please visit our sponsor

**Free Natural Health Newsletters, Click Here**

Others with a more micro-view have pointed to the failures of US intelligence and also to Military authorities in their failure to interdict the aircraft. Few have made any insightful conclusions about the failure or lack of the incumbent technology to prevent such an event The proposal of this paper is to investigate the feasability integrate a technology into the avionics of passenger aircraft that will pre-empt a September 11th type scenario and not permit an airliner to deviate from it's specified course. 

This is proposed as a pre-emptive, 1st line of defence approach, which implemented would be extremely cost effective in comparison to the static approaches now employed. Background My background is primarily in avionics engineering. At present I am completing a Master's Degree in internetworking. In avionics my main speciality has been in wireless communication systems and those associated with command and control. Virtual private networks in internet space are a major feature of the internetworking course and this exposure has helped in the formulation of my research proposal. 

The main focus of the proposal looks at model to assist routing and control passenger jets through airspace in the same way an IP packet is routed on a Virtual Private Network. The control protocol in this instance will make it immeasurably more difficult for the Hijack of an aircraft to succeed. Reflections on the September 11th attack Before examining the main thrust of the research Let's recap the main synopsis of the events of S We all know that the aircraft were force to crash the 2 towers of the World Trade Centre through co-ercive force this was either: 

a) The pilot or the captain was forced at gunpoint to steer the course b) Pilots were executed and the Hijackers took control of the aircraft Therefore the major challenge is to prevent the possibility of this ever occurring again. Differing Proposals in Prevention The majority of measures have been static for example: 

• Introduction of high –tech X-ray machines 

• Re-inforcing the cockpit entry door and keeping it locked 

• Adding more security personnel 

• Political changes in foreign policy 

• Armed Sky Marshalls The introduction of these measures has not been without controversy and some have been fairly costly for the airline industry None of these however are foolproof nor can they accommodate certain situations effectively for example in a case where the pilot himself is involved in the hijack attempt. Proposal Synopsis IP tunnelling is relatively mature sub-set of the Internet Protocol which has been utilized during the past decade for 2 disparate networks to communicate securely over the public internet, this can be termed a Virtual Private Network This proposal centres on considering the airspace as the "ether" and the virtual tunnel as analgous to the prescribed secure path of a passenger aircraft. 

Global Positioning Systems enable the accurate postitioning of any point on earth with the aid of low earth orbiting satellites Most airports are located in relatively remote areas, a number of kilometres from the city centre. My proposal involves assigning a demilitarized zone for a specified area that we don’t want any aircraft to fly below certain heights. This has the effect of securing land and airspace below certain heights. Another reason for enforcing a no fly zone below a prescribed height is that in the worse case situation, a hijacked aircraft will not be able to descend below the altitude floor into a no-fly zone around a populated area thus minimizing risk to the general population. Mandating altitude ceilings in a civil aviation protocol is not going to prevent a September 11th scenario from happening again. 

Even if this is backed up by strong interdiction action, eg fighters scramble and intercept an airline coded hostile. One must consider the suicidal nature of hijack attempts where terrorists will not be dissuaded by authorities having the political will to shoot down an airliner. The aim of this research is to model a system which will force an airliner to only take its prescribed course even if attempts are made to divert it.. In the event of a September 11th scenario where a prominent landmark becomes a target for a kamikaze style attack, the avionics and software safeguards will not permit a course divergence. Manual overrides will not be permitted so the highjacker will be unable to change the prescibed flight path, even if the hijacker is in ostensible complete control of the cockpit steering column and auto-pilot. 

The aircraft will always maintain itself to be in the prescribed safe zone with the aid of the auto pilot system or if necessary one dictated by an air traffic controller, based on the ground and part of an international flight monitoring system. A forcefull attempt by any person will lead to a jamming of steering or the control system automatically. Development of such a system is possible currently with the level of technology availabe with the aid of avionic controls, inertial guidance and computer systems. The system elaborated on below is merely a theoretical model. A viable functioning system may be entirely different.The model of this system will certainly evolve after integrating the various compenents and operating systems. The Figure below displayes a basic model of an Anti-Hijacking System. 

Figure 3: Block diagram of an Anti-hijacking System We will now walk through 3 possible scenarios on how such a system would work in practice. Although the research will be focused on the third we will explain the first 2 as well. 

Case 1: Initiation of Flight As the Aircraft initiates a flight it takes all required parameters and information required for it's flight including flight path or course from the information database, which is shown in the figure above. Information on Information database depends upon the air traffic control database, weather detector, air traffic detector and other resources. After processing inputs from the the various inputs and database a course is computed dynamically and the information database informs the Auto pilot system with of it's flight plan. The aircraft proceeds toward the destination. 

From the information provided by the information database, the aircraft can be controlled manually too. However at all times a detection system is in place [ shown in the figure above ] which monitoring status of the flight. It gives the feedback to Information database of the exact status at any point in time . 

Case 2: Weather Changes In the case of a sudden weather change which is not an abnormal case, the weather detector detects this change and informs the information database. The Information database quickly and dynamically calculates the next best path and informs the auto-pilot system of a new flight plan. The auto-pilot automatically adjusts the aircraft heading. In the figure above I have divided the autopilot system into 2 functions. Normal auto-pilot systems act only with the information coming from the information database which uses the normally available inputs.. In the case of the course being changed using a manual control system it will be permitted if strictly following the information provided by information database.

 However the deviation detector will always be there to monitor changes. If anyone undermines the information provided by information database and tries to take control of the aircraft entirely on their own, then case number 3 applies. 

Case 3: Abnormal Situation or a Hijacked Condition This is the area which will receive the most attention in the proposed research. After the aircraft is highjacked the first thing that usually happens is a sudden change of course. As long as the aircraft is flying in an auto-pilot mode, the aircraft will follow very strictly the path which was previously assigned dynamically, with an aid of the different sub-systems. As long as aircraft is flying in an auto-pilot mode the aircraft's system is unaware of any hijacking attempts. Moreover in the auto-pilot mode, the control system is locked., so as the aircraft still follows it's prescribed secure path , oblivous to any threat. Any attempt to hijack an aircraft would be via the manual control system only. 

A hijacker has to switch the Aircraft into manual mode before attempting to override the prescribed flight plan. When hijacker attempts to force the Aircraft to follow a different path other then the path directed from the Information database a sentinel will be tripped and theAnti Hiacking system will be activated. A deviation detector is in place. This detector detects any sudden change in flight course or path. The deviation detector is a device which is attached to the flight control system. As the hijacker tries to forcefully alter the course, the deviation detector informs the information database. As the deviation does not match the information which was already dynamically assigned, the information database flags it as an abnormal situation and orders the switch to go back to auto-pilot system hence it orders the aircraft to follow its original path . 

The basis therefore is somewhat of an expert system whereby any information detected by deviation detector will not be considered normal unless it is matched with the information in the information database. This contains the flight plan and the maximum values of deviation that may be carried out in a contingency. Essentially a solid state switch gets activated and de-activated through the information database, according to the expert system inherent in the deviation detector. The relay or a switch is an intelligent device. 

Whenever the Aircraft is in auto-pilot mode, it basically does nothing other then completing the circuit. But whenever it is in manual mode, it always listens to the information database for canonical instructions and will not allow itself to be overridden. After detecting the abnormality, information system executes the following functions: 

• Informs the switch to move back into auto-pilot system at once 

• Informs the nearest tower via the airborne air traffic database about the abnormality in the flight. 

• Informs the value of the deviation 

• Locks the flight control system and moves to maintain the original path 

• Requests the air traffic controller on the ground [ which can be a computer ], for any other suitable path to follow.(This is considered necessary because, after the aircraft is detected as hijacked , then air traffic control will not want the Aircraft tofollow it's original course. The air traffic controller can override the decision made by the information system give a new heading ) In case of an abnormality the air traffic controller has the following responsabilities: 

• Monitors the hijacked aircraft for any abnormality not related to the course change 

• Monitors if the Aircraft is following the dynamically assigned path. 

• If necessary, overrides the dynamically assigned path with a new value. Major Challenges Involved in this Research 

• How to assign a different "tunnel" or path for each Aircraft dynamically 

• Role of the aircraft's control system , auto-pilot system , navigation and computer systems 

• How to design a protocol enabling ground based control to override the pilot's control of the aircraft in the case of an emergency . 

• How to integrate the disparate systems into an expert system. Projected Advantages 

• The above proposal would entail relatively small modifications of present auto-pilot systems and other control systems on commercial aircraft 

• The expert system can even accommodate complicity by airline crew in the event of a hijack 

• The expert system can detect hijacking attempts at any point in the flight plan 

• It is very cost effective compared to current static methods being implemented 

• As the expert system is software based enhancements will be readily implemented Summary Although this research proposal may seem a complex implementation. A credible working simulation is indeed feasable. Targeted research in the area of a software based expert system inter-action with the onboard auto-pilot and control sub-systems will deliver invaluable insights and contribute greatly to passenger safety By : Anoj Sharma poudyal Msc in Internetworking , University of Technology , Sydney