capeverdeinfo.org.uk

[james ensor]

The loss of 228 passengers and crew early on Monday June 1 on the scheduled Air France flight from Rio de Janeiro to Paris Charles de Gaulle is a tragic incident and much to be regretted especially for the families of the Brazilian, French, German , British and other passengers and crew on board.

The aircraft flew out of radar range of Brazilian ground stations and of the last terrestial GSM mobile phone station on the island of Fernando de Noronha some 400 miles off the Brazilian coast at 35.000 ft. There was no Mayday and no other communication from the crew after the plane had passed a waypoint on the direct route between Natal and Cape Verde.

Relatives of passenger in Brazil received text and voice messages from passengers alarmed by the severe turbulence that the aircraft was encountering on its route. Air France in Paris also received a stream of automatic messages from the plane indicating that electrical and electronic systems which control the plane`s fly-by-wire technology had failed.

The Brazilian airforce has found wreckage from Flight AF 447 close to the equator and at around 30 degree West. This is close to an outcrop called St Paul`s Rocks which is about 900 miles South-south-west of the Cape Verde islands. The aircraft was flying on the direct route between two ocean waypoints which would have led it over the Cape Verdes and on towards Portugal. It was about to enter the Dakar air traffic control region but never reported in. Dispersion of the wreckage and a long slick of aviation fuel floating on the surface of the very rough sea idicate the likelihood that the aircraft broke uop at altitude.

The crew of an Iberia Airbus which left Rio for Madrid ten minutes after AF443 has reported meeting the Air France crew in customs. They were described as in a jovial mood and laughing about the "sobrecargo" or excess weight of the French aircraft.

The Iberia crew had studied meteorological reports which indicated a long line of low pressure cells stretching across the planned flight-path of both planes. They arranged to take on an extra 2.000kg of aviation fuel in order to fly around the entire storm system. The Iberia plane did not see Air France on its radar screens or receive any of the normal radio messages describing the weather encountered.

But as the Spaniards reached the first waypoint on the route inside Dakar air traffic control the airwaves were full of messages trying to raise the Air France plane. Clearly the telemetry messages had alarmed people in Paris and as it later turned out the plane HAD ALREADY CRASHED BY THIS TIME.

Aircraft routinely divert around bad weather systems and this series of Atlantic anti-cyclones probably generated in the Cape Verde archipelago which is notorious as a source of early-season hurricanes was as bad as they get. Photographs from weather satellites taken at around midnight GMT show AF447 flying directly into the worst of the weather system, which would have extended up to at least 50,000 foot, well above the ceiling of a commercial plane.

According to its flight plan AF447 did not divert from the direct route. Nor did the pilot request a diversion route from Brazilian air traffic control which is a requirement for civil aircraft and there is no indication that it deviated from the direct route, at any stage. This raises the alarming possibility that the aircraft flew directly into a hazardous storm either because its payload of freight and passengers did not permit the extra fuel to be carried to fly around the storm without freight being off-loaded OR AIR FRANCE DID NOT WISH TO FACE THE EXPENSE OF EXTRA FUEL BURN. Another Air France A330 captain who has bravely identified himself having studied the satellite weather patterns at the scene declared "this is bad for Air France."

With Airbus and Air France already making statements that it will be difficult to recover the black box at a depth of perhaps 16,000 ft and that the pilots who may have taken over manual control due to the severe turbulence slowed the aircraft to the point that it stalled, it may be hard to get at the truth. In an Airbus crash some years ago at an airshow in Alsace, when the fly-by-wire system brought the aircraft down into a forest of trees which it had identified as a runway, the French authorities blamed the surviving test pilot who never worked again.

A very sad day for Brazil, for France and for air passengers.
_________________
James Ensor Moderator of the forum and one of the architects of www.capeverdeinfo.org.uk

[whitelaw hunt]

Tim Vasquez a famous American weatherman who worked for some years with the USAF in tropical Africa has this to say on the net.

"Overall what we know for sure is weather was a factor and the flight definitely crossed through a thunderstorm complex. There is a definite correlation of weather with the crash. However the analysis indicates that the weather is not anything particularly exceptional in terms of instability or storm structure. It's my opinion that tropical storm complexes identical to this one have probably been crossed hundreds of times over the years by other flights without serious incident.

Still, in the main MCS alone, the A330 would have been flying through significant turbulence and thunderstorm activity for about 75 miles (125 km), lasting about 12 minutes of flight time. Of course anything so far is speculation until more evidence comes in, and for all we know the cause of the downing could have been anything from turbulence to coincidental problems like a cargo fire.

My own opinion of the crash cause, as of Monday night, based on the complete lack of a HF radio call and consideration of all of the above, suggests severe turbulence (see the BOAC 911 and BNF 250 tragedies) combining in some unlikely way with CRM/design/maintenance/procedural/other deficiencies to trigger a failure cascade. We can almost certainly count on some unexpected surprises once the CVR is recovered. Until then, all we can do is await the investigation and hope that the world's flight operations stay safe until AFR447's lessons are revealed. "

[whitelaw hunt]

Here is the report of BOAC`s 707 lost through extreme turbulence.

BOAC Flight 911 operated by Boeing 707-436, on G-APFE on March 5, 1966. The Captain who had five years 707 experience decided to show Mount Fuji to his passengers, which included a large group of American businessmen on a junket on their way to Hong Kong. Among the passengers whose lives were saved by changing flights at the last moment were Cubby Broccoli, Harry Saltzman, Ken Adam the producers and directors of the James Bond films.

The weather at Tokyo had seen a cold front pass over with a steep pressure gradient bringing cool dry air and strong winds from Siberia and clear skies. The weather report en route was good and the navigator filed an Instrument Flight Rule plan for the flight to Hong Kong at 31,000 feet.

At engine start this was amended to a Visual Meteorological Conditions climb west taking the plane close to Mount Fuji. The aircraft climbed to 16,000 ft, well above Mount Fuji, peak

Approaching downwind of Mount Fuji, the aircraft hit severe clear-air turbulence caused by lee waves. Winds on Mount Fuji were north-west at 60 to 70 knots and skies were clear.

The Boeing 707 broke up in mid-air and crashed into the mountain killing all passengers and crew. An U.S. Navy plane searching for the wreckage encountered extreme turbulence and other aircraft reported moderate to severe turbulence.

An 8mm film taken by a passenger was developed by investigators, and showed evidence that the aircraft experienced severe turbulence just prior to the accident. No evidence was recovered from the flight data recorder, which was destroyed by fire with the rest of the nose section which fell separately. The aircraft did not have a cockpit voice recorder, and no Mayday was sent.

The aircraft left debris fin a 10 mile trail. The vertical tail rudder came off first taking the port tail plane with it. Then the tail fin and all four engine pylons failed putting the aircraft into a flat spin, with the forward fuselage section and the outer starboard wing breaking off shortly before impact with the ground.

Stress cracks were found in the vertical stabilizer bolt holes, and it turned out that this was a common problem on Boeing 707 and 720 aircraft but accident investigators ruled this out as a primary cause.

The probable cause determination was: "The aircraft suddenly encountered abnormally severe turbulence which imposed a gust load considerably in excess of the design limit."

[okke van roosevelt]

On October 7 2008 Qantas flight QF72 from Singapore to Perth, operated by an Airbus A330 aircraft sufferred a similar incident. It dropped with two plunges of 20 and 16 seconds 600ft and 2000ft in seconds The pilot was forced to make an emergency landing at Learmonth, 175 miles north of Perth on the Western Australian coast, and 44 passengers required hospital treatment.

The Australian Transport Safety Bureau said it believed a faulty component, called the air data inertial reference unit (ADIRU), caused the problem by feeding "erroneous and spike values'' about the angle at which the plane was flying to a flight control computer.

"This led to several consequences, including false stall and over speed warnings,'' and later generated very high and incorrect values for the aircraft's angle of attack. This led to the flight control computers commanding the aircraft to pitch down.

On this flight the plane acted of its own accord even after the pilot had taken manual control of the aircraft but minutes later, the plane made two downward plunges.

On 27 December 2008 it happenned again to Qantas Airbus A330-300 aircraft operating flight QF71 while in cruise at 36,000 ft enroute from Perth to Singapore.

At about 0829 UTC the autopilot disconnected and the crew received an ECAM message (NAV IR 1 Fault) indicating a problem with ADIRU Number 1. The crew actioned the Airbus Operations Engineering Bulletin (OEB) procedure by selecting the IR 1 push-button to OFF and the ADR 1 push-button to OFF. Both OFF lights illuminated. The crew elected to return to Perth and an uneventful overweight landing was conducted. At the time that the autopilot disconnected, the aircraft was approximately 260 nautical miles (NM) North-West of Perth airport and approximately 350 NM South of Learmonth airport.

During the incident the flight crew should get a message from ECAM (Electronic Centralized Aircraft Monitor) signaling the pilots which system is faulty and what to do to fix it.

On Airbus is the flight control computer is always flying the plane whether Auto pilot is on or not, even in manual mode all the controlling is done through the flight control computer.

After the initial problem that led to the autopilot disconnecting, they were hand-flying the plane and then the aircraft pitched down by itself.

While they try to correct the situation it happened again ... it pitched down a second time.

After the inciden they found one of the three Air Data Inertial Reference Unit (ADIRU) was defective and it sent to the US base of its manufacturer, Northrop Grumman for to find out what led to the fault and reduce the chance of that happening in the future.

Qantas’s initial review of the aircraft's maintenance history found no problems..

Airbus issued a bulletin to all operators of its planes containing the component, with advice on how to reduce the risk of a crash in the event of such a malfunction.

The aim of the bulletin is to:

update airline operators on the factors identified to date that led to the accident involving QF72,provide operational recommendations to mitigate risk in the event of a reoccurrence of the situation which occurred on QF72.

The A330 and A340 have identical systems, in the world there are 182 A-340 and 210 A-330 airplanes .

[whitelaw hunt]

Here is the view of an airline pilot from Toronto quoted on the professional pilots rumour network.

How about the option of turning back and returning to base ?

The root cause of this accident, in my opinion is "press-on-itis", along with possible complacency / over confidence re: extremely severe weather.

Just a coincidence that another AF flight tried to land during a Thunder Storm at Toronto?

ASN Aircraft accident Airbus A340-313X F-GLZQ Toronto-Pearson International Airport, ON (YYZ). Here is the official report.

"Air France flight AF358 departed Paris at 13:32 local time for a scheduled flight to Toronto. Weather conditions were poor as the aircraft approached Toronto with heavy thunderstorms and rain. Around 15:52 the crew contacted Toronto Approach. The controller replied: "Air France 3-5-8 Heavy roger, 2-4 Left is your runway, the altimeter 3-0-0-0 and when you are able fly heading 2-10 and intercept the localizer." The Air France pilot then responded: "When able within.... five nautical miles we can intercept the localizer, Air France 3-5-8." The crew then received further instructions to descend to 5000 and to reduce their speed to 190 knots. About 15:55 they were cleared down to 4000 feet and one minute later the controller cleared the flight for the ILS approach to runway 24 Left. Within less than a minute the controller asked "...Air France 3-5-8 reduce speed now to 1-60 knots", which was correctly read back. Thirty seconds later the controller radioed: "Air France 3-5-8 slow to your final approach speed". Then, about, 15:58 they were instructed to contact the Toronto Tower: "Air France 3-5-8 contact Toronto tower at the KIREX fix on frequency 1-18 point 3-5". The KIREX fix is located at 6.0 DME. After being cleared to land, the Airbus touched down on runway 24L, a 9000 feet (2743 m) runway. The airplane was not able to stop before the end of the runway and overran. It careened to the left, down a slope, ending up in a gulley. The airplane caught fire, but everyone on board was evacuated safely."

See www.brazilinfo.co.uk/af447.htm

[okke van roosevelt]

The Airbus A330 first flew in 1992. There are currently 955 in airline service. Out of this fleet five have been written off, either by crashing or being severely damaged, not necessarily with fatalities. The Boeing 777 first flew in 1995 and 12,331 have entered airline service. Of these just one BA Flight BA038 from Beijing to Heathrow has been written off, with no casualties due to great skill in piloting.

In terms of fatal events per million flights BA has 0.36 (that is an accident where someone died) and Air France 0.74 whilst the Airbus A330 has 0.53 and the Boeing 767 0.43. Maybe the airline makes more difference than the plane. Nobody has yet died in a Boeing 777.

You can see more figures on www.airsafe.com

[okke van roosevelt]

The Concorde has the worst safety record of any modern aircraft. This is due to just one spectacular accident at Paris Roissy with a party of German businessmen, who all died in the crash. The aircraft took off overweight and from the wrong runway. But the accident was caused by debris from the runway smashing up into the vulnerable underside of the main fuel tank and causing it to catch fire on take-off.

British Airways engineers were well aware of this issue due to a substantial number of reported non-fatal incidents and had fitted protective plates to British Concordes. However, when they met with Air France engineers to discuss possible solutions. they were rebuffed with the claim tht Air France had had no such experience. Air France Concordes were never fitted with protective plates

This is something worse than press-on-itis. It is a lack of care for safety, which might also be a factor in the Brazil crash, which some feel was caused by the defective design of pitot tubes, which misinformed the on-board flight control computers.

[whitelaw hunt]

French air accident investigators now have some scenarios from the state of wreckage and bodies. They could not find the black box. But they figure the plane hit the ocean at a speed of 200 kts but with a fast drop rate. It was stalled with both engines stopped but otherwise undamaged, at this point.

One can speculate on events leading to this outcome. Three pitot tubes which project from the fuselage to measure air pressure and calculate speed, could have iced up. The plane was flying through cirro-stratus at 35,000 feet with ice shards. This could block the pitot tubes giving false airspeed. Fly by wire would increase thrust and point the nose down to compensate. With the captain snoozing back of the plane, co-pilots might have misread signals The throttle does not show the computer increasing thrust as the controls do not move at all. Visibility was nix.

The computer confused by bad data shut down and handed the pilots control under alternate law. Inexperienced pilots would point the nose down and increase thrust, fearing a stall with the low airspeed readout. This would mean disaster when Mach number became critical.

French made pitot tube malfunctions in icy conditions have been noted before but no action taken. Other Airbus utilize tubes from the American BF Goodrich corporation.

A combination of bad airline engineering management and pilot inexperience?

[whitelaw hunt]

The news that the captain of British Airways Flight 038 from Beijing which landed short of the runway at Heathrow, miraculously with only minor injuries, is seeking a job with Korean Airlines raises some further questions about computer controlled flying.

The Boeing 777 300ER of British Airways is fitted with automatic landing systems and extensive flight automation systems. This means that pilots only rarely undertake pilot controlled landings at Heathrow although they are required to complete several each year to retain their certification. Are hey becoming deskilled?

The co-pilot was at the controls of BA 038 on the Heathrow approach and the contribution of the captain to the landing process was unclear. No Mayday was made and passengers were not warned to brace for a crash landing. Many described it just as an abnormally heavy landing and were surprised to have to evacuate by chute.

The Accidents Investigation Board will be examining all possible reasons for the crash-landing including fuel starvation through icing and pilot error.

[james ensor]

A Libyan Airbus A330 has now crashed at dawn on the appoach to Tripoli airport. Associated Press reports.

"BRUSSELS — The Afriqiyah Airways jet that crashed just before touchdown in Libya may have been attempting a go-around in poor visibility caused by sunlit haze, safety officials and pilots familiar with the airport said Thursday.

The Airbus 330-200 was carrying 103 people from South Africa to the Libyan capital, and a 9-year-old boy from the Netherlands appeared to be the lone survivor.

Both black boxes, the cockpit voice recorder and the flight data recorder, were immediately recovered at the crash site in the capital, Tripoli. Investigators from the United States, France, South Africa, the Netherlands are reportedly helping Libya with the probe into the causes of the accident.

"I am assured that there will be a very thorough investigation, since (the French accident investigation authority) will be party to it and they are one of best accident investigators in the world," said William Voss, president of the U.S.-based Flight Safety Foundation.

He cautioned that "it's important to realize that early assumptions about an accident are often wrong."

Investigators will likely consider technical reasons for the crash, such as catastrophic engine or structural failure just before touchdown. They will also look into whether the pilots were fatigued after a long overnight flight.

Still, safety officials interviewed by The Associated Press say questions have already been raised about the crash because of the condition of the plane's wreckage.

Images and footage from the scene showed a wide debris field, with the aircraft having completely disintegrated, indicating a high-energy impact. But the images did not show any significant evidence of fire, which often accompanies accidents in which the plane's fuel tanks are destroyed.

"I would first look into this, the lack of fire, when searching for a cause. Could it indicate fuel starvation?" said an aviation official who could not be named due to the sensitivity of the matter.

A safety expert who declined to be identified because of possible involvement in the investigation also noted that the lack of a fire may indicate that the plane was low on fuel after the long flight from South Africa.

Pieces of the fuselage appeared to have ended up facing backward — away from the direction of flight — raising the possibility that the Airbus had cartwheeled on impact.

That, in turn, would mean that the plane likely slammed into the ground with one wing tip first, instead of coming down with its wings level — indicating that the pilot may have been banking during the flight's final moments, possibly attempting a go-around after problems on approach.

A frequent cause of aviation disasters during the approach and landing phase is known as "controlled flight into terrain," in which an otherwise airworthy plane is accidentally flown into the ground or water, usually because of the pilots' spatial disorientation.

Tripoli International Airport's navigational systems are considered austere by international standards. On Wednesday, pilots were notified that a key navigational aide was showing false readings due to interference from a construction project — though interference is not uncommon at airports.

The main runway is positioned in an east-west direction, with most arriving aircraft flying in from the east because navigational aides are at that end of the runway and the prevailing wind is from the west. Airliners normally land and take off against the wind because it makes the process easier.

Still, the Afriqiyah Airbus approached the runway from the west, although the airport weather report showed the wind was blowing in the same direction. The pilots were thus looking directly into the sunrise while searching for the runway and also had to contend with an early morning layer of haze that reduced visibility at lower altitude.

A European pilot who has flown to Tripoli numerous times said the standard approach was from the east. He described as "strange" the decision to come in from the opposite direction, particularly in light of the wind direction. "
_________________
James Ensor Moderator of the forum and one of the architects of www.capeverdeinfo.org.uk

[okke van roosevelt]

Here is the comment from a British pilot based at gatwick

Utterly predictable accident
1 Operating Airbus into TIP or BEN can be risky in low vis with standard poor/unserviceable navaids

2 ATC standard in Libya is poor, and often ATC have no access to current met info, esp anemometer

3 Operating Airbus with part-Libyan crew is often dangerous due to the incompetence and over-confidence of Libyan pilots. Many have little relevant recency, and often have previously flown out-dated primitive aircraft.

4 A330 is too complex an aircraft for the average Libyan crew.

Above comments based on extensive experience operating A320's with Libyans out of TIP and BEN. And current experience on A330.

[okke van roosevelt]

Here is some information from a pilot in Manchester,

"I happen to know a colleague of the deceased pilot (Capt. Yousif Saadi) and spoke to him on the phone yesterday. Pilot is experienced, UK trained in 1970s, flew Boeing 727 for 2 decades then worked outside Libya for 6 years in 1990s. Joined Afriqiyah and converted to A330 with Air France. His colleague says he is a good pilot with excellent record (40 years flying), but the Tripoli-Johannesburg trip is a killer. Pilot gets less than 12 hours net resting time during daylight between two 9 hour flights (10 in the cockpit) - not enough to refresh. Having two FOs is no help because they are equally not fresh. He says that he himself begged to be removed from similar flights because on occasions he knew he was too fatigued to take quick important decisions if an emergency or bad visibility is encountered. He recalled an FO recently trying to persuade him to go low to identify runway in poor visibility in Benghazi. Under such circumstances ILS or an accurate system is a must. He said the late Capt Yousif knew the problems with Tripoli VOR system but can only explain what happened in two ways: either fatigue got the better of him and he did not check his descent soon enough to keep plane above minima or there was something wrong with the instruments that made him realise he was too close to the ground too late in poor visibility. Given VOR's performance for Tripoli 09, visual identification is needed for safe landing. In poor visibility, which is now confirmed for the time of the accident, pilots either abort early and request somewhere else (fuel considerations?) or push the limits towards a possible and predictable lethal outcome.

Commercial considerations and pressures would make the airways lethal without ILS and quality information and directions. Pilots are always pushed to the limit of their human capacity and can only survive by relying on automation, which is not always helpful in emergency. Recall the Hudson river pilot's testimony before Congress? He spoke about the conditions pilots increasingly face.

By the way, in Libya, although the authority do not equip airports well at all, they apparently would bring a pilot before a committee if (minima) rules are breached or even if diversion is requested to explain their decision. Effect on pax connections, fuel cost, etc. will all be discussed by such committee. Sounds familiar, anyone?"

[james ensor]

An Indian Airlines Airbus A320 crashed 20 years ago at Bangalore in similar circumstances. This is what the New York Times had to say

" The crash of an Airbus A320 jet that killed 97 people in India last week has reignited a dispute in France over whether the computerized, highly advanced aircraft is too complicated to fly. The French pilots union is urging that the airliner be grounded in France.

''This plane is sometimes put into operation by people who aren't qualified enough,'' said Jean-Claude Bidot, secretary general of the French Airline Pilots Union. ''It's a supercomplicated aircraft.''

But the maker of the plane, the four-nation consortium known as Airbus Industrie, said that the plane was quite safe and that the French pilots were opposing it to protect their economic interests. The plane uses two pilots; many other aircraft use three.

The Indian authorities are examining the causes of the Feb. 14 crash of the Indian Airlines Airbus jet, and they have not disclosed any findings.

Computers and Control Stick

The 150-seat A320 is one of the most successful new planes in history. A total of 530 have been ordered, including the 77 aircraft already in service. Northwest Airlines is the only United States airline to fly the A320 jet, said David Venz, an Airbus spokesman. That carrier began flying six A320's in July and has orders for 100.

Computers control the A320's engines and flight systems, and video screens replace traditional instruments that display information to the pilots.

Mr. Bidot said he feared not only that the plane was too complicated in terms of pilots' programming its computers but that too much reliance on computers could erode the pilots' basic flying skills. That, he said, could hurt the pilots' reflexes in time of emergency.

Pilots fly the Airbus jet with a single control stick mounted on the side of the cockpit rather than with the traditional control wheel. The plane's computers are programmed to prevent the pilot from inadvertently overextending the plane's controls. Some aviation experts have expressed concern that the system may prevent the pilot from taking full control of the plane in an emergency.

'Fly by Wire' System

The Air Line Pilots Association, the American pilots' union, has not objected to the A320. But ''there's still the basic question that resides in some pilots' minds whether there should be that kind of responsibility placed in a computer program,'' said John O'Brien, the union's director of safety and technology.

The Airbus A320 is also the first commercial jet with cockpit controls that operate by electrical pulses rather than mechanical means, a system called ''fly by wire.''

The Boeing Corporation and the McDonnell Douglas Corporation, the two other airliner builders, have chosen not to use the fly-by-wire system in their new jets, partly because of fears that very strong radar and electrical signals could interfere with the plane's control system.

Mr. Venz said the planes underwent rigorous testing, with extremely strong electrical signals beamed at them from close range. ''There wasn't even one iota of a problem,'' he said. Meanwhile, the Federal Aviation Administration is proposing new rules that will require additional safeguards for newly designed jets that use the fly-by-wire system. #14 Jets Grounded by India On Sunday, Indian aviation authorities grounded the 14 A320's operating in their country. When Indian Airlines ordered 31 A320's for more than $1.2 billion, some Indian pilots went on strike, contending that their nation's maintenance crews were not prepared to handle the aircraft.

Officials at Airbus Industrie, a Toulouse-based consortium including France, Britain, West Germany and Spain, said there had been no evidence that the aircraft was at fault in the crash in Bangalore, in southern India.

''The Indian authorities took the decision to ground the fleet of A320's, but they appear to have done that without any justification,'' said an Airbus spokesman.

The plane crashed in clear weather on approach to land, falling about 1,000 feet short of the runway. The plane, which was delivered two months ago and had 366 hours of flight time, was carrying 139 passengers and seven crew members.

Crash at French Air Show

An Air France A320 crashed in June 1988, killing three passengers, at an air show in Habsheim, France. French investigators concluded that the crash was the fault not of the aircraft but of the pilot, who had flown too low and too slowly over an airfield and was unable to lift the plane above trees just beyond.

Airbus officials say the French pilots' protest is linked to their long-standing complaint that the A320 requires two pilots rather than three. The pilots say a two-pilot cockpit is unsafe. Airbus and many airlines say the aircraft is safe and the pilots are trying to preserve jobs.

Airbus officials also say the pilots are seeking to redeem the captain in the Habsheim crash, who was stripped of his license afterward.

On Tuesday, Jean Pierson, chairman of Airbus, wrote to the Montreal-based International Civil Aviation Organization to protest the decision of the Indian authorities not to include in their investigation team Airbus Industrie experts or French aviation authorities, who originally certified the plane.

The aircraft's digital flight recorder has been shipped to Canada, where it is being decoded by Indian and Canadian experts. Indian officials said they chose Canadian rather than French, British, German or Spanish investigators to insure an impartial investigation. "
_________________
James Ensor Moderator of the forum and one of the architects of www.capeverdeinfo.org.uk

[okke van roosevelt]

An Armavia Armenian Airlines Airbus A320 Flight 967 crashed into the Black Sea at Sochi on May 2 2006 after doing a go around flight after the pilot discovered that visibility of the runway was too poor to attempt a landing. An Air France A319 attempting a landing at Paris CDG in 2009 survived a near catastrophe when the pilots decided to go around after they could not see the runway at a height of 2,000 ft.

The official Air France Accident Prevention and Flight Analysis unit received a report from the pilots on what happenned next. The pilots made an error with the complex computer system that helps to fly Airbus and did not select sufficient engine thrust. As a result the computer system remained in Landing mode and pointed the aircraft nose downwards to make a landing. As the engines were on increased thrust the aircraft accelerated and began to descend rapidly. Fortunately the pilots had sufficient experience and altitude to recover the situation and after climbing again and completing a circuit were able to land normally.

There is speculation that at Tripoli as well as at Sochi, something similar may have happenned but the pilots were less lucky or less skilful. All Airbus aircraft use computerised control systems to reduce the risk of accidents.

[james ensor]

The BBC assembled a group of British and American air accident investigators, air safety experts, Airbus and jet fighter pilots. They used an Airbus flight simulator and some good graphics to investigate what they dubbed the mystery of Flight 443 which had abruptly disappeared from radar screens just a year earlier.

So long as the Black Box has not been recoverd from the depths of the South Atlantic it is impossible to be definitive about the cause of the accident. The official BEA report (Bureau d`Etudes et d`Analyses) has yet to be published in Paris. In the meantime the experts seemed to agree on the theory that the Air France Airbus A330 flew straight into a massive storm. Supercooled moisture at 35,000 ft froze up all three pitot tubes. These are the small tubes fitted to the fuselage which register air pressure and allow the aircraft computer to calculate airspeed.

Without any accurate airspeed indication the computer started to shut down the aircraft`s automatic systems. Some 25 systems switched themselves off within four minutes. amid blaring warning noises and flashing messages.

It is surmised that the aircraft started flying too slowly and with its heavy load of passengers, fuel and cargo stalled at high altitude. It looks possible that the pilots managed to recover the stall after diving many thousands of feet towards sea level. But the experts consider that the plane then stalled again abd hit the sea whilst moving rapidly downwards.

It was suggested that most commercial airline pilots would have had little training in stall recovery techniques and a big passenger airline is far from being an aerobatic aircraft. Airbus is now advising that pilots should be trained in stall recovery and in operating an aircraft without speed indication. Multiple pitot tube failure is not that rare, arising on average once a week. So perhaps this was an accident waiting to happen.

Many factors combined to cause the tragic loss. But perhaps if Air France had taken on more fuel at Rio to divert around the storm, which stretched for 250 miles across its path, it might have survived as did the Iberia flight that took off along the same course ten minutes later.
_________________
James Ensor Moderator of the forum and one of the architects of www.capeverdeinfo.org.uk