1. PLANNING INFORMATION

A. Effectivity

All S-76 Model helicopters equipped with No. 1 and No. 2 LCR-100 AHRS units, including

all spare LCR-100 AHRS units in stock.

B. Purpose

To inform operators of the implementation of an interim minimum flight crew restriction of

two pilots for Instrument Flight Rules (IFR) and night flight for helicopters equipped with

LCR-100, Mod Status 18 AHRS units. Only LCR-100, Mod Status 18 AHRS units are

affected by this Alert Service Bulletin (ASB).

Background:

Due to obsolescence issues, the LCR-92 AHRS units were superseded by LCR-100 AHRS

units Part Number (P/N) 145130-7100. The LCR-100 AHRS units at Mod Status 18 have a

very sensitive 26 VAC monitor which may possibly cause both AHRS units valid outputs to

become invalid, leading to the loss of both autopilots during flight. Under rare

circumstances, one or both autopilots may be unable to be reset.

NOTE: The loss of an AC inverter when in a fixed angle of bank may result in one of

the following helicopter responses: the helicopter maintains attitude, rolls wings

level or increases angle of bank. Pilot in command needs to be attentive to

inverter loss, or autopilot decoupling, and act promptly to manually restore or

maintain the desired flight path.

C. Description

Helicopter is prepared for maintenance. Nose electronics compartment access panels are

removed. AHRS units are disconnected and removed from electronics compartment. AHRS

units are inspected to determine if LCR-100 P/N 145130-7100 Mod Status 18 units are

 

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AIRCRAFT CORPORATION AND/OR ITS SUBSIDIARIES, IS AN UNPUBLISHED WORK PROTECTED UNDER APPLICABLE COPYRIGHT LAWS, AND IS DELIVERED ON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.

No. 76-34-11

Subject: NAVIGATION - LCR-100 Attitude, Heading, and Reference System (AHRS) Units - One-Time

Inspection of

May 17/10 Page 1 of 11 34-25-00
installed. AHRS units with LCR-100 P/N 145130-7100 Mod Status 18 are identified with P/N

76070-60019-101 by installing placard, P/N SS9140-1745 (or locally fabricated placard). If LCR100 P/N 145130-7100 Mod Status 18 unit(s) are installed, install placard, P/N SS9140-1746 (or

locally fabricated placard) on instrument panel, in plain view of both pilots. AHRS units are

reinstalled and reconnected. Nose electronics compartment access panels are installed.

Helicopter is returned to service.

D. Compliance

Compliance is essential. Sikorsky Aircraft Corporation recommends compliance within five (5)

days from the issue date of this ASB.

NOTE: Placards listing flight restrictions may be removed and discarded upon removal of the

LCR-100 P/N 76070-60019-101 (LITEF P/N 145130-7100 Mod Status 18) AHRS units.

E. Approval

This Rotorcraft Flight Manual (RFM) limitation is FAA approved. The change (creation and

installation of placards) made by this document is classified as Minor in accordance with the

applicable requirements of Federal regulations 14CFR 43. Such data submitted by the TC

holder for use on an EU-Registered helicopter and related articles are automatically approved by

ED Decision 2004/04/CF, as amended by ED Decision 2007/001/C. Reference to the ED

Decisions mentioned above shall be made in the release documents issued by the EASA 145

approved organization, releasing the relevant EU-registered helicopter or component to service.

F. Manpower (Estimated)

No. of Men No. of Hours Man-Hours

Inspect No. 1 and No. 2

AHRS units

1 2.0 2.0

Install placards as required 1 1.0 1.0

Total Man-Hours: 3.0

NOTE: Does not include time required to prepare helicopter, locally fabricate placards or return helicopter

to flight status.

G. Material

None.

H. Tooling

None.

No. 76-34-11

NAVIGATION - LCR-100 Attitude, Heading, and Reference System (AHRS) Units - One-Time Inspection of

1. PLANNING INFORMATION (Continued)

May 17/10 Page 2 34-25-00
I. Weight and Balance

None.

J. Electrical Load Data

None.

K. References

(1) Applicable Maintenance Manual.

(2) Temporary Revisions for Rotorcraft Flight Manual S-76A model helicopters:

(a) SA 4047-76-1, Temporary Revision No. 3.

(3) Temporary Revisions for Rotorcraft Flight Manual S-76B model helicopters:

(a) SA 4047-76B-1, Temporary Revision No. 3.

(4) Temporary Revisions for Rotorcraft Flight Manual S-76C model helicopters:

(a) SA 4047-76C-1, Temporary Revision No. 3.

(b) SA 4047-76C-10, Temporary Revision No. 4.

(c) SA 4047-76C-14, Temporary Revision No. 4.

(d) SA 4047-76C-15, Temporary Revision No. 1.

L. Publications Affected

(1) Applicable Maintenance Manual.

(2) Applicable Rotorcraft Flight Manual.

M. Attachments

None.

No. 76-34-11

NAVIGATION - LCR-100 Attitude, Heading, and Reference System (AHRS) Units - One-Time Inspection of

1. PLANNING INFORMATION (Continued)

May 17/10 Page 3 34-25-00
A. Basis for Material Data

Per Helicopter.

B. Bill of Material

Part No. Qty Key Word Instructions/Disposition

76070-60019-011 1 Modification Kit

Consisting of:

(1)(2)

SS9140-1745 2 Nameplate (Placard) (1)

SS9140-1746 2 Nameplate (Placard) (1)

(1) Modification Kit is available at no cost. Placards can be locally fabricated by operator.

Operator can vary size of placard to accommodate available space on instrument panel.

Minimum font height is 0.1 inch high. Background and lettering to be of contrasting color.

Placard to be made of material that is not easily erased, disfigured, or obscured. See

Figure 2.

(2) For Modification Kit 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) upon which these parts will be used.

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

will be accepted by letter, telephone, or facsimile (FAX). For prompt shipment, reference

address of each shipping destination. Direct your order to:

HELICOPTER SUPPORT INC.

124 Quarry Road

P.O. Box 111068,

Trumbull, CT 06611, U.S.A.

Attn: Customer Service

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

HSI website: www.HSIUS.com

No. 76-34-11

NAVIGATION - LCR-100 Attitude, Heading, and Reference System (AHRS) Units - One-Time Inspection of

2. MATERIAL INFORMATION

May 17/10 Page 4 34-25-00
C. Consumable Material

WARNING 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.

QTY KEY WORD CONSUMABLE MATERIAL

INSTRUCTIONS/

DISPOSITION

AS REQ’D TAPE, ADHESIVE 468MP (3MY BRAND)

OR EQUIVALENT

(1)(2)

AS REQ’D LOW-LINT CLEANING CLOTH MIL-C-85043

OR EQUIVALENT

(1)

AS REQ’D SOLVENT, CLEANING ISOPROPYL ALCOHOL

TT-1-735 OR EQUIVALENT

(1)

(1) Locally Procure.

(2) Required for locally fabricated placards only.

3. ACCOMPLISHMENT INSTRUCTIONS

A. Perform One-Time Inspection of No. 1 and No. 2 AHRS units as follows:

(1) Turn off all electrical and hydraulic power.

(2) Remove nose electronics compartment left and right access panels.

(3) Disconnect and remove No. 1 and No. 2 AHRS units from nose electronics compartment.

Refer to applicable maintenance manual or maintenance documentation.

No. 76-34-11

NAVIGATION - LCR-100 Attitude, Heading, and Reference System (AHRS) Units - One-Time Inspection of

2. MATERIAL INFORMATION

May 17/10 Page 5 34-25-00
NOTE: The AHRS nameplate is located on the top of AHRS units. Mod Status

information is located below P/N on nameplate.

(4) Inspect nameplate on No. 1 and No. 2 AHRS units for P/N 145130-7100 Mod Status 18.

See Figure 1.

(5) If nameplate on both No. 1 and No. 2 AHRS units is not P/N 145130-7100 Mod Status

18, reinstall and reconnect No. 1 and No. 2 AHRS units. Refer to applicable maintenance

manual or maintenance documentation. Proceed to step A.(7).

(6) If nameplate on No. 1 and/or No. 2 AHRS unit(s) indicates AHRS unit(s) is P/N 145130-

7100 Mod Status 18, do as follows:

(a) Using a low-lint cleaning cloth (MIL-C-85043 or equivalent) and Isopropyl Alcohol (TT-1-

735 or equivalent), clean off area on AHRS unit(s) to prep for installation of placard

P/N SS9140-1745. See Figure 1 for location of placard on AHRS unit(s).

NOTE: AHRS unit(s) is identified with P/N 76070-60019-101 using placard P/N

SS9140-1745 (or locally fabricated placard).

Do not obliterate existing AHRS unit(s) P/N when physically adding P/N 76070-

60019-101 to AHRS unit(s).

(b) Remove adhesive cover from back of placard P/N SS9140-1745 and install placard

onto AHRS unit(s). If locally fabricating placard, do as follows:

1 Locally fabricate placard using best shop practice. See Figure 2.

2 Using adhesive tape (468MP or equivalent), install locally fabricated placard onto

AHRS unit(s). See Figure 1 for location of placard on AHRS unit(s).

NOTE: Two (2) placards P/N SS9140-1746 (or locally fabricated placard) required

for instrument panel.

(c) Using a low-lint cleaning cloth (MIL-C-85043 or equivalent) and Isopropyl Alcohol (TT-1-

735 or equivalent), clean off area on instrument panel to prep for installation of

placards P/N SS9140-1746. See Figure 3 for typical location of placards on instrument

panel.

(d) Remove adhesive cover from back of placards P/N SS9140-1746 and install placards

on instrument panel, in plain view of both pilots. If locally fabricating placards, do as

follows:

1 Locally fabricate placards using best shop practice. See Figure 2.

No. 76-34-11

NAVIGATION - LCR-100 Attitude, Heading, and Reference System (AHRS) Units - One-Time Inspection of

3. ACCOMPLISHMENT INSTRUCTIONS (Continued)

May 17/10 Page 6 34-25-00
2 Using adhesive tape (468MP or equivalent), install locally fabricated placards on

instrument panel, in plain view of both pilots. See Figure 3 for typical location of

placards on instrument panel.

(e) Install and reconnect No. 1 and/or No. 2 AHRS unit(s) with P/N 76070-60019-101.

Refer to applicable maintenance manual or maintenance documentation.

(f) Flight restrictions have been implemented on helicopters equipped with LCR-100 P/N

76070-60019-101 (LITEF P/N 145130-7100 Mod Status 18) AHRS units. Refer to

Rotorcraft Flight Manual Temporary Revisions listed in the Reference section of this

ASB.

(7) Perform operational test of AHRS system. Refer to applicable maintenance manual.

(8) Install nose electronics compartment left and right access panels.

(9) Return helicopter to service.

B. Perform One-Time Inspection of LCR-100 AHRS units in stock as follows:

NOTE: The AHRS nameplate is located on the top of AHRS units. Mod Status information is

located below P/N on nameplate.

(1) Inspect nameplate on AHRS unit(s) for P/N 145130-7100 Mod Status 18. See Figure 1.

(2) If nameplate on AHRS unit(s) indicates AHRS unit(s) is not P/N 145130-7100 Mod Status

18, return AHRS unit(s) to stock.

(3) If nameplate on AHRS unit(s) indicates AHRS unit(s) is P/N 145130-7100 Mod Status 18,

do as follows:

(a) Using a low-lint cleaning cloth (MIL-C-85043 or equivalent) and Isopropyl Alcohol (TT-1-

735 or equivalent), clean off area on AHRS unit(s) to prep for installation of placard

P/N SS9140-1745. See Figure 1 for location of placard on AHRS unit(s).

NOTE: AHRS unit(s) is identified with P/N 76070-60019-101 using placard P/N

SS9140-1745 (or locally fabricated placard).

Do not obliterate existing AHRS unit(s) P/N when physically adding P/N 76070-

60019-101 to AHRS unit(s).

(b) Remove adhesive cover from back of placard P/N SS9140-1745 and install placard

onto AHRS unit(s). If locally fabricating placard, do as follows:

1 Locally fabricate placard using best shop practice. See Figure 2.

No. 76-34-11

NAVIGATION - LCR-100 Attitude, Heading, and Reference System (AHRS) Units - One-Time Inspection of

3. ACCOMPLISHMENT INSTRUCTIONS (Continued)

May 17/10 Page 7 34-25-00
2 Using adhesive tape (468MP or equivalent), install locally fabricated placard onto

AHRS unit(s). See Figure 1 for location of placard on AHRS unit(s).

(c) Return AHRS unit(s) P/N 76070-60019-101 to stock.

C. Record of Compliance

(1) Make an appropriate logbook 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. 76-34-11

NAVIGATION - LCR-100 Attitude, Heading, and Reference System (AHRS) Units - One-Time Inspection of

3. ACCOMPLISHMENT INSTRUCTIONS (Continued)

May 17/10 Page 8 34-25-00
TD2222SA

INSTALL:

PLACARD

SS9140-1745 

(OR LOCALLY

FABRICATED PLACARD)

LCR-100 NAMEPLATE ON AHRS UNIT

HANDLE WITH SPECIAL CARE

THIS UNIT CONTAINS DELICATE PRECISION PARTS

LCR-100 LCR-100

MOD STATUS (REF)

ATTITUDE HEADING REFERENCE UNIT

PN 145130-7100 SN 2109

MOD STATUS 18

POWER, 28VDC 60W max WEIGHT, 29.5N max MFR DATE, 04 - 09

TSO-C3d,-C4c,-C5f,-C6d ETSO-C3d,-C4c,-C5e,-C6d

DO-160E Env.Cal. [A2F2-]BBE[(SMC)(HR)(RC1)(UG)[EWXDFSZZAZ][ZC][(YY)(KK)(KG)]M[A4J44]XXAC

DO-178B Level A

DO-254 Level A

DESIGNED AND MANUFACTURED BY, Loerracher Str. 18

Northrop Grumman LITEF GmbH 79115 Freiburg, Germany

76070−60019−101

FIGURE 1

LCR-100 AHRS UNIT NAMEPLATE AND PLACARD - INSTALLATION

No. 76-34-11

May 17/10 Page 9 34-25-00
SA

TD2225

NOTES

 1. INSTALL ON LCR−100 MOD STATUS 18

(LITEF P/N 145130−7100) AHRS UNIT.

 2. FOR HELICOPTERS EQUIPPED WITH

LCR−100 P/N 76070−60019−101 (LITEF

P/N 145130−7100 MOD STATUS 18)

AHRS UNIT, INSTALL ON INSTRUMENT

PANEL, IN PLAIN VIEW OF BOTH

PILOTS.

 3. PLACARDS CAN BE LOCALLY

FABRICATED BY OPERATOR.

OPERATOR CAN VARY SIZE OF

PLACARD TO ACCOMODATE

AVAILABLE SPACE ON INSTRUMENT

PANEL. MINIMUM FONT HEIGHT IS 0.1

INCH HIGH. BACKGROUND AND

LETTERING TO BE CONTRASTING

COLOR. PLACARD TO BE MADE OF 

76070 76070−−60019 60019−−101 101

LCR−100 MOD STATUS 18 AHRS INSTALLED

SINGLE PILOT IFR FLT PROHIBITED,

SINGLE PILOT NIGHT FLT PROHIBITED 

REDUCE A/S TO 120 KIAS IF BOTH AP’S 

UNCOUPLE WHILE IMC OR NIGHT FLT

2.50

0.50

1.25

4.00

PART NO. SS9140−1745 (SEE NOTES 1 AND 3)

PART NO. SS9140−1746 (SEE NOTES 2 AND 3)

MATERIAL THAT IS NOT EASILY 

ERASED, DISFIGURED, OR OBSCURED.

 4. ALL DIMENSIONS ARE IN INCHES.

FIGURE 2

SS9140-1745 AND SS9140-1746 NAMEPLATES (PLACARDS)

No. 76-34-11

May 17/10 Page 10 34-25-00
SA

TD2226

LCR−100 MOD STATUS 18 AHRS INSTALLED

SINGLE PILOT IFR FLT PROHIBITED,

SINGLE PILOT NIGHT FLT PROHIBITED 

REDUCE A/S TO 120 KIAS IF BOTH AP’S 

UNCOUPLE WHILE IMC OR NIGHT FLT

LCR−100 MOD STATUS 18 AHRS INSTALLED

SINGLE PILOT IFR FLT PROHIBITED,

SINGLE PILOT NIGHT FLT PROHIBITED 

REDUCE A/S TO 120 KIAS IF BOTH AP’S 

UNCOUPLE WHILE IMC OR NIGHT FLT

INSTALL:

PLACARD SS9140−1746 (OR LOCALLY FABRICATED PLACARD)

S−76 BASELINE INSTRUMENT PANEL

FIGURE 3

INSTRUMENT PANEL PLACARDS - TYPICAL INSTALLATION

No. 76-34-11

May 17/10 Page 11 34-25-00
(860) 998-7565

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

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

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NAVIGATION - LCR-100 Attitude, Heading, and Reference System (AHRS) Units

- One-Time Inspection of
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