Practicing Aircraft Holding Pattern Entries
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Practice choosing the right holding pattern entry, that is, direct, teardrop, or parallel. This Demonstration simulates a holding pattern entry situation by indicating the course of the aircraft, the radial specified to hold on, and whether or not a left turn is instructed by air traffic control (ATC). Click the correct button to indicate your choice and get the next test case. How many points can you get in two minutes?
Contributed by: Andreas Lauschke (March 2011)
Open content licensed under CC BY-NC-SA
If you display the graphic, you will get one point for a correct answer and five penalty points for a wrong answer. If you do not display the graphic, you get five points for a correct answer and one penalty point for a wrong answer. As the different entry types span angles of different size (direct 50%, teardrop ~19%, parallel ~31%), the scoring is prorated according to the likelihood of the angle's occurrence to prevent cheating by always picking direct (which covers half of all cases). There is a 1/8 probability of a left turn being chosen.
In the U.S., correct pattern entry is mandatory for part 135 and part 121 operations and is recommended (but not mandatory) for part 91 operations. A parallel entry can be substituted for a teardrop entry. All turns are to the right unless a left turn is instructed by ATC. Proper entry type is determined by course, not heading, so wind correction angles must be subtracted beforehand.
For more information, see Holding (aviation).
"Practicing Aircraft Holding Pattern Entries"
Wolfram Demonstrations Project
Published: March 7 2011