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| 5/7/2007 | Brazilian collision alerts NTSB to TCAS question | Supporting material in a new US National Transportation Safety Board recommendation based on investigation into the 29 September mid-air collision over Brazil raises more questions as to why the business jet's Honeywell-built collision avoidance system does not appear to have been operating at the time.
A Legacy 600 business jet and Gol Airlines 737-800 collided over the Amazon basin while flying the airway between Brasilia and Manaus.
Last week the NTSB called on the US Federal Aviation Administration to provide enhanced visual and audio information regarding the functional status of traffic alert and collision avoidance (TCAS) systems. The board wants alerts in the event of "loss of collision avoidance system functionality, for any reason", and for the pilots to be compelled to acknowledge the TCAS status.
All 154 passengers aboard the Gol aircraft perished when it crashed out of control after its left wing struck the Legacy, which was flying a reciprocal track at the same flight level. The Legacy pilots were able to land the damaged twin-engined business jet at a military outpost. Although both aircraft were equipped with TCAS, neither provided warnings.
Currently, TCAS units display a white "TCAS OFF" or an amber "TCAS FAIL" message in "small letters" on the flight displays if there are problems with either the TCAS or the transponder that exchanges relative position data with the corresponding equipment on the other aircraft.
The NTSB notes that about 2min after the collision, the Legacy's first officer questioned whether the TCAS was turned on. The captain confirmed it was not and "immediately afterwards" the transponder data showed up on radar. "Therefore, there is evidence that the flight display warning was available to the crew but not noticed and acted upon until after impact," the board says.
Honeywell says the Legacy's avionics, including the transponders and radio management units, "were functioning properly during the accident flight and did not malfunction in any way", and that the equipment had been "fully certified" by the FAA, European and Brazilian authorities.
The company says the annunciation and alerting philosophy was "consistent with both industry and government certifying authority standards". | |
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| 5/7/2007 | NTSB Says TCAS Must Warn Pilots When Offline | Traffic alert and collision avoidance systems (TCAS) should be designed to ensure that flight crews know when they are not operating, the NTSB said in a safety recommendation issued on Wednesday. The recommendation is based on preliminary findings in the ongoing investigation into the midair collision between an Embraer Legacy bizjet and a Gol Airlines Boeing 737 in Brazil last year, which killed all 154 aboard the airliner. The NTSB said its findings indicate that, for reasons yet to be determined, the collision avoidance system in the Legacy was not functioning at the time of the accident, disabling the system's ability to detect and be detected by conflicting traffic. In addition, data from the cockpit voice recorder indicates that the flight crew was unaware that the collision avoidance system was not functioning until after the accident. "A flight crew's ability to mitigate the risk of collision is significantly degraded if the collision avoidance system becomes inoperative and the failure is not quickly and reliably brought to the crew's attention, as this accident demonstrates," the Safety Board said. | |
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| 5/1/2007 | TRANSPORT CANADA AND INDUSTRY PARTNER TO IMPROVE AVIATION SAFETY | OTTAWA ��� Transport Canada hosted the 5th annual meeting of the Canadian Aviation Executives' Safety Network yesterday. The network enables Transport Canada and leaders from the Canadian aviation industry to work together to enhance aviation safety in Canada.
"Canada's New Government must continue to work with the aviation industry to maintain the public���s high level of confidence in the safety of Canada���s air transportation system," said the Honourable Lawrence Cannon, Minister of Transport, Infrastructure and Communities. "The Canadian Aviation Executives' Safety Network provides an ideal forum for senior executives from Transport Canada and industry to explore new opportunities to continue to reduce risks to safety." More than 85 industry leaders attended this year's conference, including representatives of air carriers, pilot associations, manufacturers, air navigation service providers and airports from across the country. The attendees discussed ways to maintain and improve Canada's already enviable aviation safety record with the implementation of the Safety Management System (SMS).
"The Safety Management System is an international initiative recognized as the most significant advancement in aviation safety in recent years. SMS helps instil more accountability and a positive safety culture throughout aviation organizations and the industry as a whole," said Mr. Michael DiLollo, senior vice president of Air Transat. "I believe that the development, implementation and maintenance of SMS in all areas of aviation activity is key to improving the safety and well-being of the aviation industry.���
The introduction of SMS regulations in June 2005 coincides with the decreasing accident rate in Canada's commercial airline industry. SMS is not self-regulation, it is not de-regulation and it is not about reducing the number of inspectors or cutting costs. SMS adds an additional layer of safety oversight to Transport Canada's existing and ongoing oversight programs to help make a safe system even safer.
Transport Canada established the Canadian Aviation Executives' Safety Network in 2003. The forum enables key decision makers from Transport Canada and the aviation industry to identify aviation safety challenges, develop strategies to address them and engage in regular dialogue regarding the viability and direction of the aviation industry in Canada. | |
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| 4/9/2007 | US FAA wants 787 fuel-tank fire resistance demonstrated | Boeing will be required to demonstrate that the 787���s composite wing and fuel-tank structure can withstand a post-crash fire long enough for passengers to evacuate safely, under a special certification condition proposed by the US FAA.
Published on Monday (9 March), the notice proposing the special condition says �ǣapplicable airworthiness standards do not contain adequate or appropriate safety standards for [composite] wing and fuel tank structure with respect to post-crash fire safety���.
Existing rules are based on the service history and extensive full-scale fire testing of conventional aluminum structures. And while it has previously approved composite fuel tanks in horizontal stabilizers, the FAA says the 787���s carbonfiber composite wing �ǣwill introduce a new fuel tank construction into service���.
Aluminum is highly thermally conductive, says the FAA, and readily transmits the heat of a ground fire to fuel still in the tank. This spreads the heat over the wing surface and prevents localized hot spots, delaying structural collapse or burn-through beyond the time needed for evacuation.
In addition, as the fuel in an aluminum tank is heated, fuel vapor rapidly accumulates in the ullage, or empty space, pushing the fuel-air mix beyond its flammability limit before the wing burns through and reducing the risk of explosion.
The heat capacity of aluminum and fuel will delay burn-through or wing collapse beyond the time required for evacuation time, says the FAA, adding that studies show preventing fuselage burn-through for 5min can significantly enhance survivability.
Because carbonfiber has low thermal conductivity, the FAA says �ǣadditional substantiation by test and analysis will be required to show that the 787 provides an acceptable level of safety��� during an external fuel-fed fire.
To be consistent with the capability of aluminum structures, �ǣthe 787 fuel tanks must be capable of resisting a post-crash fire for at least 5min���, says the FAA. Under the proposed special condition, Boeing will be required to demonstrate compliance at a range of fuel loads from minimum to maximum. | |
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| 4/8/2007 | Runway safety system has gap | Restrictions on a $550 million system to prevent runway collisions are compromising safety by keeping the system from accurately tracking snowplows, firetrucks and other ground vehicles at most airports, according to government data and air-traffic controllers.
The National Transportation Safety Board (NTSB) says the risks of a crash on the ground represent the greatest threat in aviation, and the potential for a plane to strike one of the vehicles that crowd commercial airports is a significant part of the problem.
Collisions between vehicles and planes were narrowly averted 26 times from 2003 through January, according to a USA TODAY review of Federal Aviation Administration (FAA) data. That represents 22% of all serious runway incidents, or about one serious incident every other month.
The new system is known as Airport Surface Detection Equipment Model X. It allows controllers, who may not be able to see runways at night or in bad weather, to monitor the location of aircraft on color computer displays in the tower. The system has been hailed by the government and safety advocates as a major improvement over previous technology because it can track aircraft on the ground in all weather.
However, the FAA is blocking the system's ability to track ground vehicles, the agency acknowledges. Because the FAA won't allow those vehicles to carry radio identification beacons, the system has difficulty tracking them, particularly during heavy rain.
The agency is worried that the beacons ��� known as transponders ��� could interfere with broadcasts from similar beacons on planes. That could cause planes to disappear from radar screens or trigger other safety problems, spokeswoman Laura Brown said. The agency is moving slowly because it wants to avoid unanticipated problems, Brown said.
Controllers at several airports with the new system believe the government's decision undermines safety and is unnecessary, said Brad Rosenthal, local president of the National Air Traffic Controllers Association at Lambert-St. Louis International Airport.
Rosenthal and others say airports that tested the runway system, including Milwaukee and Providence, have beacons on ground vehicles, and the system has functioned well. Similar systems being installed in Europe and Asia include beacons for ground vehicles.
The FAA switched on the system last year at Hartsfield-Jackson Atlanta International Airport, the world's busiest, but not one of the airport's fleet of 1,500 ground vehicles has a radio beacon, said Gary Brittain, local president of controllers.
"It's just amazing to me that they don't have transponders on these vehicles," Brittain said. "I don't know how they justify that. I have a feeling they are making a safety decision based on dollars instead of sense."
Brown said the FAA believes that, in spite of the difficulty with ground vehicles, the system is a significant overall improvement on previous runway safety equipment. Runway safety is a top priority at the agency, which has spent nearly $1 billion on improvements over the past decade, she said. The agency hopes to require beacons on ground vehicles as it scraps radars and moves to satellite-based technology, she said.
Eight airports now have the runway system, including Seattle, Orlando and St. Louis. It will be installed at an additional 27 airports, including all of the USA's largest, over the next several years.
The system was originally intended for smaller airports, but its color displays and advantages in bad weather persuaded the FAA to install it at larger ones.
The NTSB considers runway collisions a top priority. "We've been running on luck too long, and that's no way to run an aviation system," NTSB Chairman Mark Rosenker said at a forum last month. | |
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