The Aviation Science

Radio Waves 🛩️A radio wave is invisible to the human eye. It is electromagnetic in nature and part of the electronic spectrum of wave activity that includes gamma rays, x-rays, ultraviolet rays, infrared waves, and visible light rays, as well all radio waves. The atmosphere is filled with these waves. Each wave occurs at a specific frequency and has a corresponding wavelength. The relationship between frequency and wavelength is inversely proportional. A high frequency wave has a short wave length and a low frequency wave has a long wave length. 🛩️In aviation, a variety of radio waves are used for communication. Here, It is illustrated the radio spectrum that includes the range of common aviation radio frequencies and their applications. 🛩️A wide range of frequencies are used from low frequency (LF) at 100 kHz (100,000 cycles per second) to super high frequency (SHF) at nearly 10gHz (10,000,000,000 cycles per second). The Federal Communications Commission (FCC) controls ...

Types of Radio Waves 🛩️Radio waves of different frequencies have unique characteristics as they propagate through the atmosphere. VLF, LF, & MF waves have relatively long wavelengths and utilize correspondingly long antennas. 🛩️Radio waves produced at these frequencies ranging from 3kHz to 3mHz are known as ground waves or surface waves. They follow the curvature of the earth as they travel from the broadcast antenna to the receiving antenna. Ground waves are particularly useful for long distance transmissions. Automatic direction finders (ADF) & LORAN navigational aids use these frequencies. ✈️High frequency (HF) radio waves travel in a straight line & do not curve to follow the earth’s surface. This would limit transmissions from the broadcast antenna to receiving antennas only in the line-of-sight of the broadcast antenna except for a unique characteristic. HF radio waves bounce off of the ionosphere layer of the atmosphere. This refraction extends the range of...

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Inertial Navigation System 🛩️INSs contain Inertial Measurement Units (IMUs) which have angular and linear accelerometers (for changes in position). 🛩️some IMUs include a gyroscopic element (for maintaining an absolute angular reference). 🛩️Angular accelerometers measure how the vehicle is rotating in space. 🛩️Generally, there is at least one sensor for each of the three axes: pitch (nose up and down), yaw (nose left and right) and roll (clockwise or counter-clockwise from the cockpit). 🛩️Linear accelerometers measure non-gravitational accelerations of the vehicle. 🛩️Since it can move in three axes (up & down, left & right, forward & back), there is a linear accelerometer for each axis. 🛩️A computer continually calculates the vehicle's current position. 🛩️First, for each of the six degrees of freedom, it integrates over time the sensed acceleration, together with an estimate of gravity, to calculate the current velocity. Then it integrates the vel...

Non Directional Beacon 🛩️A Non-Directional Beacon is a ground-based, low frequency radio transmitter used as an instrument approach for airports and offshore platforms. 🛩️The NDB transmits an omni-directional signal that is received by the Automatic Direction Finder, a standard instrument onboard aircraft. 🛩️The pilot uses the ADF to determine the direction to the NDB relative to the aircraft. 🛩️To navigate using the ADF, the pilot enters the frequency of the NDB and the compass card (or arrow) on the ADF will indicate the heading to the station. 🛩️The signal is transmitted on an uninterrupted 24/7 basis. 🛩️An audible Morse Code call sign of one or more letters or numbers is used to identify the NDB being received. 🛩️NDB’s used for aviation are standardized by ICAO, Annex 10 which specifies that NDB be operated on a frequency between 190 to 1800 kHz. 🛩️In North America, the frequency range is typically from 190 to 625 kHz, for offshore operation...

Runway Designation 🛩️Since aircraft are affected by the wind during takeoffs and landings, runways are laid out according to the local prevailing winds. 🛩️Runways are numbered (designated) to the nearest 10° in relation to magnetic north based on approach direction. ✈️Example: 084° is marked 08 ✈️Example: 085° is marked 08 or 09 ✈️Example: 086° is marked 09 🛩️This number becomes the runway's name, and is how it is referenced by Air Traffic Control (ATC)and other pilots. 🛩️The opposite end of the runway is then marked with the reciprocal heading. 🛩️Reciprocal heading is determined by adding or subtracting 180° from the runway heading. 🛩️You must therefore add 180 to any runway 180 or below, and subtract 180 to anything 180 or above. ✈️Example: (using runway 26) 260° - 180° = 080° ✈️Example: (using runway 08) 080° + 180° = 260° 🛩️If your answer comes out to be greater than 360, or negative, then you added when you should have subtrac...

Microwave Landing System 🛩️The microwave landing system (MLS) is an all-weather, precision radio guidance system intended to be installed at large airports to assist aircraft in landing, including 'blind landings'. 🛩️MLS enables an approaching aircraft to determine when it's aligned with the destination runway and on the correct glidepath for a safe landing. 🛩️MLS has a number of operational advantages over ILS, including a wider selection of channels to avoid interference with nearby installations, excellent performance in all weather, a small "footprint" at the airports, and wide vertical and horizontal "capture" angles that allowed approaches from wider areas around the airport. 🛩️MLS employs 5 GHz transmitters at the landing place which use passive electronically scanned arrays to send scanning beams towards approaching aircraft. 🛩️An aircraft that enters the scanned volume uses a special receiver that calculates its positi...

Electronic Flight Instrument System 🛩️ An electronic flight instrument system (EFIS) is an electronic display technology on the flight deck display system. 🛩️It usually consists of Engine Indicating and Crew Alerting System (EICAS), Primary Flight Display (PFD) and Multi-Function Display (MFD) display. 🛩️They commonly use a liquid crystal display (LCD) even though they earlier used cathode ray tube (CRT) displays. 🛩️Installation of the EFIS varies greatly this is where a wide-body aircraft is equipped with six or more display units on which flight and navigation data are displayed while a light aircraft is likely to have one unit. ✈️The installation of EFIS follows the sequence ✈️ Displays ✈️Controls ✈️ Data processors 🛩️Basic EFIS contains all the facilities in one unit.... ✈️Display Units- 🛫Primary flight display (PFD) 🛫Navigation display (ND) 🛫Multi-function display (MFD) 🛫Electronic centralized aircraft monitoring (ECAM)/Engine indicatio...

Primary Flight Display 🛩️A Primary Flight Display or PFD, found in an aircraft equipped with an Electronic Flight Instrument System is the pilot's primary reference for flight information. 🛩️The unit combines the information traditionally displayed on several electromechanical instruments onto a single electronic display reducing pilot workload and enhancing Situational Awareness. 🛩️The layout and information displayed on the PFD varies depending upon manufacturer and installation. 🛩️However, most Primary Flight Displays are configured with a central attitude indicator (AI) and flight director surrounded by other flight parameters. 🛩️Convention normally places the airspeed tape on the left side of the AI and the altitude and vertical speed references on the right. 🛩️Vertical deviation for ILS glideslope or VNAV (vertical navigation) is displayed to the right of the AI while lateral deviation from the ILS, VOR or FMS track is displayed below...