Implications of TAWS

Introduction

With the introduction of TAWS and the evolution of these devices, there needs to be an understanding of why they are important and some of the implications of these systems. The main reason for this technology was to increase the situation awareness of pilots in the late 70’s and early 80’s because there was an unacceptable number of controlled flights into terrain (CFIT). This meant that a system had to be designed to stop aircraft from flying into terrain. This lead to simple devices that could tell a pilot how far away the ground was from underneath them. Though this improved the situation it was useful in mountainous terrain where the ground could rise very quickly. Therefore, improvements have been made into a system that can predict where the aircraft will be and if it will crash.

Advantages

The introduction of this technology has help reduce CFIT accidents down to the point that it can be claimed in commercial aviation TAWS has “made a massive difference to safety: there have been no CFIT accidents since that time involving aircraft fitted with TAWS.”1. This is a impressive claim that means that aircraft are not flown into terrain when there was no technical problem with the aircraft.

Cautions

Though the above statistics sounds like CFIT are no longer a problem, it should be noted that “80% of all CFIT accidents involve GA aircraft, of which 70% occur in single-engine models. Even more tragically, 75% of CFIT calamities result in the deaths of all occupants.”2 This means that there are still accidents like these where pilots loss situational awareness.
These figures however, are likely to decrease as more aircraft in GA are being fitted with TAWSs along with the introduction of Technically Enhanced Cockpits (Glass Cockpits).

Implications for pilots

There is no doubt that with the ability of warning signals will help reduce aircraft having accidents class as CFITs. There are however a number of problems:

Reliant
At what point does the pilot become too reliant on these systems to protect them. The pilots who are trained in these new aircraft fitted with this protective equipment gain the ability of more information that will help them be more situational aware of the aircraft and what it is doing. However, some of these pilots are not taught the skills to gather this information without the systems or are unable to fly the aircraft without them.
Theory
Each aircraft may have a different TAWS (or none at all) and therefore the pilot will have to learn about these systems and how they work. In a train fleet it may part of their syllabus because it is in the aircraft they fly. However, not all pilots start, train or have used a TAWS. This means that in order to be able to operate the system properly they have to understand how it works and functions.
Representation
Each TAWS system is different and has its own limitations and representations. This means that it is important that the pilots understand what is going on and what it means. Sometimes knowing just how to use it isn’t enough because though the user can use the system they may not know what it means. Having an understanding of the theory behind the system and its history the pilot will be better suited when changing systems or becoming lost in the different functions of each TAWS. Also by understanding the technology and its own limitations the pilot can then use the system properly at the appropriate times and also understand why the system may be giving false input and take the correct corrective action.
Management
These TAWS systems also give management a tool to blame pilots for CFITs or other occurrences should they happen while the system is operating. Though the final decision should come from the pilot because they are able to see beyond the limitations of system and the information presented. When looking at the procedures of dealing with technology there has to be an understanding of how it works3 .
Accident Still Possible
Even though this technology has the potential to reduce CFIT accidents, it only replaces the shortfall in equipment deficiencies and not the whole picture. This equipment is a tool to help increase situational awareness not completely stop accidents4.

Conclusion

As technology passes down through the industry, it can help increase safety and decrease any unnecessary accidents such as CFITs. However, there still needs to be the theoretical knowledge of TAWS to avoid becoming reliant on them and using them at the appropriate times.

References
1. Learmount, D. (Jan 2010). Global airline accident review of 2009. Retreived from http://www.flightglobal.com/news/articles/global-airline-accident-review-of-2009-336920/
2. Ison, D. (April 2006). Avoiding CFIT. Retrieved from http://www.planeandpilotmag.com/proficiency/pilot-skills/avoiding-cfit
3. Anca J. M. (2007). Multimodal safety management and human factors. Page 91 Retrieved from http://books.google.co.nz/books?id=iM-8xrIJYncC&printsec=frontcover#v=onepage&q&f=false
4. Capt. Maurino, D. (n.d.). HUMAN FACTORS AND TRAINING ISSUES IN CFIT ACCIDENTS AND INCIDENTS. Retrieved from http://www.faa.gov/training_testing/training/media/cfit/volume2/pdf/pages/page5_04.pdf
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Want to know more?

TAWS and GPWS
http://aviationknowledge.wikidot.com/aviation:ground-proximity-warning-system
Glass Cockpit in Aviation
http://aviationknowledge.wikidot.com/aviation:glass-cockpits-in-general-aviation
Safety Benefits of EGPWS
http://www.inforefuge.com/egpws
Certifcation of GPWS
http://www.airweb.faa.gov/regulatory_and_guidance_library/rgorders.nsf/0/94473b57dfae30e985256d2000773d29/$FILE/N8110-64.pdf

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Authors / Editors

M-JohnsonM-Johnson


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