Airworthiness Directive · Amendment 39-17607 · Turbine section
Agusta S.p.A. (Type Certificate Currently Held by AgustaWestland S.p.A) (Agusta) Helicopters
This AD applies to Agusta Model A109A, A109AII, and A109C helicopters with a third stage turbine wheel, part number 23065833, installed, certificated in any category.
We are adopting a new airworthiness directive (AD) for Agusta Model A109A, A109AII, and A109C helicopters with a certain third stage turbine wheel installed. This AD requires installing a placard on the instrument panel and revising the limitations section of the rotorcraft flight manual (RFM). This AD was prompted by several incidents of third stage engine turbine wheel failures, which were caused by excessive vibrations at certain engine speeds during steady-state operations. These actions are intended to alert pilots to avoid certain engine speeds during steady-state operations, prevent failure of the third stage engine turbine, engine power loss, and subsequent loss of control of the helicopter.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
Within 30 days:
(1) For Model A109A helicopters, revise the Power Plant Limitations section, page 1-7, of the Model A109A Rotorcraft Flight Manual (RFM) by inserting page 5 of Agusta Bollettino Tecnico No. 109-129, dated February 16, 2009 (BT 109-129).
(2) For Model A109AII helicopters, revise the Power Plant Limitations section, page 1-6, of the Model A109AII RFM by inserting page 6 of BT 109-129.
(3) For Model A109C helicopters, revise the Power Plant and Transmission Limitations section, page 1-8, of the Model A109C RFM by inserting page 7 of BT 109-129.
(4) Install a placard on the instrument panel adjacent to the Engine and Rotor RPM Power Turbine (N2) Indicator that states: MIN. CONT. 97% N 2 —MIN. TRANS. 95% N 2.
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.
Aircraft
