non directional
31VHF omnidirectional range — This article is about the radio navigation aid. For other uses, see Vor. D VOR (Doppler VOR) ground station, co located with DME …
32Instrument landing system — The Instrument Landing System (ILS) is a ground based instrument approach system that provides precision guidance to an aircraft approaching a runway, using a combination of radio signals and, in many cases, high intensity lighting arrays to… …
33Direction finding — (DF) refers to the establishment of the direction from which a received signal was transmitted. This can refer to radio or other forms of wireless communication. By combining the direction information from two or more suitably spaced receivers… …
34Radio direction finder — Civil Air Patrol members practice using a handheld radio direction finder to locate an emergency locator transmitter …
35Alternative hypothesis — Main article: Statistical hypothesis testing In statistical hypothesis testing, the alternative hypothesis (or maintained hypothesis or research hypothesis) and the null hypothesis are the two rival hypotheses which are compared by a statistical… …
36Fermi paradox — The Fermi paradox is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations.The extreme age of the universe and its …
37Kite types — Colorful delta wing kite Kites are tethered flying objects which fly by using aerodynamic lift, requiring wind, (or towing), for generation of airflow over the lifting surfaces. Contents 1 Kite …
382010 Polish Air Force Tu-154 crash — Polish Air Force Tu 154 crash Part of the fuselage near Smolensk Accident summary Date 10 April …
39People counter — A people counter is a device used to measure the number and direction of people traversing a certain passage or entrance per time unit. The resolution of the measurement is entirely dependent on the sophistication of the technology employed. The… …
40Instrument flight rules — (IFR) are a set of regulations and procedures for flying aircraft whereby navigation and obstacle clearance is maintained with reference to aircraft instruments only , while separation from other aircraft is provided by Air Traffic Control. In… …
