### Commercial **Airplanes** 

# MD90 Service Bulletin **ALERT Number: MD90-55A015**  Original Issue: July 16, 2010 ATA System: 5510 **SUBJECT:** STABILIZERS - Horizontal Stabilizer - Inspect/Replace Upper Center Skin Panels Export of this technology is controlled under the United States Export Administration Regulations (EAR) (15 CFR 730-774). An export license may be required before it is used for development, production or use by foreign persons from specific countries. The controller of this data has the individual responsibility to abide by all export laws. 9E991 ECCN: 

## BOEING PROPRIETARY, CONFIDENTIAL, AND/OR TRADE SECRET Copyright © 2010 The Boeing Company Unpublished Work - All Rights Reserved Boeing claims copyright in each page of this document only to the extent that the page contains copyrightable subject matter. Boeing also claims copyright in this document as a compilation and/or collective work. This document includes proprietary information owned by The Boeing Company and/or one or more third parties. Treatment of the document and the information it contains is governed by contract with Boeing. For more information, contact The Boeing Company, P.O. Box 3707, Seattle, Washington 98124. Boeing, the Boeing signature, the Boeing symbol, 707, 717, 727, 737, 747, 757, 767, 777, 787, Dreamliner, BBJ, DC-8, DC-9, DC-10, KC-10, KDC-10, MD-10, MD-11, MD-80, MD-88, MD-90, P-8A, Poseidon and the Boeing livery are all trademarks owned by The Boeing Company; and no trademark license is granted in connection with this document unless provided in writing by Boeing.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 1 of 32 3.0BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 2 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**

BLANK PAGE**Table of Contents** Summary...................................................... 5 1. PLANNING INFORMATION ........................................ 9 A. Effectivity................................................ 9 1. Airplanes............................................. 9 2. Spares Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 B. Concurrent Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 C. Reason. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 D. Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 E. Compliance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 F. Approval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 G. Manpower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 H. Weight and Balance Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 I. Electrical Load Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 J. References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1. Existing Data: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2. Data supplied with this Service Bulletin:. . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3. Installation Drawings Used in the Preparation of this Service Bulletin:. . . . . . . . . . . 18 K. Publications Affected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 L. Interchangeability and Intermixability of Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2. MATERIAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 A. Material - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 B. Industry Support Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 C. Parts Necessary For Each Airplane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 1. Kits/Parts: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2. Parts and Materials Supplied by the Operator:. . . . . . . . . . . . . . . . . . . . . . . . 23 3. Parts Modified and Reidentified:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 4. Parts Removed and Not Replaced:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 D. Parts Necessary to Change Spares. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 E. Special Tooling - Price and Availability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 F. Special Tooling Necessary to do this Service Bulletin. . . . . . . . . . . . . . . . . . . . . . . 24 3. ACCOMPLISHMENT INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 A. GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 B. WORK INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 FIGURE 1: HORIZONTAL STABILIZER LEFT AND RIGHT UPPER CENTER SKIN PANELS - EDDY CURRENT INSPECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 3 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 4 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# MD90 Service Bulletin **ALERT Summary**  **Number: MD90-55A015** Original Issue: July 16, 2010 ATA System: 5510 **SUBJECT:** STABILIZERS - Horizontal Stabilizer - Inspect/Replace Upper Center Skin Panels THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **CONCURRENT REQUIREMENTS** None. **BACKGROUND** During inspection of the horizontal stabilizer upper aft skin panel of an MD-80 airplane in accordance with Service Bulletin MD80-55A065, one operator reported finding a crack in the right horizontal stabilizer upper center skin panel at the aft inboard corner. The MD-80 airplane had accumulated 47,146 flight-hours and 26,490 flight cycles when the crack was found. The cause of the horizontal stabilizer upper center skin panel cracking on the MD-80 airplane is suspected to be fatigue. The MD-90 horizontal stabilizer is similar in design and loading as that of the MD-80 horizontal stabilizer. Boeing issued Service Bulletin MD90-55A012 which provides instructions to do inspection of the horizontal stabilizer upper aft skin panel. If undetected, a crack in the upper center skin panel may transfer load to the upper aft skin panel. This may result in the upper aft skin panel cracking faster than the existing inspection intervals, defined in Service Bulletin MD90-55A012, will detect. Inspection of the affected areas will determine the condition of the horizontal stabilizer upper center skin panels. If not corrected, undetected cracks may ultimately lead to the loss of overall structural integrity of the horizontal stabilizer. **ACTION** Refer to Paragraph 1.D., Description. **EFFECTIVITY** MD-90-30 Airplanes. Refer to Paragraph 1.A.1., Airplanes, for the list of affected airplanes. **COMPLIANCE** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory. Refer to Paragraph 1.E., Compliance.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 5 of 32**INDUSTRY SUPPORT INFORMATION** Boeing warranty remedies are not available for the inspection and/or repair procedures given in this service bulletin. **MANPOWER** Refer to Paragraph 1.G., Manpower. **MATERIAL INFORMATION** Boeing Supplied Kits/Parts. Refer to Paragraph 2.A., Material - Price and Availability.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 6 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 7 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 8 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**

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### Commercial **Airplanes** 

# MD90 Service Bulletin **ALERT Number: MD90-55A015**  Original Issue: July 16, 2010 ATA System: 5510 **SUBJECT:** STABILIZERS - Horizontal Stabilizer - Inspect/Replace Upper Center Skin Panels THIS BULLETIN IS SENT TO THE OPERATORS OF RECORD OF THE AIRPLANES SHOWN IN PARAGRAPH 1.A., EFFECTIVITY. IF AN AIRPLANE HAS BEEN LEASED OR SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OPERATOR. IF APPLICABLE SPARES HAVE BEEN SOLD, SEND THIS SERVICE BULLETIN TO THE NEW OWNER. **1. PLANNING INFORMATION A. Effectivity**  1. Airplanes This service bulletin is for the airplanes shown below.
**DESCRIPTION CONFIGURATION**  **GROUP** MD-90-30 Airplanes

- 1

Airplane Models: MD-90-30 **Group Fuselage Num-**  **ber** 1 2094 - 2100 1 2115 1 2117 1 2120 1 2122 - 2123 1 2125 - 2126 1 2129 1 2131 1 2133

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 9 of 32**Group Fuselage Num-**  **ber** 1 2136 1 2138 1 2140 - 2144 1 2146 - 2147 1 2149 - 2150 1 2153 - 2154 1 2156 - 2159 1 2161 - 2166 1 2169 - 2171 1 2173 1 2175 1 2177 1 2179 1 2181 1 2184 1 2186 1 2190 - 2191 1 2193 - 2195 1 2197 - 2198 1 2200 1 2202 - 2203 1 2205 1 2207 1 2209 - 2213 1 2215 - 2217 1 2219 - 2233 1 2235 - 2237 1 2240 1 2243 1 2245 1 2248 1 2250 - 2251

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 10 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT Group**  **Fuselage Num- ber**  1 2253 1 2255 - 2263 1 2288 - 2290 1 4001 - 4002 2. Spares Affected None. **B. Concurrent Requirements** None. **C. Reason** During inspection of the horizontal stabilizer upper aft skin panel of an MD-80 airplane in accordance with Service Bulletin MD80-55A065, one operator reported finding a crack in the right horizontal stabilizer upper center skin panel at the aft inboard corner. The MD-80 airplane had accumulated 47,146 flight-hours and 26,490 flight cycles when the crack was found. The cause of the horizontal stabilizer upper center skin panel cracking on the MD-80 airplane is suspected to be fatigue. The MD-90 horizontal stabilizer is similar in design and loading as that of the MD-80 horizontal stabilizer. Boeing issued Service Bulletin MD90-55A012 which provides instructions to do inspection of the horizontal stabilizer upper aft skin panel. If undetected, a crack in the upper center skin panel may transfer load to the upper aft skin panel. This may result in the upper aft skin panel cracking faster than the existing inspection intervals, defined in Service Bulletin MD90-55A012, will detect. Inspection of the affected areas will determine the condition of the horizontal stabilizer upper center skin panels. If not corrected, undetected cracks may ultimately lead to the loss of overall structural integrity of the horizontal stabilizer. **D. Description** This service bulletin provides instructions to do an eddy current inspection of the horizontal stabilizer left and right upper center skin panels for cracks, and based on inspection results for each panel, does as follows: **Condition 1 (No Crack Found)** 1. Does repetitive eddy current inspections of the horizontal stabilizer upper center skin panel. **Condition 2 (Crack Found)** 1. OPTION 1:

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 11 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**a. Replaces the cracked horizontal stabilizer upper center skin panel. b. Does repetitive eddy current inspection of the replacement horizontal stabilizer upper center skin panel. 2. OPTION 2:
a. Contacts Boeing for possible temporary repair of crack and does the repair in accordance with Boeing's instructions. The work in this service bulletin is done in the maintenance zone(s) given below.
**Affected Maintenance Zones Zone**  **Model** 333, 343 MD-90-30 **E. Compliance** The Federal Aviation Administration (FAA) will possibly release an Airworthiness Directive related to this service bulletin. The Airworthiness Directive will make the compliance tasks and times given in this service bulletin mandatory.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 12 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT Table 1: Inspect Horizontal Stabilizer Left and Right Upper Center Skin Panels for Cracks**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- Within 3,778flight cycles after the original issue date onthis service bulletin.Before the accumulation of 20,000 total flight cycles.Do initial eddy current inspection of the horizontal stabilizer left and right upper center skin panelsin accordance with Paragraph 3.B., Work Instructions, using one of the options as follows: All Airplanes

OPTION 1: Scan 1 - Eddy Current, High Frequency (ETHF) Scan 2 - Eddy Current, High Frequency (ETHF) Scan 3 - Eddy Current, Low Frequency (ETLF) OR OPTION 2: Scan 1 - Eddy Current, High Frequency (ETHF) Scan 2 - Eddy Current, High Frequency (ETHF) Scan 3 - Eddy Current, High Frequency (ETHF)

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 13 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT Table 1: Inspect Horizontal Stabilizer Left and Right Upper Center Skin Panels for Cracks**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- - - Do repetitive eddy currentinspection of the horizontal stabilizer left and right upper center skin panelsin accordance with Paragraph 3.B., Work Instructions, using one of the options as follows: Condition 1 (No Crack Found)

5,200 flight cycles

- Within 5,200flight cycles after doing the initial eddy current inspection. OPTION 1: Scan 1 - Eddy Current, High Frequency (ETHF) Scan 2 - Eddy Current, High Frequency (ETHF) (a)

(a) Scan 3 - Eddy Current, Low Frequency (ETLF) OR 2,500 flight cycles

- Within 2,500flight cycles after doing the initial eddy current inspection. OPTION 2: Scan 1 - Eddy Current, High Frequency (ETHF) Scan 2 - Eddy Current, High Frequency (ETHF) (a)

(a) Scan 3 - Eddy Current, High Frequency (ETHF)

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 14 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT Table 1: Inspect Horizontal Stabilizer Left and Right Upper Center Skin Panels for Cracks**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition** 

- - - OPTION 1: Do items (1), (2), and (3) as follows: Condition 2 (Crack Found)

- - Before further flight (1) Replace the cracked horizontal stabilizer uppercenter skin panel in accordance with Paragraph 3.B., Work Instructions AND

- - Within 20,000flight cycles after installation of the replacementhorizontal stabilizer upper center skin panel. (2) Do initial eddy currentinspection of the replacement horizontal stabilizer upper center skin panelin accordance with Paragraph 3.B., Work Instructions, using one of the options as follows: OPTION 1: Scan 1 - Eddy Current, High Frequency (ETHF) Scan 2 - Eddy Current, High Frequency (ETHF) Scan 3 - Eddy Current, Low Frequency (ETLF) OR OPTION 2: Scan 1 - Eddy Current, High Frequency (ETHF) Scan 2 - Eddy Current, High Frequency (ETHF) Scan 3 - Eddy Current, High Frequency (ETHF) AND

- - - (3) Do repetitive eddy current inspection of the horizontal stabilizer left and right upper center skin panels in accordance with Paragraph 3.B., Work Instructions, usingone of the options as follows: 5,200 flight cycles.

- OPTION 1: (a)

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 15 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT Table 1: Inspect Horizontal Stabilizer Left and Right Upper Center Skin Panels for Cracks**  **Repeat Interval (Not to Exceed)**  **Compliance Time (Whichever Occurs Later)**  **Action Condition**  Scan 1 - Eddy Current, High Frequency (ETHF) Within 5,200flight cycles after doing the eddy current inspection. Scan 2 - Eddy Current, High Frequency (ETHF) Scan 3 - Eddy Current, Low Frequency (ETLF) (a) OR 2,500 flight cycles

- Within 2,500flight cycles after doing the eddy current inspection. OPTION 2: Scan 1 - Eddy Current, High Frequency (ETHF) Scan 2 - Eddy Current, High Frequency (ETHF) (a)

(a) Scan 3 - Eddy Current, High Frequency (ETHF) OR

- - Before further flight OPTION 2:Contact Boeing for possible temporary repair of crack and do the repair in accordance with Boeing's instructions. Condition 2 (Crack Found)

(a) It is acceptable to change inspection procedures from Option 1 to Option 2 or from Option 2 to Option 1 if you do as follows: 1. If the inspection procedure is being changed from Option 1 to Option 2, the first Option 2 inspection must be done within 5,200 flight cycles after the Option 1 inspection. The Option 2 inspections that follows must be done within 2,500 flight cycle repeat intervals 2. If the inspection procedure is being changed from Option 2 to Option 1, the first Option 1 inspection must be done within 2,500 flight cycles after the Option 2 inspection. The Option 1 inspections that follows must be done within 5,200 flight cycle repeat intervals **F. Approval** This service bulletin was examined by the Federal Aviation Administration (FAA). The changes specified in this service bulletin comply with the applicable regulations and are FAA approved, as well as European Aviation Safety Agency (EASA)/Joint Aviation Authorities (JAA) approved for all EASA/JAA approved airplanes listed in the service bulletin effectivity. This service bulletin and its approval were based on the airplane in its original Boeing delivery configuration or as modified by other approved Boeing changes. If an airplane has a non-Boeing modification or repair that affects a component or system also affected by this service bulletin, the operator is responsible for obtaining appropriate regulatory agency approval before incorporating this service bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 16 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT G. Manpower**  The table below shows an estimate of the task hours necessary to do the inspection and/or configuration changes for each horizontal stabilizer upper center skin panel. This estimate is for direct labor only, done by an experienced crew. Adjust the estimate with operator task hour data if necessary. The estimate does not include lost time. These are some examples of lost time: • Time to adjust to the workplace • Time to schedule the work • Time to inspect the work • Time to cure the materials • Time to make the parts • Time to find the tools. **All Airplanes: Horizontal Stabilizer Upper Center Skin Panel Initial Inspection Elapsed Hours**  **Task Hours Number of Persons**  **Task** 2.0 4.0 2 Figure 1 - Inspection 2.0 4.0 TOTAL FOR EACH UPPER CENTER SKIN PANEL **Condition 1: Horizontal Stabilizer Upper Center Skin Panel Repetitive Inspection Elapsed Hours**  **Task Hours Number of Persons**  **Task** 2.0 4.0 2 Figure 1 - Inspection 2.0 4.0 TOTAL FOR EACH UPPER CENTER SKIN PANEL **Condition 2, Option 1: Horizontal Stabilizer Upper Center Skin Panel Replacement Elapsed Hours**  **Task Hours Number of Persons**  **Task** 8.0 48.0 6 Remove Horizontal Stabilizer 12.0 24.0 2 Remove LeadingEdge and Upper Forward Skin Panel 168.0 504.0 3 Replace Horizontal Stabilizer Upper Center Skin Panel 12.0 24.0 2 Install Leading Edge and Upper Forward Skin Panel 8.0 48.0 6 Install Horizontal Stabilizer 208.0 648.0 TOTAL FOR EACH UPPER CENTER SKIN PANEL

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 17 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT H. Weight and Balance Changes**  None. **I. Electrical Load Data** Not changed. **J. References** 1. Existing Data: a. Non-Destructive Test Standard Practices Manual (NDTSPM) 06-00-07, 06-10-01.001, 06-10-02.005. b. MD90 Aircraft Maintenance Manual (AMM) 55-10-01, 55-12-01. 2. Data supplied with this Service Bulletin: None. 3. Installation Drawings Used in the Preparation of this Service Bulletin: **Change Title**  **Document Number** T PANEL-SKIN AND STGR, HORIZ STAB, CTR 5922577

K STRUCTURAL ASSEMBLY - OUTER PANEL HORIZONTAL STABILIZER 5964815

E STABILIZER ASSY-COMPLETE HORIZONTAL 5940483

These drawings were used to prepare this service bulletin. These drawings are not necessary to make the specified changes, and are not supplied with this service bulletin. These drawings may not be applicable to all airplane configurations or operators. **K. Publications Affected** 1. Publications: None. 2. Damage Tolerance Based Structural Inspections: Boeing has evaluated the repairs and/or changes in this service bulletin for effects on Fatigue Critical Structure (FCS) and for changes to Damage Tolerance Inspections (DTI) required in the Maintenance Program. This service bulletin affects FCS. DTI requirements for the structure affected are contained in Paragraph 1.E., Compliance of this service bulletin.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 18 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT L. Interchangeability and Intermixability of Parts**  Accomplishment of this service bulletin does not affect interchangeability or intermixability of parts.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 19 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 20 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**

BLANK PAGE**2. MATERIAL INFORMATION A. Material - Price and Availability**  Boeing can supply the kits shown below which contain the parts listed in Paragraph 2.C., Parts Necessary for Each Airplane. Operators are encouraged to share schedule requirements with Boeing for incorporation of the service bulletin. The kits are subject to the terms and conditions of the Boeing standard purchase order acknowledgment. Prices are in United States Dollars. Terms: Net 30 days. Reference this service bulletin and submit your purchase order by one of these methods: 1. Order on-line via ATA Spec 2000 or The Boeing PART Page 2. Fax to (206) 662-7145

**REFER TO THE BOEING PART PAGE ON MYBOEINGFLEET.COM OR CONTACT FIRST RE SPONDER AT FR@BOEING.COM FOR THE LATEST REORDER LEAD TIME (ROLT) AND PRICE**  **INFORMATION**
**Unit Price as of the original issue** **date of this Ser vice Bulletin (US**  **Dollars) ROLT as of the**  **original issue date of this Ser** **vice Bulletin (Cal endar Days)**  **Name Kit Number** 

$55,608.00 120 Service Kit - Upper Center SA90550015-3 Skin Panel (Left) 55,608.00 120 Service Kit - Upper Center SA90550015-5 Skin Panel (Right) **B. Industry Support Information** Boeing warranty remedies are not available for the inspection and/or repair procedures given in this service bulletin. **C. Parts Necessary For Each Airplane** 1. Kits/Parts: To get the kits/parts shown below, refer to Paragraph 2.A., Material - Price and Availability. **NOTE:** One top kit per panel location (left or right) and the items shown in Paragraph 2.C.2., Parts and Materials Supplied by the Operator, are necessary for each airplane. **SERVICE KIT APPLICABILITY SR Drawing Configuration**  **Name SA Kit Number**  SR09550033-7017 Service Kit - Upper Center SA90550015-3 Skin Panel (Left)

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 21 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT SERVICE KIT APPLICABILITY**  **SR Drawing Configuration Name**  **SA Kit Number** SR09550033-7019 Service Kit - Upper Center SA90550015-5 Skin Panel (Right)

**Kit SA90550015 Notes**  **Existing Part Number**  **Name QTY**  **New Part Number -5**  **-3** (a)

. - SA90550015-3 (a)

- . SA90550015-5 (b) 3964835-509 FILLER 6 6 3964835-509 (c) 3964835-511 FILLER 8 8 3964835-511 NUT ASSEMBLY 1 1 3D0006-3 NUT, BARREL 4 4 3D0011-5 BARREL NUT 3 3 3D0011-6 RETAINER 4 4 3D0012-5 RETAINER 3 3 3D0012-6 BOLT 3 3 3D0031-5-22 BOLT 1 1 3D0031-5-26 BOLT 3 3 3D0031-6-24 5922577-511 UPPER PANEL (RIGHT) 1

. 5922577-511

5922577-512 UPPER PANEL (LEFT) . 1 5922577-512

WASHER 4 4 73232-5-8.1 WASHER 3 3 73232-6-12.4 PIN 14 14 HLT435-6-3 PIN 27 27 HLT435-6-4 PIN 7 7 HLT435-6-5 PIN 5 5 HLT435-6-6 PIN 2 2 HLT435-6-8 PIN 73 73 HLT435-8-3 PIN 43 43 HLT435-8-4 RIVET 12 12 MS20426AD5-6D RIVET 44 44 MS20426AD5-7D

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 22 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT Kit SA90550015**  **Notes Existing Part**  **Number Name**  **QTY New Part Number**  **-5 -3**  RIVET 6 6 MS20426AD5-8D RIVET 8 8 MS20426AD6-8D RIVET 16 16 MS20470AD6-7D RIVET 22 22 MS20470AD6-8D NUT 58 58 MS21042L3 NUT 116 116 MS21042L4 RIVET 54 54 NAS1097KE8-10D RIVET 2 2 NAS1097KE8-11D RIVET 18 18 NAS1097KE8-12D RIVET 147 147 NAS1097KE8-9D WASHER 58 58 NAS1252-10L WASHER 116 116 NAS1252-416L PIN 4 4 S4931919-6-5 (a) If grip length shown is not available at Boeing, fasteners supplied in kits may be one grip length longer than indicated. Also, if any fasteners part numbers listed are not available or have been superseded, substitute fasteners may be supplied in kits. (b) 5930603-7 Filler may be used in lieu of 3964835-509 Filler. (c) 5930603-9 Filler may be used in lieu of 3964835-511 Filler.

2. Parts and Materials Supplied by the Operator:
**Notes QTY**  **Name Part Number/Specification**  (a) As Required Sealant PR-1422 B-2 (DMS 2082) or Equivalent

**CAGE Supplier**  83574 PRC - DeSoto International, Incorporated (a) Can be purchased from: 24811 Avenue Rockefeller Valencia, California 91355 -3468
3. Parts Modified and Reidentified: None.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 23 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**4. Parts Removed and Not Replaced: None. **D. Parts Necessary to Change Spares** None. **E. Special Tooling - Price and Availability** None. **F. Special Tooling Necessary to do this Service Bulletin** No special tools or equipment are necessary to do the change in this service bulletin. But, maintenance and overhaul tools in the manuals given in Paragraph 1.J., References, can be necessary. Examine operator tool supply to make sure all necessary tools are available.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 24 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT 3. ACCOMPLISHMENT INSTRUCTIONS**  **A. GENERAL INFORMATION WARNING:**  IF ELECTRICAL POWER IS APPLIED TO THE AIRPLANE, MAKE SURE YOU OBEY ALL PRECAUTIONS WHILE YOU DO WORK. IF YOU DO NOT OBEY THE PRECAUTIONS, DEATH OR INJURY TO PERSONS, AND DAMAGE TO THE AIRPLANE CAN OCCUR. **CAUTION:** ELECTRICALLY GROUND THE AIRPLANE. THIS WILL HELP TO PREVENT DAMAGE TO THE AIRPLANE OR EQUIPMENT. **CAUTION:** KEEP THE WORK AREA, WIRES AND ELECTRICAL BUNDLES CLEAN OF METAL PARTICLES OR CONTAMINATION WHEN YOU USE TOOLS. UNWANTED MATERIAL, METAL PARTICLES OR CONTAMINATION CAUGHT IN WIRE BUNDLES CAN CAUSE DAMAGE TO THE BUNDLES. DAMAGED WIRE BUNDLES CAN CAUSE SPARKS OR OTHER ELECTRICAL DAMAGE. **NOTE:** 1. The instructions identified in Paragraph 3.B., Work Instructions, and the Figure(s) give the recommended sequence of steps. The sequence of steps to do this service bulletin can be changed. 2. Manual titles are referred to by acronyms. Refer to Paragraph 1.J., References, for definition of the acronyms. 3. Equivalent parts are listed in the AEPL, Drawing 7595071. 4. Use the approved fastener substitutions and process material substitutions, in accordance with MD-90 Structural Repair Manual (SRM) 51. 5. If the length of any fastener specified in this service bulletin does not meet the installation standards in MD-90 SRM 51, then a fastener of the same specification, or an approved substitute, with a length which meets the installation standards in MD-90 SRM 51 may be used. 6. A 1/8-inch thick stack of the same type washers called for in this service bulletin is the maximum thickness which may be used under fastener head or nut to counteract accumulation of tolerances. EXCEPTION: When the available fastener length increments are greater than 1/16-inch, a 3/16-inch thick stack of the same type washers may be used. 7. Unless shown differently, these dimensions and tolerances are used: – Linear dimensions are in inches – Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch. – Tolerance on rivet and bolt edge margin is plus or minus 0.05 inch – Angular tolerance is plus or minus 2 degrees – Hole dimensions for standard solid rivets are in MD-90 SRM 51. – Torque limits to tighten nuts and bolts are in MD-90 SRM 51.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 25 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**8. Obey all of the warnings and cautions given in the specified manual sections. 9. These work instructions refer to procedures included in other Boeing documents. When the words "refer to" are used and the operator has an accepted alternative procedure, the accepted alternative procedure can be used. When the words "in accordance with" are included in the instruction, the procedure in the Boeing document must be used. 10. Some Boeing parts are supplied in a temporary configuration. Those parts are identified with a 'U' or 'Y' in place of the '-' (dash) in the part number. It is permitted to install parts identified with a 'U' or 'Y' as an alternative to the '-' (dash) number part. Boeing Drawing SE10000000, Sheets 5.0 and 6.0 contain more data. **B. WORK INSTRUCTIONS** 1. Do an eddy current inspection of the horizontal stabilizer left and right upper center skin panels in accordance with FIGURE 1 and based on inspection results for each panel, do as follows:
**Condition 1 (No Crack Found)** a. Do repetitive eddy current inspections of the horizontal stabilizer upper center skin panel in accordance with FIGURE 1, at intervals specified in Paragraph 1.E., Compliance. **Condition 2 (Crack Found)** a. OPTION 1: (1) Remove and keep horizontal stabilizer. Refer to MD90 AMM 55-10-01. (2) Remove and keep horizontal stabilizer leading edge. Refer to MD90 AMM 55-12-01. (3) Remove and keep horizontal stabilizer upper forward skin panel to gain access to the cracked horizontal stabilizer upper center skin panel. Refer to drawing 5964815. (4) Remove and replace the cracked horizontal stabilizer upper center skin panel in accordance with the applicable configuration of Service Rework Drawing SR09550033 using the applicable kit as follows:
**KIT SA90550015**  **CENTER SKIN PANEL LOCATION**  **DRAWING SR09550033**  -3 UPPER LEFT -7017 -5 UPPER RIGHT -7019 (5) Install kept horizontal stabilizer upper forward skin panel. Refer to drawing 5964815 and MD90 SRM 51.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 26 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**(6) Install kept horizontal stabilizer leading edge. Refer to MD90 AMM 55-12-01. (7) Install kept horizontal stabilizer. Refer to MD90 AMM 55-10-01. (8) Do repetitive eddy current inspection of the replacement horizontal stabilizer upper center skin panel in accordance with FIGURE 1, at intervals specified in Paragraph 1.E., Compliance. b. OPTION 2: (1) Contact Boeing for possible temporary repair of crack and do the repair in accordance with Boeing's instructions. 2. Put the airplane back to serviceable condition.

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 27 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT FIGURE 1: HORIZONTAL STABILIZER LEFT AND RIGHT UPPER CENTER SKIN PANELS - EDDY CURRENT**  **INSPECTION (SHEET 1 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 28 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT FIGURE 1: HORIZONTAL STABILIZER LEFT AND RIGHT UPPER CENTER SKIN PANELS - EDDY CURRENT**  **INSPECTION (SHEET 2 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 29 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT FIGURE 1: HORIZONTAL STABILIZER LEFT AND RIGHT UPPER CENTER SKIN PANELS - EDDY CURRENT**  **INSPECTION (SHEET 3 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 30 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT FIGURE 1: HORIZONTAL STABILIZER LEFT AND RIGHT UPPER CENTER SKIN PANELS - EDDY CURRENT**  **INSPECTION (SHEET 4 OF 5)** 

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 31 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**The step numbers shown below agree with the numbers shown in the circle symbols in the figure. The QTY numbers shown below are the number of parts necessary for each airplane.
**MORE DATA QTY**  **IDENTIFICATION NAME**  **TASK STEP**  (a) (e) 1 5922577-511 Upper Center Skin Panel - Right Inspect - (Scan 1) OPTION 1, 2: 1 Eddy Current, High Frequency (ETHF) 5922577-512 Upper Center Skin Panel - Left (b) (e) 1 5922577-511 Upper Center Skin Panel - Right Inspect - (Scan 2) OPTION 1, 2: 2 Eddy Current, High Frequency (ETHF) 5922577-512 Upper Center Skin Panel - Left (c) (e) 1 5922577-511 Upper Center Skin Panel - Right Inspect - (Scan 3) OPTION 1: 3 Eddy Current, Low Frequency (ETLF) 5922577-512 Upper Center Skin Panel - Left (d) (e) 1 5922577-511 Upper Center Skin Panel - Right Inspect - (Scan 3) OPTION 2: Eddy Current, High Frequency (ETHF) 5922577-512 Upper Center Skin Panel - Left Do an Eddy Current, High Frequency surface inspection of the horizontal stabilizer upper centerskin panels around the fastener in the inspection area. Scan around the fastener using a nonconductive circle template looking for cracks propagating from the fastener hole. Refer to NDTSPM 06-10- 01.001 (ETHF - Procedure 1). Use Calibration Method "P" and Scan Method "47". (a)

Do an Eddy Current, High Frequency surface inspection of the horizontal stabilizer upper center skin panels along the inboard portion of the aft edge as shown in the inspection area. Scan the edgeslooking for cracks propagating from the panel edge. Refer to NDTSPM 06-10-01.001 (ETHF - Procedure 1). Use Calibration Method "A" and Scan Method "79". (b)

Do an Eddy Current, Low Frequency sub-surface inspection of the horizontal stabilizer upper center skin panels at all other areas in the rectangular shaped inspection area not inspected by Scan 1 or 2. Scan the noted area of the upper surface of the upper panels. Refer to NDTSPM 06-10-02.005 (ETLF - Procedure 5). (c)

NOTE: Space each scan approximately 1/2 probe coil diameter apart. Do an Eddy Current, High Frequency surface inspection of the horizontal stabilizer upper center skin panels at all other areas in the rectangular shaped inspection area not inspected by Scan 1 or 2. Scan the noted area of the upper surface of the upper panels. Refer to NDTSPM 06-10-01.001 (ETHF - Procedure 1).Use Calibration Method "C" and Scan Method "61". (d)

NOTE: Space each scan approximately 1/2 probe coil diameter apart. Evaluate and verify crack indications found during inspection. Refer to NDTSPM 06-00-07. (e)

**FIGURE 1: HORIZONTAL STABILIZER LEFT AND RIGHT UPPER CENTER SKIN PANELS - EDDY CURRENT INSPECTION**  **(SHEET 5 OF 5)**

BOEING PROPRIETARY - Copyright © Unpublished Work - See page 1 for details. Original Issue: July 16, 2010 MD90-55A015 32 of 32 **BOEING SERVICE BULLETIN MD90-55A015 ALERT**  **ALERT**