本航空标准涵盖带或不带内置同步示波器的磁阻力转速表。规定主要用于往复式发动机驱动的民用运输机的电动转速表的最低要求，其运行可能会使仪表受到第3.3节规定的环境条件的影响。

This Aeronautical Standard covers magnetic drag tachometers with or without built-in synchroscopes.To specify minimum requirements for Electric Tachometers primarily for use in reciprocating engine powered civil transport aircraft, the operation of which may subject the instruments to the environmental conditions specified in Section 3.3.