Sunday, September 14, 2008


Basics about the Cockpit
In aviation, the Captain has been assigned a very important position. He is the designated leader, and is given the legal authority for the flight. He is responsible, along with his crew, for the safe and efficient operation of the flight. His decision under most normal conditions of flight is final. However, he may take the help of all available resources to arrive at the final decision, as he may not have the full picture, at all times. He is also responsible for crew performance, directing actions of the crew and can ask for assistance of any crew member. The First Officer (F/O) is a qualified crew member who has the education, training, and skills and as some one rightly put it ‘he is like a second in command’ who can take over as Captain in the event of incapacitation of the Captain. This is an important point. However, depending on his experience and personality, the F/O may not be able to handle all situations like the Captain but would be competent to handle all probable situations in flight. With these basics, let us analyse the worst case.

Human Limitations
It must be understood that both the Captain and the F/O are human beings and that their performance is susceptible to all human limitations. These include being prone to loss of situational awareness, stress and fatigue; having an attitude and perceptual problems. Other problems may include limitations in the application of knowledge, exercise of judgment, short term memory (working memory, which is akin to the RAM in a computer) overload, and finally incapacitation. Also, we are all familiar with the saying that ‘to err is human’. This saying will continue to be true as long as we human beings have limitations. However, in aviation – a profession that is very constrained by time; is highly stressful; has complex processes; and which is closely scrutinized the media, regulator and public, we can ill afford to have human errors, as these errors can be fatal, and have been so in the past. Human errors are defined as ‘the unintentional act of performing a task incorrectly which can potentially degrade the system’. Errors can include problems in practice, procedures, and systems. Human error has been a major contributor to incidents/ accidents in the past. Here it also needs to be emphasized that accidents do not generally happen due to a single factor. They are a culmination of a ‘chain of events’ of small factors. The aircrew is the last link in this chain that can prevent these errors from turning into incidents/ accidents. To prevent these incidents/ accidents, the crews need to be aware of error management.
Error Management
Error management can be best accomplished by ‘Error Avoidance’. In case this is not possible then the next step would be ‘Early detection’. Finally, in case the error has been detected late or not detected, then steps have to be taken to ‘minimise the consequences’ as a result of these residual errors. Let’s take an example to understand this process. We have been cleared for a radar vectored ILS approach for R/W 28 at Delhi. The local QNH is 983 hpa and the weather is Rain/ Thundershowers with low clouds at 300ft. We are descending through transition level, and about to change the altimeter setting when the TCAS warning goes off. You are put off for a while, and forget to change your altimeter setting to local QNH with the result that you are now flying 900 ft. below the required altitude. An error has been made. This could have been prevented if the crew had remembered to call out the QNH changeover, after the excitement about the TCAS had been resolved. Once this error has been made, the next option is to detect it at the earliest. This can happen when the PF calls for the completion of the approach checklist. The next checkpoint would be when the radio altimeter is called out and altimeter cross checked. The next stage would be the callout at the Outer Marker, followed lastly by the Landing checklist. In case this error goes undetected then it would be vital to mitigate the consequences of this error by initiating go around at the Decision Altitude, if there are no visual references to land. This is a very mild example of an error and the three step process to prevent incident/ accident. The PNF (PM) by just doing his job of giving the callouts at the correct time would help in neutralizing the error. In an actual case the error could have been introduced by any component of the aviation system involved with the preparation, launch, execution and recovery of the flight. In such cases it may be very difficult, at times, to prevent the error and equally so to detect the error. A 2-crew operation can help in such cases. Our checks, callouts, and procedures have been designed with an aim of detecting and neutralizing errors before they can become problematic. The 2-crew cockpit has the inherent advantage of built in redundancy. It also helps in workload sharing and in ensuring constant crosschecking and monitoring of all actions (by both crew members); monitoring of aircraft trajectory; automation systems and mode status; and aircraft systems and components. To ensure all of this, it is vital to practice CRM. The major rationale for CRM is to enhance crew co-ordination and through this ‘to reduce the frequency and severity of errors’, or error management. Error management can be further enhanced by optimizing human performance in the here and now. What is CRM? NTSB defines CRM as ‘using all available resources – information, equipment and people to achieve safe and efficient flight operations’

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