Stability is tough to achieve in these times

May 4, 2011 by Bruce Landsberg

Apparently all the turmoil in the world is also affecting some pilots – all of whom should know better. We’ve had quite a number of  really experienced aviators flying turbine equipment off the end of runways that are adequate in length. Both the airlines and corporates have had their share of flubbed landings that resulted from flubbed approaches usually in visual conditions.

Tailwinds and water certainly don’t mix. Most performance charts don’t list anything more than a 10 knot tailwind and no one guarantees that the winds are accurate – lots of opportunity for mischief and mishap here.

This was all going through my mind on a couple of my own landings recently.  I had the privilege to fly a friend’s Conquest II the other day, which is one of the nicest turboprops going. The aerodynamics are slick, the thing is fast at just under 300 knots and it practically makes fuel at altitude with Garrett (now Honeywell) engines. Great aircraft, and in today’s fuel-conscious world Cessna should be building them again, but I digress.

We got a “little” behind the descent profile in good VFR conditions and wound up about 4000 ‘ above the destination airport and coming down like the proverbial safe full of anvils. It was my leg to fly and I looked over at my friend who said “continue.” In turboprops flight idle solves a lot of hot and high problems – gear, flaps, props to high pitch  and down she comes – fast.  Obviously this was great time to widen out the pattern and look for other aircraft that we were sure weren’t there at this isolated non-towered airport. I mentally ran though my repertoire of recent overrun mishaps although there was nearly 6,000 feet of runway and decided that if  we weren’t stabilized by base, I would plead “incompetence” and reenter the pattern. Strong winds down the runway, the dry pavement also helped in the decision.

Chop and drop worked – this time – and the Conquest came to an acceptable stop a little beyond the mid field turnoff. Don’t try this with a jet! They don’t have the rotating air brakes that allow prop drivers to fix a lot of things before running out of options.

The second reminder was in AOPA’s Diamond DA40 at the other end of the spectrum. This aircraft is of glider heritage and 10 extra knots will result in A LOT of float. I hadn’t flown it in awhile and needed to brush up a bit before taking some passengers. It’s amazing how well airplanes fly and land when configured properly, on speed and on altitude. Good landings are  a matter of  proper procedure, a touch of technique and just a little luck.

Leave the shuttle approaches to NASA and get stable before hitting 500 agl in light aircraft. Let’s leave instability to the rest of the world!

Bruce Landsberg
Senior Safety Advisor, Air Safety Institute

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  • Michael J.Carroll

    Does anybody practice slips anymore? As in sideslips to lose altitude and compensate for wind and forward slips to lose altitude when landing. I used to fly into a narrow,short grass runway completely surrounded by tall trees. Some flyers used to say,”It was like landing in a bathtub”. But since I learned to fly there it was just normal for me. With a good headwind over the trees on final, It was impossible to land there without a full rudder forwardslip due to the updraft caused by the trees over the approach end of the runway. Then you would abruptly run out of excess lift once past the treeline and proceed to “drop like the proverbial rock”. It was a great test of your airmanship and reflexes and reminded me of a Coney Island thrill ride. Sadly, this little field is now become a Suffolk County small park. Mike AOPA00893089

  • Bruce Liddel

    I’ll agree that in complex aircraft, there’s not much that’s more important on approach than stability (and or course, GUMPS).

    However, in SE fixed conventional-gear airplanes, after about 300-400 landings, I think there’s a whole lot to learn by gently pushing the stability envelope. I eventually got to the point where I could consistently convert a diving approach at 110mph to a safe landing at 45mph, or abort a departure at any altitude (over sufficient runway), and over 300′ I could land on adjacent runway, because I had practiced enough that I could generate a fairly stable approach in very short order.

    I guess my point was that practice is beneficial. Hmmph, no big revelation there.

  • Gerard

    Yes people still practice slips and occasionally use them, but I know a few who seem to slip on every landing they make. I wonder are they practicing or just getting lazy about making a stabilized approach.

    Exploring the envelope and practicing the skills we need to deal with flying’s little challenges is definitely good thing, but we should make just as much effort to practice flying precisely and making stable approaches, especially under challenging conditions.

  • Lee Gilbert

    Rotating speed brakes make slipping twin turbine aircraft redundant and therefore unnecessary. Because of the great approach speed versatility of jet prop aircraft (approach speeds can vary in any one aircraft from 180 to 100 KIAS), it seems important for pilots of those aircraft to become familiar and comfortable in that range of operation. Powerful engines and the rotating speed brakes of a jet prop simply may make establishing a stable approach a more dramatic manuever because the pilot has so much control over a wide range of speed and altitude. The key here being that the pilot should be familiar and comfortable with that range of gift.

  • Daniel Arthur-Jones

    Could not agree more with your last statement: “Let’s leave instability to the rest of the world!”

    Spot on!