Superseded. This AD was superseded by AD 2021-11-01. Verify which one applies to your serial and effectivity before any maintenance action.
AD 2013-20-13
Effective 12/10/2013 · Published 11/05/2013
Airworthiness Directives; Bell Helicopter Textron Canada Limited (Bell) Helicopters
Summary
We are adopting a new airworthiness directive (AD) for certain Bell Model 206B and 206L helicopters. This AD requires installing a placard beneath the engine power dual tachometer and revising the operating 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 speed…