72-07-04 HAWKER SIDDELEY AVIATION: Amdt. 39-1409. Applies to Models DH.125-1A, -1A/522, -1A/R-522, -1A/S-522, -3A, -3A/R, -3A/RA, and -400A airplanes which have been modified in accordance with Hawker Siddeley Modification 252052.
To prevent possible seizure of the windscreen de-icing handpump No. M.2604, within the next 100 hours' time in service after the effective date of this AD, unless already accomplished, accomplish either of the following:
(a) Modify the pump by replacing the washers and seal with pre-Modification 252052 parts in accordance with Hawker Siddeley Service Bulletin No. 30-24-(2194), dated December 23, 1970, or later ARB-approved issue or FAA-approved equivalent; or
(b) Replace the pump with a new pump No. M.2601/1 in accordance with Hawker Siddeley Service Bulletin No. 30-24-(2194), dated December 23, 1970, or later ARB-approved issue or FAA-approved equivalent.
This amendment becomes effective April 15, 1972.