So far, we have defined the difference between RNAV and conventional flight procedures and what airspace is. This installment in the series will discuss what a Flight Procedure is. Later installments will merge these concepts as we continue to explore airspace and flight procedure development as a whole for an airport and its surrounding communities.
A Flight Procedure, the topic of this blog, is a lateral path through the air that moves from point to point and connects airports. In some cases, flight procedures can have a vertical element to them as well, however, for the purpose of this discussion we will only be concerned with the lateral path.
The lateral path is tantamount to the freeway system that you use every day when going to work. When you leave your home, you drive onto an on-ramp to become established on the freeway. In aviation, this on-ramp is tantamount to a Standard Instrument Departure (SID) that connects the departure airport, or your home, to the freeway, or in aviation, the aviation “enroute” system. Think of the freeway as a series of straight paths defined by a “waypoint” at each turn or change of direction. For example, when the freeway turns to the right, imagine there is a fixed point there that ends that straight segment and begins the next straight segment. Figure 1, outlines this concept using a flight procedure from the FAA for the John Wayne Airport (KSNA). Once on the freeway you follow that path until it is time to get off.
When nearing your destination, you must exit the freeway to arrive. In aviation, this is called a Standard Terminal Arrival Route (STAR). These three paths, SID, enroute, and STAR comprise most of what we know as flight procedures. The last basic category, which will be covered in a later post, are arrival procedures, or instrument approaches.
Historically, flight procedures, such as the one outlined in Figure 1 above, were defined and developed by air traffic control facilities through coordination between airspace sectors (for definition of airspace sectors, see the last blog posted). These procedures were either based on ground based navigation aids or RNAV paths (the difference between the two was covered in an earlier blog). During the last 10+ years, the development of these procedures has grown to a more collaborative process where airspace stakeholders, such as air carriers, air traffic control, military, and FAA headquarters representatives convene to amend, add, or delete flight procedures to the air traffic system.
Although this collaboration has expanded over the years, typically, airport authorities and/or airport representatives have not been a part of this process. This was not a snub to them, but instead a by-product of where the airports fell in the overall flight path. For example, most flight procedure modifications address activities beyond a 5-mile radius from an airport since within this radius the paths to and from a runway are less apt to be modified. However, these paths too can be changed, and that will be the topic of another post in this series. Therefore, airports have not been a part of the flight procedure and airspace modification process. Recent FAA flight procedure implementations have prompted airports to seek some involvement. At BridgeNet, we work with airports and their communities to help address concerns and provide an understanding how all of these elements merge to impact noise and other environmental effects.
About the Author: Grady Boyce is a current and active Captain for a major airline flying the B-737. He has participated in, and led, airspace developments and ATC modernization efforts on all continents except Antarctica. Grady is a consultant to BridgeNet bringing flight procedure development, ATC expertise, and TERPS assistance into their current and future activities.