1. DESCRIPTION

This sheet transmits Revision 01 to Service Bulletin 170-24-0048.

This is a complete reissue of the Bulletin.

2. ADDITIONAL ACTION

Aircraft that have complied with the previous issue of this bulletin do not need any additional

action.

3. RECORD OF REVISION

Basic issue: 31/Mar/2010.

Revision 01: 12/May/2010.

4. HIGHLIGHTS

The topics, affected pages, and a brief description of the content-related changes introduced

by this revision are presented below.

Revision bars are put in the left margin of each page to show the location of the significant

changes. Text displacement and text format changes are not indicated.

TOPIC/PAGE DESCRIPTION OF REVISION

1. PLANNING INFORMATION

1.C. REASON/ 03 Added reason of Revision 01.

1.G. ESTIMATED MANPOWER/ 06 Updated manpower of test.

3. ACCOMPLISHMENT INSTRUCTIONS/ 10 Removed step 3.D.3) and corrected editorial error.

TRANSMITTAL LETTER

SB No.: 170-24-0048

PAGE: 1 of 1

Embraer Copyright © 2010. All rights reserved.

ELECTRICAL POWER - RAT (RAM AIR TURBINE) - REPLACEMENT OF BALANCE

WASHER SCREWS

1. PLANNING INFORMATION

A. SB EFFECTIVITY

Aircraft affected:

MODEL SN

Embraer 170( ) and 175( ) 17000002, 17000004 thru 17000013, and 17000015 thru

17000307.

Affected component:

The Hamilton Sundstrand Ram Air Turbines (RAT), Model ERPS37T, PN 1703781 Series,

serial numbers: 0101, 0104, 0105, 0106, 0108, 0112, 0115, 0116, 0117, 0118, 0119, 0122,

0125, 0131, 0132, 0134, 0139, 0140, 0142, 0143, 0145, 0146, 0148, 0152, 0155, 0158,

0159, 0161, 0164, 0165, 0166, 0167, 0169, 0170, 0171, 0172, 0173, 0175, 0176, 0177,

0178, 0179, 0181, 0186, 0187, 0188, 0190, 0196, 0198, 0199, 0200, 0201, 0202, 0203,

0204, 0205, 0208, 0209, 0210, 0212, 0213, 0214, 0217, 0218, 0221, 0222, 0223, 0224,

0225, 0226, 0227, 0228, 0229, 0230, 0233, 0234, 0236, 0238, 0240, 0241, 0242, 0243,

0244, 0245, 0246, 0249, 0250, 0251, 0253, 0255, 0256, 0257, 0264, 0265, 0266, 0268,

0272, 0273, 0277, 0279, 0281, 0283, 0285, 0286, 0287, 0288, 0290, 0291, 0293, 0294,

0295, 0299, 0300, 0301, 0302, 0303, 0307, 0308, 0309, 0311, 0313, 0314, 0315, 0316,

0317, 0318, 0319, 0320, 0321, 0322, 0323, 0324, 0326, 0329, 0331, 0333, 0334, 0335,

0336, 0337, 0339, 0340, 0341, 0346, 0347, 0348, 0349, 0350, 0352, 0353, 0364, 0370,

0371, 0374, 0375, 0385, 0386, 0389, 0394, 0412, 0416, 0417, 0424, 0430, 0454, 0467,

0469, 0473, 0474, 0479, 0480, 0481, 0482, 0483, 0484, 0485, 0486, 0487, 0488, 0489,

0490, 0491, 0492, 0493, 0494, 0495, 0496, 0497, 0498, 0499, 0500, 0501, 0502, 0503,

0504, 0505, 0506, 0507, 0508, 0509, 0510, 0511, 0512, 0513, 0514, 0515, 0516, 0517,

0518, 0519, 0520, 0521, 0522, 0523, 0524, 0525, 0526, 0527, 0528, 0529, 0530, 0531,

0532, 0533, 0534, 0535, 0536, 0537, 0538, 0539, 0540, 0541, 0542, 0543, 0544, 0545,

0546, 0547, 0548, 0549, 0550, 0551, 0552, 0553, 0554, 0555, 0556, 0557, 0558, 0559,

0560, 0562, 0563, 0564, 0565, 0566, 0567, 0568, 0569, 0570, 0571, 0572, 0573, 0574,

0575, 0576, 0577, 0578, 0579, 0580, 0581, 0582, 0583, 0584, 0585, 0586, 0587, 0588,

0589, 0590, 0591, 0592, 0593, 0594, 0595, 0596, 0597, 0598, 0599, 0600, 0602, 0603,

0604, 0605, 0606, 0607, 0608, 0609, 0610, 0611, 0613, 0614, 0615, 0616, 0617, 0619,

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 1 of 27

Embraer Copyright © 2010. All rights reserved.
0620, 0621, 0622, 0623, 0624, 0625, 0626, 0628, 0629, 0630, 0631, 0633, 0634, 0636,

0637, 0638, 0639, 0640, 0641, 0642, 0643, 0644, 0645, 0647, 0648, 0649, 0650, 0651,

0652, 0653, 0654, 0655, 0656, 0657, 0658, 0659, 0660, 0661, 0662, 0663, 0664, 0666,

0667, 0668, 0669, 0670, 0671, 0672, 0673, 0674, 0675, 0676, 0677, 0678, 0679, 0681,

0682, 0683, 0684, 0686, 0687, 0688, 0689, 0690, 0691, 0692, 0693, 0695, 0696, 0697,

0698, 0699, 0700, 0701, 0702, 0703, 0704, 0705, 0706, 0707, 0708, 0709, 0710, 0712,

0713, 0714, 0715, 0716, 0717, 0719, and 0720.

NOTE: This effectivity list includes the aircraft originally equipped with the affected

component. Since this component is a “Line Replaceable Unit” (LRU), it may

be necessary to refer to the fleet maintenance control record and verify

whether the unit has been replaced with another one during routine

maintenance.

In-production effectivity:

Embraer 170( ) and 175( ) model aircraft SN 17000308 and on, have an equivalent

modification factory-incorporated.

B. CONCURRENT REQUIREMENTS

None.

C. REASON

(1) HISTORY

Hamilton Sundstrand has discovered that some Ram Air Turbine (RAT)s were

manufactured with nonconforming screws.

Analysis indicated that this nonconformance could be a result of the supplier’s heat

treat process, which increases susceptibility to brittle fracture.

(2) OBJECTIVE

To inspect the RAT model, part number and Serial number and, if applicable, to

replace the existing balance screw installed in the unit.

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 2

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
(3) EXPECTED BENEFITS

To return the RAT to its original design configuration.

(4) REVISION HISTORY

REVISION 01: This revision has been issued to update item 1.G. ESTIMATED

MANPOWER, to remove step 3.D.3) and to correct editorial error in

item 3. ACCOMPLISHMENT INSTRUCTIONS.

D. DESCRIPTION

The accomplishment of this bulletin consists in inspecting the Ram Air Turbine (RAT)

model, PN and Serial Number and, if applicable, replacing the balance screw of the

equipment and to reidentify it.

This service bulletin also presents Hamilton Sundstrand SB ERPS37T-24-5, dated March

22/2010, attached to Section 4. APPENDIX 1, which provides instructions for the

replacement of the balance screw and the re-identification of the RAT.

This Bulletin is divided into 2 PARTS, as follows:

PART I INSPECTION OF RAT MODEL, PART NUMBER AND SERIAL NUMBER

Applicable to: SB EFFECTIVITY

PART I of this bulletin consists in inspecting the Model, PN and serial number of the RAT.

– If the RAT is identified as Model ERPS37T, PN 1703781 Series, serial numbers: 0101,

0104, 0105, 0106, 0108, 0112, 0115, 0116, 0117, 0118, 0119, 0122, 0125, 0131, 0132,

0134, 0139, 0140, 0142, 0143, 0145, 0146, 0148, 0152, 0155, 0158, 0159, 0161,

0164, 0165, 0166, 0167, 0169, 0170, 0171, 0172, 0173, 0175, 0176, 0177, 0178,

0179, 0181, 0186, 0187, 0188, 0190, 0196, 0198, 0199, 0200, 0201, 0202, 0203,

0204, 0205, 0208, 0209, 0210, 0212, 0213, 0214, 0217, 0218, 0221, 0222, 0223,

0224, 0225, 0226, 0227, 0228, 0229, 0230, 0233, 0234, 0236, 0238, 0240, 0241,

0242, 0243, 0244, 0245, 0246, 0249, 0250, 0251, 0253, 0255, 0256, 0257, 0264,

0265, 0266, 0268, 0272, 0273, 0277, 0279, 0281, 0283, 0285, 0286, 0287, 0288,

0290, 0291, 0293, 0294, 0295, 0299, 0300, 0301, 0302, 0303, 0307, 0308, 0309,

0311, 0313, 0314, 0315, 0316, 0317, 0318, 0319, 0320, 0321, 0322, 0323, 0324,

0326, 0329, 0331, 0333, 0334, 0335, 0336, 0337, 0339, 0340, 0341, 0346, 0347,

0348, 0349, 0350, 0352, 0353, 0364, 0370, 0371, 0374, 0375, 0385, 0386, 0389,

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 3

Embraer Copyright © 2010. All rights reserved.
0394, 0412, 0416, 0417, 0424, 0430, 0454, 0467, 0469, 0473, 0474, 0479, 0480,

0481, 0482, 0483, 0484, 0485, 0486, 0487, 0488, 0489, 0490, 0491, 0492, 0493,

0494, 0495, 0496, 0497, 0498, 0499, 0500, 0501, 0502, 0503, 0504, 0505, 0506,

0507, 0508, 0509, 0510, 0511, 0512, 0513, 0514, 0515, 0516, 0517, 0518, 0519,

0520, 0521, 0522, 0523, 0524, 0525, 0526, 0527, 0528, 0529, 0530, 0531, 0532,

0533, 0534, 0535, 0536, 0537, 0538, 0539, 0540, 0541, 0542, 0543, 0544, 0545,

0546, 0547, 0548, 0549, 0550, 0551, 0552, 0553, 0554, 0555, 0556, 0557, 0558,

0559, 0560, 0562, 0563, 0564, 0565, 0566, 0567, 0568, 0569, 0570, 0571, 0572,

0573, 0574, 0575, 0576, 0577, 0578, 0579, 0580, 0581, 0582, 0583, 0584, 0585,

0586, 0587, 0588, 0589, 0590, 0591, 0592, 0593, 0594, 0595, 0596, 0597, 0598,

0599, 0600, 0602, 0603, 0604, 0605, 0606, 0607, 0608, 0609, 0610, 0611, 0613,

0614, 0615, 0616, 0617, 0619, 0620, 0621, 0622, 0623, 0624, 0625, 0626, 0628,

0629, 0630, 0631, 0633, 0634, 0636, 0637, 0638, 0639, 0640, 0641, 0642, 0643,

0644, 0645, 0647, 0648, 0649, 0650, 0651, 0652, 0653, 0654, 0655, 0656, 0657,

0658, 0659, 0660, 0661, 0662, 0663, 0664, 0666, 0667, 0668, 0669, 0670, 0671,

0672, 0673, 0674, 0675, 0676, 0677, 0678, 0679, 0681, 0682, 0683, 0684, 0686,

0687, 0688, 0689, 0690, 0691, 0692, 0693, 0695, 0696, 0697, 0698, 0699, 0700,

0701, 0702, 0703, 0704, 0705, 0706, 0707, 0708, 0709, 0710, 0712, 0713, 0714,

0715, 0716, 0717, 0719, or 0720, the balance screw should be replaced according to

PART II.

– If the RAT is not identified as described above, no action is required.

To gain access to the work area, it is necessary to deploy the RAT located in the RH

forward fuselage bottom, zone 124.

PART II REPLACEMENT OF THE BALANCE SCREW

Applicable to: SB EFFECTIVITY

The modification applicable to PART II of this bulletin consists in replacing the balance

screw of the RAT.

To gain access to the work area, it is necessary to deploy the RAT located in the RH

forward fuselage bottom, zone 124.

NOTE: 1) The modification presented in PART I of this bulletin does not affect the

Fatigue Critical Structure (FCS)

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 4

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
2) The modification presented in PART II of this bulletin affects the Fatigue

Critical Structure (FCS); however, no change to the related Damage

Tolerance Inspection (DTI) instructions is required.

E. COMPLIANCE

Refer to paragraph 1.E. Compliance of HS SB ERPS37T-24-5 attached to Section 4.

APPENDIX 1 of this bulletin.

F. APPROVAL

The technical aspects of this service bulletin are approved by: Agência Nacional de

Aviação Civil (ANAC).

G. ESTIMATED MANPOWER

This estimate is for direct labor only, performed by experienced personnel, and does not

include the time to plan, prepare, or inspect the work.

It is assumed that all the tools, parts, and other means are readily available when

necessary.

This estimate does not include the sealant, paint, or adhesive curing time.

(1) PART I - RAT INSPECTION

– Access opening: 0.1 man-hours.

– Inspection: 0.1 man-hours.

– Modification: Not applicable.

– Access closure: Not applicable.

– Test: Not applicable.

(2) PART II - BALANCE SCREW REPLACEMENT AND REIDENTIFICATION OF RAT

– Access opening: Not applicable.

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 5

Embraer Copyright © 2010. All rights reserved.
– Inspection: Not applicable.

– Modification: Refer to paragraph 1.G.Manpower of HS SB ERPS37T-24-5

attached to Section 4. APPENDIX 1 of this bulletin.

– Access closure: 0.2 man-hours.

– Test: Refer to paragraph 1.G.Manpower of HS SB ERPS37T-24-5 attached to

Section 4. APPENDIX 1 of this bulletin.

H. WEIGHT AND BALANCE

None.

I. SOFTWARE ACCOMPLISHMENT SUMMARY

None.

J. REFERENCES

AMM 170/( ) Aircraft Maintenance Manual PART II - 20-00-00 - STANDARD

PRACTICES-AIRFRAME.

AMM 170/( ) Aircraft Maintenance Manual PART II - 24-23-00 - ELECTRICAL

POWER.

HS SB

ERPS37T-24-5

EMERGENCY ELECTRICAL POWER - RAM AIR TURBINE -

REPLACE BALANCE WASHER SCREWS.

K. OTHER PUBLICATIONS AFFECTED

None.

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 6

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
2. MATERIAL INFORMATION

A. MATERIAL - PRICE AND AVAILABILITY

(1) MATERIAL AVAILABLE FROM EMBRAER

None.

(2) MATERIAL AVAILABLE FROM OTHER VENDORS

Refer to paragraph 2. A. MATERIAL - PRICE AND AVAILABILITY of

HS SB ERPS37T-24-5 attached to Section 4. APPENDIX 1 of this bulletin.

B. INDUSTRY SUPPORT INFORMATION

Refer to paragraph 2. B. INDUSTRY SUPPORT INFORMATION of

HS SB ERPS37T-24-5 attached to Section 4. APPENDIX 1 of this bulletin.

C. MATERIAL NECESSARY FOR EACH AIRCRAFT

Refer to paragraph 2. C. MATERIAL NECESSARY FOR EACH UNIT of

HS SB ERPS37T-24-5 attached to Section 4. APPENDIX 1 of this bulletin.

D. MATERIAL NECESSARY FOR EACH SPARE

Refer to paragraph 2. D. MATERIAL NECESSARY FOR EACH SPARE of

HS SB ERPS37T-24-5 attached to Section 4. APPENDIX 1 of this bulletin.

E. REIDENTIFIED PARTS

Refer to paragraph 2. E. REIDENTIFIED PARTS of HS SB ERPS37T-24-5 attached to

Section 4. APPENDIX 1 of this bulletin.

F. TOOLING - PRICE AND AVAILABILITY

Whenever required, necessary the tooling presented in the AMM Tasks referred to in this

bulletin should be procured from the operator’s inventories or ordered as spares.

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 7

Embraer Copyright © 2010. All rights reserved.
3. ACCOMPLISHMENT INSTRUCTIONS

NOTE: 1) For the purpose of this Service Bulletin, a General Visual Inspection (GVI) is “A

visual examination of an interior or exterior area, installation or assembly to

detect obvious damage, failure or irregularity. This level of inspection is made

from within touching distance, unless otherwise specified. A mirror may be

necessary to enhance visual access to all exposed surfaces in the inspection

area. This level of inspection is made under normally available lighting

conditions such as daylight, hangar lighting, flashlight or drop-light and may

require removal or opening of access panels or doors. Stands, ladders or

platforms may be required to gain proximity to the area being checked.”

2) Obey all of the WARNINGS and CAUTIONS included in the referenced manuals

and procedures.

3) The manuals and other documents are referred to by acronyms or using a

simplified form. Refer to section 1.J. REFERENCES for a more complete

definition.

4) This Service Bulletin effectivity is divided into 2 PARTS. The SB PARTS are

featured to allow their independent accomplishment.

The steps below outline the general accomplishment instructions.

The detailed sequence is given in SB ERPS37T-24-5 attached to Section 4. APPENDIX 1 of

this bulletin.

A. Make sure that the aircraft is safe for maintenance. Refer to AMM TASK

20-00-00-910-801-A/200 - Aircraft Maintenance Safety Procedures - Standard

Procedures.

B. Deploy the RAT. Refer to AMM TASK 24-23-00-710-801-A/500 - Ram-Air-Turbine (RAT)

Manual Deployment - Operational Test.

C. PART I - RAT INSPECTION

(1) Check the RAT Model, PN and Serial number, as shown in Figure 1.

(a) If the RAT is identified as Model ERPS37T, PN 1703781 Series, serial numbers:

0101, 0104, 0105, 0106, 0108, 0112, 0115, 0116, 0117, 0118, 0119, 0122, 0125,

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 8

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
0131, 0132, 0134, 0139, 0140, 0142, 0143, 0145, 0146, 0148, 0152, 0155,

0158, 0159, 0161, 0164, 0165, 0166, 0167, 0169, 0170, 0171, 0172, 0173,

0175, 0176, 0177, 0178, 0179, 0181, 0186, 0187, 0188, 0190, 0196, 0198,

0199, 0200, 0201, 0202, 0203, 0204, 0205, 0208, 0209, 0210, 0212, 0213,

0214, 0217, 0218, 0221, 0222, 0223, 0224, 0225, 0226, 0227, 0228, 0229,

0230, 0233, 0234, 0236, 0238, 0240, 0241, 0242, 0243, 0244, 0245, 0246,

0249, 0250, 0251, 0253, 0255, 0256, 0257, 0264, 0265, 0266, 0268, 0272,

0273, 0277, 0279, 0281, 0283, 0285, 0286, 0287, 0288, 0290, 0291, 0293,

0294, 0295, 0299, 0300, 0301, 0302, 0303, 0307, 0308, 0309, 0311, 0313,

0314, 0315, 0316, 0317, 0318, 0319, 0320, 0321, 0322, 0323, 0324, 0326,

0329, 0331, 0333, 0334, 0335, 0336, 0337, 0339, 0340, 0341, 0346, 0347,

0348, 0349, 0350, 0352, 0353, 0364, 0370, 0371, 0374, 0375, 0385, 0386,

0389, 0394, 0412, 0416, 0417, 0424, 0430, 0454, 0467, 0469, 0473, 0474,

0479, 0480, 0481, 0482, 0483, 0484, 0485, 0486, 0487, 0488, 0489, 0490,

0491, 0492, 0493, 0494, 0495, 0496, 0497, 0498, 0499, 0500, 0501, 0502,

0503, 0504, 0505, 0506, 0507, 0508, 0509, 0510, 0511, 0512, 0513, 0514,

0515, 0516, 0517, 0518, 0519, 0520, 0521, 0522, 0523, 0524, 0525, 0526,

0527, 0528, 0529, 0530, 0531, 0532, 0533, 0534, 0535, 0536, 0537, 0538,

0539, 0540, 0541, 0542, 0543, 0544, 0545, 0546, 0547, 0548, 0549, 0550,

0551, 0552, 0553, 0554, 0555, 0556, 0557, 0558, 0559, 0560, 0562, 0563,

0564, 0565, 0566, 0567, 0568, 0569, 0570, 0571, 0572, 0573, 0574, 0575,

0576, 0577, 0578, 0579, 0580, 0581, 0582, 0583, 0584, 0585, 0586, 0587,

0588, 0589, 0590, 0591, 0592, 0593, 0594, 0595, 0596, 0597, 0598, 0599,

0600, 0602, 0603, 0604, 0605, 0606, 0607, 0608, 0609, 0610, 0611, 0613,

0614, 0615, 0616, 0617, 0619, 0620, 0621, 0622, 0623, 0624, 0625, 0626,

0628, 0629, 0630, 0631, 0633, 0634, 0636, 0637, 0638, 0639, 0640, 0641,

0642, 0643, 0644, 0645, 0647, 0648, 0649, 0650, 0651, 0652, 0653, 0654,

0655, 0656, 0657, 0658, 0659, 0660, 0661, 0662, 0663, 0664, 0666, 0667,

0668, 0669, 0670, 0671, 0672, 0673, 0674, 0675, 0676, 0677, 0678, 0679,

0681, 0682, 0683, 0684, 0686, 0687, 0688, 0689, 0690, 0691, 0692, 0693,

0695, 0696, 0697, 0698, 0699, 0700, 0701, 0702, 0703, 0704, 0705, 0706,

0707, 0708, 0709, 0710, 0712, 0713, 0714, 0715, 0716, 0717, 0719, or 0720,

the balance screw should be replaced according to PART II.

(b) If the Model is not identified as described above, no action is required, and go

to Step 3.E.

D. PART II - BALANCE SCREW REPLACEMENT AND REIDENTIFICATION OF RAT

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 9

Embraer Copyright © 2010. All rights reserved.
1) Replace the balance screw of the RAT as per the instructions presented in item 3.

ACCOMPLISHMENT INSTRUCTIONS of HS SB ERPS37T-24-5 attached to Section

4. APPENDIX 1 of this bulletin.

2) Identify the RAT according to item 3.C. Identification of HS SB ERPS37T-24-5

attached to Section 4. APPENDIX 1 of this bulletin. Refer to Figure 1 of this bulletin.

E. Stow the retraction of the RAT. Refer to AMM TASK 24-23-00-840-801-A/200 -

Ram-Air-Turbine (RAT) - Retraction.

F. Restore the aircraft to normal.

G. Enter the accomplishment of this bulletin in the applicable documents.

NOTE: 1) Please inform us by e-mail fleet.reliability@embraer.com.br of the aircraft

manufacturer serial number and the SB incorporation date, specifying the SB

Part(s) incorporated or whether the whole SB has been incorporated. This

will enable Embraer to consider your aircraft configuration when providing

future modifications.

2) To formally inform that the SB has been incorporated fleet-wide or that the

SB will not be incorporated, so that Embraer can update the affected

technical publications, use the “Service Bulletin Full-Fleet Incorporation

Report” form, which is available on the Flyembraer portal

(http://www.flyembraer.com).

3) Use the attached “Service Bulletin Evaluation” form to send us your

comments regarding this SB. Your feedback will be much appreciated as an

aid to help us improve the quality of the SBs.

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 10

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
ZONE

124

A

A

B

C

RAT

IDENTIFICATION

PLATE (REF.)

C

B

SYMBOL "24−5"

(ENGRAVE)

RAT 

(REF.)

PART NO

FAA/PMA

SERIAL NO

DATE OF MFG

AMENDMENT

RAM AIR TURBINE FAA/PMA

24−5

EM170SB240404A.DGN

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 11

FIGURE 1 - IDENTIFICATION OF THE RAM AIR TURBINE (RAT)

(SHEET 01 OF 01)

Embraer Copyright © 2010. All rights reserved.
4. APPENDIX 1

HS SB ERPS37T-24-5 - EMERGENCY ELECTRICAL POWER - RAM AIR TURBINE -

REPLACE BALANCE WASHER SCREWS

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 12

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
SERVICE BULLETIN

Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 1 of 15

EMERGENCY ELECTRICAL POWER - RAM AIR TURBINE - 

REPLACE BALANCE WASHER SCREWS

© 2010 Hamilton Sundstrand Corporation

PROPRIETARY

THIS DOCUMENT AND THE INFORMATION CONTAINED HEREIN ARE THE PROPERTY OF HAMILTON SUNDSTRAND 

CORPORATION (HSC). RECIPIENT AGREES TO HOLD ALL SUCH INFORMATION IN CONFIDENCE AND AGREES IT SHALL BE 

USED ONLY FOR RECIPIENT’S INTERNAL PURPOSES TO MAINTAIN RECIPIENT’S EQUIPMENT OR AS MAY OTHERWISE BE 

PERMITTED IN AN APPLICABLE AGREEMENT BETWEEN RECIPIENT AND HSC. THIS DOCUMENT AND THE INFORMATION 

CONTAINED HEREIN SHALL NOT BE USED FOR ANY OTHER PURPOSE, INCLUDING THE CREATION, MANUFACTURE, 

DEVELOPMENT, OR DERIVATION OF ANY REPAIRS, MODIFICATIONS, SPARE PARTS, DESIGN, OR CONFIGURATION CHANGES, 

OR TO OBTAIN FAA OR ANY OTHER GOVERNMENT OR REGULATORY APPROVAL FOR SAME. RECIPIENT AGREES NOT TO 

DISCLOSE SUCH INFORMATION TO ANY THIRD PARTY, EXCEPT AS MAY OTHERWISE BE PROVIDED FOR IN AN APPLICABLE 

AGREEMENT BETWEEN RECIPIENT AND HSC. COPYING OR DISCLOSURE OF THIS DOCUMENT AND THE INFORMATION 

CONTAINED HEREIN BY ANYONE WITHOUT HSC’S PRIOR WRITTEN PERMISSION IS NOT AUTHORIZED AND MAY RESULT IN 

CRIMINAL AND/OR CIVIL LIABILITY.

Information Subject to Export Control Laws

The technical data in this document (or file) is controlled for export under the Export Administration Regulations (EAR), 

15 CFR Parts 730-774, ECCN: 9E991. Violations of these laws may be subject to fines and penalties under the Export Administration Act.

The data in this document were developed only to maintain systems and/or parts manufactured by or for Hamilton Sundstrand or approved 

by Hamilton Sundstrand. The data may not be applicable to any other systems and/or parts, regardless of their apparent similarity to 

systems and/or parts manufactured by or for Hamilton Sundstrand or approved by Hamilton Sundstrand. Do not rely in any way on data in 

this document to maintain or otherwise support systems and/or parts that were not manufactured by or for Hamilton Sundstrand or approved 

by Hamilton Sundstrand without evidence that the Federal Aviation Administration or other regulatory agency has determined that the data 

in this document is valid for such use.

1. Planning Information

A. Effectivity

The Hamilton Sundstrand Ram Air Turbines (RAT), Model ERPS37T, that are listed below 

and used on Embraer 170 and 190 aircraft. 

Part Number 

Series Serial Numbers

1703781 0101, 0104, 0105, 0106, 0108, 0112, 0115, 0116, 0117, 0118, 0119, 0122, 0125, 

0131, 0132, 0134, 0139, 0140, 0142, 0143, 0145, 0146, 0148, 0152, 0155, 0158, 

0159, 0161, 0164, 0165, 0166, 0167, 0169, 0170, 0171, 0172, 0173, 0175, 0176, 

0177, 0178, 0179, 0181, 0186, 0187, 0188, 0190, 0196, 0198, 0199, 0200, 0201, 

0202, 0203, 0204, 0205, 0208, 0209, 0210, 0212, 0213, 0214, 0217, 0218, 0221, 

0222, 0223, 0224, 0225, 0226, 0227, 0228, 0229, 0230, 0233, 0234, 0236, 0238, 

0240, 0241, 0242, 0243, 0244, 0245, 0246, 0249, 0250, 0251, 0253, 0255, 0256, 

0257, 0264, 0265, 0266, 0268, 0272, 0273, 0277, 0279, 0281, 0283, 0285, 0286, 

0287, 0288, 0290, 0291, 0293, 0294, 0295, 0299, 0300, 0301, 0302, 0303, 0307, 

0308, 0309, 0311, 0313, 0314, 0315, 0316, 0317, 0318, 0319, 0320, 0321, 0322, 

0323, 0324, 0326, 0329, 0331, 0333, 0334, 0335, 0336, 0337, 0339, 0340, 0341, 

(continued on the next page)

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 13

Embraer Copyright © 2010. All rights reserved.
Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 2

SERVICE BULLETIN

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

B. Concurrent Requirements

None.

C. Reason

Hamilton Sundstrand has discovered that RATs were manufactured with nonconforming 

screws. To date, there have been five instances of a fractured balance washer screw on 

multiple RAT part number configurations. Fracture of a balance washer screw can result in 

the loss of the associated balance washer and create an unacceptable turbine imbalance. 

Inspection of other screws in Hamilton Sundstrand stock revealed metallographic 

nonconformities consistent with those of the fractured screws. The suspect screws have 

been isolated to a lot from a specific supplier. Analysis indicates the nonconformance could 

be a result of the supplier’s heat treat process, which increases susceptibility to brittle 

fracture. Replacement of the suspect screws with confirmed conforming screws will 

eliminate potential loss of a balance washer. Incorporation of this bulletin will ensure that 

the RAT balance washer screws conform to specification.

Part Number 

Series Serial Numbers

1703781 (continued from the previous page) 

0346, 0347, 0348, 0349, 0350, 0352, 0353, 0364, 0370, 0371, 0374, 0375, 0385, 

0386, 0389, 0394, 0412, 0416, 0417, 0424, 0430, 0454, 0467, 0469, 0473, 0474, 

0479, 0480, 0481, 0482, 0483, 0484, 0485, 0486, 0487, 0488, 0489, 0490, 0491, 

0492, 0493, 0494, 0495, 0496, 0497, 0498, 0499, 0500, 0501, 0502, 0503, 0504, 

0505, 0506, 0507, 0508, 0509, 0510, 0511, 0512, 0513, 0514, 0515, 0516, 0517, 

0518, 0519, 0520, 0521, 0522, 0523, 0524, 0525, 0526, 0527, 0528, 0529, 0530, 

0531, 0532, 0533, 0534, 0535, 0536, 0537, 0538, 0539, 0540, 0541, 0542, 0543, 

0544, 0545, 0546, 0547, 0548, 0549, 0550, 0551, 0552, 0553, 0554, 0555, 0556, 

0557, 0558, 0559, 0560, 0562, 0563, 0564, 0565, 0566, 0567, 0568, 0569, 0570, 

0571, 0572, 0573, 0574, 0575, 0576, 0577, 0578, 0579, 0580, 0581, 0582, 0583, 

0584, 0585, 0586, 0587, 0588, 0589, 0590, 0591, 0592, 0593, 0594, 0595, 0596, 

0597, 0598, 0599, 0600, 0602, 0603, 0604, 0605, 0606, 0607, 0608, 0609, 0610, 

0611, 0613, 0614, 0615, 0616, 0617, 0619, 0620, 0621, 0622, 0623, 0624, 0625, 

0626, 0628, 0629, 0630, 0631, 0633, 0634, 0636, 0637, 0638, 0639, 0640, 0641, 

0642, 0643, 0644, 0645, 0647, 0648, 0649, 0650, 0651, 0652, 0653, 0654, 0655, 

0656, 0657, 0658, 0659, 0660, 0661, 0662, 0663, 0664, 0666, 0667, 0668, 0669, 

0670, 0671, 0672, 0673, 0674, 0675, 0676, 0677, 0678, 0679, 0681, 0682, 0683, 

0684, 0686, 0687, 0688, 0689, 0690, 0691, 0692, 0693, 0695, 0696, 0697, 0698, 

0699, 0700, 0701, 0702, 0703, 0704, 0705, 0706, 0707, 0708, 0709, 0710, 0712, 

0713, 0714, 0715, 0716, 0717, 0719, 0720

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 14

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
SERVICE BULLETIN

Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 3

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

D. Description

This bulletin gives instructions to replace the balance washer screws and identify the RAT.

For a RAT with a missing balance washer, or with a balance washer screw that cannot be 

removed in its entirety, instructions are also given to disassemble the RAT as necessary to 

remove the fractured screw and balance washer, balance the turbine assembly, assemble 

the RAT, and test the RAT.

E. Compliance

Incorporation of this service bulletin is to be accomplished at the earliest opportunity.

F. Approval

Government or other regulatory agency approval of the bulletin is the responsibility of 

Embraer.

Embraer has reviewed and approved this document.

G. Manpower

A maximum of 0.5 man-hour will be required to replace the balance washer screws and 

identify the RAT. 

For a RAT with a missing balance washer, or with a balance washer screw that cannot be 

removed in its entirety, a maximum of 8.0 man-hours will be required to disassemble the 

RAT as necessary to remove the fractured screw and balance washer, balance the turbine 

assembly, assemble the RAT, and test the RAT.

H. Weight and Balance

None.

I. Electrical Load Data

Not applicable.

J. Software Accomplishment Summary

Not applicable.

K. References

Applicable Aircraft Maintenance Manual (AMM), Hamilton Sundstrand Component 

Maintenance Manual (CMM) 24-23-60, Hamilton Sundstrand Standard Practices Manual 

(SPM) 20-00-00, and Embraer Service Bulletins 170-24-0048 and 190-24-0019. 

L. Other Publications Affected

Hamilton Sundstrand CMM 24-23-60 will be revised to incorporate this service bulletin.

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 15

Embraer Copyright © 2010. All rights reserved.
Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 4

SERVICE BULLETIN

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

M. Interchangeability or Intermixability of Parts

Not affected. 

2. Material Information

A. Material - Price and Availability

(1) Hamilton Sundstrand will supply the replacement parts required for accomplishment of 

this bulletin on a no-charge basis until March 21, 2012. The replacement parts are 

currently available in limited quantities (refer to Table 1 of this bulletin for the parts 

breakdown). Operators approved by Hamilton Sundstrand to perform the modification 

of units at their facility should place a single “no-charge” order to Hamilton Sundstrand. 

Operators can forward these orders to their assigned Hamilton Sundstrand 

Commercial Spares Administrator (or fax to +1-815-226-2624, if the responsible 

Administrator is not known). In addition, operators can also use the Hamilton 

Sundstrand website at www.hamiltonsundstrand.com to contact the Commercial 

Spares group. Upon entering the website, select “Customer Service” followed by 

“Commercial Spares” for other contact and order processing options that are available. 

Orders must clearly reference fleet requirements, noting the bulletin number, serial 

numbers of affected units, total quantity of parts, and anticipated incorporation 

schedule. Hamilton Sundstrand will acknowledge the operator order with an 

established delivery rate.

B. Industry Support Information

(1) Hamilton Sundstrand will also give the following:

(a) A maximum labor allowance of 0.5 man-hour multiplied by the operator's current 

approved hourly rate for accomplishment of this service bulletin in the shop. The 

labor allowance will expire March 21, 2012.

(b) A maximum labor allowance of 0.5 man-hour multiplied by the operator's current 

approved hourly rate for replacement of the balance washer screws on the aircraft 

(refer to Embraer Service Bulletin 170-24-0048 or 190-24-0019). The labor 

allowance will expire March 21, 2012.

(c) If removal from the aircraft is required, a maximum labor allowance of 6.0 manhours multiplied by the operator's current approved hourly rate for replacement of 

the RAT on the aircraft and test on wing (refer to Embraer Service 

Bulletin 170-24-0048 or 190-24-0019). The labor allowance will expire 

March 21, 2012.

(d) Operators should forward a claim for labor reimbursement to their assigned 

Hamilton Sundstrand Rockford Warranty Administrator. If the responsible 

Administrator is not known, the claim should be mailed to Warranty 

Administration, 4747 Harrison Ave, Rockford, IL 61126, USA, MS 106-6. The 

claim should reference the service bulletin number, serial numbers modified, date 

modified, total hours, and approved labor rate.

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 16

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
SERVICE BULLETIN

Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 5

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

(2) For units with a missing balance washer, or with a balance washer screw that cannot 

be removed in its entirety, Hamilton Sundstrand will incorporate this modification into 

returned units at no charge until March 21, 2012. Contact Hamilton Sundstrand at the 

address that follows for scheduling information:

Hamilton Sundstrand

4747 Harrison Avenue

P.O. Box 7002

Rockford, IL 61125-7002

Attention: Repair Administration

Mail Stop 151-6

Telephone: +1-815-226-6849

Fax: 815-394-2414

C. Material Necessary For Each Unit

(1) Material to be Purchased

Table 1

New Parts Necessary

Table 1 Note 1: Operators should order a quantity of 10 screws for each unit for incorporation of 

this bulletin.

Table 1 Note 2: Hamilton Sundstrand will supply the noted part at no charge (refer to paragraph 

2.A. of this bulletin). 

(2) Material Supplied by the Operator

(a) None. 

D. Material Necessary For Each Spare

(1) The same as the material necessary for each unit.

E. Reidentified Parts

(1) Refer to paragraph 3.C. of this bulletin.

F. Tooling - Price and Availability 

(1) No tooling other than that required for shop maintenance of the RAT is required to do 

this modification.

New 

Part Number Nomenclature

Old 

Part Number Qty Unit Price

Disposition 

Instructions

Same Screw MS24667-14 AR

(Note 1)

(Note 2) Remove suspect 

old screws, install 

new conforming 

screws

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 17

Embraer Copyright © 2010. All rights reserved.
Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 6

SERVICE BULLETIN

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

3. Accomplishment Instructions

A. General

CAUTION: THE RAT CONTAINS DESIGN CRITICAL CHARACTERISTICS, 

PROCESSES, AND PROCEDURES. THE DESIGN CRITICAL 

CHARACTERISTICS ARE IDENTIFIED WITH THE SYMBOL >>DCC<<. 

REFER TO THE INTRODUCTION SECTION OF CMM 24-23-60 FOR A 

COMPLETE EXPLANATION OF DESIGN CRITICAL CHARACTERISTICS.

(1) The user should obtain the material safety data sheets [Occupational Safety and 

Health Act (OSHA) Form 20 or equivalent] from the manufacturers or suppliers of 

materials to be used. The user must become completely familiar with the manufacturer/

supplier information and adhere to the procedures, recommendations, warnings, and 

cautions of the manufacturer/supplier for the safe use, handling, storage, and disposal 

of these materials. The user should also read the long version of the warnings 

contained in this service bulletin. The long version warnings are contained in Hamilton 

Sundstrand Warnings Registry 341-006 available free of charge to all organizations 

that are on distribution for this Service Bulletin. The Warnings Registry 341-006 is also 

available at www.hsvas.com.

B. Modification

(1) If the RAT is installed on the aircraft, make sure the RAT is deployed (refer to the 

applicable AMM).

CAUTION: THE RAT TURBINE BLADES SHOULD BE PROTECTIVELY COVERED 

DURING BALANCE WASHER SCREW REMOVAL AND INSTALLATION. 

THE BLADES CAN BE EASILY DAMAGED. 

(2) Install a protective covering on the RAT turbine blades to prevent damage to the blades 

from contact with the tooling or screws. 

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 18

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
SERVICE BULLETIN

Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 7

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

(3) Rotate the turbine assembly and do a check for missing balance washers (refer to the 

items that follow): 

- Balance washers (360, -360A, -360B, or -360C, IPL Figure 2, CMM 24-23-60), 

(370 or -370A), and (-375).

NOTE: The number of balance washers installed will vary according to the 

magnitude of the imbalance that existed before the turbine assembly was 

balanced. 

- The threaded holes around the turbine circumference that are not used for 

balance washers have a set screw installed. The set screw is secured 

using a 5/64-inch internal hex tool. The set screws should not be removed 

or replaced.

- The threaded holes around the turbine circumference with balance 

washers installed, use a countersunk socket head cap screw 

MS24667-14 to secure the washers [refer to screw (380)]. 

NOTE: Missing balance washers are evidenced by the remaining screw and primer 

residue (in a rectangular or circular shaped pattern) on the turbine assembly 

(refer to Figure 1 of this bulletin). 

(4) If any balance washers are missing (because of a fractured screw), do the steps that 

follow:

NOTE: If the RAT is installed on the aircraft, it must be removed from the aircraft 

(refer to the applicable AMM) for removal of the fractured screw and to 

balance the turbine assembly. The RAT must either be returned to Hamilton 

Sundstrand or to a repair facility that has the capability to disassemble, 

repair, balance, and test the RAT. 

(a) Report any occurrences of a fractured screw to Hamilton Sundstrand as follows:

Greg Kuczek

Hamilton Sundstrand Service Engineering 

Phone: +1- 815-226-6581

Fax: +1-860-660-4995

E-Mail: gregory.kuczek@hs.utc.com

(b) Disassemble the RAT (refer to CMM 24-23-60, DISASSEMBLY) as necessary to 

remove the following parts and to get access to the fractured screw.

- Balance washers (360, -360A, -360B, or -360C, IPL Figure 2, CMM 24-23-60), 

(370 or -370A), and (-375)

- Screws (380)

NOTE: Some screws, depending on how near they are to a turbine blade, can 

not be extracted unless the turbine blades are disassembled from the 

turbine assembly. In those cases, the RAT must be disassembled as 

necessary to remove the screw.

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 19

Embraer Copyright © 2010. All rights reserved.
Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 8

SERVICE BULLETIN

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

(c) Use a screw extractor (or equivalent) to remove the remaining portion of the 

fractured screw. Make sure no filings or fragments enter the turbine assembly. Do 

not use heat or fluid to remove the screw.

(d) Do a visual check of the self-locking screw thread insert to make sure there is no 

mechanical damage.

(e) Assemble the turbine assembly as necessary (refer to CMM 24-23-60, 

ASSEMBLY).

(f) Remove the protective covering from the turbine blades.

(g) Balance the turbine assembly (refer to CMM 24-23-60, ASSEMBLY).

(h) Assemble the RAT as necessary (refer to CMM 24-23-60, ASSEMBLY).

(i) Do a test of the RAT (refer to 24-23-60, TESTING AND FAULT ISOLATION).

(j) After all of the balance washer screws have been replaced, identify the RAT as 

follows (refer to SPM 20-00-00, ASSEMBLY): 

1 Put the symbol 24-5 in the AMENDMENT block of the identification plate 

(380, IPL Figure 1, CMM 24-23-60).

(k) Proceed to paragraph 3.E. of this bulletin. 

CAUTION: REPLACE THE BALANCE WASHER SCREWS ONE AT A TIME. DO NOT 

REMOVE ALL OF THE SCREWS AT THE SAME TIME. IF MORE THAN ONE 

SCREW IS REMOVED AT A TIME, THE TURBINE ASSEMBLY MUST BE REBALANCED.

(5) If no balance washers are missing, do the steps that follow to replace the balance 

washer screws (one at a time):

(a) For each balance washer that is unsymmetrical in shape, use a suitable 

temporary marking method (tape, indelible ink, or equivalent) to mark the radial 

orientation of the installed balance washer. The original installed radial orientation 

of the washer must be maintained. 

NOTE: If a balance washer is circular in shape, it is not necessary to mark its 

radial orientation.

(b) Do one of the steps that follow: 

1 If the RAT is installed on the aircraft, rotate the turbine assembly until the 

balance washer is positioned in a manner to minimize the potential for the 

balance washer to fall out (when the associated screw is removed).

2 If the RAT is off the aircraft, position the unit to access the balance washer 

facing up. 

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 20

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
SERVICE BULLETIN

Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 9

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

CAUTION: DO NOT USE A WORN INTERNAL HEX TOOL WITH ROUNDED 

CORNERS TO REMOVE THE SCREW. IF A WORN TOOL IS USED, 

THE POTENTIAL EXISTS FOR STRIPPING THE SOCKET HEAD OF 

THE SCREW. 

CAUTION: USE CARE NOT TO DAMAGE EITHER THE BALANCE WASHER OR 

TURBINE ASSEMBLY IF IT IS NECESSARY TO STRIKE THE HEAD OF 

THE SCREW BECAUSE THE BREAK-AWAY TORQUE IS EXCESSIVE. 

(c) While holding the balance washer in place, use a 3/32-inch internal hex tool to 

remove one screw from one balance washer.

NOTE: The use of a hex insert bit is preferred. 

NOTE: If the screw break-away torque is excessive, it is permissible to lightly 

strike the head of the screw using a small hammer and a 5/16-inch 

(8-millimeter) pin punch. It should not be necessary to strike more than 

two times. 

(d) If the screw is fractured (with the balance washer installed) or if a screw fractures 

during removal, do the steps that follow to remove the remaining portion of the 

screw: 

1 Report any occurrences of a fractured screw to Hamilton Sundstrand as 

follows:

Greg Kuczek

Hamilton Sundstrand Service Engineering 

Phone: +1- 815-226-6581

Fax: +1-860-660-4995

E-Mail: gregory.kuczek@hs.utc.com

2 If the remaining portion of the fractured screw is protruding above the turbine 

surface, do the steps that follow: 

a Apply protective tape on the turbine (in the area of the screw) to prevent 

surface damage during the removal attempt. 

b Use pliers, a vice grip, or an equivalent gripping tool to remove the 

screw.

c Remove the protective tape from the turbine. 

d If the screw is removed in its entirety, proceed to step 3.B.(5)(e) of this 

bulletin.

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 21

Embraer Copyright © 2010. All rights reserved.
Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 10

SERVICE BULLETIN

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

3 If the remaining portion of the screw is flush or below the turbine surface, or 

if the screw can not be removed in its entirety, do the steps that follow: 

NOTE: If the RAT is installed on the aircraft, Hamilton Sundstrand 

recommends the RAT be removed from the aircraft (refer to the 

applicable AMM) for removal of the fractured screw. The RAT 

should either be returned to Hamilton Sundstrand or to a repair 

facility that has the capability to disassemble, repair, balance, and 

test the RAT. 

However, as an option, and at the operator's discretion, an attempt 

to mechanically extract a screw while the RAT is installed on the 

aircraft is allowed. 

The procedure to mechanically extract a fractured screw, or one 

with a stripped socket head, must not use any heat or fluid. Care 

must be taken to make sure no filings or fragments enter the 

turbine assembly. 

The turbine hub and turbine blades should be protectively covered 

to prevent mechanically induced damage during the extraction 

procedure.

The self-locking screw thread insert should be visually inspected 

(after the screw is extracted) to make sure there is no mechanical 

damage. 

a For RATs removed from the aircraft, disassemble the RAT (refer to 

CMM 24-23-60, DISASSEMBLY) as necessary to get access to the 

fractured screw.

NOTE: Some screws, depending on how near they are to a turbine 

blade, can not be extracted unless the turbine blades are 

disassembled from the turbine assembly. In those cases, the 

RAT must be disassembled as necessary to remove the 

screw.

b Use a screw extractor (or equivalent) to remove the remaining portion 

of the fractured screw. Make sure no filings or fragments enter the 

turbine assembly. Do not use heat or fluid to remove the screw. 

NOTE: If the RAT is installed on the aircraft, and the screw can not 

be extracted, the RAT must be removed from the aircraft 

(refer to the applicable AMM) and disassembled as 

necessary to remove the fractured screw. The RAT should 

either be returned to Hamilton Sundstrand or to a repair 

facility that has the capability to disassemble, repair, balance, 

and test the RAT. 

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 22

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
SERVICE BULLETIN

Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 11

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

c Do a visual check of the self-locking screw thread insert to make sure 

there is no mechanical damage.

4 If disassembly of the turbine assembly was not required to remove the 

fractured screw, proceed to step 3.B.(5)(e) of this bulletin.

5 For RATs removed from the aircraft, if disassembly of the turbine assembly 

was required to remove the fractured screw, do the following: 

a Remove the remaining screws (380, IPL Figure 2, CMM 24-23-60) and 

the following balance washers:

- Balance washers (360, -360A, -360B, or -360C), (370 or -370A), and 

(-375)

b Assemble the turbine assembly as necessary (refer to CMM 24-23-60, 

ASSEMBLY).

c Remove the protective covering from the RAT turbine blades.

d Balance the turbine assembly (refer to CMM 24-23-60, ASSEMBLY).

e Assemble the RAT as necessary (refer to CMM 24-23-60, 

ASSEMBLY).

f Do a test of the RAT (refer to CMM 24-23-60, TESTING AND FAULT 

ISOLATION).

g After all of the balance washer screws have been replaced, identify the 

RAT as follows (refer to SPM 20-00-00, ASSEMBLY):

1) Put the symbol 24-5 in the AMENDMENT block of the identification 

plate (380, IPL Figure 1, CMM 24-23-60).

h Proceed to paragraph 3.E. of this bulletin. 

(e) If the balance washer inadvertently falls off after the screw is removed, install the 

balance washer in its original installed orientation, as determined from the 

marking method used in step 3.B.(5)(a) of this bulletin. 

(f) While holding the balance washer in place, install a new screw MS24667-14. 

Torque the screw 16 to 20 pound inches (1.9 to 2.2 Newton meters). 

NOTE: It is not necessary to remove the existing primer residue or apply new 

primer if the balance washer inadvertently fell off after the screw was 

removed. 

(g) Use a suitable temporary marking method (tape, indelible ink, or equivalent) to 

mark the location where the balance washer screw has been replaced.

(h) Repeat steps 3.B.(5)(b) through (g) of this bulletin for each balance washer screw. 

(i) Record the total number of replaced screws. 

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 23

Embraer Copyright © 2010. All rights reserved.
Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 12

SERVICE BULLETIN

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

(j) Remove any tape (that was used to mark the orientation of the installed balance 

washers or the locations where the screws had been replaced).

(k) Remove the protective covering from the RAT turbine blades.

(6) After all of the balance washer screws have been replaced, identify the RAT as follows 

(refer to SPM 20-00-00, ASSEMBLY):

(a) Put the symbol 24-5 in the AMENDMENT block of the identification plate (380, 

IPL Figure 1, CMM 24-23-60).

(7) If the RAT is installed on the aircraft, make sure the RAT is re-stowed (refer to the 

applicable AMM).

C. Identification

NOTE: After all of the balance washer screws have been replaced, the RAT is identified 

by adding the symbol 24-5 in the AMENDMENT block of the identification plate.

D. Test

(1) For units in the shop (if no balance washers were found missing, disassembly of the 

turbine was not required, and the balance washer screws were replaced one screw at 

a time), a test of the RAT is optional based on operator experience, normal shop 

practices, and reason for removal (refer to CMM 24-23-60, TESTING AND FAULT 

ISOLATION).

E. Return Balance Washer Screws to Hamilton Sundstrand

(1) If the unit had a missing balance washer or a fractured screw, return all of the removed 

screws (including the remnants of the fractured screw) to Hamilton Sundstrand for 

further investigation as follows: 

(a) Put the screws in a mailing package. 

(b) Tag the screws (or include a note) to identify the part number and serial number 

of the RAT the screws were removed from and to identify the applicable aircraft 

MSN. 

(c) Return the screws with the applicable RAT part number, RAT serial number, and 

aircraft MSN to the address that follows:

Hamilton Sundstrand Service Engineering

4747 Harrison Avenue

P.O. Box 7002

Rockford, IL 61125-7002

Attention: Greg Kuczek

Phone: +1- 815-226-6581

Fax: +1-860-660-4995

E-Mail: gregory.kuczek@hs.utc.com

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 24

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
SERVICE BULLETIN

Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 13

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

F. Notification of Completion Form

(1) Do the following upon completion of this service bulletin:

(a) Make a copy of the “Notification of Completed SB ERPS37T-24-5” form (refer to 

Table 2 of this bulletin), complete the form, and fax the completed form to 

Hamilton Sundstrand as follows:

Hamilton Sundstrand Corporation

Retrofit Management Group

Fax: +1-860-998-3695

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 25

Embraer Copyright © 2010. All rights reserved.
Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 14

SERVICE BULLETIN

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

Figure 1

Missing Balance Washer

SB-ERPS37T245-104620

SERVICE BULLETIN

SB No.: 170-24-0048

PAGE: 26

DATE: 31/Mar/2010

REVISION No.: 01 - 12/May/2010

Embraer Copyright © 2010. All rights reserved.
SERVICE BULLETIN

Original Issue Date: Mar 22/10 ERPS37T-24-5

Page 15

Hamilton Sundstrand Proprietary - Use or disclosure of this data is subject to restrictions on the title page of this document.

Table 2

Notification of Completion Form

NOTIFICATION OF COMPLETED SB ERPS37T-24-5

“Replace Balance Washer Screws”

SENT FROM:

Sender Name:

Sender Company:

Aircraft Operator: 

Sender Fax #:

Send Date:

**PLEASE SUBMIT THIS NOTIFICATION SHEET WITHIN 10 DAYS AFTER MODIFICATION**

SEND TO:

Hamilton Sundstrand Corporation

Retrofit Management Group

Fax: +1-860-998-3695

RAT

Serial Number

Aircraft MSN 

or Tail Number

 Bulletin 

Completion Date

Number 

of Replaced 

Screws

Comments

SERVICE BULLETIN

DATE: 31/Mar/2010

REVISION No.:01 - 12/May/2010

SB No.: 170-24-0048

PAGE: 27

Embraer Copyright © 2010. All rights reserved.

SERVICE BULLETIN EVALUATION

THE PURPOSE OF THIS FORM IS TO COLLECT DATA THAT WILL BE USED TO IMPROVE THE QUALITY OF OUR

SERVICE BULLETINS AND UPDATE THE TECHNICAL PUBLICATIONS. PLEASE FILL IN FORM AND RETURN IT TO:

EMBRAER - EMPRESA BRASILEIRA DE AERONÁUTICA S.A.

EFTC - SERVICE BULLETIN ENGINEERING

AV. BRIGADEIRO FARIA LIMA, 2170

SÃO JOSÉ DOS CAMPOS - SP - 12227-901

BRASIL

Fax: + 55 12 3927-6600 (ext. 1624)

e-mail: fleet.reliability@embraer.com.br

S.B. Title: S.B.: (Number / Rev.)

Operator:

SB Implementation Report

Aircraft Serial Number or Registration Number: Incorporation Date:

Aircraft Flight Hours: Aircraft Landings:

POST-ACCOMPLISHMENT EVALUATION: (Check applicable squares below)

ESTIMATED MANPOWER: [ ] OK [ ] NOT OK (Explain Below)

MATERIAL & KITS: [ ] OK [ ] NOT OK (Explain Below)

ACCOMPLISHMENT INSTRUCTIONS: [ ] OK [ ] NOT OK (Explain Below)

FIGURES: [ ] OK [ ] NOT OK (Explain Below)

SB GENERAL EVALUATION: [ ] OK [ ] NOT OK (Explain Below)

COMMENTS: (Bulletin quality/ Difficulties found at the time of incorporation/ Suggested improvements/ Other)

Organization: Fax: Phone:

E-mail:

Address: Prepared by:(Name/Title) Date:

Embraer Copyright © 2010. All rights reserved.