Approach and landing is the most common phase of flight for aviation accidents, accounting annually for approximately 65 percent of all accidents. A Flight Safety Foundation study of 16 years of runway excursions determined that 83 percent could have been avoided with a decision to go around. Approximately 3 percent of unstable approaches result in go-around policy compliance.(FSF Go-around decision making and execution project)
The obvious question that arises is “why do pilots do not go-around?”.
Since training is the foundation of learning knowledge and skills, there must be a training module for unstable approach and go-around.
The theoretical part of an unstable approach comprises of the parameters to be flown, the various gates to be complied with. If the approach is unstable, then a go-around must be carried out to prevent the consequences of a runway excursion primarily and this fact is known to all pilots.
Situation awareness is the perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future.
No pilot would deliberately put their lives, the lives of the passengers and the aircraft in danger. Therefore if a pilot/crew continues with an unstable approach to land, there is an issue with one or more of the three elements of situational awareness. The pilot/crew are unable to perceive the risk and project their status towards the end of the approach when the aircraft lands.
While information theory is about how information is processed in cognition, Schema theory describes how knowledge is structured in cognition.
Why is Schema important?
- For information to be stored in the long term memory, the learner should form a Schema.
- More schemata and more schema, easier to learn and perform tasks
How is Schema constructed?
- Experiences. Richer the experiences are, more will the schema will be developed. e.g. If various scenarios involving unstabilized approach/mitigation are taught and practiced, the schema becomes stronger.
- Connecting new information to existing schema
Once activated in a situational context, schemas provide a framework for interpreting events, people, and situations. In addition to guiding the encoding and retrieval of information from memory, schemas provide a basis for filling in information gaps and short cuts for problem solving (Taylor & Crocker, 1981). For any given situation, a person may have more than one applicable schema. In that case, the schema used is the one most easily retrieved from memory (Bruner, 1957).
E.g. On the final approach the human brain is always acquiring information from visual parameters and auditory senses. These are constantly being compared with the stored schema of an approach in the long term memory.The crew therefore is expecting the approach to be flown in an expected patters.
With experience , the schema is enhanced by adding experiences like the gust levels on approach which is typical to many airports or unexpected tail winds. Therefore the human brain expects certain conditions to prevail and the comparison with the stored schema passes. As the schema is used and more variations are experiences, new schema is also developed.
During training a number of scenarios are flown. The pilot/crew develops schema with their experience and keep adding to it. The crew practices for e.g. wind shear during takeoff and approach. This is registered in the long term memory and when encountered in real life, the situation is recognised. The crew is also aware of the consequences of mishandling a windshear scenario and the same is recalled immediately when the aircraft is in an undesirable state.
Conceptual understanding increases with increased knowledge, experience and critical thinking. Debates and discussions are important tools too. These help further develop schema and reduce the possibility of unexpected scenarios.
In a typical unexpected event, the crew takes time since the scenario is not stored in the schema but has to be built by recall of different concepts and making a choice from the various options available. Therefore, critical thinkers are always looking at variations of scenarios and thus enhance their schema.
Usually most airlines do not train pilots for specific scenario’s of handling an unstabilized approach or a long flare. The crew is aware of the parameters to be complied with when flying an approach for landing. Consequences are also taught theoretically but not demonstrated or flown in the full flight simulator when undergoing training. If the crew has not seen the variables of an unstable approach, then how will the pilot/crew develop a schema for the same. In this scenario, the crew will have to use the recall technique rather than the recognize (single step). The recall step is time consuming and the brain has to search for combinations in order to come to a conclusion.
The crew is not trained on the numerous possible ways that an approach can be categorized as unstable. If only theoretical training is carried out then the attention levels are low due to the time consuming process of recall.
Schema is used in sports where skill is required. Take for e.g. boxing. The boxer is trained repeatedly to throw punches and guard from incoming punches. However this is not enough since the opponent’s style, speed and power cannot be predicted with accuracy. Therefore the boxer is also trained on variations from the normal. The boxer is thus developing more and more schemas. This increases the recall since the recognition is faster and is able to visualize the consequences and counter them.
The crew will be able to visualize the consequences of the prevailing situation with a more developed schema and perceive the risk. A mitigating action in time and with accuracy is the need of the hour. In order to enhance safety by ensuring that the crew is able to take timely mitigating action when encountering situations which destabalize the approach, the crew must be exposed to more and more situations during training so that the schemas are more developed.
Critical thinking requires looking at a concept from different dimensions so as to develop strategies and schemas. This prevents being caught off guard with out a plan.