www.popularmechanics.com/print-this/what-really-happened-aboard-air-france-447-6611877?page=all
For more than two years, the disappearance of Air France Flight 447 over the mid-Atlantic in the early hours of June 1, 2009, remained one of aviation's great mysteries. How could a technologically state-of-the art airliner simply vanish?
With the wreckage and flight-data recorders lost beneath 2 miles of ocean, experts were forced to speculate using the only data available: a cryptic set of communications beamed automatically from the aircraft to the airline's maintenance center in France. As PM found in our cover story about the crash, published two years ago this month, the data implied that the plane had fallen afoul of a technical problem—the icing up of air-speed sensors—which in conjunction with severe weather led to a complex "error chain" that ended in a crash and the loss of 228 lives.
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A major problem is that pilots do not do that much "hands on" flying. If this had occurred in daylight instead of a stormy dark night it could have been sorted by looking out of the cockpit and putting the horizon into the middle of the windscreen and the wings parallel to the horizon = a fair approximation of straight and level, with no instruments working at all, and a normal cruise power setting would have given them thinking time. Not easy at night not possible in cloud.
When an aircraft can be flown by the autopilot from 200 ft after take-off at Heathrow to a landing in Hong Kong 1? hours later, and very accurately too, there in no incentive or need for the crew to do more than monitor the automatics.
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I know a guy who did a lot of crew training with BA on Concorde and is also a qualified A320 pilot.
He chooses not to fly commercially and instead trains others in various aspects of the aerospace industry. Told me that commercial flying is now just really boring, and although he loves aircraft, would rather spend his day being more engaged.
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Quote: The two copilots discuss the unusually elevated external temperature, which has prevented them from climbing to their desired altitude, and express happiness that they are flying an Airbus 330, which has better performance at altitude than an Airbus 340.
Both aircraft have the same fuselage and basically the same wings. The A340 has more thrust and a higher MTOW, perhaps at their respective MTOW the A330 has better high altitude performance though at the same loading over the same route, despite using, and therefore carrying, a little more fuel the 340 would surely be the better performer.
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Cheddar - which variant of the A340 are you referring to?
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Like for like, A330-300 and A340-300.
I guess as Air France have A330-200s and A340-300s that could explain the view expressed.
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The A340 200/300 have CFM56's @ 34,000lbs thrust - and a max take off weight of 275t they are pretty "leisurely"
A330's have trent 700 or PW4168 @70,000lbs thrust and a max take off weight of 230t, so almost identical power, but probably lighter in many situations.
The later A340 500/600 are very different aircraft altogether and far superior to the earlier 200/300's, and with 60,000lbs thrust. I'm not too sure from memory if AF ever bought any of these though
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Sorry Mikeyb - I am following the thread, obviously, How is 34000 of thrust "almost identical" to 70000 of thrust? Are we talking per engine or the whole airframe or a confusing mixture of the two?
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Mikeyb means that the A340-300 has 4 x 34,000lb whereas the A330-300 has 2 x 70,000lb, he has a point.
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Meldrew - as Cheddar has already mentioned - the A330 is a twin jet, and the A340 a quad, so the figures I quoted were per power plant
There is a very limited market now for the A340 due to the increased maintenance costs and high cost of fuel. The only real reason for having one these days is to avoid ETOPs on very extended routes
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>>There is a very limited market now for the A340
>>
Especially as it is no longer made.
At the begining of November -
Airbus has announced that it is ending production of the A340, not having sold any for two years. The A340 was no bestseller, with less than 400 units sold.
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The whole thing must have been pretty hellish for the passengers.
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Think of it in terms of excess power - the A340 needs to fly safely on three engines, so in normal flight has (approx.) 25% excess power. The A330, on the other hand, needs to fly on only one engine so in normal operations has 50% excess power, hence the reason it is better to fly (allegedly!).
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>> Think of it in terms of excess power - the A340 needs to fly safely
>> on three engines, so in normal flight has (approx.) 25% excess power. The A330, on
>> the other hand, needs to fly on only one engine so in normal operations has
>> 50% excess power, hence the reason it is better to fly (allegedly!).
>>
A 4 engine plane needs to be able to fly safely on 2 engines or 50%.
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It is a limited market for the A340 though it exists, An A340-500 has a similar passenger capacity to an A330-300 though with 100,000lb more thrust and a 100 tonne higher MTOW it can carry more fuel and a lot more cargo over a longer distance.
The problem is that the 777-300ER is in the A340-500/600 class though is more economical on fuel and has lower maintenance costs due to its two 115,000 lb engines* rather than four 60,000lb.
*the most powerful jet engines in existence.
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The A340 shares a lot with an A330, so the costs to develop and produce it are not massive, and it complements the A330 as a range. It was never intended to be a big seller
Primary reason for any operator to now have a 4 engined aircraft is to avoid ETOPS and operate very long routes point to point.
Indeed the demand for this product is slim, but still exists, although in Airbus's mind the plant and tooling is better used in extending the A330 production. No point in having that capital tied up in something that you only sell once in a blue moon. They almost forced the closure of A340 by making it difficult to order - it became a "build to order" product a while back with a minimum lead-time of 24 months IIRC so operators were almost being deterred from buying
Also you may be able to sell that operator an A380 if 4 engines is what they really want
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>> >> Think of it in terms of excess power - the A340 needs to fly
>> safely
>> >> on three engines, so in normal flight has (approx.) 25% excess power. The A330,
>> on
>> >> the other hand, needs to fly on only one engine so in normal operations
>> has
>> >> 50% excess power, hence the reason it is better to fly (allegedly!).
>> >>
>>
>> A 4 engine plane needs to be able to fly safely on 2 engines or
>> 50%.
>>
Certification rules require the aircraft to safely to lift from the runway, accelerate, climb, and avoid off-airport obstruction after losing the most important engine at the most critical point of the takeoff roll, at the maximum take-off weight. That's where my comment about excess power comes from.
An approach and landing with two engines failed can be made but it's a landing that you're committed to - once the gear is down the aircraft will not be able to climb away again. An A320, on the other hand, can fly single-engine approaches all day. :-)
Last edited by: Fursty Ferret on Sun 11 Dec 11 at 07:47
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In my very simplistic book, the more engines you have the better I feel.
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>> In my very simplistic book, the more engines you have the better I feel.
True enough but I suspect you'd struggle to find an accident/incident in the turbine era where multi engine failure arose from separate causes. All have been either fuel issues or foreign bodies.
BA 747 over Java was volcanic ash ingestion.
The 777 at Heathrow was fuel starvation due icing. Air Canada at Gimli in the eighties was insufficient fuel; quantity gauges u/s and crew cocked up over quantities loaded.
Last edited by: Bromptonaut on Sun 11 Dec 11 at 10:32
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Hudson A320 was as a result of the loss of both engines, however I doubt that the outcome would have been any different if they had 4
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Yes I hear what you are saying, and people say well look at this clip
www.youtube.com/watch?v=9KhZwsYtNDE
And they say "Look two engines are safe"
I say, what if it had been a flock of birds?
As an aside, everyone involved here behaved and performed superbly. It should be a training video.
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Sobering reading - AF447 - Old Navy
