ADS-68-IS

Abstract

<u>Purpose</u>. The primary purpose of this standard is to provide the requisite information to promote compatibility between aircraft electrical power, external electrical power, and the airborne equipment that uses that power, with MIL-STD-704 serving as the governing document. Accordingly, the content of past versions of MIL-STD-704 is presented here to enable comparisons of the detailed requirements. To ensure that an individual piece of equipment will work satisfactorily in multiple types of aircraft, a worstcase set of electrical interface criteria should be developed from the applicable versions of MIL-STD-704 and subsequently imposed as an interface requirement for that equipment to ensure compatibility with the various types of aircraft being addressed.<br>The development of numerous combinations of worst-case characteristics is considered to be beyond the scope of this document; however, the required information is presented to enable development of an appropriate set of worstcase criteria. Table V provides an example of a set of worst-case criteria for 28 volts DC; i.e., it represents the worst-case requirements of revisions A through E of MIL-STD- 704. At the time this standard was developed, the (then) latest approved version of MIL-STD-704 (revision E) was used as the starting point for this ADS, and where earlier versions differ, that information is also provided to enable side-by-side comparisons, as well as development of worst-case criteria. The various versions of MIL-STD-704 that are included are Revisions A through F. The requirements and some of the textual content of Revision F have also been included as its release was pending at the time this standard was being written; consequently, it includes some information that has not been included in previous versions, such as reference to test methods and procedures for determining compliance with these requirements. Information included in this document and derived from (peculiar to) the released version of MIL-STD-704F is clearly identified as such.<b><u>Intended Use:</u></b> The intent of this document is to define the electric power quality requirements for utilization equipment used in DoD aircraft; however, the document may also be used for utilization equipment used in commercial aircraft or other types of vehicles. Other industry standards, such as SAE AS1212 and ISO 1540, also define aircraft electric power quality requirements; however, these documents are generally not appropriate for use with military aircraft. They do not address all the areas of concern with military aircraft electric power quality, and often require wider limits compared to this document due to the differences in the types and sizes of aircraft covered. In addition, the documents do not always take into account legacy DoD aircraft electrical power systems or legacy DoD utilization equipment. The power characteristics requirements of this document also apply to commercial and non-developmental utilization equipment purchased in compliance with OUSD (AT) SD-2. If such equipment does not fully comply with the power characteristics requirements of this standard, the effect of equipment noncompliance on the electrical power quality and on the equipment capability to perform its intended function in DoD aircraft should be evaluated.&#160;<br>