Regard the Jeppesen version of the RNAV (GPS) Rwy 19 approach to Meridian, MS (KMEI). This chart shows the simplest TAA you can have. The limit for a turn based on GPS is 90 degrees, so the maximum allowable turn from a route direct to the IAF to the leg after crossing the IAF is 90 degrees. This means each TAA should contain at least two sectors, divided by courses 90 degrees off the inbound course.
The article details the evolution of approach charting from traditional feeder routes to GPS-based Terminal Arrival Areas (TAAs), which simplify navigation by providing sector-based minimum altitudes around an Initial Approach Fix (IAF) and replacing Minimum Safe Altitudes (MSAs) on RNAV approaches.
Early attempts to integrate TAAs into conventional ILS charts, referred to as "Frankencharts," led to significant confusion due to ambiguous or incorrect "GPS required" and "DME required" notes, stemming from a lack of established charting rules at the time.
Modern charting standards have refined the clarity of required equipment notes for specific procedure entries, and future changes, such as the decommissioning of certain VORs, are expected to further simplify charts by making GPS a universal requirement for self-navigation.
We pilots trust our cartographers. We must. We may wend our way from waypoint to waypoint, following the magenta pixels, but it’s black course lines and data on the chart that actually keep us out of trouble.
And then some well-meaning ground-dweller tries to simplify the presentation and bollixes up the whole thing.
CREATE A FREE ACCOUNT
Sign up to keep reading
Create a free account to continue. Already a member? Sign in below.
