How Fast?

two and three rectangular bars symmetrically arranged in pairs about the runway centerline." (Runways with touchdown zone markings on both ends omit them when they'd be within 900 feet (270m) of the midpoint between the thresholds.)"

Editorial Staff

Friday, March 20, 2015 at 12:00 AM ET

Verified

Key Takeaways:

ILS approach speeds for prop aircraft involve two distinct phases: one for the FAF inbound and another after transitioning to visual references.
Flying ILS approaches too slowly (e.g., near VY) is inefficient, delays traffic, and reduces energy for a missed approach; maintaining speed and scrubbing it off later is preferred.
Once in visual conditions (VMC), avoid flying much faster than 1.3 Vso to prevent loss of control or aircraft damage, smoothly reducing power to reach this target speed.

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The speed at which we want to fly an ILS in a prop-driven airplane results from several variables, and it will be two speeds: one to fly from the FAF inbound and another to use after transitioning to visual references. There’s no upside to coming down the ILS or LPV slowly, down around VY. It ties up traffic and leaves no reserve energy for a missed approach climb. It’s usually easy to scrub off that speed when it’s time.

Once you get into VMC, flying much faster than 1.3 Vso can mean bad things are likely to happen. Pilots lose directional control, jam the nosewheel onto the runway and generally do expensive things to the airplane. When it’s time, smoothly reduce power to idle and speed to the 1.3 VSO target, while either continuing to descend, or holding altitude. There’s a bunch of runway in front of us: The diagram at right highlights precision runway distance markings.