59-05-07 VICKERS: Applies to All Viscount Model 745D Which Have PB.10 Automatic Pilot Installed.
Compliance required as soon as possible but not later than December 1, 1959.
In order to permit the pilots to positively disengage the trim servo clutch either by the emergency cutoff buttons on the pilots control wheel, or by the mechanical disconnect lever, a control relay (Plessey P/N 7LZ.107352 or P/N 7CZ.97508/1) should be installed in the A.C. junction box.
The British Air Registration Board considers this mandatory. The FAA concurs with this action and considers compliance therewith mandatory.
(Vickers-Armstrongs Modification Bulletin No. 2703 and associated Modification Leaflet covers this subject.)