General topics on how do airplanes fly?

Radio communications in flight

Flying airplanes is statically considered safer than driving cars. This is due to many factors. Besides the technical checks and airworthiness certifications of an aircraft, and the pilot's training, radio communications plays a vital roll in making flying relatively safe.

Radio communications

Communications take place between the pilot in the aircraft and the air traffic control (ATC). There are 3 types of communications: verbal communications, transponder communications and navigational communications. This is applicable to small airplanes as well as to big jetliners.

ATC's responsibility is to control and organize controlled airspace to separate aircraft in flight and on the ground. There is a none controlled airspace as well, where no ATC is available, however pilots communicate with each other over the radio to periodically report their position.

Verbal communications happens between pilots and the ATC through a two-way radio device makred as COMM1 and COMM2 with standby STBY. Having 2 radios is for safety reasons in case one of them fails. If the the pilot had a radio failure, he has to follow a certain procedure to the appoarch the airfield and land. Moreover, he has to dial a certain code on the transponder. Radio failure code is universal at 7600.

The two-way radio in a Cessna 172 

Transponder communications (XPDR)

In controlled airspace, and prior to any flight, the ATC gives each aircraft a squawk code to dial on the transponder, This squawk code becomes the identifier of the aircraft.

There are preset codes that the pilot dials on the transponder for certain situations as follow:

• Hijacked: Squawk 7500
• Radio failure: Squawk 7600
• Emergency: Squawk 7700

Once these codes picked up by the ATC, they immediately identify the aircraft situation and deal with it accordingly.

Navigation communications

Navigation communication is most complex, and it is essential for aircraft and pilots to navigate their way from point to point, and to follow ATC instructions.

There are radio stations on the ground that keep on transmitting signals at preset frequencies. The NAV radio at the aircraft picks up the signal and provides the pilot with important information to orient and fly the aircraft.

Navigational equipment on the ground are: 

Very High Omni Directional Radio (VOR) which is usually equipped with a distance measuring device that provide the pilot with the distance in nautical miles DME to or from from the station. 

ADF Automatic Direction Finder, some are also equipped with DME.

ILS Instrument landing system, this system helps the aircraft to approach the runway through providing the pilot with information the aircraft's approach slope, and guidance to the runway center line. Also it provides the pilot with the distance from the TDZ, the touchdown zone. This is a very helpful instrument and pilots rely on it a lot in poor weather.