Federal Register of Legislation - Australian Government

Primary content

AD/VIPER/4 Amdt 1 Blow-Off Valve

Authoritative Version
AD/VIPER/4 Airworthiness Directives as made
This instrument repeals and replaces AD/VIPER/4 - Blow-Off Valve and removes references to legislative instruments no longer in force.
Administered by: Infrastructure, Transport, Regional Development and Communications
Exempt from sunsetting by the Legislation (Exemptions and Other Matters) Regulation 2015 s12 item 15
Registered 06 Oct 2021
Tabling HistoryDate
Tabled HR18-Oct-2021
Tabled Senate18-Oct-2021
To be repealed 30 Mar 2022
Repealed by Division 1 of Part 3 of Chapter 3 of the Legislation Act 2003


On the commencement date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below repeals Airworthiness Directive (AD) AD/VIPER/4 and issues the following AD under subregulation 39.001 (1) of CASR and subsection 33 (3) of the Acts Interpretation Act 1901. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct an unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Rolls Royce Deutschland Turbine Engines - Viper Series

AD/VIPER/4 Amdt 1

Blow-Off Valve




Rolls Royce Deutschland Viper Mk.521 and Mk.522 turbine engines.


Action in accordance with Rolls Royce Service Bulletin (SB) No. 75-31, as in force from time to time.

Note:  The words “as in force from time to time” require compliance with the most recent version of the referenced document.


At intervals not to exceed 300 flight hours from the commencement date of this AD.


This AD commences on 8 October 2021.


This Directive was originally issued requiring repetitive inspections of the blow-off valve.  Engine surge/stall events have been attributed, in part, to stiction of the blow-off valve.

This amendment retains the original requirement to carry out the actions detailed in the reference SB and removes reference to CAO 106 AD/RRT-V/14 which is no longer in force.

Signature of Delegate

David Punshon
Delegate of the Civil Aviation Safety Authority

23 September 2021