Air France jet vanishes

http://en.wikipedia.org/wiki/Coffin_corner_(aviation)

 

I haven't seen all this info but from what I read I think that they could have flown into a well developed and vicious thunderhead that disassembled the airplane. The danger not mentioned is the wind shear inside these storm systems. The back side of the storm collar inside could have 100 MPH winds going up and right next to it winds going DOWN at 100MPH. That ain't fun and it tears airplanes up quick.
The coffin corner is a narrow spectrum of flight where the air is so thin that you can fly fast enough to exceed critical Mach and get into compressability and if you slow down just a tad you cannot sustain lift and you become a streamlined brick on its way down. I hope that is clear enough and correct enough.
Switches

 

I got this same thing from Comcast;

FERNANDO DE NORONHA, Brazil — Military planes located new debris from Air France Flight 447 Wednesday while investigators focused on a nightmarish ordeal in which the jetliner broke up over the Atlantic as it flew through a violent storm.

Heavy weather delayed until next week the arrival of deep-water submersibles considered key to finding the black box voice and data recorders that will help answer the question of what happened to the airliner, which disappeared Sunday with 228 people on board. But even with the equipment, the lead French investigator questioned whether the recorders would ever be found in such a deep and rugged part of the ocean.

As the first Brazilian military ships neared the search area, investigators were relying heavily on the plane's automated messages to help reconstruct what happened to the jet as it flew through towering thunderstorms. They detail a series of failures that end with its systems shutting down, suggesting the plane broke apart in the sky, according to an aviation industry official with knowledge of the investigation, who spoke on condition of anonymity because he was not authorized to discuss the crash.

The pilot sent a manual signal at 11 p.m. local time saying he was flying through an area of "CBs" — black, electrically charged cumulonimbus clouds that come with violent winds and lightning. Satellite data has shown that towering thunderheads were sending 100 mph (160 kph) updraft winds into the jet's flight path at the time.

Ten minutes later, a cascade of problems began: Automatic messages indicate the autopilot had disengaged, a key computer system switched to alternative power, and controls needed to keep the plane stable had been damaged. An alarm sounded indicating the deterioration of flight systems.

Three minutes after that, more automatic messages reported the failure of systems to monitor air speed, altitude and direction. Control of the main flight computer and wing spoilers failed as well.

The last automatic message, at 11:14 p.m., signaled loss of cabin pressure and complete electrical failure — catastrophic events in a plane that was likely already plunging toward the ocean.

"This clearly looks like the story of the airplane coming apart," the airline industry official told The Associated Press. "We just don't know why it did, but that is what the investigation will show."

French and Brazilian officials had already announced some of these details, but the more complete chronology was published Wednesday by Brazil's O Estado de S. Paulo newspaper, citing an unidentified Air France source, and confirmed to the AP by the aviation industry source.

Air France spokesman Nicolas Petteau referred questions about the messages to the French accident investigation agency, BEA, whose spokesman Martine Del Bono said the agency won't comment. Brazil's Defense Minister Nelson Jobim also declined to comment, saying that the accident "investigation is being done by France; Brazil's only responsibility is to find and pick up the pieces."

Other experts agreed that the automatic reports of system failures on the plane strongly suggest it broke up in the air, perhaps due to fierce thunderstorms, turbulence, lightning or a catastrophic combination of events.

"These are telling us the story of the crash. They are not explaining what happened to cause the crash," said Bill Voss, president and CEO of the Flight Safety Foundation in Alexandria, Va. "This is the documentation of the seconds when control was lost and the aircraft started to break up in air."

Voss stressed that the messages alone were not enough to understand why the Air France jet went down, noting that the black boxes will have far more information to help determine the cause.

One fear — terrorism — was dismissed Wednesday by all three countries involved in the search and recovery effort. France's defense minister and the Pentagon said there were no signs that terrorism was involved, and Jobim said "that possibility hasn't even been considered."

A U.S. Navy P-3C Orion surveillance plane, a French AWACS radar plane and two other French military planes joined Brazil's Air Force in trying to spot debris and narrow the search zone.

Brazil's Defense Minister Nelson Jobim said debris discovered so far was spread over a wide area, with some 230 kilometers (140 miles) separating pieces of wreckage they have spotted. The floating debris includes a 23-foot (seven-meter) chunk of plane and a 12-mile-long (20-kilometer-long) oil slick, but pilots have spotted no signs of survivors, Air Force spokesman Col. Jorge Amaral said.

"Oil stains on the water might exclude the possibility of an explosion, because there was no fire," Defense Minister Nelson Jobim told reporters Wednesday.

The new debris was discovered about 55 miles (90 kilometers) south of where searchers a day earlier found an airplane seat, a fuel slick, an orange life vest and pieces of white debris. The original debris was found roughly 400 miles (640 kilometers) northeast of the Fernando de Noronha islands off Brazil's northern coast, an area where the ocean floor drops as low as 22,950 feet (7,000 meters) below sea level.

Brazil lacks the equipment needed to reach the ocean floor. If the black boxes are at the bottom of the sea, their recovery will have to wait for the arrival early next week of a French research ship with remotely controlled submersibles that can explore as deeply as 19,600 feet (6,000 meters).

The sturdy black boxes — voice and data recorders — are built to give off signals for at least 30 days, even underwater, and could keep their contents indefinitely.

But the head of France's accident investigation agency, Paul-Louis Arslanian, said in Paris that he is "not optimistic" about recovering the recorders — and that investigators should be prepared to continue the probe without them.

"It is not only deep, it is also mountainous," he said. "We might find ourselves blocked at some point by the lack of material elements."

Arslanian said investigators didn't have enough information to determine whether the plane broke up in the air or upon impact with the sea, and that in the absence of black box data, they are studying maintenance and other records.

"For the moment, there is no sign that would lead us to believe that the aircraft had a problem before it took off," Arslanian said.

He said investigators did not know the exact time of the accident or whether the chief pilot was at the controls when the plane went down. Pilots on long-haul flights often take turns at the controls to remain alert.

If no survivors are found, it would be the deadliest crash in Air France's history, and the world's worst civil aviation disaster since the November 2001 crash of an American Airlines jetliner in the New York City borough of Queens that killed 265 people.

___

Bradley Brooks wrote from Rio de Janeiro. Associated Press writers Alan Clendenning in Sao Paulo; Marco Sibaja in Brasilia; Slobodan Lekic in Brussels, Belgium; Shawn Pogatchnik in Dublin; Emma Vandore in Bourget, France; and Angela Charlton in Paris also contributed to this report.
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God what a terrible thing..................................................

 

I read elsewhere that the "Boxes" can transmit up to 20,000 feet under water. This is going to make it tough to find them. 20,000 feet isn't much in the Atlantic.

 

Ram Air Turbines are not required on aircraft that have independent auxiliary power units (APUs) (essentially Jet-A powered turbine-powered generators) capable of powering the main bus. The all electric F-16 has a hydrazine powered turbine that powers the main bus for several minutes to enable flame-out landings. A RAT large enough to power the electro-mechanical and electro-hydraulic actuators on all-electric aircraft is impractical, and even less practical for a large aircraft like an A330.

The coffin corner is a cryptic term for the point where stall speed (or loss of directional control airspeed) very closely approaches the maximum structural airspeed (velocity never exceed) of a subsonic aircraft. As aircraft fly higher, the air becomes thinner and the aircraft must fly faster to generate enough lift to maintain altitude. In heavyweight aircraft, the problem is even worse, because more lift must be generated to support the heavier weight and this requires flying still faster. If problems occur or turbulence is encountered causing a loss of thrust or airspeed, it may become necessary to descend to thicker air to maintain enough lift to prevent a stall or loss of directional control. At or near the coffin corner, however, this descent can result in overspeeding the airframe and structurally damaging the aircraft. Assuming, of course, that directional control is maintained during the descent. You are literally balanced on a razor's edge at the coffin corner. A little faster and the aircraft comes apart, a little slower and you lose directional control.

An extreme example is the U-2 surveillance aircraft, which typically operate at altitudes above 65,000'. At those altitudes, the difference between losing directional control of the aircraft (stalling) and ripping the wings off is only 10 nautical miles per hour or so of indicated airspeed. Airspeed indicators for U-2s have a dual range airspeed indicator and audible warningswarnings to let the pilot know anytime he approaches either limit.

All indications now suggest the A330 flew through a heavy band of extreme weather, lost directional control, and structurally failed during the subsequent descent. It must have been a terrifying couple of moments for all involved.

Taz
Terry Phillips

 

Yeah, that's what I said...I think.
Switches

 

This may be dumba** question, but why would the PIC continue through these nasty storms when the tops were above his ceiling? If he couldn't detour around them, wouldn't the protocol be to return to a Brazilian strip?

 

You have got me on that one. PIC choice, company direction, hubris, casual approach to weather, etc. That's a tough one.
Switches

 

Bob- Sorry about that. I started the post, ate dinner and watched the news, and then finished the post. Yours went up in between. We said the same thing.

Don- In the military there is never a peacetime reason to penetrate a thunderstorm. Airlines cancel tons of flights for weather, including severe thunderstorms in an area where they are scheduled to take off or land. The weather radar on the A330 should have allowed them to pick their way through the line of bad weather. For whatever reason, the weather was worse than they expected, apparently, and vertical shears of up to 100 mph (~87 knots) were measured that day. The fact they were at high altitude probably lulled them into thinking they were above the worst of it. Perhaps they were above the worst of it and just got really unlucky. Sort of like the movie Perfect Storm. On some days you are just not going to make it without doing a 180 and returning to the take-off spot. Once directional control is lost on an Airbus near its maximum operating altitude for its fuel weight, it would be really difficult to regain control. Vertical velocity in an out of control situation can exceed 30,000 ft/min of descent rate (~296 knots of vertical velocity). In this particular case, probably 2-4 minutes from loss of control until the heavy parts hit the water. In the F-111s I flew, the Dash-1 states descent rates of up to 50,000 ft/min (~493 knots) may be seen in a fully developed spin, but our aircraft was not going to come apart until impact, and this one apparently came apart well before impact.

Taz
Terry Phillips

 

I remember a flight that I had in a NWA 707-320 in Sept. 1967 coming back from a company meeting in Penn. We hit huge thunderheads over the Rockies. We were at something like 37,000-40,000 and the tops were a good 10,000 above us. The pilot tried twice to sneak through some breaks and valleys but searched in vain. He turned left and headed south for a long way and I think that I recognized Davis-Monthan runways finally before we headed west again. We were an hour late getting into Seattle. I was sure glad of that. Flying in B-24's I remember seeing lightening filled thunderheads topping out WAY above us and it was always a go around or a 180. Flying in Florida in the summer I learned early to steer clear of the big thunderbumpers because it was death sentence to get caught in one. In lower latitudes they can soar to heights of 55,000 and are filled with mayhem.
I corresponded with an ex-Eastern Airways pilot who flew the mail in a Pitcairn Mailwing in the 20's and 30's in Georgia . He related a story about getting caught in " something" one night that really got rough. The lightning made a bad taste in his teeth and he soon realized that he was inverted and being beat up pretty bad. He looked at the altimeter and he was CLIMBING at an astronomical rate. Nothing he did had any effect on what was happening. He began to ice up and decided to bail out. Then he gave it some thought and realized that he would simply follow the airplane wherever it was going so he sat there in the open cockpit and rode it out. The storm "spit him out" at an extreme altitude and he managed to get his airplane back down and away from the storm somehow and continue his journey. He had many other stories about his early flying that would curdle your milk. He was finally blinded in the crash of a American Airlines Stinson low winged tri-motor. He was a great guy to chat with and I always felt that I was a nobody talking to a hero. He would never have liked that but it was ever thus.
he flew Curtiss Condors and had wonderful stories about those too. May the GOOD LORD rest his soul.
Switches

 

Although NOT all electric, the 777, 767 and 747 DO have RATS, electro-hydraulic, just enough to maintain limited controls. The 767 that went into the ocean off the coast of Africa near the Comoros Islands (Hijacked) dead-sticked on a RAT for over 100 miles. You could see it sticking UP out of the bottom of the A/P when it crashed.
The Hijackers ran the plane out of fuel hence negating the APU.

Maybe designers should reconsider......................

(The 777 and 747 also have TWO Ram Air Turbines for hydraulics that run off of APU by-pass air, located in the wing-to-body fairing)

 

It isn't a dumb question at all, and Bob's answer is a good one. There is another thing that should be said: the pilot may well have thought himself far away enough to avoid 'the worst' of it. But even in 'clear air' you aren't guaranteed an easy ride. I was on a 747 over the Atlantic when the aircraft 'bumped' and then dropped a few thousand feet. No thunderstorms, nothing out the window that looked odd, but we descended quickly enough that people standing in the aisles were flung around like rag dolls.

Naturally, you'd expect there to be more turbulence near/in a storm, but the PIC may have thought himself 'safe' where he was.

 

Maybe this applies: "There are old pilots. There are bold pilots. There are very few old, bold pilots."

 

Spasso- Good points. Interesting on the APU exhaust running a RAT. Same theory as a turbocharger.

Taz
Terry Phillips

 

The Air Canada 767 that deadsticked into Gimli after running out of fuel was able to make it there because of the RAT.

 

For those of you not in the airplane business, a simple discussion of what a ram air turbine (RAT) does for you on an aircraft with conventional hydraulically powered control surfaces compared with an all electric aircraft. A RAT relies on the airstream of the aircraft to power its turbine, either by opening a door to provide an inlet for the airstream or by being raised into the airstream. On aircraft like the 747 and 767, an aircraft's flight control surfaces are powered by high pressure (~3000 psi) hydraulics powered by pumps geared to the engines. These hydraulic flight controls work much like the power brakes on your car, only at much higher pressure. The hydraulic lines going from the pumps and accumulators to flight control surface actuators and landing gear/brakes are a constant source of maintenance on most aircraft because of the high pressures, long lengths, and constant vibration environment to which they are subjected. The electrical system on most aircraft is powered by very large generators driven by the engines. On most aircraft, the generators drop off line (quit) when the engine rpm drops below a certin level. The hydraulic pumps, however, are directly geared to the engines and the huge high bypass turbofans on airliners can generate some hydraulic pressure just by the airstream windmilling the fan blades.

There is a direct hydraulic and mechanical connection between the pilot's flight controls and the aircraft's control surfaces on these aircraft. The electrical system provides the inputs to the flight control system, powers the instruments and provides a multitude of other functions. When all the engines fail on a conventional hydraulic flight control aircraft, a RAT, combined with windmilling engines and any auxiliary hydraulic pumps, can provide sufficient electrical power and hydraulic power for enough flight control authority to make an emergency landing.

On an all-electric aircraft, the hydraulic lines and pump-driven hydraulic actuators are replaced by electro-mechanical actuators, which are electrically driven geared or geometry moven actuators, and electro-hydraulic actuators for large control surfaces, each of which has its own small reservoir of hydraulic fluid driving a hydraulic actuator, powered by an electric motor. The only connection between the pilots and the flight control surfaces is wiring, or, in future cases, fiber optic cables. All of these EMAs and EHAs draw substantially more current than hydraulically powered flight controls, and the question becomes can a RAT provide sufficient power to provide enough flight control authority to provide an emergency landing capability? Beats me, but probably
worth looking into.

Many aircraft are a combination of the old hydraulically powered systems and the electrically powered systems towards which the industry is moving.

In the case of this A330, a RAT is most likely a moot point, since all indications are it broke up in flight after directional control was lost.

Taz
Terry Phillips

 

After reading the posts by some of the experts who are willing and able to share there knowledge about all phases of aviation it has occurred to me that this is a valuable source of aeronautical information be it WW1, airlines, military (current and historical), WW2, air racing, meterology or general aviation. I'm enormously impressed by the vast resources of plain ol' airplane talk and the in- depth technical " bank" from which all of us can withdraw.
Switches

 

Sorry to stray from the topic.

The video. http://www.youtube.com/watch?v=nV7yE4hK2hI
What most people don't realize is the A/P landed on a coral reef. This is what caught the LH engine and twisted the plane apart.
The pilot was being beaten about the head when he was trying to land hence the bad approach.
He lived to tell about it as did almost half of the people on board.

 

Exactly, they look like big turbos with a gear box on them. The exhaust air is vented through louvers in the aft fairing. They run functional test on them inside the building, LOUD!
With valving they can also be used with by-pass air from the mains if/as required.

 

Just saw in the news that the Brazilian air force has confirmed that the debris they found is not from the AF crash as originally thought

 

Sequence of events as gleaned from automated messages,

FERNANDO DE NORONHA, Brazil

"The pilot sent a manual signal at 11 p.m. local time Sunday saying he was flying through an area of black, electrically charged cumulonimbus clouds that come with violent winds and lightning. The automated messages that followed suggest the plane broke apart in the sky, according to the aviation industry official.

At 11:10 pm, a cascade of problems began: the autopilot had disengaged, a key computer system switched to alternative power, and controls needed to keep the plane stable had been damaged. An alarm sounded indicating the deterioration of flight systems.

Three minutes after that, systems for monitoring air speed, altitude and direction failed, and then controls over the main flight computer and wing spoilers failed as well.

The last automatic message, at 11:14 p.m., signaled loss of cabin pressure and complete electrical failure — catastrophic events in a plane that was likely already plunging toward the ocean.

Patrick Smith, a U.S. airline pilot and aviation analyst, said the failures could have begun with a loss of electrical power, possibly as the result of an extremely strong lightning bolt.

"What jumps out at me is the reported failure of both the primary and standby instruments," Smith said. "From that point the plane basically becomes unflyable."

"If they lost control and started spiraling down into a storm cell, the plane would begin disintegrating, the engines and wings would start coming off, the cabin would begin falling apart," he said.

The pilot of a Spanish airliner flying nearby at the time reported seeing a bright flash of white light plunging to the ocean, said Angel del Rio, spokesman for the Spanish airline Air Comet.

"Suddenly, off in the distance, we observed a strong and bright flash of white light that took a downward and vertical trajectory and vanished in six seconds," the pilot wrote in his report, del Rio told the AP.

The pilot of the Spanish plane, en route from Lima, Peru to Madrid, said he heard no emergency calls."

 

After a Braniff Electra broke up in a thunderstorm over Texas in 1968, the FAA put out a notice reminding all commercial pilots that the purpose of weather radar aboard airliners was strictly to avoid thunderstorms, not to help them find their best way to go through them. One wonders if the Air France pilot never got that message.

 

Well that certainly makes one wonder what it might by from.....

 

Did not read through the whole thread, but maybe:

The entire plane was abducted by aliens.

or

The thunderstorm was a gate to another dimension.

 

our new G650 has a RAT. i am in R&D and have been doing Testing.

so they would have had to have suffered a severe structural failure for the messages to generate such conflicting messages.

this is so sad.