I MIL-STD-810D Downloaded from https://www.everyspec.com 19 July 1983. I I-3.2.2.3 ~ selec~. The combined environment test is to select the first:eteD in constructing a mission p~ofilee to be us~d. An individual aircraft ie designed to operate within a specified flight envelope (Mach numberlaltitude regime) and to fly specific miesion profiles. Generally, sc aircraft can fly many different miesions, such as training, air superiority, interdiction, ground eupport, etc. In addition, aircraft are flown under specialized conditions that simulate a high-threat combat environment.
These wartime skill exercises, such as Red Flag, are designed to train operational squadrona under realistic wartime conditions. Usually, not all the miaaions flown by the aircraft need to be included in the teet cycle. It is possible to identify two or three of the most highly utilized mission profiles that, as a group, reasonably approximate the =. aggregate effect of all the missions flown by the aircraft. This will adequately simulate the routine deployment life. In.addition, the utilization of wartime skill exercises as part of the miesion profile will stress the equipment under eimulated combat conditions.
To’eelect the mission profiles to be used, the following approach is recommended. = a. Identify all aircraft missions and the utilization rate for each miseion of the aircraft in which the equipment is to be installed. This information may be obtained from the operational commands or the flight manual used by aircraft crews. For aircraft under development, the design flight envelopes, design miaeion profilea, and the design utilization rate of each mission shall be used when actual flight data are not available. b. Determine the missione that comprise a majority,(if possible, .8o , percent of total flown) of the total routine, daily mission utilization.
To do this, examine the utilization rates for all mission profiles of the aircraft and rank them in order from highest to lowest. Then, take the miesion profilee that compromise the majority utilization rate and uee these ae mission profilee for combined environment testing. Missions with similar functions and flight charaoteriatica oan be lumped together to minimize the number of profiles to be generated. Table 520.0-1 shows an example”distribution of missione. c. In order to simulate the high-threat environment, miseions flown under the wartime skill exercisee shall be separately identified. Theee data may be obtained from the operational command or provided by the procuring agency.
Once these data have been obtained, two separate test cycles can be constructed according to paragraph I-3.2.2.2. One test cycle using the mission profiles in paragraph I-3.“2.2. 3b will be developed to simulate routine usage and another test cycle using the mission profilee in paragraph I-3.2.2.2C will be developed to gimulate usage under combat or combat-training conditions. Obtain the altitude and Mach number versus tim”evalues for each mission profile selected, as shown schematically y in figure 520.0-3. These parameters of tbe mission profile are used to calculate the environmental stresses. .’.,, METHOD 520.0 19 July 1983 520.0-6