Faulty readings ahead of 2009 Air France crash

Confronted with faulty instrument readings and alarms going off in the cockpit, the pilots of an Air France jetliner struggled to tame the aircraft as it went into an aerodynamic stall, rolled, and finally plunged 38,000 feet into the Atlantic Ocean in just 3½ minutes.
But the passengers on that doomed Rio de Janeiro-to-Paris flight were probably asleep or nodding off and didn't realize what was going on as the aircraft fell nose-up toward the sea, the director of the French accident investigating bureau said after releasing preliminary black-box data on the June 1, 2009, disaster.
All 228 people aboard the Airbus A330 died.
The brief, highly technical report by the BEA contains only selective remarks from the cockpit recorder, offers no analysis and assigns no blame. It also does not answer the key question: What caused the crash?
But several experts familiar with the report said the co-pilot at the controls, at 32 the youngest of the three-man cockpit crew, Cedric Bonin, may have responded incorrectly to the emergency by pointing the nose upward, perhaps because he was confused by the incorrect readings.
The plane's external speed sensors, called Pitot tubes, have long been considered a likely culprit in the disaster, with experts suggesting they may have been iced over. And the BEA investigators found that two sets of instruments on the plane gave different speed readings, with the discrepancies lasting less than a minute.

Since the accident, Air France has replaced the speed monitors on all its Airbus A330 and A340 aircraft.
An official at Airbus said the aircraft's nose should have been pointed slightly downward to enable the plane to regain lift after it had gone into an aerodynamic stall.
"This is part of the general pilot training for any aircraft," said the official. He was not authorized to speak on that subject and asked not to be identified by name.
Other aviation experts concurred. In an aerodynamic stall, a plane most often loses lift because it is traveling too slowly, and begins to fall out of the sky. Pointing the nose downward enables the aircraft to pick up speed, gain lift and pull out of the stall.
Pulling the nose up is "an inappropriate way to respond" to an aerodynamic stall, said Paul Hayes, director of air safety for aviation consulting firm Ascend Worldwide Ltd. "He either misidentified what was happening or became confused."
He cautioned that Friday's report was brief and that it was still unclear how the series of events started.
The flight data recorder and cockpit recorder were dredged from the ocean in early May, along with some bodies.
They showed, in addition to inconsistent speed readings, two co-pilots working methodically to right the plane manually after autopilot stopped. Captain Marc Dubois returned from a routine rest to the cockpit amid what moments later became an irretrievably catastrophic situation.
After the plane went into a stall, warnings sounded, the autopilot and autothrust shut off as designed, and the co-pilot not at the controls "tried several times to call the captain back," the BEA report said. The captain returned one minute and 10 seconds later, when the plane had climbed to 38,000 feet.
"During the following seconds, all of the recorded speeds became invalid and the stall warning stopped," the report said, but added that the plane never came out of its aerodynamic stall.
"The airplane was subject to roll oscillations that sometimes reached 40 degrees," the report said. The engines never stopped operating and "always responded to crew commands," the BEA said.
"The pilots never panicked," BEA director Jean-Paul Troadec said on RTL radio, adding that they maintained professionalism throughout.
The passengers, he suggested, probably fell to their deaths without knowing they were doomed.
Dinner had been served and "you can imagine that most passengers were already asleep or nodding off," Troadec said. He said the cabin crew never contacted the cockpit to see what might be wrong.
"It seems they didn't feel more movements and turbulence than you generally feel in storms, so we think that till impact they did not realize the situation," said Jean-Baptiste Audousset, president of a victims' solidarity association, "which for the family is what they want to hear, they did not suffer."
He was among a group of representatives of families who met with BEA officials to be briefed on their findings.
At least one expert disagreed with the theory of a soft descent.
Data from the flight recorders shows the plane was falling almost 11,000 feet per minute (124 mph, or 200 kilometers per hour), its nose slightly tilted upward.
"Eleven-thousand feet a minute is a huge rate of descent," said Ronan Hubert, who runs the Aircraft Crashes Record Office in Geneva. "I would say some of the people on board would have lost consciousness."
The crew had feared turbulence, and more than eight minutes before the crash the co-pilot at the controls advised the cabin crew "you should watch out" for turbulence ahead. He said the plane could not climb out of the cloud layer where the turbulence was happening because it was not cold enough.
Turbulence caused the pilots to make a slight change of course, but was not excessive as the plane tried to pass through the clouds.
Four minutes later, the plane's autopilot and autothrust shut off, the stall alarm sounded twice and the co-pilot at the controls took over manual control. A second co-pilot, David Robert, 37, was also in the cockpit.
Pilots on long-haul flights often take turns resting to remain alert. After Dubois returned to the cockpit, he did not take back the controls.
Just over two minutes before the crash, Bonin is heard to say, "I don't have any more indications." Robert says: "We have no valid indications."
Michael Barr, who teaches aviation safety at the University of Southern California, said the atmosphere in the darkened cockpit would have been chaotic: lights flashing, loud alarms, frequent messages.
He compared the pilots to emergency-room doctors struggling with a sudden influx of seriously injured patients: They were bombarded with problems that they had to quickly prioritize.
On top of that, they were completely dependent on the information the plane's computers gave them.
"You have to rely on your instruments," Barr said. "That's why when the instruments aren't telling you the truth, you have a hard time deciding what to do. Which ones are right and which ones are wrong?"
Air France said in a statement that, based on the report, it appears "the initial problem was the failure of the speed probes which led to the disconnection of the autopilot" and loss of pilot protection systems.
The airline defended the captain, saying he "quickly interrupted his rest period to regain the cockpit."
Independent aviation analyst Chris Yates said the report appears "to raise more questions than it answers."
"It would seem to me, reading between the lines, that the cockpit crew weren't confident of the information that was being presented to them on the data displays," Yates said. "Maybe — and it's only a maybe — they took some action that led to the stall warning, and the plane stalling and then being unable to correct it."
A new, but not final, report with some analysis is to be issued in July.

New leak feared at stricken Japan nuclear plant

Radioactive water appears to be leaking from a waste disposal building at Japan's Fukushima nuclear complex, operator Tokyo Electric Power said on Thursday, in a new setback to the battle to contain radiation from the crippled power plant.
The disclosure by Tepco raises the stakes in a race to complete by next month a system to decontaminate a massive pool of radioactive water at the site that critics see as a growing risk to both the nearby Pacific and groundwater.
A magnitude 9.0 earthquake and the massive tsunami that followed killed about 24,000 people and knocked out the Fukushima plant on March 11, triggering the world's worst nuclear accident since Chernobyl.
The crisis, which has displaced some 80,000 residents from around the plant, prompted a review of Japan's energy policy and growing calls for efforts to step up health monitoring for a crisis now in its 11th week.
Experts from the International Atomic Energy Agency began an inspection on Thursday of equipment damaged by the tsunami at a second nuclear plant, the Tokai complex about 120 km (75 miles) north of Tokyo, as part of an investigation prompted by the Fukushima accident.
A poll by the Asahi newspaper published on Thursday showed that 42 percent of Japanese people opposed nuclear power, up from 18 percent before the disaster.
The survey underscored the public's deepening concerns about nuclear safety and criticism of the way the government and Tepco initially responded to the crisis and how they appeared to have been repeatedly slow in admitting the gravity of the situation.
Although many outside experts had concluded that uranium fuel in three Fukushima reactors had melted down within days of the crisis, Tepco only announced that conclusion this week.
"We have to take seriously the criticism that we haven't done enough to provide and circulate information," Chief Cabinet Secretary Yukio Edano said at a news conference. "But we have never covered up information that we had."
POSSIBLE LEAK
The effort to regain control of the plant relies on pumping massive quantities of water to cool the three reactors that suffered meltdowns and storing the contaminated water in an improvised storage facility. Tepco officials said, however, that the water level in the storage facility had dropped, suggesting a leak.
Environmental groups have focused on the threat to sea and ground water from the accident. Greenpeace said earlier this month it had collected samples of fish, seaweed and shellfish along the Fukushima coast that showed radiation levels above Japanese safety limits.
Residents of the town of Futaba, forced to evacuate along with others inside a 20-kilometre (12-mile) zone around the plant, were allowed to return briefly to their homes on Wednesday.
A day earlier, residents of the nearby town of Minami Soma had been allowed back to their homes for a two-hour visit wearing hooded white protective suits, masks and goggles.
Video shot by a couple returning home and broadcast on Japanese television showed a ghost town with weeds overrunning a garden and a stray dog barking in the distance.
"It didn't even feel like my own home," one woman told Nippon Television. "I thought I was prepared for that, but I wasn't."

Volcanic cloud heads to Scotland, flights canceled

A dense ash cloud from an Icelandic volcano blew toward Scotland, causing airlines to cancel Tuesday flights, forcing President Barack Obama to shorten a visit to Ireland, and raising fears of a repeat of last year's huge travel disruptions in Europe that stranded millions of passengers.
Britain's Civil Aviation Authority said it appears that ash from the Grimsvotn (GREEMSH-votn) volcano could reach Scottish airspace early Tuesday and affect other parts of the U.K. and Ireland later in the week.
British Airways suspended all its flights for Tuesday morning between London and Scotland, while Dutch carrier KLM and Easyjet canceled flights to and from Scotland and northern England at the same time. Three domestic airlines also announced flight disruptions.

Still, authorities say they don't expect the kind of massive grounding of flights that followed last year's eruption of the Eyjafjallajokull volcano in Iceland because systems and procedures have been improved since then and the cloud is currently not expected to move over continental Europe.
Pilots unions, however, expressed concerns that the ash could still be dangerous.
Obama, who had been scheduled to spend Monday night in Ireland, was forced to fly to London early because of the ash cloud — he landed at the capital's Stansted Airport late Monday. Last year's Icelandic eruption also forced a change in his schedule then, causing him to cancel a trip to Poland.
Glasgow-based regional airline Loganair canceled 36 Scottish flights scheduled for Tuesday morning, as well as some flights to Birmingham and Belfast. It said its flights between Scottish islands would be unaffected. Two other British regional airlines, Flybe and Eastern Airways, also canceled flights to and from Scotland on Tuesday.
"Due to predictions on the movement of the volcanic ash, we are anticipating the cancellation of flights tomorrow morning and disruption to many more services," a spokesman for Edinburgh Airport said.
Andrew Haines, chief executive of the CAA, said the first priority is ensuring the safety of people both onboard aircraft and on the ground.
"We can't rule out disruption, but the new arrangements that have been put in place since last year's ash cloud mean the aviation sector is better prepared and will help to reduce any disruption in the event that volcanic ash affects U.K. airspace."
Many airlines said authorities last year overestimated the danger to planes and overreacted by closing airspace for five days amid fears that the abrasive ash could cause engines to stall.
CAA spokesman Jonathan Nicholson said authorities this time would give airlines information about the location and density of ash clouds. Any airline that wanted to fly would have to present a safety report to aviation authorities in order to be allowed to fly.
He said most British airlines had permission to fly through medium-density ash clouds, but none had asked for permission to fly through high-density clouds, classified as having over 4,000 micrograms of ash per cubic meter.
Even at that concentration of volcanic ash, experts said the air would not look much different from airspace unaffected by the ash, but officials say the tiny particles in the ash can sandblast windows and stop jet engines.
The international pilots' federation warned that it believed the cloud still presented a potential danger to commercial aircraft despite developments since last year.
"It remains our view that when there is an unknown then it is always better to err on the side of caution," said Gideon Ewers, spokesman for the International Federation of Air Line Pilots' Associations.
Thurai Rahulan, a senior lecturer in aeronautics at Salford University in northwest England, said the technology on how to measure and monitor ash has improved, but aircrafts' ability to cope with ash has not changed.
"Aircraft manufacturers have made more resources available to conduct studies on tolerating higher concentrations of ash, but as far as I know, no possible improvements have yet made it to front line operations yet," he said.
The disruption in Scotland is being caused by the smaller of two ash clouds from the volcano. The main cloud was causing minor disruptions around Scandinavia.
Iceland's main airport, Keflavik, and domestic airport Reykjavik both reopened Monday after being closed for almost 36 hours. Grimsvotn began erupting Saturday.
Hjordis Gudmundsdottir, spokeswoman for the airport administrator Isavia, said the first flight to take off would be an Icelandair flight to London Heathrow.
"The outlook is good for Keflavik and other Icelandic airports in the coming 24 hours," said Gudmundsdottir. "We don't have a forecast for after that so we wait and see."
The Met Office, Britain's weather forecasters, said there have been no major changes in the forecast — that some ash will drift across U.K. airspace, mostly in Scotland and Northern Ireland, by Tuesday morning.
But the weather in the U.K. has been very unsettled in the past two days and will continue to be that way in the days ahead, making predictions difficult.
"When it's all over the place, it's a bit trickier to predict where things may go," said forecaster Charlie Powell.
An Icelandic meteorological official said the eruption already appeared to be getting smaller, but Thierry Mariani, France's transport minister, said it was too early to tell whether air travel over Europe would be affected by the eruption.
Mariani told Europe 1 radio that the composition of the cloud will be examined in the coming days and if the ash is found to be harmful to airplanes, countries may take a joint decision to close part of Europe's airspace.
"The priority must always remain to ensure security," he said.
U.K. Transport Secretary Phillip Hammond told the BBC that Britain had equipment in Iceland analyzing the ash as it comes out of the volcano, and equipment in the U.K. that analyzes the density of the ash.
"We won't see a blanket closing of airspace," he said.
The plume was drifting mostly southward at a height of 5 kilometers to 9 kilometers (16,404 feet to 29,528 feet), the Icelandic Meteorological Office said in a report late Monday. Those are the normal altitudes for passenger airliners, and the plume was down from a maximum height of 50,000 feet (15,000 meters) Sunday, said Steinunn Jakobsdottir, a geophysicist at the forecaster.
The eruption has abated slightly since Sunday and no earthquakes have been recorded at the site since then, the forecaster said.
The European air traffic control agency's models showed the main plume of ash gradually extending northward from Iceland in the next two days. The cloud is predicted to arch its way north of Scandinavia and possibly touch the islands off the northern Russian coastline within the next two days.
Eurocontrol said the smaller ash plume was not expected to move farther east than the west coast of Scotland.
Some airline chiefs complained that regulators had overreacted by shutting much of Europe's airspace last year, stranding millions of passengers and causing big losses to airlines. But a study last month in the Proceedings of the National Academy of Sciences concluded the shutdown had been justified.
The possibility of disruption appeared to be affecting airline shares, which fell more than the market average. IAG, the parent company of British Airways and Iberia, closed down 5.1 percent on the day while Lufthansa shed 3.5 percent and Air France KLM fell 4.5 percent.