How pilots keep their skills sharp during COVID-19 downtime
Last year was tough for everyone, and it was especially tough for the aviation industry. Despite the fact that there were drastically fewer flights, aircraft accidents claimed more lives in 2020 than in 2019.
Of the 40 reported accidents, five proved to be fatal. Tragically, 176 people were lost when a Ukrainian International Airlines Boeing 737 was mistakenly shot down after taking off from Tehran’s Imam Khomeini airport. This accounted for over half the fatalities in accidents in 2020.
In another incident, a man was killed after being struck by a Southwest Airlines 737 as it landed at Austin-Bergstrom International Airport in Texas. The man had climbed a perimeter fence and found his way onto the runway.
Whilst both tragic, both these incidents are events that we rarely see happen. The other three accidents are sadly all too familiar territory. Runway excursions, events where an aircraft leaves the paved surface of the runway, are a well-known threat to flight safety.
Aircraft involved in accidents in Pakistan, India and Turkey all touched down on the paved surface, but for different reasons ended up with the aircraft either off the side or end of the runway.
Even though each event featured a well-known threat, could the reduced amount of flying pilots are doing have an effect on flight safety? Faced with long periods in between flights, what are pilots doing to keep on top of their game?
Skills fade
If you do not practice a particular skill for some time, your ability to execute that skill to the best of your ability will reduce; whether it’s hitting a tennis ball, playing a musical instrument or flying an aircraft.
In pre-COVID-19 days, pilots would be flying regularly enough to allow them to operate at the highest level of proficiency. However, with the reduced number of flights, some pilots are barely getting one flight a month, if at all. This means that their skills will get rusty.
When it comes to hitting a tennis ball, getting rusty isn’t a problem. When it comes to a safety-critical job, it certainly is. Scientific studies have found that after a long period away from the aircraft, our ability to react quickly is retained better than our ability to act reliably. This means that we get up to speed flying the aircraft quickly, but we are three times more likely to make errors in doing so.
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To prevent this from happening, there are a number of things we can do when sat at home before our next flight. Reading the aircraft manuals and reading safety notices as they are published is a simple way of keeping abreast of what is changing during a period of downtime.
In addition, discussing technical subjects with colleagues is a good way to bounce ideas off each other and pick up useful gems of information. Many airlines have been running Zoom calls where a training captain will lead a discussion on a particular technical topic.
One of the more interesting methods of retaining a skill is through mental rehearsal. A study at the Canadian Airforce found that pilots who sat and mentally ran through a flight whilst on the ground performed much better when it came to actually flying the sortie.
This "sofa flying" is something that airline pilots can do at home, taking some time to mentally run through a flight, visualizing the buttons and switches they will use at a particular moment.
Not only is this useful to remember the actions in certain events, for example, an engine failure after takeoff, but it also helps to stay in the mindset of identifying threats.
Identifying threats
Before every takeoff and landing, pilots will conduct a brief. Not only does this give us an opportunity to talk about what we expect to do and how we will fly the aircraft, but it also enables us to identify any threats, reducing our workload later in the flight.
However, it’s not just a matter of stating what we see. Whilst this identifies the threat, it does nothing to help reduce the workload. Threat analysis comes in three levels and is known as NUTA -- notice, understand and think ahead.
Notice
The notice level is the most basic level of threat analysis. As an example, we see on the weather report that there will be a tailwind on landing. It's all well and good to have noticed this fact, but so what? What does this actually mean for how it will impact the approach and landing?
Operating at the notice level doesn’t help reduce the workload. It merely identifies a fact which needs developing.
Understand
The understand stage takes the observation and turns it into something that we can use to our advantage. As there is a tailwind, it will increase the landing distance we require to stop safely.
This has developed from the basic notice level into something which is of better use to us. We now understand how this tailwind could impact the arrival. While this is certainly a better level to operate at, it still won’t keep clear of all potential dangers.
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Think ahead
A good crew will take the information from the understanding level and think ahead to see how they can stop this from becoming a problem before it happens.
If we know that we may land with a tailwind, we will realize that this could affect our landing distance. We would then calculate how much of a tailwind we could accept before there is not enough runway left to stop.
As soon as that wind value is reached, we will know that we have to abandon the approach and either wait for it to reduce or make an approach to the other end of the runway.
Landing distance calculation
The process of stopping safely on the runway begins hours earlier in the calm of the cruise. Here, the first step is to decide if the runway we plan to land on is long enough for the aircraft weight and the given weather conditions.
Landing distance required
Landing distance is defined as the horizontal distance traversed by the airplane from a point on the approach path at a selected height above the landing surface to the point on the landing surface at which the airplane comes to a complete stop.
In plain English, this means the distance required from passing over the start of the runway at 50 feet to becoming stationary. This is also known as the calculated landing distance. However, as this is the minimum distance calculated for a textbook landing, most airlines use a safety factor of 5% to 15% on top of this.
This ensures that should the landing not be perfect -- for example, if the aircraft touches down a little deeper than planned, there is still sufficient runway remaining. This is known as the required landing distance.
Therefore, in all cases, the landing distance available must be greater than the required landing distance.
Wind direction
A contributing factor to the accident in India was the presence of a tailwind on landing. For the same airspeed on touchdown, the speed over the ground will vary with the wind. Say the aircraft is flying at 100 knots -- this is the speed of air over the wings in order to generate lift.
If there is a 20-knot headwind, the speed of the aircraft over the ground is just 80 knots -- the ideal situation as it results in a shorter required landing distance. This is why pilots prefer to land their aircraft into the wind. However, the reverse is therefore the case with a tailwind.
For an aircraft approaching at 100 knots with a 20-knot tailwind, the ground speed is 120 knots. This will massively increase the required landing distance, much more than you’d think. As a result, pilots are acutely aware of the wind shifting during their approach.
Runway condition
The aircraft involved in the accident in Turkey made its approach during a heavy rainstorm onto a wet runway. Once the wheels are on the ground, it’s time for the wheel brakes to start to slow the aircraft. However, like in your car, the condition of the runway surface can have a huge effect on the effectiveness of the brakes and, as a result, how much runway you need to stop.
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If the airfield weather states that it is raining, or it may rain during the time of landing, pilots will treat the runway as wet and calculate the performance accordingly. The quantity of water and how well it drains off the runway will affect the stopping performance of the aircraft. As a result, a "braking action" is declared, letting pilots know how effective their brakes will be.
Stabilized approach
In the history of aviation, a major contributing factor to runway excursions is when the aircraft has reached 1,000 feet above the runway too fast and/or too high. The chances of recovering the situation from here are minimal. However, as the pilots are likely to be overloaded, their capacity to call for a go-around at this moment is greatly reduced.
To prevent pilots from getting into this position, most airlines have a stable approach rule.
At 1,000 feet above the ground, the pilots must confirm that the aircraft has met three parameters for landing. The aircraft must be at or close to its final approach speed, on the correct vertical profile and in the landing configuration.
If these criteria have been satisfied, the aircraft is declared as “stable” and the approach may continue. If any of these have not been met, the aircraft is “unstable”‘ and a go-around must be flown.
Correct speed
The speed of the aircraft is directly linked to its energy. Too much energy could result in a runway excursion. If the speed is too great at the 1,000-feet point, there is a good chance that it won’t be back at the approach speed as the aircraft crosses the runway threshold.
That said, ATC quite often requires pilots to fly a certain speed, normally until around four to five miles from touchdown. This is to ensure the separation between aircraft is maintained. However, four to five miles normally equates to around 1,400 to 1,700 feet above the ground. This still gives us plenty of time to slow the aircraft to the final approach speed.
Correct vertical profile
Most approaches to international airports are flown using some kind of signal to guide pilots to the runway. This can either be sent up from the ground such as an ILS (instrument landing system) or using the GPS position of the aircraft to fly a guided approach to the ground.
When the aircraft reaches 1,000 feet above the ground, the aircraft must be in the correct position vertically, based on the guidance available to us. Too low and there’s a chance that we could end up hitting the ground short of the runway. Too high and there’s a chance that we will touch down too far along the runway.
Landing configuration
In order to land safely, we must make a number of configuration changes to the aircraft. The most obvious one is that the landing gear must be down. This may sound obvious but depending on the aircraft type, it can take several seconds from moving the landing gear lever to the gear actually being down and locked in position. The gear in transit is not acceptable. It must be down and locked.
Secondly is the flap position. The flaps are used to increased the surface area of the wing, thus creating more lift when flying at slower speeds. The greater the flap setting, the slower the aircraft can fly.
When reaching the 1,000-feet point, the flap setting chosen for landing must be in position. Like with the gear, the flaps in transit are not acceptable. They must be locked in the desired setting.
Bottom line
The job of a good pilot is to identify threats, not only those which could affect the aircraft, but also in their own performance. Going weeks and even months with very little flying can result in significant skills fade.
There are a number of things pilots can do to combat this, one of the most useful being mentally rehearsing a flight. By thinking through exactly what buttons we will use and what actions we will take in a certain situation, we can ensure that we act to the best of our ability when we finally get back in an aircraft.
Thinking through and identify threats is also a great way to keep our evaluation skills on point. The environment in which we operate can change rapidly and it’s our responsibility to ensure that we always perform at our best.