0
The crash of Air France Flight 447 may finally galvanize the air transport industry to address long overdue equipment and training shortcomings.
Particular attention is being given to mitigating the occurrence of high-altitude stall and helping pilots to better recognize that condition. The need for such measures has been understood for some time, but the third interim report on the crash of AF Flight 447—the Airbus A330-200 that disappeared June 1, 2009, en route from Rio de Janeiro to Paris, killing all 228 onboard—has again highlighted the need for action, with cockpit voice recorder (CVR) data indicating that the pilots did not fully recognize the stall condition or take proper recovery action.
While this report, issued on July 29 by the French aviation accident investigation office, the BEA, reinforces earlier suspicions that the pilots failed to recognize the stall and did not take appropriate action to recover the aircraft, it is still possible the final report will fault Airbus and how some safety-critical information is displayed to air crews.
The report has also intensified the focus on loss-of-control accidents, by far the most common category. Many air safety experts agree that the industry has not done enough to deal with their root causes. One issue that keeps surfacing—both in the AF Flight 447 crash and in other cases—is how pilots can be trained to better understand highly automated aircraft and to improve their manual flying skills in case automation fails.
With several recent loss-of-control accidents, even slow-moving authorities are beginning to feel that action is needed. The European Aviation Safety Agency (EASA), itself the target of much criticism for its lax pitot tube certification standards, is holding a two-day seminar on loss of control in Cologne, Germany, in early October. Iced-over pitot tubes almost certainly led to temporarily incorrect speed readings that caused the A330’s flight management system to switch from normal to alternate law, in which most automatic functions, such as auto throttle and autopilot, are unavailable.
One safety recommendation calls for regulatory authorities to consider adding an angle-of-attack indicator in the cockpit. This echoes an emerging consensus from an independent group of safety experts among the pilot community and manufacturers, which is trying to help pilots recognize how small stall margins are at high altitude. Its findings are likely to be finalized in the coming months, potentially even before the final AF Flight 447 accident report is issued in the first quarter of 2012, an industry official says. The work actually predates the AF Flight 447 crash.
The group also appears to echo another BEA recommendation linked to pilot training. The interim report calls for authorities to devise regular training programs “aimed at manual airplane handling, approach to and recovery from stall, including at high altitude.” The BEA report notes that “the copilots had received no high-altitude training for the unreliable [indicated air speed] procedure and manual aircraft handling.”
Poor crew resource management once again is getting scrutiny as part of the accident report. The BEA raises questions about how the pilots flying the aircraft at the time interacted. “No standard call outs regarding the differences in pitch attitude and vertical speed were made,” the report says. Moreover, “neither of the pilots made any reference to the stall warning” and “neither of the pilots formally identified the stall situation.”
Information provided by the BEA from the cockpit voice recordings suggests confusion persisted while the aircraft was descending. Among other things, the pilots did not know how to deal with one consecutive stall warning that stopped only after 54 sec. The captain only re-entered the cockpit at the end of that sequence and when the aircraft was descending in a deep stall, at a vertical speed of around 10,000 ft./min.
In that situation, the pilot flying reacted by selecting takeoff/go-around thrust, but CVR recordings indicate fundamental confusion. “But we’ve got the engines, what is happening?” the pilot non-flying (PNF) said. And a few seconds later the pilot flying said, “I have no more control of the aircraft. I have absolutely no control of the aircraft.” At about the same time the captain came back into the cockpit, the PNF asked, “What is happening? I don’t know. . . I don’t know what is happening.”
There is already controversy about some of the 10 safety recommendations. One calls for cameras to be installed in the cockpit “that make it possible to observe the whole of the instrument panel,” the BEA says. But pilots have rejected previous efforts for video monitoring in the cockpit, arguing the information would be misused, and are poised to do so again. Although the BEA report suggesting the installation would be coupled with “strict rules relating to the use of such recordings,” pilots note that safety data that should be safeguarded are already leaked, and the risk of that happening with video is seen as even greater.
In a draft of its third interim report, the BEA considered issuing a recommendation about the functioning of the stall warning, which was not included in the final review. There is concern the stall warning sounded intermittently, rather than persistently. But eliminating the recommendation has raised suspicion among members of SNPL, one of Air France’s pilot unions, that it was withdrawn to protect the manufacturer and shift blame to the crew. The union threatened last week to withhold further participation in the accident investigation until the BEA explains its course of action.
In response, the investigators have said they merely held off on publishing that recommendation to further analyze the situation. A human factors working group has been set up to closely examine the human-machine interaction during the final phases of the flight. Once that work is completed, a safety recommendation on the stall warning could still emerge in the final report. “The current controversy focuses on a recommendation that corresponds to the functioning of the stall warning in a situation where the airplane reached an extreme angle of attack that is never encountered in flight tests, or even considered,” the BEA says. But “it should be noted that the warning sounded uninterruptedly for 54 sec. after the beginning of the stall, without provoking any appropriate reaction from the crew. This fact must be analyzed as a priority by the working group.”
Air France, which early on ran into trouble with its pilot community over statements made in the wake of the crash, has since been defensive and unwilling to permit questioning of the crew, trying to keep the spotlight on technical problems leading to the crash. In response to the latest findings, the airline says, “It is important to understand whether the technical environment, systems and alarms hindered the crew’s understanding of the situation.” In Air France’s view, the pilots showed “an unfailing professional attitude, remaining committed to their task to the very end.” Air France has also expressed concerns to EASA about the A330’s stall warning system.
The latest review of the accident data, the first formal report since the cockpit voice and flight data recorders were recovered and analyzed, again highlights that the aircraft stalled at high altitude and that the pilots never performed the nose-down inputs to recover. Normal speed readings came back on both recorders after 29 and 54 sec., respectively. At that time, the aircraft was at 38,000 ft. at a displayed speed of 185 kt. In that moment, the aircraft was not stalled and could have been fully recovered by returning to its initial cruise altitude of 35,000 ft. with power being reduced. The pilot flying however, continued to pull back on the stick, with speed rapidly decreasing. He was not corrected by his two colleagues.
Throughout the descent, the crew maintained the nose-up attitude of the airliner. In fact, the pilot flying made nose-up inputs and set thrust to takeoff/go around. The BEA notes that “In less than one minute after the disconnection of the autopilot, the airplane was outside its flight envelope following the manual inputs that were mainly nose-up.”
There was no indication of an engine malfunction, with the report noting flight control surfaces matched inputs.
Other safety recommendations relate to gathering accident-related data. For instance, the BEA wants additional information to be recorded on the flight data recorder and relevant safety information to be broadcast once an emergency situation occurs onboard. In particular, it wants the position of the flight director crossbars and the conduct of the flight displays on the right side of the cockpit recorded (those on the left side already are). The FAA and EASA also are urged to examine the utility of storing air data and inertial parameters.
Similarly, the BEA suggests authorities examine whether an emergency locator transmitter should be activated in such a situation.
Fonte: http://www.aviationw..._p39-355091.xml
Autores: Robert Wall, Jens Flottau
London, Frankfurt
Particular attention is being given to mitigating the occurrence of high-altitude stall and helping pilots to better recognize that condition. The need for such measures has been understood for some time, but the third interim report on the crash of AF Flight 447—the Airbus A330-200 that disappeared June 1, 2009, en route from Rio de Janeiro to Paris, killing all 228 onboard—has again highlighted the need for action, with cockpit voice recorder (CVR) data indicating that the pilots did not fully recognize the stall condition or take proper recovery action.
While this report, issued on July 29 by the French aviation accident investigation office, the BEA, reinforces earlier suspicions that the pilots failed to recognize the stall and did not take appropriate action to recover the aircraft, it is still possible the final report will fault Airbus and how some safety-critical information is displayed to air crews.
The report has also intensified the focus on loss-of-control accidents, by far the most common category. Many air safety experts agree that the industry has not done enough to deal with their root causes. One issue that keeps surfacing—both in the AF Flight 447 crash and in other cases—is how pilots can be trained to better understand highly automated aircraft and to improve their manual flying skills in case automation fails.
With several recent loss-of-control accidents, even slow-moving authorities are beginning to feel that action is needed. The European Aviation Safety Agency (EASA), itself the target of much criticism for its lax pitot tube certification standards, is holding a two-day seminar on loss of control in Cologne, Germany, in early October. Iced-over pitot tubes almost certainly led to temporarily incorrect speed readings that caused the A330’s flight management system to switch from normal to alternate law, in which most automatic functions, such as auto throttle and autopilot, are unavailable.
One safety recommendation calls for regulatory authorities to consider adding an angle-of-attack indicator in the cockpit. This echoes an emerging consensus from an independent group of safety experts among the pilot community and manufacturers, which is trying to help pilots recognize how small stall margins are at high altitude. Its findings are likely to be finalized in the coming months, potentially even before the final AF Flight 447 accident report is issued in the first quarter of 2012, an industry official says. The work actually predates the AF Flight 447 crash.
The group also appears to echo another BEA recommendation linked to pilot training. The interim report calls for authorities to devise regular training programs “aimed at manual airplane handling, approach to and recovery from stall, including at high altitude.” The BEA report notes that “the copilots had received no high-altitude training for the unreliable [indicated air speed] procedure and manual aircraft handling.”
Poor crew resource management once again is getting scrutiny as part of the accident report. The BEA raises questions about how the pilots flying the aircraft at the time interacted. “No standard call outs regarding the differences in pitch attitude and vertical speed were made,” the report says. Moreover, “neither of the pilots made any reference to the stall warning” and “neither of the pilots formally identified the stall situation.”
Information provided by the BEA from the cockpit voice recordings suggests confusion persisted while the aircraft was descending. Among other things, the pilots did not know how to deal with one consecutive stall warning that stopped only after 54 sec. The captain only re-entered the cockpit at the end of that sequence and when the aircraft was descending in a deep stall, at a vertical speed of around 10,000 ft./min.
In that situation, the pilot flying reacted by selecting takeoff/go-around thrust, but CVR recordings indicate fundamental confusion. “But we’ve got the engines, what is happening?” the pilot non-flying (PNF) said. And a few seconds later the pilot flying said, “I have no more control of the aircraft. I have absolutely no control of the aircraft.” At about the same time the captain came back into the cockpit, the PNF asked, “What is happening? I don’t know. . . I don’t know what is happening.”
There is already controversy about some of the 10 safety recommendations. One calls for cameras to be installed in the cockpit “that make it possible to observe the whole of the instrument panel,” the BEA says. But pilots have rejected previous efforts for video monitoring in the cockpit, arguing the information would be misused, and are poised to do so again. Although the BEA report suggesting the installation would be coupled with “strict rules relating to the use of such recordings,” pilots note that safety data that should be safeguarded are already leaked, and the risk of that happening with video is seen as even greater.
In a draft of its third interim report, the BEA considered issuing a recommendation about the functioning of the stall warning, which was not included in the final review. There is concern the stall warning sounded intermittently, rather than persistently. But eliminating the recommendation has raised suspicion among members of SNPL, one of Air France’s pilot unions, that it was withdrawn to protect the manufacturer and shift blame to the crew. The union threatened last week to withhold further participation in the accident investigation until the BEA explains its course of action.
In response, the investigators have said they merely held off on publishing that recommendation to further analyze the situation. A human factors working group has been set up to closely examine the human-machine interaction during the final phases of the flight. Once that work is completed, a safety recommendation on the stall warning could still emerge in the final report. “The current controversy focuses on a recommendation that corresponds to the functioning of the stall warning in a situation where the airplane reached an extreme angle of attack that is never encountered in flight tests, or even considered,” the BEA says. But “it should be noted that the warning sounded uninterruptedly for 54 sec. after the beginning of the stall, without provoking any appropriate reaction from the crew. This fact must be analyzed as a priority by the working group.”
Air France, which early on ran into trouble with its pilot community over statements made in the wake of the crash, has since been defensive and unwilling to permit questioning of the crew, trying to keep the spotlight on technical problems leading to the crash. In response to the latest findings, the airline says, “It is important to understand whether the technical environment, systems and alarms hindered the crew’s understanding of the situation.” In Air France’s view, the pilots showed “an unfailing professional attitude, remaining committed to their task to the very end.” Air France has also expressed concerns to EASA about the A330’s stall warning system.
The latest review of the accident data, the first formal report since the cockpit voice and flight data recorders were recovered and analyzed, again highlights that the aircraft stalled at high altitude and that the pilots never performed the nose-down inputs to recover. Normal speed readings came back on both recorders after 29 and 54 sec., respectively. At that time, the aircraft was at 38,000 ft. at a displayed speed of 185 kt. In that moment, the aircraft was not stalled and could have been fully recovered by returning to its initial cruise altitude of 35,000 ft. with power being reduced. The pilot flying however, continued to pull back on the stick, with speed rapidly decreasing. He was not corrected by his two colleagues.
Throughout the descent, the crew maintained the nose-up attitude of the airliner. In fact, the pilot flying made nose-up inputs and set thrust to takeoff/go around. The BEA notes that “In less than one minute after the disconnection of the autopilot, the airplane was outside its flight envelope following the manual inputs that were mainly nose-up.”
There was no indication of an engine malfunction, with the report noting flight control surfaces matched inputs.
Other safety recommendations relate to gathering accident-related data. For instance, the BEA wants additional information to be recorded on the flight data recorder and relevant safety information to be broadcast once an emergency situation occurs onboard. In particular, it wants the position of the flight director crossbars and the conduct of the flight displays on the right side of the cockpit recorded (those on the left side already are). The FAA and EASA also are urged to examine the utility of storing air data and inertial parameters.
Similarly, the BEA suggests authorities examine whether an emergency locator transmitter should be activated in such a situation.
Fonte: http://www.aviationw..._p39-355091.xml
Autores: Robert Wall, Jens Flottau
London, Frankfurt
