70-22-07 ROLLS-ROYCE: Amdt. 39-1098. Applies to Rolls-Royce Dart engines Models 506, 510, and 526, installed on, but not necessarily limited to, British Aircraft Corporation Viscount 744 and 745D; and Armstrong Whitworth Argosy 650 Series 101 airplanes.
Compliance is required within the next 500 hours' time in service after the effective date of this AD, unless already accomplished.
To prevent the loss of propeller control in the event of an annulus gear failure, accomplish the following:
(a) For Rolls-Royce Dart Model 506 engines, incorporate Rolls-Royce Dart Modification 1431 in accordance with Rolls-Royce Dart Aero Engine Service Bulletin Number Da72-297, Revision 7, dated February 20, 1970, or later ARB-approved revision, or an FAA-approved equivalent.
(b) For Rolls-Royce Dart Models 510 and 526, incorporate Rolls-Royce Dart Modification 1550 in accordance with Rolls-Royce Dart Aero Engine Service Bulletin Number Da72-348, Revision 9, dated November 28, 1969, or later ARB-approved revision or an FAA-approved equivalent.
This amendment becomes effective November 23, 1970.