71-11-01 De HAVILLAND AIRCRAFT OF CANADA, LIMITED: Amdt. 39-1212. Applies to de Havilland Model DHC-6 Airplanes certificated in all categories.
Compliance required within the next 500 hours time in service after the effective date of this AD unless already accomplished.
To provide adequate protection for particular circuit wires, accomplish the following in accordance with the instructions contained in DHC Service Bulletin No. 6/245 dated October 9, 1970:
(a) Alter airplanes, S/Ns 6 through 289, except S/Ns 176, 221, 233, 268 and 286, by incorporating DHC Modification No. 6/1369;
(b) Alter airplanes, S/Ns 1 through 289, except S/Ns 176, 233, 268, and 286, by incorporating DHC Modification No. 6/1370;
(c) Alter airplanes, S/Ns 6 through 289, except S/Ns 176, 221, 233, 268 and 286, by incorporating DHC Modification No. 6/1371. Modification No. 6/1371 is applicable only to those airplanes in which DHC Modification No. 6/1053 has been incorporated;
(d) Alter airplanes, S/Ns 136 through 289, except S/Ns 176, 221, 233, 268, and 286, by incorporating DHC Modification No. 6/1372;
(e) Alter airplanes, S/Ns 136 through 289, by incorporating DHC Modification No. 6/1389.
Equivalent alterations may be used provided they are approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.
Upon request with substantiation data submitted through an FAA maintenance inspector, the compliance time specified in this AD may be increased by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region.
This amendment is effective May 19, 1971.