How Far is That?
In your October clinic, “Driving All Night” you mention “Flying the full procedure is a cross-country drive of 12 miles to HUSKR.” Thinking HUSKR should be JUSAM, or am I interpreting it incorrectly?
Barry McCollom
Kerrville, TX
Readback May 2018
I was able to pull the ODP data but not the SID data, but I can give a fairly good guess as to whats going on. On the ODP, the controlling obstacle is a 2729-foot tower a few miles to the east of the runway. The initial climb is extended a bit more than usual in order to allow for a standard climb gradient when turning right (note that for turns other than to the right, a normal 400-foot turn is allowed). The WENDY and TRUPR are examples of Open SIDs, which have a route off the runway followed by radar vectors to a route. In these cases, the route off the runway is evaluated, but then the radar vector area gets no additional evaluation (other than MVA, etc.). SID evaluation begins again at the defined route. Because theres no SID evaluation required after the initial climb, the controlling obstacle for the ODP isnt considered. The minimum turning altitude for an RNAV SID is 500 feet above the runway, which would give you a turn at 1800 vs. the turn at 1900 on the ODP to keep a standard climb gradient and clear the tower. -LS
Key Takeaways:
- Minimum turn altitudes for SIDs can differ from ODPs due to varying obstacle evaluation criteria; ODPs may require higher turns to clear obstacles and maintain a standard climb gradient.
- Lead radials are only depicted on DME arcs when the turn from the arc to the intermediate course is not a 90-degree change, which occurs when the VORTAC providing the arc is not directly on that course.
- The magazine's electronic and paper archives do not extend back to 1990, leading them to solicit reader help for requests for older articles.
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