AD 2021-16-12 Amendment 39-21674

The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Canada Limited Model 505 helicopters. This AD was prompted by three occurrences of metallic debris in the engine oil lubrication system causing the 12 volts direct current (VDC) reference voltage to be shorted to ground and loss of important flight information to the pilot. This AD requires replacing a certain part- numbered relay panel assembly. The FAA is issuing this AD to address the unsafe condition on these products.