Learn About Nautical Miles and Statute Miles

Learn About Nautical Miles and Statute MilesLearn About Nautical Miles and Statute MilesThe Nautical Mile, as a unit of measurement, was first defined as an international voreingestelltin Monaco in 1929 at the First International Extraordinary Hydrographic Conference. Prior to that, there was no international voreingestellt for measuring distances either while traveling in water or, or more importantly,over water. The United States did not adopt the Nautical Mile as its standardmeasurement in 1929, but did jump on board in 1954 and now recognizes this internationally used standard. (A nautical mile, logically based on the circumference of the earth, is equal to one minute of latitude and is slightly longer than a statute mile which is a land measurement.) Nautical Miles Versus Statute Miles In the worldof aviation, the standard way to measure distance is the nautical mile. However, the word standard opens the door for deviation from the norm. One exception isusing the statutemile (SM) as opposed to the nautical mile (NM) with regards to the VFR visibility requirements, which all pilots know refer to the basic VFR weather minimum (14 CFR 91.155), which is specific to different types of airspace and altitudes. And, unless you are just getting started, you are familiar with the term VFR which stands for Visual Flight Rules. The VFR weather minimum boils down to the rationale for needing greater visibility (and more distance from clouds) when flying above 10,000MSL (or, mean sea level, which measures aviation altitude) because pilots need more time to see (and avoid) aircraft that may popin and out of clouds. Cloud Clearance is Another Exception Another exception to the rule that the nautical mile is the iron-clad generisch measure and is the measurement regarding cloud clearance, that also employs statute miles (SM) rather than nautical miles (NM). A precise cloud clearance requirement is necessary because its hard to know if that scene out of the hangar d oor measures up with true meteorological conditions, or, if the scene out of a pilots windscreen measures up, for that matter. Nevertheless, here are the definitions of both nautical miles and statute miles, along with a few easy conversions. Distance Measurements Statute Mile 1 SM 1,609 meters1 SM 5,280 feet1 SM .869 NM Nautical Mile One nautical mile (NM)as defined by the NOAA as A unit of distance used in marine navigation and marine forecasts. It is equal to 1.15 statute miles or 1,852 meters. It is also the length of 1 minute of latitude. 1 NM 1,852 meters1NM 6,076 feet1NM 1.151 statute miles In the world of aviation, distance is generally measured in nautical miles, with the exception of visibility, which is usually stated or forecasted in statute miles. Speed Measurements When exploring nautical miles, its worth noting the difference with often-used terms such MPH and knots. MPH In statute miles, speed measurements are given in miles per hour, the same as in veh icles.Knot The standard speed measurement in aviation is the knot. One knot is equal to one nautical mile per hour. Airspeed indicators on aircraft are calibrated in knots.