Now that we have considered the aspects of the stabilized approach, we can consider a practical example at our home airport. At Cape town international the main runway that we use is 01/19. We will consider two possibilities for each runway. Firstly, when landing at the threshold. Secondly landing deeper into the runway, abeam taxiway ‘E’ when RWY 19 is in use, and landing abeam intersection ‘C’ when runway 01 is in use. The reason for the latter is to aid the flow of air traffic in and out of the busy Cape Town International airport. It is however a cause for concern, as this puts undue pressure on the pilot (threat) to fly faster and he/she/they end up trying to land at an excessively high speed (undesirable aircraft state). This can be compounded when the pilot is intent on vacating at the at the first available taxiway. Due to the higher touch down speed, (undesirable aircraft state) the pilot will usually float (error) and touch down later than desired (undesirable aircraft state). They will then apply harsh/excessive braking (error). This can lead to a tyre locking and possible blow out can occur (undesirable aircraft state). If it is one of the main wheels, the aircraft can veer off the runway. The end state of the aircraft can vary dramatically, depending on if it hits an object on the side of the runway or goes into a ditch (Accident/incident). Either way, it is incredibly dangerous. You will notice I have put in brackets where threats, errors, resultant undesirable aircraft states have come together and resulted in Accident/Incident. As you can see this is a very real and possible scenario at our home airport. By using the concept of the stabilized approach, it is totally avoidable.

Stabilized approach to the threshold of either runway is the first scenario we are going to look at. Our first step is to consider the elevation of the airfield. FACT is 151 feet above mean sea level. We will have to add our 300ft window to this elevation. This gives us 451ft above mean sea level. Every time that you fly your approach, when you reach this altitude, you will need to confirm that you have met the parameters as set out in the standard operating procedures. If these parameters have not been met, call “Go-around” and execute the procedure.

Remember we are using a 3-degree descent angle which equates to 300ft for every mile flown. This will put the aircraft at 1500ft when you are at 5nm from touch down point. For every mile flown you can subtract 300ft from your initial approach altitude of 1500ft. Remember, this will only be possible if you can measure the distance with the use of DME or GPS distance. Please remember that this still remains a guideline as the VOR(DME distance) or the Airport Reference Point (GPS distance) might not be exactly at the threshold of the runway. However, using this method allows for more precision in your approaches. If you are using the threshold as your aiming point, the window should be approximately 1nm or 1852 meters from the start of the runway. From the start of the approach, it is important to manage the speed and configuration of the aircraft. If you are comfortable and know the performance characteristics of your aircraft, you will be able to fly optimum speeds on the approach whilst achieving the desired parameters by the time you reach the decision window. I would suggest an exercise with a simulated approach from this at altitude in the general flying area, to attain an understanding of how much height, distance and time your aircraft will need to slow down whilst descending at a 3-degree angle of descent.

Stabalized Approach Part 2

The second scenario we discussed, is when we are planning on landing at the intersections namely ‘E’ TWY and ‘C’ TWY at Cape Town International Airport. Remember, we are changing our aiming point and must therefore adjust our approach. The common mistake is that the pilot will use the same aiming point (the threshold) and then fly the aircraft with power on, just above the runway until they reach the intersection. This should be avoided if possible. On the diagram, I have plotted the two different stabilized approach height windows, using a 3-degree slope. One is plotted based on the aiming point being the threshold. The other is based on the aiming point being the intersections of the taxiways. Please note that it has been plotted for the purpose of pointing out approximately where these windows would be located. You will also see that when using the intersection as an aiming point, the window is approximately just before the threshold of either runway. At this point your aircraft should be at 451ft AMSL and stabilized as per our desired parameters. This goes to show that there should be no reason, when using intersections as aiming points, that the aircraft should not be stabilized by the start of the active runway threshold at Cape Town international.

By using this procedure, we will be able to assist with the flow of traffic in and out of Cape Town International, whilst maintaining and mitigating the risks of using touchdown points further down the runway. It is also clear that by using the concept of the stabilized approach, we are able to be at 300ft with 1nm to touch down, with an aircraft that will react safely, and predictably. This also improves our consistency when learning how to land.

Lastly, I would like to stress the need to be proficient at conducting a go-around with confidence and precision. Practice this with your instructor, or alone in the general flying area at a safe altitude. This will greatly aid you in a real-life situation when your response will determine the safe outcome of a flight.

At Cape Town Flying Club we are committed to the efficient and ultimately, the safe operation of our aircraft and our pilots. We are always keen to train our students, whether they are recreational pilots or career pilots, with the mindset that an aircraft can always be flown professionally no matter the mission.

If you have any questions, please contact Cape Town Flying via telephone, email or one of our social media platforms and one of our knowledgeable instructors will be able to assist.

I wish everyone safe flying,

Erich Britz