Airworthiness Directive · Amendment 39-17734 · Main rotor mast/swashplate
Agusta S.p.A. Helicopters
This AD applies to Agusta S.p.A. Model AB412 helicopters with a swashplate outer ring part number (P/N) 412-010-407-105 installed, certificated in any category.
We are adopting a new airworthiness directive (AD) for Agusta S.p.A. (Agusta) Model AB412 helicopters. This AD requires visually inspecting the main rotor swashplate outer ring (outer ring) for a crack and replacing that outer ring if a crack exists. This AD is prompted by two cases of cracks caused by fatigue on certain outer rings. These actions are intended to prevent the failure of the outer ring, which would lead to loss of main rotor blade pitch control and subsequently loss of helicopter control.
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.
(1) Within 5 hours time in service (TIS), and thereafter at intervals not to exceed 25 hours TIS, visually inspect the swashplate outer ring, P/N 412-010-407-105, for a crack, using a 5X or higher power magnifying glass and a bright light and referring to Figures 1 and 2 in AgustaWestland S.p.A. Alert Bollettino Tecnico No. 412-134, dated July 15, 2013. If a crack exists, before further flight, remove the swashplate outer ring from service.
(2) Within 300 hours TIS or 8 months, whichever occurs first, remove the swashplate outer ring, P/N 412-010-407-105, from service.
(3) Do not install a swashplate outer ring, P/N 412-010-407-105, on any helicopter.
