It is quite long: for isotopes of strontium it is 28 years, cesium — 30.2 years.
It has been flying from 1947 until today. This is the famous “Annushka” — Antonov An-2 aircraft.
It is a Ground Based Augmentation System functioning with the help of global positioning satellite system.
Example: “Boeing-767” consists of 3.1 million parts produced by 800 suppliers of different countries.