73-22-04 INSPECTION Page 14 This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 15 (OCR) ASB 76-73-8 S-76 ALERT Revision A - December 4/15 SERVICE BULLETIN Section 3. ACCOMPLISHMENT INSTRUCTIONS (Continued) SAMPLE # OHMS TYPICAL RESISTANCE LINEARITY MEASUREMENTS 2000 3100 2050 2100 2150 2900 2200 2250 2300 2700 2350 2400 10 2450 2500 11 2500 12 2550 13 2600 2300 14 2650 15 2700 16 2750 2100 17 2800 * 18 2850 19 2900 1900 20 2950 20 25 21 3000 EXAMPLE OF POSITIVE PEAK RESISTANCE SAMPLE # OHMS NON-LINEARITY (ABNORMAL) MEASUREMENT 2000 2050 3100 2100 2150 2900 2200 2250 2300 2700 2600 2450 10 2450 2500 11 2500 12 2550 13 2600 2300 14 2650 15 2700 16 2750 2100 17 2800 2850 2900 1900 2950 10 20 25 3000 TD3480 EXAMPLES OF LINEAR AND NON-LINEAR MOVEMENTS FIGURE 3 ONE-TIME ATA NSPECTIONONE TIME 73-22-04ATA Page 15 This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 16 S-76 ALERT ASB 76-73-8 SERVICE BULLETIN Revision A ▪ December 4/15 Section 3. A CCOMPLISHMENT INSTRUCTIONS (Continued) P. 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 (Aircraft ASB and CSN Release Signoff). (b) When ASB modifies a component that can be removed from this helicopter: 1. Make component log card entries on forms SA7343-22 (Aircraft Component Log Cards) and SA7343-21 (Component Log Cards), 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/E- Notification Search page. Page 16 ATA 73-22-04 ONE-TIME INSPECTION This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 17 (Fold over and tape closed) SIKORSKY AIRCRAFT CORPORATION FACSIMILE NUMBER (860) 998-7565 EMAIL ADDRESS: GPSIKSASProductSafet@utc.com ATTENTION: PRODUCT SAFETY MANAGER SIKORSKY AIRCRAFT CORPORATION (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. 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 HELICOPTER SERIAL NUMBERS: ___________ ___________ ___________ ___________ ___________ ___________ ___________ ___________ ___________ ___________ ___________ ___________ No. 76-73-8A ENGINE AND FUEL CONTROL – 2S1 and 2S2 Engine Digital Engine Control System Collective Position Transducer (CPT) – One-Time Inspection and Differential Voltage Test of CPT This Document contains technical data subject to the EAR. See WARNING and classifications on first page. ### Page 18 No Postage Necessary BUSINESS REPLY MAIL FIRST-CLASS MAIL PERMIT NO. 432 BRIDGEPORT CT POSTAGE WILL BE PAID BY ADDRESSEE SIKORSKY AIRCRAFT CORPORATION Commercial Systems and Services Mailstop K100 124 QUARRY ROAD TRUMBULL, CT 06611 U.S.A. ATTENTION: PRODUCT SAFETY MANAGER SIKORSKY AIRCRAFT CORPORATION 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 This Document contains technical data subject to the EAR. See WARNING and classifications on first page. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.