Airworthiness Directive · Amendment 39-11858 · Bell Helicopter Textron Canada (BHTC) Model 430 Helicopters
Bell Helicopter Textron Canada (BHTC) Model 430 Helicopters
Model 430 helicopters, certificated in any category.
Note 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment supersedes an existing airworthiness directive (AD) for BHTC Model 430 helicopters. That AD currently requires inspecting all four main rotor adapter assemblies for evidence of flapping and lead-lag contact. That AD also requires installing a never-exceed-velocity (VNE) placard with markings on the airspeed indicator glass and instrument case and revising the rotorcraft flight manual (RFM) to reflect the airspeed revision. This amendment provides mandatory terminating action for requirements of that AD by replacing the fluidlastic damper blade sets with improved sets that incorporate a pressure indicator to detect loss of damper fluid. This amendment is prompted by the need for a positive means of detecting loss of damper fluid that could result in main rotor tip path plane separation. The actions specified by this AD are intended to prevent increased vibrations, damage to the main rotor system, and subsequent loss of control of the helicopter.
To prevent tip path plane separation, increased vibrations, damage to the main rotor system, and subsequent loss of control of the helicopter, accomplish the following:
(a) Before further flight:
(1) Inspect all four main rotor adapter assemblies for flapping contact between the adapter liners and the upper stop assembly plugs. Refer to Figures 1, 2, and 3 of the Accomplishment Instructions of Bell Helicopter Textron Canada (BHTC) Alert Service Bulletin (ASB) No. 430-97-2, dated July 11, 1997. Flapping contact is indicated by the scrubbing (or smudging) of the adapter liner surface, characteristic of relative motion between the surfaces of the adapter lines and upper stop assembly plugs.
(2) Inspect all four main rotor adapter assemblies for lead-lag contact between the adapter pads and the yoke assembly. Refer to Figures 1 and 2 of the Accomplishment Instructions of BHTC ASB No. 430-97-2, dated July 11, 1997. Lead-lag contact is indicated by a permanent indentation or split in the surface of the adapter pads.
(3) If the inspections in paragraphs (a)(1) or (a)(2) of this AD reveal that there has been contact, inspect and replace the main rotor yoke and stop assemblies in accordance with Part I, No. 3 of the Accomplishment Instructions of BHTC ASB No. 430-97-2, dated July 11, 1997, except return of any damaged upper stops to the manufacturer is not required.
(4) For helicopters with skid landing gear or retractable landing gear, remove the existing never-exceed-velocity (VNE) placard from the overhead console and install VNE placard, P/N 430-075-208-107, or P/N 430-075-208-109, as applicable, in accordance with Part II, of the Accomplishment Instructions of BHTC ASB No. 430-97-2, dated July 11, 1997.
(5) Install on each airspeed indicator a red arc between 120 knots and 150 knots to indicate that airspeeds above 120 knots indicated airspeed are prohibited. Install a slippage mark on each airspeed indicator glass and instrument case.
(6) Insert the temporary revisions, BHT-430-FM-1 and BHT-430-FMS-1, as appropriate, both dated July 7, 1997, into the rotorcraft flight manual.
(b) Within 100 hours time-in-service,
(1) Remove the fluidlastic damper blade set, P/N 430-310-100-101 or 430-310-107-101 in accordance with the Accomplishment Instructions of ASB 430-97-4, dated December 19, 1997, Part 1, steps 1 through 5, and install damper blade set, P/N 430-310-104-105, in accordance with the Accomplishment Instructions, Part I, of BHTC ASB 430-98-8, dated December 31, 1998.
(2) Return pilot and copilot airspeed indicators to their original configuration by removing the markings specified by paragraph (a)(5) of this AD.
(3) Remove the temporary revisions, BHT 430-FM-1 or BHT-430-FMS-1, as appropriate, both dated July 7, 1997. Insert the temporary revisions, BHT-430-FM-1, or BHT-430-FMS-1, as appropriate, both dated December 11, 1998, into the rotorcraft flight manual.
(c) If paragraph (b)(1) was previously accomplished by installation of fluidlastic damper blade set, P/N 430-310-104-103, remove fluidlastic damper blade set, P/N 430-310-104-103, and install fluidlastic damper blade set, P/N 430-310-104-105, in accordance with the Accomplishment Instructions of BHTC ASB 430-98-8, dated December 31, 1998.
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.
