Airworthiness Directive · Amendment 39-19474 · Turbine section
Honeywell International Inc. Turboprop Engines
This AD applies to Honeywell International Inc. (Honeywell) TPE331-8, -10, -10N, -10R, -10U, -10UA, -10UF, -10UG, -10UGR, -10UR, and -11U turboprop engines with second stage turbine rotor assemblies, part number (P/Ns) 3102106-1, -6, and -8 or P/N 3101514-1, -10 and -12, installed.
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.
(1) Remove from service the applicable second stage turbine rotor assembly, P/Ns 3102106-1, -6 and -8, according to the schedule in Table 1 to Paragraph (g)(1) of this AD:
| Second stage turbine rotor cycles since new (CSN) on the effective date of the AD | Removal schedule |
|---|---|
| 0 to 2,600 | Prior to 3,000 CSN. |
| 2,601 to 3,300 | Within 400 cycles-in-service (CIS) after the effective date of this AD or 3,600 CSN, or at next access, whichever occurs first. |
| 3,301 to 4,000 | Within 200 cycles-in-service after the effective date of this AD or 4,100 CSN, or at next access, whichever occurs first. |
| 4,001 to 4,800 | Within 100 cycles-in-service after the effective date of this AD or 4,800 CSN, or at next access, whichever occurs first. |
(2) Remove from service the applicable second stage turbine rotor assembly, P/Ns 3101514-1, -10 and -12, per the schedule in Table 2 to Paragraph (g)(2) of this AD:
| Second stage turbine rotor CSN on the effective date of the AD | Removal schedule |
|---|---|
| 0 to 2,600 | Prior to 3,000 CSN. |
| 2,601 to 3,200 | Within 400 CIS after the effective date of this AD or 3,600 CSN, or at next access, whichever occurs first. |
| 3,201 to 3,800 | Within 200 CIS after the effective date of this AD or 4,100 CSN, or at next access, whichever occurs first. |
| 3,801 to 4,400 | Within 100 CIS after the effective date of this AD or 4,400 CSN, or at next access, whichever occurs first. |
For the purpose of this AD, “next access” is defined as when the applicable second stage turbine rotor assembly is removed from the engine.
As of the effective date of this AD, do not install second stage turbine rotor assemblies, P/Ns 3102106-1, -6, and -8 and P/Ns 3101514-1, -10, and -12 on any engine.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
