59-01-02 de HAVILLAND: Applies to All Model 104 "Dove" Aircraft.
Compliance required as follows: Aircraft prior to Serial Number 04463-April 1, 1959; Aircraft Serial Numbers 04463 through 04477 September 30, 1959.
Cases have occurred where the main undercarriage locking levers P/N 4U 139A (Pre Modification 231) and P/N 4U 461A (Post Modification 231) have cracked in service.
Dove Modification 868 has therefore been introduced which provides for locking lever assemblies in a material to a revised specification.
On aircraft Pre Modification 231 standard, Dove Modification 187-repositioning the undercarriage warning lamp and microswitches-and Dove Modification 308-improving the operation of the main undercarriage mechanical position indicator-must be embodied at the same time as Modification 868.
The British Air Registration Board considers this mandatory. The FAA concurs with this action and considers compliance therewith mandatory.
(de Havilland TNS CT(104) No. 155 covers the same subject.)