Airworthiness Directive · Amendment 39-14034 · Rolls-Royce (1971) Limited, Bristol Engine Division Model Viper Mk.601-22 Turbojet Engines
Rolls-Royce (1971) Limited, Bristol Engine Division Model Viper Mk.601-22 Turbojet Engines
This AD applies to Rolls-Royce (1971) Limited, Bristol Engine Division (RR) Model Viper Mk.601-22 turbojet engines. These engines are installed on, but not limited to, Raytheon HS.125 Series 600 and BH.125 Series 600 airplanes.
The FAA is superseding an existing airworthiness directive (AD) for Rolls-Royce (1971) Limited, Bristol Engine Division (RR) model Viper Mk.601-22 turbojet engines. That AD currently requires reducing the life of certain 1st stage turbine rotor blades from 7,000 hours time-in-service (TIS) to 4,600 hours TIS, and provides a drawdown schedule for blades that have already exceeded the new reduced life limit. This AD requires the same actions but changes certain compliance times to be in agreement with RR Alert Service Bulletin (ASB) No. 72- A184, dated January 2001. This AD results from comments received on AD 2004-13-03, that the AD is unnecessarily more restrictive than the requirements in the associated RR ASB No. 72-A184. We are issuing this AD to prevent multiple failures of 1st stage turbine rotor blades that could result in a dual-engine shutdown.
You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.
Change the RR Time Limits Manual life limit for the 1st stage turbine rotor blades, part numbers (P/Ns) V926000, V926293, and V926319, from 7,000 hours time-in-service (TIS) to 4,600 hours TIS.
(g) Limit the number of installed engines with 1st stage turbine rotor blades that exceed 4,600 hours TIS on the effective date of this AD as specified in the following Table 1:
| On the effective date of this AD, if: | Then: |
|---|---|
| (1) Both engines installed on the airplane have 1st stage turbine rotor blades that exceed 5,800 hours TIS | Replace the 1st stage turbine rotor blades in the engine that has the higher blade life within 50 hours TIS or 6 weeks after the effective date of this AD, whichever occurs first. |
| (2) One engine installed on the airplane has 1st stage turbine rotor blades that exceed 5,800 hours TIS, and the other engine has 1st stage turbine rotor blades that exceed 4,600 hours TIS | Replace the 1st stage turbine rotor blades in the engine that has the higher blade life within 100 hours TIS or 4 months after the effective date of this AD, whichever occurs first. |
| (3) One engine installed on the airplane has 1st stage turbine rotor blades that exceed 5,800 hours TIS, and the other engine has 1st stage turbine rotor blades with fewer than 4,600 hours TIS | Replace the 1st stage turbine rotor blades in the engine that has the higher blade life within 200 hours TIS or 6 months after the effective date of this AD, whichever occurs first. |
| (4) One engine installed on the airplane has 1st stage turbine rotor blades that exceed 4,600 hours TIS, but have fewer than 5,800 hours TIS, and the other engine has 1st stage turbine rotor blades with fewer than 4,600 hours TIS | Replace the 1st stage turbine rotor blades in the engine that has the higher blade life at 5,800 hours TIS or 6 months after the effective date of this AD, whichever occurs later. |
(h) No engine may operate with a blade life exceeding 5,800 hours TIS, applicable beginning 6 months from the effective date of this AD.
(i) No engine may operate with a blade life exceeding 4,600 hours TIS, applicable beginning 3 years from the effective date of this AD.
After the effective date of this AD, do not install any engine that has 1st stage turbine rotor blades, P/Ns V926000, V926293, or V926319, that exceed 4,600 hours TIS, except as allowed in Table 1 of this AD.
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
