Action
Final rule.
Summary
We are superseding Airworthiness Directive (AD) 88-12-10 for certain Honeywell International Inc. (Honeywell) TPE331 turboprop engines. AD 88-12-10 required reducing the life limit for certain second stage turbine rotors. This AD requires removing certain second stage turbine rotors from service at a reduced life limit. This AD was prompted by report that a TPE331-11U engine experienced an uncontained rotor separation. In addition, cracks were discovered through eddy current inspection (ECI) in the bore of the second stage turbine rotor assembly after publication of AD 88-12-10. We are issuing this AD to address the unsafe condition on these products.