Our navigational tools have certainly developed since Charles Lindbergh found his way across the Atlantic with little more than a compass, a clock, and his own eyes. Early attempts to build a more precise navigation infrastructure revolved around a network of ground beacons, which enabled pilots to fly very precisely from one specific point to the next. As the airline industry grew, ground-based navigational aids proliferated in the United States and around the world. With the advent of Inertial Reference Units (IRUs) in the 1960s, RNAV took a big step forward. In an IRU, several gyroscopes combine with delicate sensors to calculate an aircraft’s position, based on a known starting position and the motion of the aircraft. IRUs have proven particularly useful in remote areas, with relatively few beacons, as well as over the ocean.
As you would expect, as computers grew more powerful and capable, our RNAV abilities got even better. The first Flight Management Computers (FMCs), which emerged in the 1970s, could use IRU information and were able to take the position of ground beacons, perform rapid and multiple triangulation calculations, and come up with more direct, economical flight paths. Instead of flying in a straight line — in effect, beacon to beacon — aircraft now had an almost infinite number of routes they could fly. Curved flight paths were built into the system, greatly increasing the capacity of the country’s airspace.
If IRUs and FMCs represented important steps forward in navigation, the Global Positioning System (GPS) has been nothing short of revolutionary. As you probably know, GPS is a satellite-based navigation system that is now used not only by the FMCs on today’s aircraft but in everything from autos to sailboats. Airlines have been employing the extremely precise GPS navigation signal since the early 1990s.
While we have come a long way when it comes to the en-route portion, we still depend on ground-based beacons during the departure and arrival phases of most flights. However, today the RNAV systems I described are increasingly used at the start and finish of a flight as well. There are many benefits of this approach: Takeoffs are speeded up, aircraft get to final approach more directly, less fuel is consumed, congestion is reduced, and the capacity of our nation’s airspace is increased. And most important of all, safety is enhanced.
Making the safest, most productive, and efficient use of our nation’s airspace is important to all of us. I am excited about the progress our navigational tools have enabled us to make already, and
I am confident the system will get even better in the years to come. In the meantime, wherever you are headed today, we are grateful you have chosen to fly with us.
I hope all your trips this year are safe and enjoyable.
GERARD J. ARPEY
Chairman & CEO