56-11-01 de HAVILLAND: Applies to All Model 104 "Dove" Aircraft.
Compliance required by May 31, 1956.
As a result of the two accidents caused by pilots feathering the wrong propeller after engine failure, the British Air Registration Board has classified the following as an essential modification. The FAA concurs.
The left-hand needle (oil pressure) of the combined oil pressure and temperature gage for the starboard engine could be mistakenly interpreted as applying to the port engine. To minimize the possibility of such confusion either Part A or part B of Dove Modification 879 must be incorporated as soon as possible but not later than May 31, 1956:
Part A. To turn the instruments clockwise through 90 degrees and put temporary markings on the instrument bezel.
Part B. To turn the instruments clockwise through 90 degrees and re-mark the dials to give correct presentation or to fit modified instruments with vertical lettering and figures.
(Dove Modification 879 is covered in de Havilland Service Technical News Sheet Series CT (104) No. 132 dated April 13, 1956.)