# Beechcraft Mandatory Service Letter MTL-57-01: Revision 1 - Rights: © Textron Aviation Inc. Filed by the FAA in regulations.gov docket FAA-2020-0718; AD 2020-25-01 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Beechcraft Mandatory Service Letter MTL-57-01](https://openairdocs.org/service-documents/beechcraft/mtl57-01.md) - Title as filed: MTL-57-01 - Pages: 8 - PDF: https://openairdocs.org/files/sha256/6e/2c/6e2c28bff3cd5939463a1e71c3f8331ee09ad2faf293e6cc4b1404be4102c20d - Page: https://openairdocs.org/service-documents/beechcraft/mtl57-01/file/6e2c28bff3cd ## Text This text is OCR from a scan. OCR can misread letters and numbers. Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 (OCR) Beechcraft Hawker Beechcraft SERVICE LETTER TEXTRON AVIATION MANDATORY MTL-57-01 REVISION TRANSMITTAL This sheet transmits Revision 1 to MTL-57-01, which: Clarifies that Kit 90-4077 only applies to 65-90, 65-A90, 65-A90-1, 65-A90-2, 65-A90-3, 65-A90-4, B90, C90, E90 airplanes. B. Updates Figure 1. NOTE: This revision replaces the original issue of MTL-57-01 in its entirety. REVISION COMPLIANCE NO EFFECT. Airplanes previously modified by this service letter are not effected by this revision. LOG OF REVISIONS Original Issue July 19, 2018 Revision 1 September 19, 2018 Original Issue - July 20, 2018 MTL-57-01 Revision 1 - September 19, 2018 Page 1 of 1 Textron Aviation Customer Service, P.O. Box 7706, Wichita, KS 67277, U.S.A. 1-316-517-5800 COPYRIGHT © 2018 ### Page 2 (OCR) Reechcraft Hawker Beechcraft SERVICE LETTER TEXTRON AVIATION Cessna MANDATORY MTL-57-01 TITLE WINGS - LOWER FORWARD WING BOLT CRUSH WASHER INSPECTION/REPLACEMENT EFFECTIVITY MODEL SERIAL NUMBERS F90 LA-1 thru LA-225 with Kit 101-4024-3 installed H90 (T44A) LL-1 thru LL-61 with Kit 101-4024-3 installed C99 0-50, 0-165 and on, with Kit 101-4024-3 installed 65-90, 65-A90, 65-A90-1, All serials with Kit 90-4077 and Kit 101-4024-3 65-A90-2, 65-A90-3, installed 65-A90-4, B90, C90, E90 99, 99A, 99A (FACH), A99, All serials with Kit 101-4024-3 installed A99A, B99 100, A100 (U-21F), A100A, All serials with Kit 101-4024-3 installed A100C, B100 NOTE: Authorized Service Facilities must remove all 90-380058-1 Washer Assemblies from spares stock. REASON Alternate 90-380058-1 Washer Assembly has been determined to provide premature torque indication. This could lead to cracking of the wing fitting. The washer assembly may have been installed during incorporation of Kit 101-4024-3. DESCRIPTION This service document provides parts and instructions to inspect for the presence of 90-380058-1 Washer Assembly on the left and right lower forward wing bolt. This washer assembly shall be replaced if found to be installed. COMPLIANCE MANDATORY. This service document must be accomplished within 200 flight hours or twelve months from the date of receipt, whichever occurs first. A service document published by Textron Aviation may be recorded as completed in an aircraft log only when the following requirements are satisfied: 1) The mechanic must complete all of the instructions in the service document, including the intent therein. 2) The mechanic must correctly use and install all applicable parts supplied with the service document kit. Only with written authorization from Textron Aviation can substitute parts or rebuilt parts be used to replace new parts. 3) The mechanic or airplane owner must use the technical data in the service document only as approved and published. 4) The mechanic or airplane owner must apply the information in the service document only to aircraft serial numbers identified in the Effectivity section of the document. Original Issue - July 20, 2018 MTL-57-01 Revision 1 - September 19, 2018 Page 1 of 5 Textron Aviation Customer Service, P.O. Box 7706, Wichita, KS 67277, U.S.A. 1-316-517-5800 his document contains technical data and is subject to U.S. export regulations. This information has been exported from the United State n accordance with export administration regulations. Diversion contrary to U.S. law is prohibited. ECCN: 9E99 COPYRIGHT © 2018 ### Page 3 (OCR) Reechcraft Hawker Beechcraft SERVICE LETTER TEXTRON AVIATION Cessna MANDATORY MTL-57-01 5) The mechanic or airplane owner must use maintenance practices that are identified as acceptable standard practices in the aviation industry and governmental regulations. No individual or corporate organization other than Textron Aviation is authorized to make or apply any changes to a Textron Aviation-issued service document or flight manual supplement without prior written consent from Textron Aviation. Textron Aviation is not responsible for the quality of maintenance performed to comply with this document, unless the maintenance is accomplished at a Textron Aviation-owned Service Center. CONSUMABLE MATERIAL You must use the consumable material that follows, or the equivalent, to complete this service document. NAME NUMBER MANUFACTURER USE Corrosion Preventive LPS-3 (equivalent Textron Aviation Parts Distribution To coat bolt and associated Compound (Rust of MIL-C-16173 7121 Southwest Boulevard hardware Inhibitor) Grade 2) Wichita, KS 67215 TOOLING No specialized tooling is required to complete this service document. REFERENCES King Air Structural Inspection and Repair Manual. PUBLICATIONS AFFECTED King Air Illustrated Parts Catalog. ACCOMPLISHMENT INSTRUCTIONS Prepare the airplane for maintenance. A. Make sure that the airplane is electrically grounded. B. Make sure that all switches are in the OFF/NORM position. C. Disconnect electrical power from the airplane. (1) Disconnect external electrical power. (2) Disconnect the airplane battery. D. Attach maintenance warning tags to the battery and external power receptacle that have "DO NOT CONNECT ELECTRICAL POWER - MAINTENANCE IN PROGRESS written on them. NOTE: The following steps apply to the left and right lower forward wing bolts. 2. (Refer to Figure 1, Sheet 1.) Remove applicable access panel and locate the lower forward wing bolt. (Refer to Figure 1, Sheet 1.) Inspect to determine if the washer assembly that is attached to the lower forward wing bolt is dyed green or brown. A. If the washer is dyed green, replacement of the washer is necessary. Go to Step 4. B. If the color of the washer is difficult to determine, replacement of the washer is necessary. Go to Step 4. C. If the washer is dyed brown, no further action is necessary. Go to Step 8. 4. Remove the lower forward wing bolt and washer. Remove the green-dyed washer from the bolt. Inspect the bolt, nut and fitting. (Refer to King Air Structural Inspection and Repair Manual, Chapter 57, Lower Forward Wing Bolt, Nut and Fitting Inspection.) MTL-57-01 Page 2 Revision 1 - September 19, 2018 ### Page 4 (OCR) Beechcraft Hawker: Beechcraft SERVICE LETTER TEXTRON AVIATION Cessna MANDATORY MTL-57-01 (Refer to Figure 1, Sheet 1.) Reinstall the lower forward wing bolt using new 90-380019-1 Washer. (Refer to King Air Structural Inspection and Repair Manual, Chapter 57.) 8. Install the access panel that was removed in Step 2. 9. Remove the maintenance warning tags and connect the airplane battery. 10. Make an entry in the airplane logbook that states compliance and method of compliance with this service document. NOTE: Textron Aviation recommends that compliance with all service documents is reported to Camp Systems International. Complete a record of compliance. (Maintenance Transaction Report, Log Book Entry, or other record of compliance.) Put a copy of the completed record of compliance in the airplane logbook Send a copy of the completed record of compliance to: Camp Systems International Incorporated, 8201 East 34th Street North, Building 1100 Suite 1101 Wichita, KS 67226. MTL-57-01 Revision 1 - September 19, 2018 Page 3 ### Page 5 (OCR) Reechcraft Hawker Beechcraft SERVICE LETTER TEXTRON AVIATION MANDATORY MTL-57-01 E72281 WING FITTING- CENTER SECTION (REFERENCE) WING FITTING LUBRICATION FITTING CRUSH WASHER OUTBOARD (REFERENCE) (REFERENCE) •CAUTION BARREL NUT ASSEMBLY POSITION WITH RADIUS AGAINST RADIUS (REFERENCE) IN WING FITTING BOLT TIGHTENING PROCEDURE: Coat the complete bolt, nut, washer, washer assembly and wing fitting bolt bores with MIL-C-16173, Grade 2 corrosion preventive compound. Tighten the bolt while applying a tangential force of 30t5 pounds to the indicator ring of the preload indicating washer. No further wrenching should be applied to the bolt when 3015 pounds of tangential force will no longer move the indicator ring. - CAUTION After tightening the bolt, inject MIL-C-16173, Grade 2 Corrosion preventive POSITION WITH compound in to the lubrication fitting on the barrel nut. Coat the exposed threads with COUNTERSINK AGAINST MIL-C-16173, Grade 2 corrosion preventive compound. THE BOLT HEAD RADIUS 99-31-59 Figure 1. Lower Forward Wing Bolt Crush Washer Inspection / Replacement (Sheet 1) MTL-57-01 Page 4 Revision 1 - September 19, 2018 ### Page 6 (OCR) Reechcraft Hawker Beechcraft SERVICE LETTER TEXTRON VLATION MANDATORY MTL-57-01 MATERIAL INFORMATION Order the part below to install this modification. NEW P/N QUAN- KEY WORD OLD P/N INSTRUCTIONS/ TITY DISPOSITION 90-380019-1 2 Washer 90-380058 Discard MTL-57-01 Revision 1 - September 19, 2018 Page 5 ### Page 7 (OCR) Beechcraft Hawker Beechcraft OWNER ADVISORY Cessna TEXTRON AVIATION MTL-57-01 TITLE WINGS - LOWER FORWARD WING BOLT CRUSH WASHER INSPECTION/REPLACEMENT TO: Beechcraft King Air and Airliner Aircraft Owner REASON Alternate 90-380058-1 Washer Assembly has been determined to provide premature torque indication. This could lead to cracking of the wing fitting. This washer assembly may have been installed during incorporation of Kit 101-4024-3. COMPLIANCE MANDATORY. This service document must be accomplished within 200 flight hours or twelve months from the date of receipt, whichever occurs first. LABOR HOURS For planning purposes only: WORK PHASE LABOR-HOURS Modification 8 Inspection 2 MATERIAL AVAILABILITY PART NUMBER AVAILABILITY COST 90-380019-1 * * Please contact Textron Aviation Parts Distribution for current cost and availability of parts listed in this service document. Phone at 1-800-835-4000 (Domestic) or 1-316-517-5603 (International). Send email to: parts@txtav.com. Based on availability and lead times, parts may require advanced scheduling. WARRANTY This service document is mandatory. Eligible airplanes may qualify for parts and labor coverage to the extent noted in the Labor Hours and Material Availability sections of this document. MTL-57-01 July 20, 2018 Page 1 of 2 Textron Aviation Customer Service, P.O. Box 7706, Wichita, KS 67277, U.S.A. 1-316-517-5800 This document contains technical data and is subject to U.S. export regulations. This information has been exported from the United States n accordance with export administration regulations. Diversion contrary to U.S. law is prohibited. ECCN: 9E991 COPYRIGHT © 2018 ### Page 8 (OCR) Reechcraft Älewker Beechcraft OWNER ADVISORY TEXTRON AVIATION MTL-57-01 Eligibility: Airplanes identified within the serial number effectivity of this service document must have active Airtrame warranty coverage on the original issue date of this document and the coverage must be active on the day the work is accomplished. Parts Coverage: Textron Aviation-owned and Textron Aviation-authorized Service Facilities, operators, or other maintenance facilities may submit a claim for the parts required to accomplish this service document as defined in the Material Availability section of this document. Labor Coverage: Textron Aviation-owned and Textron Aviation-authorized Service Facilities rated to perform maintenance on the specific model of Beechcraft Aircraft may submit a claim for the labor necessary to accomplish this service document as defined in the Labor Hours section of this document. Credit After this service document has been accomplished, a claim must be submitted to Textron Application: Aviation within 30 days of the service document completion. Claims for compliance of this service document are to be filed as a W4 type claim. Please submit your claim form online at ww2.txtav.com/Parts or email the completed Textron Aviation Claim Form to warranty@txtav.com. If submitted on-line a Return Authorization will be provided. If a paper claim is submitted your claim will be entered into the system and a Return Authorization will be sent to you. The Return Authorization must accompany any required return parts (see Material Availability), to the point of purchase. Parts to be returned to Textron Aviation Parts Distribution should be forwarded to: Textron Aviation Parts Distribution Warranty Administration 285 South Greenwich Road Blag B89, Docks 1-4 Wichita, KS 67206 Expiration: July 20, 2019 (after this date the owner/operator assumes the responsibility for compliance costs) Textron Aviation reserves the right to void continued airplane warranty coverage for the parts affected by this service document until the service document is accomplished. NOTE: As a convenience, service documents are now available online to all our customers through a simple, free-of-charge registration process. If you would like to sign up, please visit the Customer Access link at www.txtavsupport.com to register. MTL-57-01 Page 2 July 20, 2018 --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.