The Collision between PR-GTD and N600XL: The Technical Faults and the Human Blunders - Term Paper Example

 The Collision Between PR-GTD And N600XL: The Technical Faults And The Human Blunders Contents Topic Page No. Abstract…………………………………………………………………………………3 Introduction …………………………………………………………………………....4 The technical factors……………………………………………………………………5 Automatic insertion of the “cleared altitude” field……………………………………….5 Loss of functionality of the collision avoidance system………………………………….6 Inadequacy of information………………………………………………………………….7 Fault in the radio communication………………………………………………………….8 Human factors…………………………………………………………………………8 No communication between the air traffic control officers………………………………9 No order for changing the flight level……………………………………………………..9 Ignoring the loss of mode C in N600XL ………………………………………………….9 Lack of communications between the ATC officers and the ATC supervisors………10 Unawareness of the crew…………………………………………………………………..11 Not taking the required steps……………………………………………………………..11 Other human factors……………………………………………………………….11 Lack of due training………………………………………………………………..12 Conclusion/Could the collision be avoided? ..........................................................13 References …………………………………………………………………………15 Abstract The midair collision between the Boeing 737 and the Embrear Legacy resulted in the crash of the Boeing 737, claiming 154 human lives. Investigations have revealed that there were a number of technical faults that play important roles in causing the midair accident. What is even more important, the human factors are so prominent that they cannot be ignored. It appears that had there not been so much of human follies, the disaster might not have happened. An introspective analysis of the technical as well as the human factors can testify to this fact very well. Introduction It was on 29th September in the year of 2006 that there was a collision between a Boeing737-800 (PR-GTD) operated by Gol Airlines of Brazil along with an Embraer Legacy 600(N600XL) owned as well as operated by Excelaire of Long Island, New York. The collision took place over the Amazon jungle, nearly one hundred nautical miles away to the south east of the Cachimbo Air Base in Brazil. Though the Embraer Legacy could manage an emergency landing at the Cachimbo Air Base, the Boeing 737 had faced a disastrous fate. It succumbed to an utter destruction by the in-flight break up and the impact forces, resulting in all of the one hundred and fifty four occupants being killed. There have been series of investigations with the attempts to point out the factors that led to such a disaster. The National Transportation Safety Board was of great assistance in the matter of the investigation of the midair collision between the two planes. So far as the reports of the investigations are concerned, one thing is very common with the reports submitted by investigation boards like the Brazilian Centro de Investigacao Prevencao de Acdentes Aeronauticos, ICAO Annex of the United States and NTSB’s major Investigation Division. Apart from accepting the fact that the technical faults in the planes as well a in the Air Traffic Control systems played an important role in causing the midair collision between Boeing 737 and the Embraer Legacy, the contribution of the human faults were hardly to be ignored. The stress on the human responsibilities for the midair collision might be different with the varying opinions of the different investigating boards. But, there is little doubt that none of the investigating boards has managed to suppress the human factors that led to the mid-air plane collision. Both the technical factors as well as the human factors were responsible for the midair collision between the two planes. The technical factors Before we come to discuss the human follies that are responsible for the midair collision between the Boeing 737 and the Embraer Legacy and for the loss of one hundred and fifty four lives, let us explore into the technical factors that led to the situation where the two planes collided with each other in the air over the Amazon jungle. Much blame has been put on the ATC or the Air Traffic Control services. It is not exactly without definite reasons. It was possible only for the ATC systems that both the planes were on the same altitude. Again, it would be a wrong idea if it is thought that the since the ATC system is controlled or operated by the human beings, it is the aviation professionals that are to be blamed. There are a huge number of technical aspects that are related to the operations of ATC systems. Automatic insertion of the “cleared altitude” field One of the very first events that led to the midair collision between the planes was the Air Traffic Control computers’ automatic insertion of the ‘cleared altitude’ field which was displayed in the datablock. It might lead to the thought that the air traffic controllers should have taken care to react correctly when the dire situation arrived. To understand this problem, it is necessary to have some idea about the functionality of the ‘cleared altitude value’ and the ‘requested altitude value’. The ‘cleared altitude value’ serves the purpose of reflecting the status of the clearance of the aircraft while the ‘requested altitude value’ serves as a reminder to the controller. The basic problem was that a design in which two pieces of information appear to be identical in spite of their being distinctively different from each other, the error displayed is too latent. There remains almost no distinction between the ‘cleared altitude value’ and the ‘requested altitude value’. Loss of functionality of the collision avoidance system Another technical factor that remained responsible for the midair collision was the loss of functionality of the collision avoidance system of the aircrafts, which generally comprises of a transponder and a traffic alert system. The CVRs or the cockpit voice recorders and also the FDRs or the Flight Data Recorders of both the aircrafts reveal that none of them had received any indication of any TCAS alert. There is also no evidence of any kind of pre-collision visual acquisition by the flight crew. Neither is there any evidence of any kind of evasive action or effort on part of the crew in any of the aircrafts. It is necessary to mention in this regard that both Boeing 737 and Embraer Legacy were equipped with TCAS II computer units and mode S Transponders. (“Brazilian CENIPA Issues Accident Report, Midair Collision Between Boeing 737-800 and Embraer Legacy 600”) It is necessary in this regard, to discuss the functionality of transponders that form the basic part of the collision avoidance systems of an aircraft. The purpose that a transponder serves is to report a unique code that not only aids in the radar identification but also offers the exact indication of the altitude of an airplane. There are three types of transponders that are currently used in the airplanes, namely, mode A, mode C and mode S transponders. The mode A transponders serve the purpose of providing enhanced radar return that is characterized by a discrete beacon code to the radars that are ground based. Mode C transponders serve almost the same purpose. The only factor that differentiates mode C transponders from the mode A transponders is that fact the radar returns that it provides has an encoded altitude data to the ground based radars. So far as the function of the mode S transponders is concerned, its functionality is same as the other two. Apart from that, it helps in an air to air data link capability, making communication between two airplanes possible. Though both Boeing 737 and the Embraer Legacy had mode S transponders, the loss of the functionality of them made the air to air data link impossible. Inadequacy of information The pilots in the Embraer Legacy aircraft that was one of the two planes involved in the collision, was not adequately notified about the loss of the functionality of the TCAS. It had received just a small and static text message on the ‘pilot’s flight display’. The message that the pilot got read “TCAS OFF” the message was all in white letters. Since the situation was quite severe, the pilot could have been sent some other message in some other way so that he could realize the severity of the situation. (CENIPA) The static text messages are used in order to serve the purpose of indicating a loss of functionality in the collision avoidance system. This means is not at all a reliable one since such mere visual warnings may not always be able to draw the attention of the pilot if his or her mind is concentrated on the flight environment. According to the Safety Board, the notifications of some critical or extremely serious aircraft system failure that have the probability of resulting in catastrophic consequences should usually use conspicuous visual alerts accompanied by aural alerts. The use of a perceptible movement or a salient color might have been very much affective in drawing the attention of the pilot so that he might have taken some immediate action that could have contributed to the collision being avoided. Fault in the radio communication Fault in the radio communication is also one of the vital factors that led to the midair collision between the two airplanes. The total ATS communication procedure for N600XL having failed, the crew could not be informed of the awaiting danger. The management process of the radio frequencies and the transceiver assignments had also failed. The technical faults in the configurations of the Air Traffic Control or the ATC sectors have been held as one of the factors that led to the collision between the two airplanes in the midair. (“U.S. Summary Comments on the Draft Final Report of the Aircraft Accident”) Human factors Now, there might have been some more technical problems that have not yet been discovered. However, technical faults alone can never lead to such disaster. Moreover, it has to be kept in mind that neither it is that the planes are operated by machines not it is that there is no human contribution to the operations and functions in the Air traffic control system. The investigations that were conducted to find out the causes of the in-the-air collision between the Boeing 737 and the Embraer Legacy have pointed out a number of human factors that are immensely responsible for the collision between the two planes. If these mistakes or human factors are given a serious thought, it will appear that even more serious disasters are quite likely without any kind of technical faults, if human actions in aviation are so fallible. Let us point the human factors that led to the collision between the two airplanes. (“U.S. Summary Comments on the Draft Final Report of the Aircraft Accident”) No communication between the air traffic control officers The Air Traffic Control officer of Sector 7, 8 and 9 was not provided with the proper and complete information by the Air Traffic Control officer of Sector 5 and 6. It is obviously a major human mistake since it was the duty of the Air Traffic officer of Sector 5 and 6 to transmit the complete information to the Air Traffic control officer of Sector 7, 8 and 9 while coordinating with the N600XL aircraft as well as while handing it off to the next sector. The Air Traffic control Officer had probably given priority to transferring the N600XL aircraft to the next sector since his sector had an increasing volume of traffic. The moment he transferred the N600XL to the next sector, his own sector had 9 aircrafts. It has also to be noted that 9 aircrafts were much below the limits, as it was prescribed for the sector groups. (Hradecky) No order for changing the flight level Here is another human factor that seems to be the most vital phenomenon that led to the midair collision. The Air traffic Control officer of sector 7, 8 and 9 was not found to have made any kind of radio contact with the N600XL. If the officer had made radio contact with the N600XL, and given the order to change the flight level and switch the frequency to sector 7 from sector 9, the collision could have been avoided. Ignoring the loss of mode C in N600XL The Air traffic Control officer of sector 7, 8 and 9 just did not notice the loss of mode C in N600XL. What is even more amazingly frustrating is that fact that he assumed that the N600XL aircraft was at a flight level of FL360. It is on the basis of this assumption that the Air Traffic Control Officer did not perform the procedures that are a must to be performed in case of loss of transponder in RVSM airspace. Neither did the officer perform those procedures that are required for the control position relief. What happened as a result of the failure of the Air Traffic control officers of sector 7, 8 and 9 is that the information was not transmitted to the due sector resulting in the failure of the crew’s gaining the situational awareness. Lack of communications between the ATC officers and the ATC supervisors The lack of communications between the air traffic controllers and the air traffic supervisors is another human factor that is thought to be severely responsible for the collision between the two airplanes. Apart from inadequate information transmission, transmission of incorrect information is also another reason that led to the collision between the two planes. When the procedures for coordination as well as hand-off of the N600XL were being executed, the information transmission was utterly chaotic either for lack of information transmission or for transmission of wrong information. Therefore, the hand-off of the N600XL aircraft between the sectors and between the control centers and even at the control position relief was performed in a bungled situation that was even worsened by the lack of communication among the controllers and the supervisors. (Blakey) It will definitely seem that the human factors were solely responsible for the collision between the two planes, if certain human factors are brought into focus. The air traffic controllers did not at all advise the supervisors after the problems that they experienced in controlling the N600XL flight. It testifies to the fact that decisions that were made at that situation were individual as well as isolated. Decisions made in such a way cannot but be inadequate. If the air traffic control system is characterized by the reflection of thins kind of deficient coordination among the team resources, a number of such accidents are most likely to happen in strange frequency. Unawareness of the crew The flight crew too did not prove to be enough responsible. Rather, their lack responsibility was much responsible for the midair collision that claimed more than 150 lives. The transponder of the N600XL aircraft had lost its functionality. The crew should have noticed the status of the transponder. Had they had an eye on the status of the transponder they must have come to know that the transponder is not in a functioning situation. The unawareness of the crew about the loss of functionality of the transponder made it impossible for them to have any chance of being informed about the coming danger. Not taking the required steps The crew of the N600XL cannot alone be blamed for the collision had it been caused only by the loss of the transponder functionality. What is most surprising is that fact that the Air Traffic Control did not take the required actions that could have responded to the loss of the functionality of the transponder in the best and most effective way. There is even more surprising steps that the air traffic control officials had taken when the crisis could be smelled. The ATC kept on applying the RVSM separation standards in spite of the fact that there was lack of altitude information from the mode C transponder. Other human factors Another human blunder that contributed to the collision of between the two planes was the wrong assumption of the ATC that the N600XL aircraft was descending. This incorrect assumption was inspired by the automated display of an altitude value (3D). The irony is that such automated display is not valid for being used in the Air Traffic Control. None of the Air Traffic Control and the crew could manage to realize the significance of the long span that was spent at a non-standard cruise altitude for the direction of the flight. Neither did any of the crew and the ATC could manage to recognize the significance of the time that passed by without any two way communication between the ATC and the crew of the N600XL. The Air Traffic Control was aware of the fact that they had lost communication with the N600XL aircraft. Yet, it was quite surprising that they did not take much of adequate actions so that the no-communication situation or the lost-communication situation could be corrected or recovered in time. Apart from the miscommunications between the ATC officers and the supervisors and the transmission of incorrect information among them, the act of the controller of sector 7 not informing the Amazonic ACC about the current situations had added to the conditions that led to the collision between the two aircrafts. Though the controller of sector 7 was aware of the facts that the N600XL was out of communicability and that it was in a status where the transponder was not working, he did not inform the Amazonic ACC about all these facts. The entire situation came to a point where the sector 7 controller neither did anything by himself not did let anyone do something. (Hradecky) Lack of due training Apart from all the technical faults and errors and also the human factors discussed here, there is one more factor that is quite tough to be categorized. The investigation procedures have pointed it out that the DECEA did not provide the ATC officers with adequate training and supervision. As a result, the professionals did not grow the effective skills that are required for handling such tough situations. Had they been trained well and thoroughly, they must have gained the originality by which they might have had the knowledge and courage to get through this situation. It has also been pointed out by the investigators that the crew was not totally familiar with the situation they were in. The unfamiliarity to some extent might have contributed to leading to the collision, but it cannot be held as a cause of the midair collision between the planes. (Hradecky) Conclusion/Could the collision be avoided? Now the question that arises after the discussion of both the technical factors and the human factors that are responsible for the plane collision in some way or the other is if the collision could be avoided by any chance. There cannot be a ‘no’ or ‘yes’ that would be utmost definite since it has already happened. Rather it would be wise to discuss what steps could have been taken so that the collision could be avoided and the lives of those one hundred and fifty four people could be saved. There is no scope to deny the fact that technical errors can happen at any time. Had it been a plane crash, it would have been accepted that the technical faults could not be helped, though it should be made a must that there should be extreme rigidity during the checking of the mechanism and the status of the various systems before the flight. In this case it can be said that the collision could be avoided had there not been such poor communication between the Air Traffic Controllers. If the communication and the transmission between the controllers and the supervisors were perfect, the two flights must not have been on the same altitude. In that case, there would have been no chance for the collision at all. Moreover, the controllers, the officers and also the supervisors were too late and also too poor in taking the appropriate steps after they come to be aware o the difficult situations. Had they been much more efficient or had a bit more presence of mind or the strength of mind not to lose heart in time of necessity, they would have had the confidence to take the appropriate steps that might have saved the two planes and the human lives. References 1. Blakey, Marion, C. National Transportation Safety Board, Safety Recommendation, 2007, available at: http://www.ntsb.gov/Recs/letters/2007/A07_35_37.pdf (accessed on January 28, 2009) 2. Brazilian CENIPA Issues Accident Report, Midair Collision Between Boeing 737-800 and Embraer Legacy 600, 2006, available at: http://www.ntsb.gov/Aviation/Brazil-CENIPA.htm (accessed on January 28, 2009) 3. CENIPA, AERONAUTICAL ACCIDENT INVESTIGATION 4. AND PREVENTION CENTER, COMMAND OF AERONAUTICS 5. GENERAL STAFF OF THE AERONAUTICS, 2006, available at: http://blog.wired.com/27bstroke6/files/midair_collision_final_report_1907_english_version1_redacted.pdf (accessed on January 28, 2009) 6. Hradecky, Simon, Crash: GOL B737-800 overhead Brasil on Sep 29th 2006, collided with bizjet in flight, The Aviation Herald, 2008, available at: http://avherald.com/h?article=3e90f4ef/0098&opt=1536 (accessed on January 28, 2009) 7. “ U.S. Summary Comments on the Draft Final Report of the Aircraft Accident”, National Transportation Safety Board, 2006, available at: http://www.ntsb.gov/Aviation/Brazil-CENIPA/US_Summary_Comments.pdf (accessed on January 28, 2009) Read More