Mitsubishi MU-2B Service Letter

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MITSUBISHI HEAVY INDUSTRIES AMERICA INC. MITSUBISHI SERVICE PUBLICATIONS TRANSMITTAL The attached Mitsubishi MU-2B series Service Publication has been issued by Mitsubishi Heavy Industries, Ltd. in Japan, who is the type certificate holder of the MU-2 aircraft. It is the owner and/or operator’s responsibility to adhere to or comply with new information contained in the attached publication. SL 116 SL 089/27-002 FAA SAIB CE-13-27R1 – Flight Control Frayed Cables NOTE THIS PUBLICATION IS PRINTED AND/OR DISTRIBUTED BY MITSUBISHI HEAVY INDUSTRIES AMERICA, INC., UNDER LICENSE FROM MITSUBISHI HEAVY INDUSTRIES LTD. FOR COMMENTS OR INQUIRIES REGARDING DISTRIBUTION OF THIS PUBLICATION OR RECEIPT OF ANY OF THE PUBLICATIONS LISTED HEREIN, PLEASE CONTACT: Mitsubishi Heavy Industries America, Inc. Aircraft Product Support Division 17304 Preston Road, Suite 1270 Dallas, Texas 75252 USA Email: mu-2support@mhia.com MU–2 SERVICE LETTER MITSUBISHI HEAVY INDUSTRIES, LTD. NAGOYA AEROSPACE SYSTEMS WORKS 10 OYE-CHO, MINATO-KU, NAGOYA, JAPAN Page 1 of 2 JCAB T.C.: No. 116 DATE: January 25, 2022 FAA T.C.: No. 089/27-002 SUBJECT: FAA SAIB CE-13-27R1 – Flight Control Frayed Cables MODELS AFFECTED: All MU-2B Airplanes This Mitsubishi Heavy Industries, Ltd. (MHI) Service Letter is issued to ensure that all MU-2 owners and operators have received the Federal Aviation Administration (FAA) Special Airworthiness Information Bulletin, CE-13-27R1, dated January 5, 2022. This SAIB addresses concerns that inadequate inspection of flight control cables may result in undetected wear and/or corrosion that could lead to cable failure. While Mitsubishi MU-2B series aircraft flap systems are driven by torque tubes, all flight control surfaces (elevators, rudders, spoilers, trims) and engine controls are all cable driven. Recommendations from the SAIB include: (a) visual inspection of each flight control cable in accordance with MHI periodic inspection requirements, (b) operation of the flight controls through their full travel, and (c) review AC 43.13-1B, Chapter 7, paragraph 7-149., “Cable System Inspection.” MHI Maintenance Requirements Manual (MRM) requires that all flight control and engine control cables are to be inspected at 600 hours / three-year intervals. In the past, MHI issued Service Letter No. 107 and No. 080/27-001, dated September 30, 2019, along with FAA SAIB CE-19-13, dated July 2, 2019, addressing concerns on cracking and fracturing of flight control cable terminal attachment fittings connected to turnbuckle barrels. MU-2 Service Letter JCAB T.C.: No.116 DATE: January 25, 2022 FAA T.C.: No.089/27-002 Page 2 of 2 If you have any questions or personal experiences of erratic radio altimeter indication, please contact MHIA at: Mitsubishi Heavy Industries America, Inc. Aircraft Product Support Division 17304 Preston Road, Suite 1270, Dallas, Texas 75252 Email: mu-2support@mhia.com | Website: www.mu-2aircraft.com 1 FAA Aviation Safety SPECIAL AIRWORTHINESS INFORMATION BULLETIN SUBJ: TE FLAP CONTROL SYSTEM, Flight Controls – Frayed Flap Extend Cables SAIB: CE-13-27R1 Date: January 5, 2022 This is information only. Recommendations aren’t mandatory. Introduction This Special Airworthiness Information Bulletin (SAIB) is intended to remind owners and operators of any airplane with cable-driven flight controls of the importance of adhering to existing inspection procedures in the applicable maintenance or shop manuals. The FAA is issuing this revision to list additional models with characteristics similar to those originally listed. At this time, the airworthiness concern is not an unsafe condition that would warrant airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR) part 39. Background The FAA recently received a report of a failed flap extend cable. The failure occurred on approach when the flaps were deployed to 45 degrees. The sudden retraction of the right flap caused the airplane to roll about 80 degrees to the right. The pilot was unable to retract the left flap, but was able to maintain control with the assistance of a passenger, divert to another airport, and land safely by utilizing almost full left aileron control. The report stated the cable was original (over 4,800 flight hours), and the most recent 100-hour inspection had been completed approximately 10 flight hours prior to cable failure. A search of the FAA’s service difficulty report (SDR) system revealed numerous events of a similar nature over a 20 year period. Most reports of fraying occurred near pulleys, and some included comments such as “failure occurred behind a pulley and is not easily inspected without the use of a mirror.” If the cable is not properly inspected, it can appear to be acceptable when it really is not. This SAIB focuses on the condition of the flap extend cables as they route around pulleys on all Textron Aviation, Inc. (formerly Cessna) 310, 310A, 310B, 310C, 310D, 310E, 310F, 310G, 310H, 310I, 310J, 310J-1, 310K, 310L, 310N, 310P, 310Q, 310R, 320, 320-1, 320A, 320B, 320C, 320D, 320E, 320F, 321, 335, 336, 337, 337A, 337B, 337C, 337D, 337E, 337F, 337G, 337H, 340, 340A, 401, 401A, 401B, 402, 402A, 402B, 402C, 411, 411A, 414, 414A, 421, 421A, 421B, 421C, and 425 airplanes. However, it also applies to the entire flight control system on any airplane model with cable-driven flight controls. Inadequate inspection of the flight control cables may result in undetected wear and/or corrosion that could lead to cable failure. Recommendations The FAA recommends the following: 1. Follow the existing maintenance manual instructions and inspection intervals. For the Textron Aviation airplanes listed above, this typically is a visual inspection of each flight control cable every 200 hours or 12 months, and an expanded inspection of each flight control cable every 2 600 hours. These intervals may vary slightly depending on model and use of the airplane, so