Slip Sliding Away & Goldilocks

April 29, 2014 by Bruce Landsberg
Photo: Brianna Bentley

Photo: Brianna Bentley

It’s not the first time—and certainly won’t be the last—that someone slides off the end of a moderately short but adequate runway. This “oops” was an expensive mistake from a hardware perspective, but fortunately there were no injuries.

A Citation CJ3 slid off the end of a 4,000-foot runway this weekend and into a water trap (appropriately named) of a nearby golf course. (Mind if we play through?) Golf etiquette notwithstanding; remember how critical energy management is to safe landings. It’s good practice to be on speed, on altitude, and on the center line, no matter how long or wide the runway is. I refer to this as the Goldilocks parameters: Not too much, not too little—just right.

In this accident we know mostly what happened—aircraft went off the end. Runway length according to the flight manual was sufficient for the aircraft. There was a displaced threshold of about 350 feet but, even with that, if Goldilocks was in the cockpit everything should have worked. This is also assuming little or no runway slope, no standing water or other contamination, and little or no tailwind. These affect all aircraft but are more critical in jets.

In bigger aircraft and jets the Vref, or landing speeds, can change significantly. This is based on weight, since fuel or passenger load can be a much larger percentage than on a light aircraft. But even in a Cessna 182, a 5- to 7-knot variation can make the difference between a floater and a sinker. Obviously to get book performance, flaps have to be full down. The CJ3 has ground flaps and speed brakes to help dump lift, and timely deployment is essential. Too soon to know if and how they were deployed.

These aircraft are typically equipped with angle of attack indicators, which will automatically adjust the speed for weight, configuration, and density altitude. Keep the energy on the green meatball (1.3 Vso) and you’ll get book performance every time.

The accident report will clarify more of the “what” and then it’s up to us to understand the “why.” If Goldilocks isn’t in your cockpit beware the wolf. In Florida—which is where this mishap occurred—one more caveat: It would be a pity to be gator bait after having survived unscathed!

ASI recently completed a “Takeoffs and Landings” video series made possible by the Canadian Owners and Pilots Association and the Donner Canadian Foundation. The videos cover short field landings, normal takeoffs, determining an abort point, crosswind landings, stabilized approaches, and the base-to-final turn. A great opportunity for pilots of all levels to hone these important skills.

What more, if anything, should we be doing to raise awareness?

Bruce Landsberg
Senior Safety Advisor, Air Safety Institute

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3 Responses to “Slip Sliding Away & Goldilocks”

  1. Jim Caufman Says:

    In jet flying it is critical to fly the numbers. if you are fast, float or land long on a short runway you are now a test pilot. A good stabilized approach beguines at top of decent. A go-around would have been a much better option after an unstabilized approach. EVERY SECOND OF FLOAT IS A COUPLE HUNDRED FEET BEHIND YOUR AIRCRAFT AND EVERY KNOT FAST ADDS STOPPING DISTANCE. FLOAT 3 SECONDS AND TOUCH DOWN 5 KNOTS FAST AND YOU HAVE ADDED ANOTHER 1000 FEET TO THE STOPING DISTANCE. Which in this case was a pond. it could have been a tree, lighting systems, building or a fence. unfortunately this is an all to common event in aviation.

  2. Chris Rodrigues Says:

    I would have preferred that you had waited until sufficient facts were available to properly ananlyze this incident rather than speculate based on sketchy or unconfirmed information. Of course, most of your “conclusions” are actually rock solid principles of landing any aircraft any time rather than lessons to be learned from this incident. We aren’t sure about this one until the facts are in. You and your blog are better than this…

  3. Bruce Landsberg Says:

    Chris…

    Thanks for your note. Thought I was pretty careful NOT to speculate on unconfirmed information.

    The reasoning for highlighting the mishap is to remind all of us that the Goldilocks parameters are essential for every landing. They are not conclusions drawn from this incident which you properly state are “Rock solid” principles..

    Why the reminder of the “obvious?” Because, we keep having trouble with available runway vs the reality of physics.

    Appreciate your thoughts – this does seem like one way to raise awareness without unfairly disparaging anyone. The accident will resolve the probable cause.

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