How Do Commercial Aircraft And Their Pilots Navigate?
A look at how commercial passenger jets navigate across thousands of miles every day
Ever wondered how the pilots know which way they are going? This article takes a look at hour commercial aircraft are navigated over thousands of miles, seamlessly reaching their destination.
Commercial aircraft utilise a number of navigation systems to help guide the flight from point A to B.
These navigation systems consist of:
- Global Positioning System (GPS)
- Inertial Reference Systems (IRS)
- Radio Aids (VORs, DMEs, ADFs, ILSs)
At the start of the flight, the pilots load a predetermined route into the Flight Management System. This imposes the route of the flight onto a moving map which the pilots can monitor on their screens throughout the flight. The pilots can see other things around their flight path on their screens, like other airports, other aircraft, high terrain and bad weather.
The aircraft can detected where we are compared to the predetermined route through the following navigation systems:
GPS – Global Positioning System
This is one of the primary navigation sources and the aircraft is continuously monitoring it’s GPS position. However, should the GPS receivers fail, or if the system were to go offline, we need other means of computing our position.
IRS – Inertial Reference System (IRS)
The IRS is a self contained system that is able to track our position using accelerometers and gyroscopes. At the start of the flight whilst on the ground setting the aircraft up ready for flight, the pilots tell it the exact location in terms of Latitude and Longitude. It then detects any acceleration across any axis and then calculates the aircraft position based on this movement. It requires no external input, other than telling it where the aircraft is at the start of the flight.
Radio beacons, located on land, send out radio beams which tell us our range and direction from that radio aid. This allows the aircrafts computer systems to calculate where we are. The more radio signals we can detect, the more accurate our estimated position is.
As you can see, if one of these fails, it’s not a problem as there is lots of redundancy onboard. Pilots don’t get lost very often!