information:classification, stylistic:tone, quality:correction, structural:summarization, structural:scholar_edition
Aeronautical terms

Prior to 1969, airworthiness standards for civil aircraft in the United States Federal Aviation Regulations specified that distances were to be in statute miles, and speeds in miles per hour. In 1969, these standards were progressively amended to specify that distances were to be in nautical miles, and speeds in knots.

The following abbreviations are used to distinguish between various measurements of airspeed:

The indicated airspeed is close to the true airspeed only at sea level in standard conditions and at low speeds. At 11 000 m (36 000 ft), an indicated airspeed of 300 kn may correspond to a true airspeed of 500 kn in standard conditions.