Airworthiness Directive · Amendment 39-17870 · Main rotor gearbox
Agusta S.p.A. (Agusta) Helicopters
This AD applies to Agusta Model AB412 helicopters with a transmission oil outlet hose (hose) part number 70-061L275W210A installed, certificated in any category.
We are adopting a new airworthiness directive (AD) for Agusta Model AB412 helicopters. This AD requires inspecting the main transmission lubricating system oil outlet hose (hose) for damage, and, if required, replacing the hose. This AD is prompted by reports of damage found on the hose. These actions are intended to prevent loss of main gear box (MGB) lubrication, which could lead to failure of the MGB 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.
(1) Within 10 hours time-in-service (TIS), and thereafter at intervals not to exceed 100 hours TIS:
(i) If installed, remove the external cargo suspension hook. In the cargo hook opening, underneath the transmission oil sump, slide the data plate and clear sleeve, if installed, aside and, using a light, inspect the stainless steel hose braiding for damage, fretting, or a broken wire.
(ii) If the stainless steel hose braiding has any damage, fretting, or a broken wire, before further flight, replace the hose.
(2) Within 35 hours TIS, and thereafter at intervals not to exceed 25 hours TIS:
(i) Through the left side pylon door, using a light and a mirror, inspect the stainless steel hose braiding for damage, fretting, or a broken wire.
(ii) If the stainless steel hose braiding has any damage, fretting, or a broken wire, before further flight, replace the hose.
