segunda-feira, 29 de setembro de 2008

Two year balance: Technical investigation of Flight 1907 Accident

26/09/2008 - 11:33

Bulletin - Technical Investigation of Flight 1907 Accident - 2 year balance



Aircraft prefix N600XL took off from São José dos Campos (SP) at 14:51 (Braslia time) and Flight 1907, leaving Manaus, at 15:35.

The collision between the two aircraft occurred at 16:56. The left wing of N600XL hit the left wing of Flight 1907. The former lost the winglet and a piece of the horizontal stabilizer, while the latter had close to six meters of wing struck off.

Out of control, Flight 1907 fell in an area of dense forest. There were no survivors. The N600XL business jet made an emergency landing at a Brazilian Air Force (FAB) base in the Serra do Cachimbo Mountains.
The Final Report last month went to the Commission of Investigation's accredited representatives overseas (in the United States and Canada), in accordance with Annex 13 of the Chicago Convention. According to the legislation, the accredited representatives have up to 60 days to present their considerations on the document's content. Afterwards, there will be a final meeting of the Commission of Investigation, before its work concludes.

The main aim of a technical investigation is the issuance of safety recommendations which are the establishment of an action, or series of actions that can been directed to the public in general, or to a group of specific users, or to a particular public or private organization in regards to a specific dangerous occurrence, and by trying to eliminate it, or by trying to control the risk condition.

More than seventy professionals participated in the Flight 1907 accident investigations, in the various phases of the proceedings, in Brazil and overseas. Trials, tests, and simulations were undertaken in Brazilian and foreign laboratories.

During the course of the procedure, the Commission held five official meetings with the relatives of accident victims, at the Center for the Investigation and Prevention of Aeronautic Accidents (CENIPA), in Brasilia, to keep them informed of the proceedings. The press received updates of the progress of the work, and all judicial orders for supplying documents, were met in accordance with the law. .

Dozens of safety recommendations were issued and still others may still be issued. They will be released at the end of the commission's work.

In the course of the technical investigation, the following tasks were performed:
- initial action at the accident site,
- collection of the registered flight data (black box),
- Interviews and medical exams of the Legacy crew,
- storing of the registered data of the Air Traffic Control organization involved,
- Checking of the wreckage of the Boeing 737-800 aircraft,
- Reading, processing and analysis of the registered flight data of both aircraft,
- Tests and preliminary exams of the technical nature, like range, precision and configuration of the communication and surveillance equipment in the accident scenario performed by the Command of the Aeronaútica and put at the disposal of the Commission,
Invitation extended to the controllers of CINDACTA 1 in order to give information to CENIPA. None of the controllers of CINDACTA 1 was willing to concede an interview to the commission on the counsel of their various lawyers. It is important to emphasise that giving information in this kind of process is voluntary and depends on the cooperation of those involved,
- Visit to the headquarters of ExcelAire, in the United States, where it was not possible to interview any employee, including the pilots. According to a document presented to the NTSB (National Transportation Safety Board), by the company's lawyers, no employee granted an interview to the Brazilian investigators, fearing problems with legal procedures, supplying information only to the American investigators. The NTSB, within what the rules of cooperation foresee, received the questionnaires from the Brazilian investigators and supplied the information requested, concerning the American pilots and the company that operates the aircraft,
- Visits at the Air Traffic Control Centre in New York and at the Air Traffic Flow Control Center in Washington (Command Center);
- Meetings with the relates of the victims of the accident,
- Participation, responding to invitations by the CPIs of the Deputy Chamber and of the Federal Senate,
- Periodical coordination meetings of the Investigation Commission, made and concluded in the manufacturers installations (Honeywell and ACSS) in the United States, the analysis of radio and navigation equipment, communication, transponder and TCAS of the aircraft N600XL. Those analyses were accompanied together by investigators and technicians from Brazil and America, coordinated by the chief of the branch “Material” of the investigation. The obtained results didn’t show any type of failure or defect in the analyzed equipment,
- Various analyses of the recordings and of the transcriptions between the aircraft and the Air Traffic Control organs were made,
- Various analysis of the data recorded by Air Traffic Control organs in the occurrence were made in regards to the radar visualization,
- The rules and pre-requisistes for American pilots to fly overseas are being analyzed,
- In average two sectorial meetings with the responsible of the branches Operations, Humans and Material were performed,
- Only in December of 2007, was the Commission contacted by representatives of the pilots of aircraft prefix N600XL, when the work was at the last stage of production of the final report. Given the importance of this testimony, which had not been given earlier by the crew members' own decision, a meeting was set with the Brazilian investigators. It is important to observe that information in this sort of investigation is supplied voluntarily. Between January 29 and 31 of this year, the two American pilots were heard, in individual interviews, at NTSB headquarters in Washington, in the United States. The pilots heard the two hours of audio recording registered by aircraft N600XL's black box (CVR) and answered a long questionnaire elaborated by the Commission of Investigation on the accident. The information supplied is important to clarify points in the investigation, by being crossed with previously determined data and to elaborate possible scenarios that could lead to the transponder's non-functioning;

From the point of view of prevention, every accident results from the conjunction of a series of factors lining up, the so-called safety barriers, and never as a consequence of a single factor (cause). It it the investigation's role to derive lessons from these occurrences that result in the improvement of all and every area involved.
In the case of Flight 1907, the Commission has already released the following information about the events:
1) No errors were found in the design or integration of the communications, transponder and TCAS (anti-collision) equipment of aircraft N600XL;

2) The pilots said that they did not undertake any intentional act to interrupt the functioning of the transponder and, consequently, of the aircraft's anti-collision system, as well as not having noticed or remembered having done anything that could have caused the accidental interruption of that equipment;
3) Evaluations made by the Commission show that the Transponder equipment was in operating condition, although it was not in use at the time of the collision;

4) Some rules and procedures were not correctly followed in the occurrence, which led the Commission to analyze the reasons for this having happened, with the objective of elaborating flight safety recommendations. These considerations will be made in the final report;
5) In the accident no indication was found of influence of radar coverage, through inefficiency or deficiency in air traffic control communications and surveillance equipment;
Center for the Investigation and Prevention of Aeronautic Accidents


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