VISION AND AIRCRAFT ACCIDENTS

 

VISION AND AIRCRAFT ACCIDENTS

 

INTRODUCTION

 

(In the recently released film Drishyam the hero’s family murders a boy inadvertently. To deceive the Police the family plants a visual image in the mind of potential witnesses to show that he and his family were in a different place on the date of the crime. He manages to create this illusion by repeatedly narrating certain incidents which had actually taken place and cleverly juxtaposing them with certain imaginary happenings on falsified dates. The listeners mind is thus tricked into amalgamating both the fact and fiction and made to supply the end product i.e. the family is at a different place on the day of the crime. The witnesses testify for the family without realising that their brains have been tricked into creating a picture which was only partly true. The science of vision supports the possibility of such a deception. The brain subconsciously supplies details based on the experience thus filling in the gaps which could have been missed by the eyes or might not have been present altogether to make a complete story of what has been projected in front of the eyes. It is possible not to see things which are directly in front of the eyes and also possible to see things which are never there. The first school lesson on vision comparing our eyes with camera after all may not be totally true. The truth is that we do not see by our eyes, we see by our brain.)

 

 

1.       It was the year 1995 when I was part of the COI constituted to look into the incident of wheels up landing. It was a multi crew aircraft with five people in the cockpit and apparently all failed to see the lever right in front of them which was in up position. Of course, everyone missed out on many other visual and aural alerts which blared in the form of beeps, horns and flashing warning lights. But missing out on so many clues did not come as a surprise, for such ignoring of obvious clues has been happening in the field of aviation since long. Crew mistaking airfields and towns in spite of huge differences in their appearance, misreading the instruments, confusing switches, misinterpreting approach charts etc. have been so regular that its occurrence ceases to surprise the aviators. What surprised me though and set me thinking was the insistence of the Captain that he was sure that on finals he had glanced at the lever and remember clearly seeing it down. It had been conclusively established that not only the wheels but the lever too was in up position. Hence the captain in no way was trying to extricate himself as he well understood that his stand has no validity in front of the overwhelming proof. He however told me this with full sincerity adding that he himself is confused and perplexed with this contradiction. While going through the CVR it was clear that the crew were overloaded as multiple emergencies had been simulated. There was a call for undercarriage at least 3 times and one or the other crew had responded that it was down. I, like everyone assumed that the crew answered without looking at the lever which was in the up position. The limitation and vulnerability of our senses also disturbed me as each member of the crew was an accomplished professional with good flying record. Having a natural interest in human factors affecting aviation I recollected many accidents and incidents where obvious visual clues were missed out and ignored.

 

2.       Further reading into such accidents I could see a pattern emerging. Such mistakes had been committed where the work load of the crew was high either due to some emergency or increased difficulty by way of fatigue or bad weather or a combination of all of them. During such times the attention of the crew has been tunnelled and fixated on the immediate task of handling the flying controls thereby ignoring the other parameters which also need to be scanned or monitored. Reading through these accidents and correlating with my past experience of flying multi crew aircrafts I could see the pattern pointing clearly that juggling numerous tasks especially under condition of increased stress, like on board emergency, the ability of Captain in taking well balanced decisions was compromised. Books on vision agrees to this finding as it has been an accepted fact in the medical world that human mind is not good at multi tasking. The science of vision also points to the possibility of deception which the vision mind combination can create where the brain subconsciously supplies details based on the experience thus filling in the gaps which could have been missed by the eyes or might not have been present altogether to make a complete story of what has been projected in front of the eyes. It is possible not to see things which are directly in front of the eyes and also possible to see things which are never there. The truth is that the eye does not see. It is the brain that sees. The eye just transmits to the brain. With these revelations I concluded that during the high workload conditions the eye brain combination has tricked the Captain into believing that the undercarriage lever was down based on the expectancy of it being down. 

 

AIM

 

3.       The aim of this paper is to highlight the limitation of vision mind combination while handling multiple tasks and suggest modifications in role of crew in multi crew aircraft to overcome this limitation.

 

DYNAMICS OF VISION

 

4.       When we talk of vision there are two components: the eye and our perception of our eyes signals as processed by our brains.  The optical system of the eye is in fact rather crude and the sophisticated visual presentations we receive are principally due to the coordination between eye and brain. The brain and the neural retina process visual information, adding, subtracting and comparing as necessary, to improve the image falling on the retina. Hence what we see is an interpreted (by brain) image of what is exposed to our retina. What the mind interprets and fills in is not based entirely on what lies in front of the lens but is based on our perceptions which is again a result of our experiences. A considerable amount of perception is learned as we are growing up and are exposed to varying situations. We gradually start making senses of our visual stimulus arriving to making meaningful interpretations of what you see. As an example a runway has multiple cues and the brain will analyse these cues to arrive at a conclusion that what has been presented before is a runway. The process of analyses will also depend heavily on the state of the brain. If the brain is preoccupied or under stress as is the case in a serious emergency it would not work efficiently and would tend to take short cut and also would like the situation to get over fast. In fact the mind in such cases would unconsciously start supplying the associated cues which doesn’t even exist there as the brain has capability to supply missing links based on perceptions which are based on our experience. Brain may be an excellent piece of creation working more efficiently than the most efficient computer but it has its own limitations which need to be understood to be over dependent or over reliant on it. One such limitation is multi tasking.

 

5.       Our brain can effectively process only one task at a time i.e. multi tasking though spoken of as if it is a norm and expected out of all aircrew is nothing more than a myth. Human brains are not meant to multi task. Multiple tasks when done are in fact accomplished on timesharing basis i.e. the brain keeps shifting from one task to another giving an impression that the task is being carried out simultaneously, however the fact is that the brain is processing only one task at a time and leaving the other unattended during that period. We do not appreciate this as most of the tasks do not require continuous focussed attention and can be carried out without much problem on time sharing basis. However this limited mental processing capability can present problems when there is a requirement to fully attend to two sources of information at the same time like any additional task being performed during traffic or bird scan. Such an additional task can reduce the effectiveness of the search, even to the extent of reducing the pilot’s eye movements and effectively narrowing the field of view (which are controlled by the brain). In an experiment it was concluded that the most difficult secondary tasks resulted in the greatest restriction of eye movements. Talking, mental calculation and even daydreaming can all occupy mental processing capacity and reduce the effective field of vision.

 

DEDUCTIONS

 

6.       Going back to the incident narrated earlier of wheels up landing, the CVR had clearly brought out that the crew were overworked and the Captain was carrying out too many activities hence he was bound to become tunnel minded and overlook certain aspects. When the caution for the undercarriage down was read he would have glanced at the lever briefly. However his mind would have been busy in analysing the flying parameters which to him appeared to need more and immediate attention. Without getting into analysis the mind takes a short cut and resorts to a response based on expectancy. The important point to keep in mind is that the total parameters requiring attention are more than a normal human is capable of handling. The vision mind combination would have filled up the information regarding undercarriage based on expectancy and previous experience which conveys that the undercarriage has to be down. Hence the entire crew were trapped into a sort of set where everybody saw what the mind was expecting them to see. Like in case of an emergency the mind gets fixated on one particular aspect requiring more attention. Hence the other things are likely to be missed out. Another factor we keep in mind is that research indicates that multitasking reduces the efficiency. Hence it is important that the Captain during emergencies should never be loaded with too many tasks. Maximum duties should be delegated to all crew members and the Captain must be free to analyse the emergency. It is strongly suggested that during such times the actual flying should be transferred to the co-pilot who also should use auto pilot to the max. In case of a serious emergency the pilot’s ability to monitor multiple tasks is reduced and here the brain starts filling in the information based on his experience. The phenomenon could be further elucidated by going into the anatomy of the eye. In the eye there is a blind spot where the optical nerve leaves the eye, yet what we see does not have a piece missing because perception as brought out earlier consists of two processes. First the image on the retina is passed up the sensory chain to the visual cortex where the information is adjusted and interpreted by what we know, by our experiences and our interpretation of the world.

 

7.       There have been numerous accidents where the Captain has taken incorrect decisions/actions when faced with an in flight emergency. While analysing such accidents it should be kept in mind that the human brain is not good at multitasking especially under stressful situation. Hence the chances of taking a wrong decision, under stressful circumstances carrying out multiple tasks, are high. Whenever an emergency is encountered there are two aspects which need to be catered. One is the control of the aircraft and the other is the decision which the emergency elicits like the need to shut the engine, to return or continue, to declare or not to declare the emergency. In my opinion flying the aircraft is an easier and simpler task which can be easily handled by any co-pilot. The most difficult part is the decision making and ability to remain cool. This would also contribute to garnering all resources to tackle the adverse situation. Keeping in mind the fact that humans are not particularly adept at multi tasking it is most likely that both these tasks cannot be done by one single person. In case it is done than the output would not be optimum. It should be logical to task the Captain with the task which has more bearing on the outcome of the flight which is the decision making. To execute this task the Captain has to be relieved of the task of flying which can be delegated to the Co- pilot.

 

 

 

RECOMMENDATIONS

 

7.       We need to understand this human limitation and ensure that we do not fall into the trap. The tasks of the crew have drastically changed over the times especially in multi crew aircrafts. The autopilot can accomplish most of the flying tasks that were traditionally being done by human pilots. However the overall responsibility and quantum of work (work load) has drastically increased due to complication of machinery and tasks which are expected to be complied when flying the latest aircrafts. Crew during flying is continuously carrying out complicated actions in response to the requirement of flying and since multitasking is not conducive to human he should be concentrating more on taking decision and the mundane activities of flying should be totally left to the co-pilot or to the auto pilot. In case of any emergency in multi crew aircraft the pilot should be relieved of flying the aircraft. It is strongly recommended that during critical times of flight like take off and landing the captain should not be flying. The co-pilot should be handling the controls with the Captain monitoring all the actions. My experience says that a single engine emergency as far as flying is concerned can be handled by any qualified pilot or co-pilot. The difficult part is the decision making like deciding to abort or continue the takeoff in case of an emergency and similarly to continue the approach or carry out a missed approach in case of any emergency during the landing phase. Timely decision during these important phases would have saved many accidents in this critical phase of flight. Another aspect is that it is too much to expect the pilot during such cases to keep flying the aircraft and handle the emergency without limiting his abilities. The recommendations might appear drastic as it seems to reverse the roles of the Captain and the Co-pilot where the primary responsibilities of physically flying especially during critical times like Take Off , landing and emergencies is passed to the co-pilot and the decision making capability and instructions remains with the Captain.

 

8.       There is a need to change over from the concept that the actual flying i.e. handling of the controls is the prime responsibility of Captain. The prime responsibility of the Captain should be to take decisions and actual flying can be handed over to the Co-pilot more so in case of any emergency. Stretching this analogy further it is postulated that during critical phases of flight like take off and landing or in case of any emergency the flying should be done by the Co pilot and Captain should keep himself free to monitor parameters and take decision at critical times. The traditional roles of Captain and Co-pilot need a review to the extent that it requires a complete reversal where the flying is with the Co-pilot and monitoring and decision making is with the Captain.

 

CONCLUSION

                                                             

9.           The concept of flying has been Captain centric with primacy of flying capability and responsibility as a defining attribute of a good pilot. Multi crew aircraft have developed from the single cockpit aircraft where all tasks were performed by the Captain. This concept still forms the base for Captain of a multi crew aircraft where the control of aircraft remains with the Captain even in emergency. This needs to be reviewed in the light of the evidence provided by science of vision that that human are not good at multitasking especially during increased workload and stress which often results during an onboard emergency. It may be appreciated that this is a limitation of human senses and is not to be confused with piloting skill. Not understanding this in correct senses would put the pilot in the proverbial trap where he is likely to commit the mistake. It is suggested that SOP and operating instructions take into account this limitation especially during high load situations like on board emergency