Posted on 3 Comments

The short field takeoff and landing with obstacle

Approach and landing over an obstacle

The next maneuver, after mastering the short field procedure, is doing so imagining  having to clear a 50 foot obstacle on both take off and landing. This is accomplished by imagining that there is a 50 foot obstacle at the end of our runway on the takeoff, and that there is a 50 foot obstacle on the start of our runway on the landing.

This short field takeoff and landing with obstacle procedure builds on the skills practiced in the short field takeoff and landing with no obstacle. The objective is to use as little  runway as possible to land and take off, but also to accurately plan our clearance point.  On the takeoff  we need to become airborne as soon as safely possible and climb as fast as possible so we clear our obstacle. This means we need to use Vx, our best angle of climb speed.

On the landing, we have to plan it so we approach so we clear the obstacle and at a proper speed so we still have enough runway to  stop.  The obstacle approach will have us touching down further down the runway then we would if we didn’t have an obstacle to clear, so we have less usable runway. We want to be at a slow enough speed commensurate with safety so we can stop with enough runway.

Ask for clearance

Since I fly out of Springbank airport, which is a controlled airport, I ask for a short delay on departure when I’m holding short of the runway.  In this procedure we line up at the very end of the runway – “on the button.”  Like the short field, we apply full brakes add full power, carb heat cold, check the engine and mixture (if required) and release the brakes.

The speed at which we rotate – or take off – will be given in the aircraft’s POH.  The POH will also give us the climb out speed. For the aircraft I learned on, GSKF, a Cessna 172 N, this is 46 knots. Note that the speed will change with respect to the aircraft’s weight – this is all given in the POH. The POH will also tell you if you need flaps or not for the procedure. For our aircraft I used 10 degrees of flaps.

Short field takeoff and climb with obstacle

Steeper climb-out angle

The main difference is we climb out at a much steeper angle than we did when we didn’t have an obstacle.  This causes the stall horn to sound – which I found disconcerting – but remember, the stall horn sounds 5-10 knots before the stall, so you will have time to ensure you control your speed, and on take-off, our speed is increasing, not decreasing.  Be aware, even though it takes a big longer to stall the aircraft at such high power settings, if you do, this is the dreaded departure stall.

Note clearing the obstacle

We need to mentally ‘note’ where the obstacle is, and to say “clear the obstacle’ once we have cleared it.  At Springbank, the altitude is 3940 feet, so once we are approximately at 4000 feet we announce we are clear the obstacle. The same follows, at 200 feet AGL we announce two positive rates and retract our flaps if we are using them.

More controlled, power-on approach required

The approach for landing is similar to the short field, with flaps – however the objective is to use a power on approach so once we reduce power to idle once we are are clear the obstacle.  We try not to approach too high initially so we decrease power to idle too soon – I made this mistake a few times while practicing, and on the flight test, the examiner wants to see that you know to decrease power once you are clear the obstacle, so they see you understand this is what you are trying to accomplish.

Once clear the obstacle which we imagine is at the start of the runway, we announce it, reduce power, and loose the last bit of altitude, flare and touch down. When we touch down, we push the nose down, retract the flaps, and add heavy brake while applying full back pressure with the control column.

Learning this procedure is challenging, but it is A LOT of fun!

Posted on 1 Comment

Short field landing

Short field landing and takeoff procedure explained

At a certain point, your lessons will be about precision flying after you know the basics.  Now my lessons are about more precise flying, not only just about making it down to the ground safely.  Recently I was practicing to aim to land at a particular spot on the runway, using different flap configurations and no flaps.  This was to get used to being precise and prepare for the short field landing technique.

The other day I learned the short field landing method. There are two kinds of short field procedures, with an obstacle (we usually use a 50 foot obstacle) and with no obstacle.  We did the landing without obstacle and next we will do with obstacle, as that is more advanced.   The non-obstacle technique assumes that the runway is clear of obstacles (such as trees or power lines) so we don’t have to worry about clearing anything on our approach or take off.

The short field landing technique is a lot of fun to learn and practice.  It is a specialty procedure that comes in handy when landing at an airport with an unknown runway length or when there are concerns about usable runway length.

We want to plan to use as little runway surface as possible to both take off and land. So on the take off, we line up “on the button” meaning as close to the runway edge as possible.

Short field takeoff

For the Cessna 172, and our particular model, and at Springbank airport, we then follow this takeoff procedure:

  1. Apply full brake
  2. Flaps 10 degrees
  3. Full power
  4. Lean the fuel mixture (check), then mixture full rich
  5. Confirm engine gauges in the green
  6. Release brakes

Once the aircraft starts to roll we steer with rudder to maintain runway centre line. Depending on the aircraft model, we lift off at the recommended speed to fly in ground effect. The particular aircraft we were in, FDAJ, this speed was 46 knots.  We pull up to fly in ground effect, and then push down on the control column to keep from climbing and keep the aircraft level. We fly in ground effect a few feet off the ground without climbing until the airspeed builds to 60 knots, at which point we pitch up and climb out at 65 knots.  We let the aircraft gain 200 feet of altitude AGL. At Springbank the above sea level altitude is 3940 ft, so we wait until our altimeter shows 4140 ft.  We then check for two positive rates on the instruments: one on the vertical speed indicator (VSI) and the altimeter – that is, the VSI is above zero which means the aircraft is in a climb, and that altimeter is increasing which also means the same. We take flaps to 0 degrees, that will establish our speed to 70 knots, and we climb out normally!

Short field Landing

Then there is the landing, which is followed by a full flap approach. In our aircraft we used 30 degrees of flaps and approached at 61 knots as recommended in the aircraft’s pilot operating handbook (POH). We wanted to plan to touch down 500-600 feet after we flared so we look for appropriate runway markers for us to judge this distance. At Springbank, runways 16 and 34 have 500 foot and 1000 foot markers, so it is easy to see our targets.

After we touch down, we apply the brakes – hard. We push the nose of the aircraft down for maximum brake effectiveness and retract the flaps to decrease the lift also to really make those brakes effective.  The first few times I landed I wasn’t aggressive enough on the brakes but eventually got to pushing down on them hard enough. The application of brakes should be so hard you actually are pushed forward and can feel your seat belt.  This is because we are trying to use the minimum runway length possible.

It was really a lot of fun to learn this procedure and I’m excited to try this next time, this time I will be on my own.