Practice Bore-Sight IFR for Descents on the Angles

Classic descent planning usually includes a time/distance/rate algorithm worthy of space shuttle re-entry or a that-looks-about-right guess. The latter often results in a screaming, idle path that ends with, Ahhh, Center, were gonna have a little trouble crossing STING at 3000.

Editorial Staff

Wednesday, December 03, 2014 at 12:00 AM ET

Verified

Key Takeaways:

The article advocates for a "Flying Tigers gun sight" method of descent planning, using the attitude indicator (AI) as a protractor for precise pitch control, a "control-performance" approach.
For a standard three-degree descent, pilots can calculate the required distance by tripling the altitude to lose and verify the descent rate by halving their groundspeed and adding a zero (e.g., 100 knots GS requires 500 FPM).
For descents requiring different angles, the AI can be used as a 0-to-10-degree protractor, with the required pitch attitude determined by the percentage of altitude loss per distance (e.g., 500 feet per mile equates to 5 degrees nose low).
This cockpit-friendly technique simplifies achieving accurate descent targets, though very steep descents (e.g., 10 degrees nose low) are generally not sustainable.

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Classic descent planning usually includes a time/distance/rate algorithm worthy of space shuttle re-entry or a that-looks-about-right guess. The latter often results in a screaming, idle path that ends with, “Ahhh, Center, we’re gonna have a little trouble crossing STING at 3000.”

Wouldn’t it be neat if you had a ring-and-bead gun sight like the old Flying Tigers P-40s to point the nose and smoke your descent target? In a way, you do.