# AD 73-21-01: Flight Control Landing Gear Systems - Type: Airworthiness directive - Status: Current - Products: Mooney M20, M20A, M20B, M20C, M20D, M20E, M20F and M20G - Effective: October 10, 1973 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-1729 - Registered aircraft: 3,214 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/022EF974FDE32DBA86256A3B006FA1EA.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/73-21-01 ## The airworthiness directive 73-21-01 MOONEY: Amdt. 39-1729. Applies to Mooney Models M20, M20A, M20B, M20C, M20D, M20E, M20F and M20G airplanes. Compliance required as indicated. To prevent corrosion and/or misrigging in the flight control and landing gear systems which may result in binding or seizure of the joints and loss of flight control or collapse of the landing gear, accomplish the following: (a) Within 25 hours time in service after July 10, 1972, unless already accomplished within the last 25 hours time in service, and thereafter at intervals not to exceed 12 calendar months from the last inspection or 100 hours time in service from the last inspection, whichever comes first, lubricate all flight control systems and landing gear system rod end bearings with a silicone spray lubricant or with an FAA approved equivalent lubricant. (b) Within the next 50 hours time in service after July 10, 1972, unless already accomplished, install retracting links, P/N 530003-13 (1 ea.) and 510011-13 (2 ea.) on all M20B, C, E, F, and G aircraft and on M20D models converted to a retractable gear, or equivalent parts approved by the Chief, Engineering and Manufacturing Branch, Flight Standards Division, Southwest Region, FAA, Fort Worth, Texas. The new links incorporate grease fittings and improved overcenter travel resulting in lower preload rigging. New links are not required if the existing installations use -13 links which have grease fittings. (Reference Mooney Service Bulletin M20-155 dated 6-15-67, or later FAA approved revision.) AD 73-21-01 NOTE: For M20 and M20A models the present retract links are to be modified by the addition of grease fittings as shown in figures 1 and 2 attached. Follow procedures in Mooney M20/M20A Service and Maintenance Manual or other FAA approved procedure, for removal and replacement of links. Service Bulletins, Service Letters and Service Instructions referenced in this AD may be obtained from Mooney Aircraft, Louis Schreiner Field, Kerrville, Texas. (c) At the next lubrication as required in (a) and thereafter at the same interval as specified in (a), perform a landing gear retraction test and check the landing gear rigging. Information regarding rigging and torque preload may be found in Mooney Service Bulletin No. M20-35A dated 7-11-60 for Models M20 and M20A, Mooney Service Instruction No. M20-32 dated 11-3-72 for other models or later FAA approved revisions. Special tools supplied by Mooney Aircraft as noted in the reference documents or FAA approved equivalent tools are required for proper preload rigging. This supersedes Amendment 39-1455 (37 F.R. 11462), AD 72-12-02 as amended by Amendment 39-1482 (37 F.R. 13336). This amendment becomes effective October 10, 1973. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS 2A3](https://openairdocs.org/tcds/2A3): Mooney International Corporation; names 8 of 17 models: M20F, M20E, M20D, M20A, M20B, M20C, M20, M20G ## 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: 3,214 (3,214 by airframe model, 0 by engine model) - Makers: Mooney 3,191, Aerostar Acft Corp Of Texas 23 Models with the most aircraft: - [Mooney M20C](https://openairdocs.org/model/mooney-m20c): 1,258 aircraft (airframe model) - [Mooney M20E](https://openairdocs.org/model/mooney-m20e): 829 aircraft (airframe model) - [Mooney M20F](https://openairdocs.org/model/mooney-m20f): 721 aircraft (airframe model) - [Mooney M-20G](https://openairdocs.org/model/mooney-m-20g): 116 aircraft (airframe model) - [Mooney M20B](https://openairdocs.org/model/mooney-m20b): 98 aircraft (airframe model) - [Mooney M20D](https://openairdocs.org/model/mooney-m20d): 88 aircraft (airframe model) - [Mooney M20A](https://openairdocs.org/model/mooney-m20a): 58 aircraft (airframe model) - [Mooney M20](https://openairdocs.org/model/mooney-m20): 23 aircraft (airframe model) - [Aerostar Acft Corp Of Texas M20E](https://openairdocs.org/model/aerostar-acft-corp-of-texas-m20e): 9 aircraft (airframe model) - [Aerostar Acft Corp Of Texas M20F](https://openairdocs.org/model/aerostar-acft-corp-of-texas-m20f): 8 aircraft (airframe model) - [Aerostar Acft Corp Of Texas M20C](https://openairdocs.org/model/aerostar-acft-corp-of-texas-m20c): 6 aircraft (airframe model) All 11 models: https://openairdocs.org/ad/73-21-01/models.md Every aircraft: https://openairdocs.org/ad/73-21-01/aircraft.md Its text cites no advisory circulars or STCs. ## NTSB investigations that cite this AD (4) 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 LAX06LA298](https://openairdocs.org/ntsb/LAX06LA298), Sep 20, 2006: Mooney M20C (N5577Q), Auburn, CA, substantial damage. Probable cause: the fatigue failure of the elevator's control rod due to inadequate lubrication. Contributing factors were the inadequate maintenance and the owner-pilot's failure to comply with an airworthiness… - [NTSB SEA95LA058](https://openairdocs.org/ntsb/SEA95LA058), Mar 3, 1995: Mooney M20C (N7836V), Omak, WA, substantial damage. Probable cause: THE ELEVATOR PUSH ROD SEPARATION DUE TO FATIGUE. FACTORS CONTRIBUTING TO THE ACCIDENT WERE THE PILOT IN COMMAND'S FAILURE TO INSURE COMPLIANCE WITH THE AIRWORTHINESS DIRECTIVE AND THE FROZEN PUSH ROD… - [NTSB CHI90LA238](https://openairdocs.org/ntsb/CHI90LA238), Aug 18, 1990: Mooney M20B (N74745), Winfield, KS, substantial damage. Probable cause: NON-COMPLIANCE OF AN AIRWORTHINESS DIRECTIVE BY MAINTENANCE PERSONNEL. - [NTSB LAX86LA147](https://openairdocs.org/ntsb/LAX86LA147), Mar 19, 1986: Mooney M20F (N9591M), Burbank, CA, substantial damage --- 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.