RNAV Routes

Source: www.pilotworkshop.com
Featuring John Krug

Subscriber question:

"Discuss tips for filing RNAV direct routings with emphasis on off-airway altitude selection process and including any nav fixes along the way. Bring in an example of using the new RNAV routes around busy terminals." - Bill B.

John:

"RNAV routes should begin and end over the appropriate arrival and departure transition fixes for each airport. You can find these fixes on the SIDs and STARs procedures. Make sure you select the correct procedure for the altitudes you intend to fly.

Enroute, you should file at least one fix in each Center's airspace. This is to ensure correct flight plan processing. The fix you select should be within 200nm of the preceding Center's boundary. The Center boundaries are depicted on both low and high altitude IFR charts.

Although the system will accept a Fix Radial Distance description – ie ABC 123 at 012 miles, I find it a better practice to select a named intersection even if it is slightly off your route. There is less chance of misinterpreting the description when it can be spelled out and verified in the GPS navigator.

Altitude selection should be done by consulting the Off Route Obstruction Clearance Altitude (OROCA) altitudes on the low altitude enroute charts.

T-routes, also called Tango routes, are published on low altitude charts in blue. Since the minimum enroute altitude (MEA) for GPS navigation is not affected by NAVAID limitations, MEAs for Tango routes can frequently be lower than for conventional airways. The lower MEAs can be a significant benefit to pilots in their route planning and avoidance of icing if they can fly below the freezing level.

You should select an entry and exit point for the Tango Route based on your direction of flight and altitude. For example at Charlotte (KCLT), T201 and T203 provide a north south route on either side of the Charlotte Terminal area."