Landings - ever and onward.

While preparing student pilots to solo, and when reviewing experienced pilots in aircraft checkouts and flight reviews, I observe amazing variations in pattern flying.  There is a constant: Pilots who fly with consistent patterns and who set the plane up on final at a correct airspeed make fewer and  smaller corrections in the landing phase of the pattern.  

    Consistency in landings comes from consistent approaches.  Here is a checklist to accomplish just that. 

  1. 1.   Fly through the downwind “slot”

  2. 2.    Set configuration and airspeed (another way of saying angle of attack)

  3. 3.    Arrive on final perfectly aligned

  4. 4.    Fly down the “steel cable” to the touchdown area

  5. 5.    Slow down on short final

  6. 6.    Maintain the two alignments

  7. 7.    Land on the first x feet of the runway

  8. 8.    Stay in control after the wheels touch

    A good approach starts with having airspeed and attitude well under control.  Plan to arrive in the vicinity of the airport with the pilot well ahead of the airplane.  Let’s say you’re in a 172, landing at an uncontrolled field.  Of course, you’re going to do a proper pattern entry, arriving on the downwind leg at 90 knots at the correct altitude.  What correct altitude?  This goes back to preflight planning. 

    Out comes the A/FD - to see if there is a published TPA (traffic pattern altitude) for the airport.  You’ll also notice lots of other important stuff, I hope, like lengths and widths of runways, displaced thresholds, obstacles, and so on.  As of this writing, you could check two airports in the Southeast A/FD: Collegedale (FGU) and Cornelia Fort Airpark (M88).  I suggest that traffic pattern techniques will be different for these two airports!  On has  a TPA of 1040 feet AGL and the other at 598 feet AGL. 

    A look at the sectional will explain the low TPA at Cornelia Fort - it’s right under the Class C airspace for Nashville International (BNA), and the FAA would like airplanes using Cornelia Fort to not be involved with the airliners going into and out of BNA.  At Collegedale, ridges on either side of the runway make it difficult to see the runway if you aren’t higher than normal in the pattern. 

    Also note that Cornelia Fort was destroyed by flooding in May, 2010, and may never reopen.

    Now just take one more minute to check Jasper - Marion County (APT).  No non-standard altitude is specified, but right traffic for runway 22 is.  Again, a ridge is the reason. 

    So, anyway, we have arrived on the downwind (using a safe entry to the pattern, at the correct altitude at the same airspeed on every approach.  (90 knots in a 172 is a good start.) 

    I like to think of flying the airplane through three “slots” in the sky on a pattern approach.  The first “slot” is on the downwind leg, opposite the touchdown point.  In our prototypical 172, we want to pass through this slot exactly the correct distance from the centerline of the runway, at the correct altitude, at 90 knots.  Set power and trim so the aircraft likes flying level at 90.  Opposite the touchdown point, reduce the power to begin the landing approach. 

    Since most of our aircraft these days have flaps, let’s use them for landing.  And since the aircraft manufacturer designed the plane with X degrees available, let’s use full flaps for landing, because that’s the best combination of lift and drag that the engineers developed. 

      Reduce power, reconfigure the aircraft (partial flaps), and trim it to make it easy to fly in a descent at the chosen approach airspeed.   65 knots is a good typical speed for a 172.  Now aim for the second “slot”, on the base leg.  This slot is 500 or 600 feet AGL, the runway is visible to the pilot off his/her shoulder, the aircraft is descending, and the airspeed is correct.  Add flaps at appropriate times to assist you in keeping the airspeed and descent angle right.  Start the base to final turn (and adjust as you go) so that the plane rolls out of the turn aligned exactly on the centerline of the runway.  Both pattern turns are coordinated turns, for obvious reasons (see Stall/Spin). 

    Here comes the third “slot”.  This slot is about 1/2 mile from touchdown, is exactly on the centerline of the runway, and you fly through it at the precise full-flap approach speed in a descent attitude.  Flying through this slot accurately makes a consistent “picture” out the front.  The glare-shield is “below” the runway number and the runway looks like a narrow isosceles trapezoid.  From here, visualize a taught steel cable running from the touchdown point on the centerline of the runway to the belly of the airplane.  The pilot’s task is to fly the airplane right down the cable without making it flex.  Properly done, the “picture” out the front will be consistent, as the runway gets larger without changing its shape. 

    The landing itself?  When a 172 flies through the “landing slot” at 65 KIAS, full flaps, well lined up, the transition to land is a piece of cake.   On short final, reduce power smoothly to idle, maintain the two alignments, raise the nose, which bleeds off airspeed, and it will land safely. 

    The two alignments are left/right, holding the centerline with the bank angle, and nose straight, keeping the landing gear tracking straight down the runway.  This is uncoordinated flight, made necessary by the movement of the air relative to the runway.  Some people call this crosswind technique, but it applies on every landing.

    When everything else is well-controlled, putting the wheels down where we want them is easy.  Gradually increasing the angle of attack with idle power slows the plane until the wing stops flying as the wheels touch the ground.  How many feet down the runway the proper spot is varies with the length of the runway.  Good airspeed and alignment control will prevent your ever arriving in ground effect with excessive speed, and “float” won’t happen.  We pick our spot, aim the plane at it, slow down, and land where we aim.

    Another little tip: Student pilots frequently get close to landing and then “give up” controlling the plane when it’s just a couple of feet off the ground.  This usually produces a landing that screeches the tires too much and shakes the aircraft.  In a good landing, we keep on flying until the wheels are all down and the airplane is taxiing, with no more tendency to fly.  

    There it is: a landing at minimum airspeed, properly aligned, in the proper part of the runway. 

April 26, 2010