# AD 75-16-20: Propeller Pitch Control Lever - Type: Airworthiness directive - Status: Historical - Products: Mitsubishi Heavy Industries MU-2B, MU-2B-10, MU-2B-15, MU-2B-20, MU-2B-25, MU-2B-26, MU-2B-30, MU-2B-35 and MU-2B-36 - Effective: August 12, 1975 - Superseded by: [AD 2020-26-14](https://openairdocs.org/ad/2020-26-14) - Product type: Aircraft, Small airplane - Amendment: 39-2294 - Registered aircraft: 63 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/33716049B14FD4FA86256A3A007057A9.0001 - DRS record last changed: August 7, 2025 - Page: https://openairdocs.org/ad/75-16-20 ## The airworthiness directive 75-16-20 MITSUBISHI HEAVY INDUSTRIES, LIMITED: Amendment 39-2294. Applies to Mitsubishi Model MU-2B, MU-2B-10, MU-2B-15, MU-2B-20, MU-2B-25, MU-2B- 26, MU-2B-30, MU-2B-35, and MU-2B-36 airplanes certificated in all categories. Compliance is required within the next 25 hours time in service after the effective date of this AD, unless already accomplished within the last 75 hours time in service, and thereafter at intervals not to exceed 100 hours time in service from the last inspection. To prevent possible separation of the control lever on the engine propeller pitch control unit, inspect the propeller pitch control lever, Mitsubishi P/N 022A-43111, P/N 022A-43111-3, or P/N 867304-1 in accordance with paragraph (a) or (b) of this AD, as applicable. (a) For airplanes with AN3H5A bolt or MS24673-3 bolt installed in a threaded propeller pitch control lever, accomplish the following: (1) Remove safety wire and loosen bolt. (2) Ensure that the propeller pitch control leveris mounted securely on the shaft. (3) Retorque the AN 3H5A bolt to 20-25 inch pounds or the MS24673-3 bolt to 25-30 inch pounds, as applicable, and install safety wire. (4) Ensure that the power management system is properly rigged in accordance with Section VI of the Garrett-Airesearch Turboprop Engine Series 331 Maintenance Manual or an FAA-approved equivalent. (b) For airplanes with AN3-6A bolt and NAS679C3W nut installed in an unthreaded propeller pitch control lever, accomplish the following: (1) Loosen the AN3-6A bolt. (2) Ensure that the propeller pitch control lever is mounted securely on the shaft. (3) Retorque the AN3-6A bolt to 20-25 inch pounds. (4) Ensure that the power management system is properly rigged in accordance with Section VI of the Garrett-Airesearch Turboprop Engine Series 331 Maintenance Manual or an FAA-approved equivalent. (Mitsubishi MU-2 Service Bulletin No. 168, dated April 18, 1975, refers to this same subject). This amendment becomes effective August 12, 1975. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A2PC](https://openairdocs.org/tcds/A2PC): Mitsubishi Heavy Industries Ltd. 203; names 5 of 7 models: MU-2B, MU-2B-30, MU-2B-20, MU-2B-35, MU-2B-36 ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 63 (63 by airframe model, 0 by engine model) - Makers: Mitsubishi 63 Models with the most aircraft: - [Mitsubishi MU-2B-25](https://openairdocs.org/model/mitsubishi-mu-2b-25): 23 aircraft (airframe model) - [Mitsubishi MU-2B-26](https://openairdocs.org/model/mitsubishi-mu-2b-26): 16 aircraft (airframe model) - [Mitsubishi MU-2B-20](https://openairdocs.org/model/mitsubishi-mu-2b-20): 12 aircraft (airframe model) - [Mitsubishi MU-2B-36](https://openairdocs.org/model/mitsubishi-mu-2b-36): 7 aircraft (airframe model) - [Mitsubishi MU-2B-35](https://openairdocs.org/model/mitsubishi-mu-2b-35): 4 aircraft (airframe model) - [Mitsubishi MU-2B](https://openairdocs.org/model/mitsubishi-mu-2b): 1 aircraft (airframe model) All 6 models: https://openairdocs.org/ad/75-16-20/models.md Every aircraft: https://openairdocs.org/ad/75-16-20/aircraft.md ## Related documents - [AD 2020-26-14](https://openairdocs.org/ad/2020-26-14): Propellers ยท Mitsubishi Heavy Industries MU-2B, MU-2B-10, MU-2B-15 and 10 more. Effective Feb 2, 2021. Supersedes this AD Its text cites no advisory circulars or STCs. ## NTSB investigations that cite this AD (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB CEN21LA237](https://openairdocs.org/ntsb/CEN21LA237), May 27, 2021: Grumman G164 (N8376K), Celina, OH, substantial damage. Probable cause: A loss of engine power for undetermined reasons. --- 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.