Airworthiness Directive · Amendment 39-15616 · Bell Helicopter Textron Canada (BHTC) Model 430 Helicopters
Bell Helicopter Textron Canada (BHTC) Model 430 Helicopters
This AD applies to Model 430 helicopters, serial numbers 49001 through 49122, certificated in any category.
We are adopting a new airworthiness directive (AD) for BHTC Model 430 helicopters. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The aviation authority of Canada, with which we have a bilateral agreement, states in the MCAI: "It has been determined that the existing rigging procedures for the tail rotor pitch change mechanism have to be changed due to possibility of parts interference." The cumulative effect of individual part tolerances resulting in the total assemblage of those parts being out of tolerance could result in the tail rotor yoke striking another part other than the flapping stop (parts interference) cited in the MCAI. Also, the misalignment of the tail rotor counterweight bellcrank may result in higher tail rotor pedal forces and a higher pilot workload after failure of the <greek-i>1 hydraulic system. Both parts interference and the misaligned counterweight bellcrank create an unsafe condition. This AD require actions that are intended to address these unsafe conditions.
Within the next 150 hours time-in-service (TIS) or at the next annual inspection, whichever occurs first, unless already accomplished, do the following:
(1) Adjust the rigging of the tail rotor pitch change mechanism in accordance with the Accomplishment Instructions, paragraphs 1 and 2, in Bell Helicopter Textron Alert Service Bulletin 430-07-39, dated January 9, 2007 (ASB).
(2) If either at full left pedal position or full right pedal position a gap exists between the tail rotor yoke and the flapping stop, replace the tail rotor yoke with an airworthy tail rotor yoke.
(3) If no gap exists between the tail rotor yoke and the flapping stop at either full right or full left pedal position, measure the gap between the tail rotor yoke and nut, P/N 222-012-731-001, adjust the tail rotor pitch change mechanism, and adjust the tail rotor pedal forces in accordance with the Accomplishment Instruction, paragraphs 4 through 6 of the ASB.
This AD differs from the MCAI in that it requires compliance within the next 150 hours TIS or at the next annual inspection, whichever occurs first, instead of “at the next 150 hour or annual inspection, but no later than 31 December 2007.”
Alternative Methods of Compliance (AMOCs): The Manager, Safety Management Group, FAA, ATTN: Tyrone Millard, Aviation Safety Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, Fort Worth, Texas 76193-0111, telephone (817) 222-5439, fax (817) 222-5961 has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
