# AD 81-02-04: Main Blade Pitch Control - Type: Airworthiness directive - Status: Current - Products: Agusta A109, A109A and A109A II - Effective: January 5, 1981 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Rotorcraft - Amendment: 39-4014 - Registered aircraft: 26 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/C14B6CA07767EE3D86256A4E005116C2.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/81-02-04 ## The airworthiness directive 81-02-04 COSTRUZIONI AERONAUTICHE GIOVANNI AGUSTA (CAGA): Amendment 39-4014. Applies to Models A109 and A109A series helicopters, certificated in all categories. Compliance required as indicated, unless already accomplished. To prevent loss of the main rotor blade pitch control, accomplish the following: (a) Before further flight, hand correct the CAGA manuals referenced in paragraphs (a)(1) and (a)(2) by changing the torque value from "500 to 560 Kg, 434 to 486 inch/pound" to "311 to 345 Kg, 275 to 300 inch/pound." (1) CAGA A109/A109A overhaul manual (all change dates), Chapter 65-10- 01, page 240, paragraph 8, subparagraph (e); (2) CAGA A109/A109A maintenance manual (all change dates), Chapter 65-10-03, page 201, paragraph 3; and (3) Retain the hand corrected pages in both manuals until revised replacement pages are available from CAGA. (b) Within the next 25 hours time in service after the effective date of this AD - (1) Remove the mainrotor pitch horn trunion assembly; (2) Permanently remove from service, nut P/N MS 17825-7, and replace with a new nut of the same part number; and (3) Using a 5X magnifying glass, visually inspect the threaded area of P/N 109-0101-09-1, for deformation, distortion, or damage. (c) If as a result of the inspection of the trunion assembly required in paragraph (b)(3) of this AD, no deformation, distortion, damage, or defect is found. (1) Reinstall the main rotor pitch horn trunion assembly in accordance with CAGA A109/A109A overhaul manual, chapter 65.10.01, or an FAA-approved equivalent, using the torque values listed in paragraph (a) of this AD; or (2) Reinstall the main rotor pitch horn trunnion assembly in accordance with CAGA A109/A109A maintenance manual, or an FAA-approved equivalent, using the revised torque values listed in paragraph (a) of this AD; (3) During reinstallation of the main rotor pitch horn trunion assembly, check to insure that there is 0.10 to 0.20 millimeter play between the trunion shoulder and the bearing inner race; and (4) Return the serviceable trunion assembly to service. (d) If as a result of the inspection of the trunion assembly required in paragraph (b)(3) of this AD, deformation, distortion, damage, or defect indicating overtorque is found - (1) Remove the trunion assembly from service; (2) Replace with a new or serviceable trunion assembly of the same part number; and (3) Reinstall the main rotor pitch horn trunion assembly and torque in accordance with paragraph (c)(1) or (c)(2) of this AD. (e) Report defects found to the Chief, Aircraft Certification Staff, Europe, Africa and Middle East Office, c/o American Embassy, Brussels, Belgium. (Reporting approved by the Office of Management and Budget under OMB No. 04-R0174.) (f) If an equivalent means of compliance is used in complying with this AD, that equivalent must be approved by the Chief, Aircraft Certification Staff, AEU-100, Europe, Africa, and Middle East Office, FAA, c/o American Embassy, Brussels, Belgium. NOTE: Costruzioni Aeronautiche Giovanni Agusta Service Engineering Department messages LD/7/1815 and LD/7/1845, both dated April 22, 1980, refer to this subject. This amendment becomes effective January 5, 1981, as to all persons except those persons to whom it was made immediately effective by telegraphic AD T80EU-22, issued May 1, 1980, which contained this amendment. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS H7EU](https://openairdocs.org/tcds/H7EU): Leonardo S.p.A.; names 3 of 10 models: A109, A109A, A109A II ## 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: 26 (26 by airframe model, 0 by engine model) - Makers: Agusta 25, Agusta-Bell 1 Models with the most aircraft: - [Agusta A109A II](https://openairdocs.org/model/agusta-a109a-ii): 17 aircraft (airframe model) - [Agusta A109A](https://openairdocs.org/model/agusta-a109a): 5 aircraft (airframe model) - [Agusta AGUSTA A109](https://openairdocs.org/model/agusta-agusta-a109): 3 aircraft (airframe model) - [Agusta-Bell A 109A](https://openairdocs.org/model/agusta-bell-a-109a): 1 aircraft (airframe model) All 4 models: https://openairdocs.org/ad/81-02-04/models.md Every aircraft: https://openairdocs.org/ad/81-02-04/aircraft.md Its text cites no advisory circulars or STCs. --- 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.