Airworthiness Directive · Amendment 39-14829 · Turbomeca Turmo IV A and IV C Series Turboshaft Engines
Turbomeca Turmo IV A and IV C Series Turboshaft Engines
Superseded. A later AD replaced this one: AD 2016-05-08. Comply with the one in force.
This AD applies to Turbomeca Turmo IV A and IV C series turboshaft engines. These engines are installed on but not limited to Aerospatiale SA 330—PUMA helicopters.
The FAA is superseding an existing airworthiness directive (AD) for Turbomeca Turmo IV A and IV C series turboshaft engines. That AD currently requires borescope and eddy current inspections or ultrasonic inspections of centrifugal compressor intake wheel blades for cracks and evidence of corrosion pitting, and replacement with serviceable parts. This AD requires the same actions, but would require borescope inspections at more frequent intervals for certain engines. This AD results from Turbomeca's review of the engines' service experience that determined more frequent borescope inspections are required on engines not modified to the TU 191, TU 197, or TU 224 standard. We are issuing this AD to prevent centrifugal compressor intake wheel blade cracks, which can result in engine in-flight power loss, engine shutdown, or forced landing.
You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.
For engines modified to the TU 197 standard, but not to the TU 191 or TU 224 standard, before further flight, remove the TU 197 standard and install the TU 224 standard.
For all engines, borescope-inspect, and either eddy current-inspect (ECI) or ultrasonic-inspect (UI) the centrifugal compressor intake wheel blades using paragraphs 2.B.(1)(a) through 2.B.(1)(g) of Turbomeca Mandatory Service Bulletin A249 72 0100, Update No. 5, dated February 25, 2005, and the criteria in the following Table 1:
| If engine modification level is: | Then borescope-inspect centrifugal compressor intake wheel blades: | Were traces of corrosion found at borescope-inspection? | Then confirm corrosion by performing ECI or UI within: |
|---|---|---|---|
| (1) Pre TU 191 and Pre TU 224 | Within 200 flight hours-since-last inspection | (i) Yes | Six months-or 50 flight hours-since-borescope inspection, whichever occurs first. |
| (ii) No | Two hundred flight hours-since-borescope inspection. | ||
| (2) Post TU 191 or Post TU 224. | Within 1,000 flight hours-since-last inspection | (i) Yes | Six months-or 50 flight hours-since-borescope inspection, whichever occurs first. |
| (ii) No | One thousand flight hours-since-borescope inspection. |
(h) Thereafter, perform repetitive inspections using the criteria in Table 1 of this AD.
(i) Remove centrifugal compressor intake wheel blades confirmed cracked or pitted.
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.
Engines
