Posts about: "Air France 4590" [Posts: 59 Page: 3 of 3]ΒΆ

Don'ttouchthat!
March 29, 2016, 15:06:00 GMT
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Post: 9327131
Hands on

As so many have already said: what a wonderful thread. Please please keep it going.

Given the high quality of expertise and experience here, please accept my apologies for any ill informed inaccuracies. I never flew in Concorde, but I did 'fly' her thanks to the late John Cook.

In the late 1970s I was in the RAF section of the school CCF with his son Richard (tragically later killed in the Mull of Kintyre accident) and John (one of the first BA Concorde pilots) arranged for a minibus load of us to go to Filton on what I wish I'd realised at the time was an exceptionally privileged visit. Passage of time blurs the memory, but it still sticks in my mind as an extraordinary day.

The first 'Concorde' we saw was the full scale marketing mock up, essentially the left side of an external Concorde attached to a hangar wall, with a full interior cabin. I still remember being surprised how small it was - the windows especially - and the mix of different seats and trims inside, presumably to show options to potential buyers.

Next stop was the simulator and - in the analogue days of the 70's - the enormous, detailed 3D model of Heathrow and what looked like the surrounding 10 miles, mounted vertically on a wall. A huge gantry on rails ran back and forth, up and down, so a camera with tiny periscope lens could take off, fly around and land as per the simulated flight, with the resulting pictures projected for the pilots in the sim. The size of the thing - and the attention to detail of the model - was incredible. Off to one side was a large rectangular shallow dish painted light blue. It's sides were raised - like a saucer - and edged with fluffed cotton wool. We were told that once the flight in the sim reached a certain height, it would 'go into cloud' (fade to white) while the camera trundled across to the blue dish. The flight would then 'emerge' from the 'cloud' and the camera went round and round in circles, giving a very plausible impression of high altitude flight until it was time to reverse the procedure and descend, back to 'Heathrow'.

Incredibly, they let us fly the sim, two at a time up front, for a few minutes each. It was simply too much to take in and was over far, far, far too soon. But I can claim a (very poor) approach to Heathrow before the instructors called us off - apparently a crash landing didn't do the camera any favours as the lens would plough into the model. I can see why they were nervous.

(Is this the sim cockpit - without the model I presume - that is now at Brooklands, by the way?)

Final stop was a gantry overlooking one of the hangers where a solitary Concorde nestled amongst (what fuzzy memory recalls as) three VC10s being converted to tankers for the RAF. The Concorde seemed tiny by comparison, but also startling in that it was still largely in green primer, access panels were open and inspection hatches missing and vulnerable areas were covered in what looked like flattened cardboard boxes for protection. Presumably this was one of the 'unsold' numbers before BA took it on (?). Nose down, it looked very sad.

We weren't. I suspect we were insufferable for weeks afterwards.

What I'd give for a time machine to revisit that afternoon...

Last edited by Don'ttouchthat!; 29th March 2016 at 15:18 .

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Casper
November 29, 2017, 08:00:00 GMT
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Post: 9972671
https://youtu.be/fqOcYhzWUZY

I am ignorant of Concorde operations. I am an aircraft accident investigator, however, after many years of PIC international operations.

With respect to the above site, I'd be most grateful if the following points were to be confirmed in regard to AF4590:
* A spacer was not installed on the LH undercarriage
* The a/c was above its MAUW and outside its C of G limitations
* The take off was commenced with a downwind component
* The T/O run was commenced over tarmac still under repair
* No runway inspection was conducted, as required before any Concorde T/O
* No extra protection to fuel tanks had been provided, as had been done by BA
* The FE completed engine fire and engine shutdown without consultation with PIC

If the above is true, then the accident was unavoidable and I am astounded that the French authorities had the gall (Gaul) to blame Continental Airlines for FOD that should have been detected had the runway inspection been conducted as mandated. Shame!

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Shaggy Sheep Driver
November 29, 2017, 20:17:00 GMT
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Post: 9973507
Casper, I'm not aware of any fuel tank protection by either BA or AF prior to the accident.

Overweight & aft GC was due too much fuel as well as captain authorising baggage to be loaded (in the rear baggage cabin) when the aeroplane was already about 5 tons overweight.

Something else germane to the accident was that the fuel tanks were overfilled leaving no airspace to absorb any shock waves on the basis this extra fuel would be burned off during taxi, but the change of runway (to a downwind one) meant a much shorter taxy so it wasn't burned off and the FE didn't ask for a delay while it got burned off. They just 'went'.

Worse - realising they had a rearward CG, fuel was being transferred from tank 11 (in the tail) to the wing tanks DURING THE TAKE OFF ROLL. an absolute no-no in Conc ops. The idea being as fuel was burned off from the wing tanks and replaced by fuel from tank 11, the CG would move foreward.

The result was the wing tanks were always overfull even though they were supplying fuel to the engines, so when one tank was hit by a big piece of tyre the shock waves travelled up through the fuel, bounced off the top surface of the tank, having found no gap of compressible air to absorb the overpressure, and travelled back down and burst the tank floor from inside.

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CliveL
November 30, 2017, 08:27:00 GMT
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Post: 9973991
Casper

You might find it useful to read the BEA accident report (in English) f-sc000725a which has all the information you are looking for

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Shaggy Sheep Driver
December 13, 2017, 16:17:00 GMT
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Post: 9989035
Originally Posted by Lancman
. I'm just interested in what the circumstances were that allowed this restriction to be over-ridden.
Extra taxi fuel I should think, which should be burned off before take off (it wasn't on the accident aircraft because of the change to a nearer runway).

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Shaggy Sheep Driver
December 13, 2017, 18:59:00 GMT
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Post: 9989207
Originally Posted by CliveL
The final report states that the overfill was 300 litres (237kg) put into the engine feeder tanks 1 to 4. These tanks are grouped to have approximately equal moment about the CG so if it was, as seems likely, 75 kg in each there would have been negligible effect on the CG.

There was no overfill into tank 5.
So Hutch is wrong when he says in the interview that tank 5 was being continuously topped up from tank 11 as fuel was burned off during the T/O? I've had a quick look at a simplified fuel system diagram and while it shows no direct transfer route from tank 11 to tank 5, would there be an indirect one via the forward trim tanks?

And as the extra baggage was in the rear hold, and Tank 11 was full, that would explain the rearward CG and the desire of the crew to get fuel out of tank 11 ASAP and into the wings, Did it all go to tanks 1 to 4 via the forward trim tanks, with none going to tank 5 ( the 'accident' tank)?

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CliveL
December 14, 2017, 14:16:00 GMT
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Post: 9990047
@SSDriver

You are quite right; I should have checked that
A simple check of BEA's figures shows that they were assuming transfer into the feeder tanks.
Their sums say one needs to transfer about 700kg to make a CG shift from 54.2% to 54% (starting with a ZFCG of 52.4%). However, the engineer's panel after the crash showed that he had dialled in the loadsheet ZFCG at 52.3% so the fuel system would have transferred only 350 kg.
I can't see anything to suggest otherwise than that fuel transfer was stopped when TO began and that tank 5 remained at 94% total capacity throughout

We crossed in post, but where did you get the information that transfer was continued through take off? I didn't find anything in the official report

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tdracer
October 04, 2018, 23:17:00 GMT
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Post: 10266203
Decent article at Smithsonian.com with a brief history of Concorde and the crash that doomed it.
https://www.smithsonianmag.com/smith...M4MDQ0MDUyNwS2

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stilton
November 06, 2019, 10:13:00 GMT
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Post: 10612089
If you value technical accuracy and a well written book on Concorde avoid \x91last days of the Concorde\x92 by Samme Chittum

Its about the Air France crash and has an accompanying short history of the program


it\x92s riddled with historical, factual and technical errors however, for instance \x91Concorde commercial service was inaugurated with a BA flight from London to Rio while AF operated from Paris to Bahrain\x92


Who knew ?


Best avoided

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paulc
June 16, 2022, 17:00:00 GMT
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Post: 11247183
After the Air France incident at Washington DC in 1979 where events similar to those that caused the Paris crash occurred, did BA install any extra protection to the fuel tanks. Ie skin doublers in the most vulnerable areas?

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tdracer
August 04, 2023, 17:14:00 GMT
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Post: 11479369
Since we're on the subject of Concorde, I was watching an "Air Disasters' episode last weekend that touched on the Paris Concorde crash.

It got me thinking - what was the final straw that led to the crash? Was a very heavy Concorde unable to maintain altitude with two engines out? Or did the raging fire do critical flight control damage? Combination there of?

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MechEngr
August 04, 2023, 18:20:00 GMT
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Post: 11479405
Originally Posted by tdracer
Since we're on the subject of Concorde, I was watching an "Air Disasters' episode last weekend that touched on the Paris Concorde crash.

It got me thinking - what was the final straw that led to the crash? Was a very heavy Concorde unable to maintain altitude with two engines out? Or did the raging fire do critical flight control damage? Combination there of?
Too many factors cascading, but the ignition of leaking fuel led to major changes, including the crew shutting down an engine due to fire warning and the melting of considerable portions of the wing. Per the accident report a large contributor was a defective landing gear that, with one tire gone, swiveled and forced the plane off the runway where one engine ate a light. There was also a suggestion that additional drag from the misaligned gear slowed the takeoff which would otherwise have left the runway before contacting the metal strip. There were also overweight, tailwind, and leaving the ground below the calculated minimum airspeed.

Final Destination and Dead Like Me both offered more likely scenarios than the stack up of factors required for the Concorde crash.

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hans brinker
August 04, 2023, 21:08:00 GMT
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Post: 11479463
None of the reports suggested that the crew made errors in handling the plane after they elected to continue the takeoff after the first warnings.
None of the reports suggest that handling the situation different after they decided to continue would have changed the outcome.
So the only possible difference in the outcome could have been from two earlier points.
They elected to continue the take off after the bells went off, after V1 complying with SOP.
They elected to start the TO with 8kts tailwind, and questionable M/B numbers.

If they had rejected after V1 there is a chance more people would have survived, but it would have been the wrong decision as far as operating procedures, based on the information the pilots had.
If they had delayed the T/O, in all probability the same thing could have happened, and if it hadn't because they didn't hit the piece of metal it would not have prevented the crash for the right reasons.

That 25 year old airplane had less time in the air than the crew had on average, and the entire fleet had only around 300.000 hours in 25 years with 14 airframes. From inception till 2013 the 737 fleet flew over 250 million hours, and 1 crash per week over 40 years would have been equivalent in safety. The concord was an anomaly from the start.

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BigBoreFour
August 05, 2023, 15:33:00 GMT
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Post: 11479888
If it didn’t crash, would any airline(s) still fly it today? Or would the economics have become too much for it to continue?

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tdracer
August 05, 2023, 18:41:00 GMT
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Post: 11479975
Perhaps I wasn't completely clear in my question - I'm not questioning the crew's actions in any way. They knew they were in deep trouble and were looking to set the aircraft down again at another airport but were unable to maintain sufficient altitude and crash.
My question is why couldn't they maintain altitude - not enough thrust or fire related flight control damage (or some combination thereof).

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MechEngr
August 05, 2023, 23:51:00 GMT
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Post: 11480039
Too slow - they got into the drag bucket and couldn't leave. AoA is high, so drag is high. Getting out requires more thrust, but they lost one and shut down the other on the fire warning. Even leaving the ground they started behind - a little too heavy and too much tailwind. If they drop the nose to get a better drag situation they lose altitude and crash. If they don't the plane just mushes along without enough thrust to get out of the bucket. Had there been no fire they might have lost enough fuel to climb out, but with the fire they weren't able to wait long enough.

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megan
November 11, 2023, 04:56:00 GMT
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Post: 11537083
My question is why couldn't they maintain altitude
They never managed to attain the V2 of 220kt td , highest speed reached 211kt, not helped by having to avoid the holding 747 which they flew over missing the 747 by a matter of feet according to the cockpit crew. Last airspeed recorded was 136kt immediately prior to the crash.

For the weight they were at the zero rate of climb speeds were,

Gear Retracted - 0ne engine out 193kt - Two engines out 262kt
Gear Extended (the condition they were in) - One engine out 205kt - Two engines out >300kt

They had two engines effectively out.

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DogTailRed2
November 29, 2023, 19:42:00 GMT
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Post: 11548276
In regards the Concorde crash, assuming the pilots knew what the dire situation with the aircraft and fire was, would they have been able to have put the aircraft down?
Was there any clear ground in front of them?
I've often wondered if the aircraft was bellied along the ground whether it would have had a chance? All speculation based on hindsight of course.

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tdracer
November 30, 2023, 19:15:00 GMT
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Post: 11548933
Originally Posted by DogTailRed2
In regards the Concorde crash, assuming the pilots knew what the dire situation with the aircraft and fire was, would they have been able to have put the aircraft down?
Was there any clear ground in front of them?
I've often wondered if the aircraft was bellied along the ground whether it would have had a chance? All speculation based on hindsight of course.
A problem with Concorde was that its stall speed was quite high - well above 200 knots. An emergency landing in a field (gear down) is not apt to end well going that fast with a full load of fuel and an aircraft already on fire (granted, perhaps better than what ultimately happened, but a 'damned if you do - damned if you don't' choice at best). They reportedly tried to raise the gear (which would have helped reduce drag greatly) but the damage already done prevented that.
In 20-20 hindsight, I suspect they would have been better off to not shutdown the engine with the fire warning (#2?) and use whatever thrust they could still get from it to try to make another airfield, but something that would be next to impossible to realize real-time. The rapidly spready fire damage may well have made it a moot point anyway.

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