scope:

This specification covers one type of vertical speed indicator, range 0 to 6,000 feet per minute (fpm) climb and descent.

This appendix outlines the design, fabrication, and testing to provide a facility for the fungus resistance testing of aeronautical and associated equipment formerly covered by MIL-C-9452 which has been canceled. This appendix is intended for guidance only.

The purpose of this Appendix is to provide the procedure for salt fog test required by MIL-I-7721, paragraph 4.7.19.1. These procedures are copied from FED-STD-151A, Method 811.1 which is no longer administratively acceptable because it has been superseded. Method 811.1 of FED-STD-151A is desirable for use with MIL-I-7721 although it is not included in the current revision, FED-STD-151B, therefore it is identified and supplied here as a separate entity. (reference paragraph 6.5)

This method covers procedures for an accelerated-corrosion test in which specimens are exposed at a temperature of 95°F. (35° C) to a fine mist of 5 percent or 20 percent sodium chloride solution. When no solution concentration is specified, the 5-percent solution shall be used. The method constitutes an arbitrary performance test which is useful in the establishment and maintenance of certain standards of quality, although it does not closely simulate any common conditions of service (For Synthetic Sea-Water Fog Test, see method 812.)

The method is applicable to the testing of assemblies, metallic coatings, organic and inorganic coatings on metals, and many non-metallic materials. The method describes the required conditions for conducting the test for specification purposes. It does not prescribe the type of test specimen, or length of exposure periods to be used for any specific product, or the interpretation to be given to the results. It is desirable in the specification of this test, that the significant surfaces for testing, when applicable, be indicated on the drawing, or in the detail specification, contract, or order. The size and other construction details of the apparatus are optional, provided the conditions obtained meet the requirements of the method described herein.

intended Use:

The vertical speed indicators are intended for use on aircraft to indicate the vertical component of the aircraft's speed based on the rates of change of atmospheric pressure.