# AD 59-25-05: Rudder reinforcement - Type: Airworthiness directive - Status: Current - Products: Univair 415-C, 415-CD, 415-D, F-1, 415-E and 415-G - Published: December 10, 1959 - Issued: December 3, 1959 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Registered aircraft: 1,087 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BBE33897416DD8A086256A4D00677618.0001 - DRS record last changed: November 21, 2025 - Page: https://openairdocs.org/ad/59-25-05 ## The airworthiness directive 59-25-05 FORNEY (ERCOUPE): Applies to All (Ercoupe) Forney Aircraft With Serial Numbers Up to 3,335 Inclusive. Compliance required by December 31, 1959, and thereafter every 100 hours of operation or periodic inspection, whichever occurs first. Fatigue failures have continued to occur in the rudder main rib where the control horn is attached after installation of reinforcement plates. Therefore, it is required that a visual inspection be made of the area around the rudder control horn for excessive deflection of the horn, canning of rudder skin, or any other unusual peculiarity which would indicate main rudder rib damage. If damage is evident, rudder rib Erco P/N 415-240 12 L/R must be replaced with Forney P/N F-24015 L/R or equivalent. This inspection may be discontinued when the heavier gage rib is installed. (Forney Service Bulletin No. 105 covers this subject.) This supersedes AD 47-20-07. ## Affected data sheets (2) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A-787](https://openairdocs.org/tcds/A-787): Univair Aircraft Corporation; names 4 of 8 models: F-1, 415-D, 415-G, 415-E - [TCDS A-718](https://openairdocs.org/tcds/A-718): Univair Aircraft Corporation; names 2 of 2 models: 415-CD, 415-C ## 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: 1,087 (1,087 by airframe model, 0 by engine model) - Makers: Ercoupe 793, Engineering & Research 210, Forney 71, Erco 12, Univair 1 Models with the most aircraft: - [Ercoupe 415-C](https://openairdocs.org/model/ercoupe-415-c): 623 aircraft (airframe model) - [Engineering & Research 415-C](https://openairdocs.org/model/engineering-research-415-c): 160 aircraft (airframe model) - [Ercoupe 415-D](https://openairdocs.org/model/ercoupe-415-d): 101 aircraft (airframe model) - [Forney F-1](https://openairdocs.org/model/forney-f-1): 50 aircraft (airframe model) - [Ercoupe 415-CD](https://openairdocs.org/model/ercoupe-415-cd): 48 aircraft (airframe model) - [Engineering & Research 415-D](https://openairdocs.org/model/engineering-research-415-d): 24 aircraft (airframe model) - [Ercoupe 415-E](https://openairdocs.org/model/ercoupe-415-e): 18 aircraft (airframe model) - [Forney 415-C](https://openairdocs.org/model/forney-415-c): 17 aircraft (airframe model) - [Engineering & Research 415-CD](https://openairdocs.org/model/engineering-research-415-cd): 16 aircraft (airframe model) - [Engineering & Research 415-E](https://openairdocs.org/model/engineering-research-415-e): 7 aircraft (airframe model) - [Erco 415-C](https://openairdocs.org/model/erco-415-c): 7 aircraft (airframe model) - [Erco 415-D](https://openairdocs.org/model/erco-415-d): 4 aircraft (airframe model) - [Engineering & Research 415-G](https://openairdocs.org/model/engineering-research-415-g): 3 aircraft (airframe model) - [Ercoupe 415-G](https://openairdocs.org/model/ercoupe-415-g): 3 aircraft (airframe model) - [Forney 415-D](https://openairdocs.org/model/forney-415-d): 2 aircraft (airframe model) - [Forney 415-CD](https://openairdocs.org/model/forney-415-cd): 1 aircraft (airframe model) - [Forney 415-E](https://openairdocs.org/model/forney-415-e): 1 aircraft (airframe model) - [Erco 415-CD](https://openairdocs.org/model/erco-415-cd): 1 aircraft (airframe model) - [Univair 415-D](https://openairdocs.org/model/univair-415-d): 1 aircraft (airframe model) All 19 models: https://openairdocs.org/ad/59-25-05/models.md Every aircraft: https://openairdocs.org/ad/59-25-05/aircraft.md Its text cites no advisory circulars or STCs. ## NTSB investigations that cite this AD (2) 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 CEN09LA291](https://openairdocs.org/ntsb/CEN09LA291), May 12, 2009: Univair Ercoupe (N99811), Brighton, MI, substantial damage. Probable cause: The pilot's failure to attain the proper touchdown point, and his failure to initiate a go-around. - [NTSB LAX04FA150](https://openairdocs.org/ntsb/LAX04FA150), Mar 9, 2004: Ercoupe 415-C (N93707), Oakdale, CA, destroyed, 2 fatal. Probable cause: the in-flight separation of the main spar due to corrosion in the wing center section not detectable by inspection methods described in manufacturer's service bulletins and FAA Airworthiness… --- 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.