AD 79-13-06

79-13-06 DORNIER GmbH: Amendment 39-3489. Applies to Model Do 28 D-2 Skyservant airplanes, serial numbers 4050 and 4301 through 4307, certificated in all categories.

Compliance required as indicated, unless already accomplished.

To detect and eliminate corrosion and chafing of the engine fire extinguishing system pipelines, accomplish the following in accordance with Dornier Service Bulletin No. 2062-2828, dated April 1, 1977, or an FAA-approved equivalent:

(a) Within the next 25 hours time in service after the effective date of this AD, inspect the engine fire extinghishing system for corrosion, accumulation of water, and pipeline chafing.

(b) If corrosion or water accumulation is found during the inspection required by paragraph (a), before further flight, except as provided in paragraph (d) of this AD, modify the system by -

(1) Installing a pipeline seal;

(2) Incorporating pipeline water drainage holes;

(3) Installing a drain valve; and(4) Replacing corrosion-prone pipelines with stainless steel pipelines between the engine fire extinghisher bottle and frame 6020.

(c) If pipeline chafing is found during the inspection required by paragraph (a), before further flight, except as provided in paragraph (d), modify the system by -

(1) Incorporating anti-abrasive protection; and

(2) Installing a pipeline securing clamp.

(d) Airplanes may be flown in accordance with FAR 21.197 and 21.199 to a base where the modifications required by paragraphs (b) and (c) of this can be performed.

This amendment becomes effective July 11, 1979.