Posts about: "Air France" [Posts: 72 Pages: 4]

Biggles78
Sorry Biggles78, I'd forgotten to answer your CofG query, so here we go: CofG was a really critical parameter on Concorde, being a delta, with no tailplane made it more so at take off speeds, and as we've previously said, was how we trimmed the aircraft for supersonic flight. CG was expressed as a percentage of the aerodynamic chord line. To get indication of CG you needed to know the mass of fuel in each tank; easy, from the FQI system. You needed to know the moment arm of each tank, (fixed of course). You then needed the zero fuel weight (ZFW) and zero fuel CG (ZFCG); these were manually input into the CG computers by the F/E, from load control data. The final parameter you needed was total fuel weight, again easy from the FQI system.
The 'normal' T/O CG was 53.5%, but in order to increase fuel weight (and hence range) an extra 'bump' was enabled to allow a max T/O CG of 54%. (CG was indicated on a linear gauge, with forward and aft limit 'bugs' either side of the needle. These bugs would move as a function of Mach and at the lower end of the speed range, A/C weight also). As the A/C accelerated, the limit bugs would move rearwards (with of course the rearward shifting centre of pressure) and so the fuel would be moved from the two front trim tanks 9 & 10 to the rear tank. 11. Once tank 11 reached it's preset limit (around 10 tonnes), the remainder of the 'front' fuel would automatically over-spill into tanks 5 & 7. (Once the fuel panel was set up, the whole process was controlled with a single switch). At Mach 2, the CG would be around 59%, the whole rearwards shift being in the order of 6'. As we said before, the 'final' CG could be tweaked to give us a 1/2 degree down elevon, for minimum drag.
I really hope this helps Biggles78.

Guys, back to the Airbus thing; My friend ChristiaanJ gave some really accurate insights, (he always does) but there is another legacy that carries on the this day; some of the audio warning tones were COPIED from Concorde into Airbus. (For example, the A/P disconnect audio is identical). I think this is great, and gives 'our' aircraft a lasting everyday legacy.

As far as the fly by wire goes, Concorde had a relatively simple analog system, with little or no envelope protection (Except at extreme angles if attack). As has been previously poted before, production series test aircraft 201, F-WTSB, pioneered the use of a sidestick within a new digital fly by wire Controlled Conviguration Vehicle sytem, with envelope protection and attitude rate feedback. (This evolved into the superb system known and loved by the Airbus community). It is a really bizaar twist of fate that the Concorde FBW system has more mechanical similarities to the system used in the B777 than Airbus. (Mechanically similar at the front end, with an electric backdrive system moving the column in A/P mode; Concorde being backdriven by a hydraulic relay jack).
As a final piece of irony; the Primary Flight Control Computers on the B777 are designed and built by GEC Marconi Avionics in Rochester Kent, now BAe Systems. This is the same plant where Elliot (becoming Marconi and finally GEC Marconi Avionics) developed and built the UK half of the AFCS computers. Isn't this aviation world strange?
Galaxy Flyer
Your inputs here are great, and I'm sure appreciated by all. (I assume from your name that you were a C5A pilot. While I was in the RAF on C-130's, our Lockheed rep' used to supply us all with company magazines, that were full of stuff on this new (it was then) giant of the sky. I fell in love with it there and then).
Anyway, back to Conc': The decel' positions were carefully worked out and adhered to; the aim was to be subsonic to within (I think) 50 nm of the east coast. I'll wait for one of my Concorde pilot friends to confirm that here, but i think I'm correct. I do have a fond memory of one flight out of JFK; we were temporarily 'held' by Boston ATC to Mach 1.6 (and at around FL440) because of an Air France Concorde heading for JFK. We saw this guy above us, at around FL580 on a near reciprical , doing Mach 2, screaming straight over the top of us. We were excited by this amazing spectacle, and so were the AF crew over the VHF ('you never boomed us, did we boom you?'). But the most excited person of all was this guy in Boston ATC. ('I've never seen anything like it guys, your two blips whistled over each other on my my screen like crazy').
Stliton
As far as the F/D noise levels were concerned, once the nose and visor were raised, it was as if someone had switched off the noise . The main source of noise up there was just the equipment cooling, and that was not bad either. It was, in my view, little noisier up than most subsonics. (But not the 744, where you are so far away from all the racket ).
Ozgrade3
You're making us blush here; thanks for your comments, I think we are just trying to share some of our experiences (and 'bit's we've picked up over the years).
From my perspective, I did write some stuff used by our pilots, AF even got a copy or two I think.

I had the pleasure of one trip as SLF on Concorde LHR - JFK (1978/9? grey cells depleting) which involved a return to LHR after dumping fuel due to hydraulic failure of two systems. No complaints from me, two take offs and landings for the price of one plus two hours of additional catering at LHR while the aircraft was fixed. Big run on asprins by the time we approached JFK!
However on the second departure the AC also suffered loss of hydraulic systems and I understood that it arrived at JFK on one system. After a storm delay at JFK I departed on AA listening to the ATC on the IFE with the Concorde following. Yet again the Concorde requested fuel dump and return due to hydraulic failures. The previous days I believe the Concorde had also experienced hydraulic failures and at one point BA cancelled some flights. AF were not experiencing the same problems and I read several years later that the problem was attributed to minute quantities of water being introduced into the system by a repenishing tanker being parked outside, wheras AF stored their tanker inside. The water then generated steam when the system ran with consequent seal failures.

Is the above cause correct, or was there more to the story?

Apart from all the normal Concorde observations, I also noticed that when trolling around over Bristol dumping fuel at a relatively high AoA the rear outboard surfaces, I was seated at the rear, vibrated at an alarming aplititude and frequency. Would this be caused by aerodynamic buffet or rapid auto pilot control inputs?

Thanks in anticipation.

Question for engineering types:

I remember being told in my conversion course that the motors driving the secondary nozzles (buckets) were the fastest rotating devices on the aircraft. Is it true? Have you got a number for it? Was it really more than the gyro in the stby horizon?

If anyone has seen the video of AF landing at BZZ after the first post-grounding test flight, you may have noticed that you can hear the buckets translating to reverse even over the noise of the blustery wind and four Olympus 593's at idle.

telster
One for the pilots really, but there was generally far less co-operation than you'd have thought. I never saw any cases of a BA pilot flying Air France or visa-versa. I know a couple of our guys had ridden jump seat on an AF aircraft, but that's all that I pesonally recall.
On the technical side of things there were meetings between the two airlines, both together and jointly with the airframe and engine manufacturers, but on a day to day basis there was precious little exchange of information, and you'd have thought that we (BA) were the only operator of Concorde, as I'm sure the AF guys felt the same also. In all of my 30+ years on Concorde, I personally went to CDG only once for an exchange of technical views and to help them out with an air intake defect.
I'm so glad that you are enjoying this post, it's great to have you here telster. (It's certainly forcing me to look deep into the dark corners my poor old grey matter).

Dude

This thread deserves an award...

I'm not a professional pilot, just a humble owner of a PPL with a very strong interest in aviation and a long time reader here (esp. in the Tech Log board). I've never posted here, because I prefer to read and learn from those who know it better, but this thread has finally managed to lure me out of lurking mode
Like in this video?
YouTube - Concorde late 32 landing at Leeds/Bradford Airport

There is a strange high pitch sound that kicks in for about a second in the same moment the nose wheel makes contact with the ground and before the actual reverse thrust sound can be heard.

Thanks to all for sharing all this information about one of the most fascinating machines ever created by human mankind.

M2Dude,


You mention a minor instrumentation difference between the AF and BA Concordes.


Were there any other technical differences between the two Airlines respective Concorde Fleets that come to mind ?

Stilton
Hi again my friend. There were a few; BA used a Delco Carousel 4AC INS, where AF used a Litton system. BA updated the radar to a Bendix sytem, where I believe that AF retained the original RCA fit. (The RCA radar was awfully unreliable (rubbish actually, and very expensive to fix) , although most of the guys would agree that it gave a superbly detailed picture, better for mapping than the Bendix.
BA used quite a sophisticated Plessey integrated flight data system, where the AF recording system was a little simpler.
There were various other minor differences, but I think that's just about it.

Dude

Makes me wonder... In the event of a complete loss of thrust at Mach 2 (say fuel contamination) would the deceleration be significant ? If so I guess the fuel redistribution / pumping to maintain acceptable CG would become interesting...

Concorde did actually have a four engine failure drill, which covered it's complete speed rsnge including Mach 2.0. There was one assumption made in this drill and that the engines would continue to windmill which would allow them to give you full hydraulic pressure

As you could imagine, If all 4 engines cut at Mach 2.0 the F/E would be quite busy and so the the non flying pilot would use his fuel transfer switch to start the fuel moving forward. This was a pretty basic selection where fuel would be pumped out of Tank 11 using all 4 pumps [2 electrical and 2 hydraulic driven] and into the very forward tank which was no 9.

As a rule of thumb transferring 1000kgs from tank 11 to tank 9 moved the Cof G forward by 1%. Now with all 4 pumps in tank 11 running the tansfer forward was so quick that the pilot had to keep switching the transfer off and then on to stop the Cof G moving forward too quickly. It was usually to everybody's relief when the F/E could find the time to take over the fuel transfer as he had the selections to allow him to be more selective as to where the fuel went and so slow the rate down
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This was quite a neat system, as the gear was retracted, a SHORTENING LOCK valve was signalled, allowing a relatively tiny jack to pull the entire shock absorber body into the body of the oleo progressively as the gear retracted. So the shock

Forther to M2dude's explanation Concorde's main landing gear consisted of 3 seperate metal castings . there was the normal two for the oleo and these two were fitted inside the outer casting, which was the one you could see.
As the gear retracted a mechanical linkage , which was driven by the gear's retraction movement, would lift the oleo assembly up into the outer casing, so shortening the length of the leg . If I remember the shortening jack was just to assist in breking the geometric lock of the linkage
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The other difference between AF and BA aircraft was the DC electrical system

AF had Nickel cadmium batteries with an automatic charging system

BA had the good old lead acid battery sysytem, well except for AG where the DC system was one of the systems they never changed when AG was incorporated into the BA fleet

Thanks again M2Dude, since we're into details, prior to the accident did BA and AF use different tyres ?


For some reason I thought that BA used Dunlop and AF Michelin.


I think they both changed to the new design Michelin after the accident, can you offer any more info on this tyre ?


I believe it's design was part of the changes for recertification ?


Any other info on the changes incorporated afther the accident would be welcome.

Stilton -

Pre-accident I think we did use different tyres than AF. I also recall that BA elected to not use retreaded tyres while AF did, but am not 100% on that.

A pivotal part of the return to service was the Michelin 'NZG' tyre. (Near-Zero-Growth).

The tyres on Conc were incredibly hard-worked, partly because of the speed and partly because they took the full weight of the a/c throughout take-off (a conventional wing is producing a fair bit of lift prior to rotate - concorde produces none of note).

A LOT of energy is stored in a heavy tyre rotating this fast, so a burst can shed debris at great velocity.

The make-up of the NZG meant that it contained the expansion caused by rotation better (so less stored energy in the carcass), and had a far more robust and damage-tolerant structure. The videos of the destructive testing compared with the original tyres is frankly amazing.

The tyre was being developed by Michelin for the A380, I believe, and the principle was adopted for new Concorde tyres. In my opinion, this was the contribution which ensured we got back in the air.

Stilton
Prior to the Gonez disaster BA used DUNLOP tyres for both the main and nose landing gear. As EXWOK quite rightly states BA did not use retreads (although I recall these were tried in the very first few years of service). After the disaster Dunlop were approached regarding the development of an improved tyre for Concorde, but declined, and so BA went along with the superb Michelin NZG design. BA subsequently also changed the nose gear tyre to Michelin. A final modification was the curious decision to remove the steel cord that the British alone had fitted to their main gear water deflectors. This cord was fitted as a modification in the the early 1990's, it's purpose being that if a tyre burst occured, the water deflecor was held together in one piece, and would not fragment, with the resulting structuaral damage. After this modification was embodied there were no further cases of ANY BA aircraft having skin puncture as the result of a tyre failure. (Having said all this, it would not have been of any benefit at all in Paris).
EXWOKS explanation of the mechanics of why the Concorde tyre had such an incredibly stressful and vulnerable life, as well as the design makeup of the NZG tyre is as usual 100% correct; a high speed, very high pressure tyre bearing virtually the entire weight of the aircraft right up to the point of rotation.
EXWOK
It was as you say being developed for the A380. As well as all the well known benifits, this tyre lasted roughly twice as long as the original article, a further testament to this incredible design.
Oh yes, you are 100% on the ball here EXWOK. I remember hearing that the CAA was even considering 'de-mandating' the tank liner modification, as the new tyre alone was enough to prevent any chance at all of any potential fuel tank rupture. I don't want to spoil the nature of this wonderful thread by discussing the why's and wherefores of the Paris disaster (most of us 'here' have our own opinions about what really happened and why). What we do know that if there had been any case of a high speed falure of an NZG tyre, the airframe would have been safe from damage.

Dude

What a fascinating read, thanks to all guys contributing to it.

The fact that the Conc still fascinates so many people after so many years is the best prove of its uniqueness. Never flown on one, but having brought clients to it I remember a time where we parked right under the nose of an AF example at CDG with our tiny Cheyenne. The Pax was lead from our airplane up the stairs and off they went. (1989ish, I was a wet as a fish F/O then) Queing in Heathrow a few years later I couldn't hear my KingAirs engines for quite a while when the guys opened up and fired the cans. Fond memories and still the most graceful airplane I saw in my life.
I still use the opportunity to see the 2 examples at the museum at Le Bourget when there. Having seen a documentary on the first flights in Toulouse and Filton I had a trip to Filton a few days later and sitting in the air field ops Landrover was sort of a time travel.

We had the pleasure to have ex FE\xb4s and an ex Capt. as trainers at FlightSafety in Farnborough. Very nice blokes and I should add, very capable and knowledgable guys. One can see why they were on the sharp end.

Sorry that I cant ask a good question right now, just had to get my thanks off my chest!

Yes, indeed.

There were the early days...
At the time there were only two programs that everyone wanted to be on.
They were Apollo and Concorde.
I was a part of one of those

There were the years after that, when Apollo was cancelled, when only 16 Concordes ever saw service, and one felt the world was no longer going forward.

And for me, there indeed was that immense moment of satisfaction, when I finally flew on one of the last AF Concorde flights, and got my brief cockpit visit, to see that everything I had helped to develop long ago still worked exactly as we'd designed it, close to 30 years later !

CJ

Hello again all,

M2dude is quite right about the galleys being small. The crew on jets these days have far more space than we ever had, and the only galley smaller than Concorde in my opinion was that on the BAC1-ll.

As far as the service was concerned, there were actually three galleys involved. One at the front, (devilishly hot!!) one in the midships which was 'constructed' by means of fixing a table top between the bulkheads after the seat belt sign had been switched off, and of course, there was the rear galley. This could also prove to be a very hot place, especially on AF which we used to call the 'greenhouse' effect. (It was also the noisiest crew positions for the two at the back, especially on take-off, as you can imagine.)

The mid galley would be used simply as a replenishing station....a designated crew member would set it up at the begining of service with extra ice, water, glasses, lemon, wine, champagne etc., so the crew on the trolleys wouldn't have to waste precious time by going back to the galleys for these items during the meal service.

The crew member who took the forward galley position would be barricaded in by means of another table top at the begining of service, and stay there until the meal service was completed. They would have the responsibility of making up drinks orders, cooking the meals, (including F/D, cc meals and any pre-ordered special meals.) The galley person at the rear would be doing the same, but without having to be barricaded in as there was enough galley space there to work un-hindered. Unlike today, there would be no chance of the CSD or rear purser overseeing the service...they were on the trolleys!

That takes care of two crew members. The other four would be two at the front and two at the back, each having a side of the aircraft to look after. They would have memorised the names of each of thier pax, on a full flight that would be twenty-five each. (Not difficult as most of them would be familiar faces in one way or another!)(If not royalty, celebities , mps then regulars.) Because there were more pax in the rear cabin, the two crew in the forward cabin would take the first two rows in the rear cabin. (There was no row 13.)

We did have meals put on for us, but generally not the same as the pax. The F/D would have three different meals in case of food poisoning. (I have never known a case of F/D food poisoning in over 35 years of flying, but I do know it has happened.) We didn't have much time to eat, but we did throw a mouthful down, generally standing up in the galley! (How can you tell a cc member at a party? they are the ones wiping thier hands on the curtains.)

Pax meals were amazing: caviare boats, pate du fois gras, quails eggs were amongst favourite canapes; lobster curry another favourite main, a delicious pudding tray (served on a half tray after the mains tray had been cleared) and a selection of English cheeses served from the trolley, served with celery and fruit accompanied by claret and port. (The wines were exceptional - such as Krug, Chateu Talbot and Meursault.) The trays always looked exquisite with a pink carnation and a white box sporting the speedird livery containing two Thornton's chocolates.

By the time all this had been cleared in, imigration forms handed out and coats delivered back to their owners, it was seat-belts time again! Level flight was a rarity as we were climbing until half-way accross the pond and then on our way down, so the trolleys were hardly ever level.

It has been lovely remembering all these little details again. Every crew member knew their roles inside out, which created reassuringly calm atmosphere from the passengers point of view. If the system was followed to the letter, we always had time for a cup of tea before checking belts and securing the cabin!

I feel honoured to be regailing you all with these snippets of life on the Concorde fleet, especially as this thread is really concerned with the mechanics of the lady. There arn't too many crew left flying now, (it's just that I started when I was two!!!) I will try and persuade others, (retired), to help me jog my memory.

Kind regards.
Landlady.

nomorecatering asked: M2dude answered:
The BA simulator, now at Brooklands, is a long story.
For various reasons, only the simulator 'cab' could be salvaged. It was taken to Brooklands to be used as a static exhibit of what the Concorde cockpit looked like.
It was only well after its arrival at Brooklands that people started to think about bringing it back to life.... a huge piece of work, since about all that was left was the 'cab' itself, with the instruments and controls... the computers and interface circuits, needed to make them work, were all gone.
A team of volunteers, a simulator firm and university students have now brought it back to a state where it can be 'flown'. Even if not everything works yet, ex-Concorde pilots who've 'flown' it were already full of praise.
As to the visuals, the original visual system was taken back by BA, since it was recent and the same as used on other BA simulators.
It's been replaced by a specialised video projector and a wide screen, which appears quite satisfactory, although I 've heard rumours about plans to replace it with a three-projector system.

The story of the Air France simulator, that was located at CDG, is very different.
After the end-of-service it was moved almost in its entirety to Toulouse (Airbus), minus only the visual display system and the motion platform.
A small team of volunteers (mostly Airbus engineers) are slowly bringing that one 'back to life' as well, but (contrary to Brooklands) using most of the original electronics.
The intention is to have it ready for display (and use) at the Toulouse 'A\xe9roscopia' museum, which hopefully will open within a few years.
Unfortunately, until then the sim is not accessible to the public, since it's inside one of the Airbus site buildings.
And no, of course that one isn't certified either....

One small bit of trivia... the BA and AF simulators were NOT built by the same firm. The BA one was built by, IIRC, Singer-Redifon, and the French one by LMT.
Today that's a pity, really, because the Brooklands and Toulouse teams have very little technical information they can exchange.

Oh and, yes, I've visited and sat in both of them, but so far I haven't flown either of them yet.

CJ

The AF simulator was regarded as a sub standard machine, never had the required interface or processing power compared the the UK machine that was built as a joint effort by Sinker-Link Miles (structure and motion) and Redifon simulation (interface and computers), with a view that the developed product would be offered to the option holding airlines.

A key failing of the AF machine was that it could not correctly simulate an engine failure on take off without going off the runway.

So what happened when AF had an apparent engine failure/fire after V1 in 2000? The crew made a right hash of the procedures....Nuff said really.

Dave ,
I was looking to confirm my own memory on the matter and found this quote, from a personal friend, on another aviation forum. Knowing him, and knowing where he worked, I would trust that statement implicitly!
The "blips" on the radiation meter over certain "hot spots", in the UK, the US and the Middle East, are well-known bits of Concorde folklore.

CJ

You got me thinking too... equally dangerous, since it's not my 'subject'
First simplistic answer...
If the charter flight did not involve a supersonic flight, then of course it wouldn't have been a problem, you would just have loaded enough fuel into that vast collection of tanks to maintain a 'subsonic' CG.

So, second answer, which is what I think you're thinking of: the case of a short charter with a supersonic "loop" over the Bay of Biscay, as both BA and AF did quite a number of times, with less fuel.
This is where I start thinking... and I admit I may be wrong.

Take a normal transatlantic flight, with all the tanks full at take-off.
By the time you started the supersonic acceleration (so with still a lot of fuel forward, only the fuel used in take-off and subsonic climb no longer there) the 10-odd tons in tank 11 (the trim tank in the tail) were already enough to shift the CG backwards to what was needed when supersonic.

So, with a smaller fuel load, getting the CG backwards to the right position would already be easier, even without fully filling tank 11. And of course no problem returning to the 'subsonic' CG.... plenty of space in the already partly empty tanks..

So I think the answer to your question is "no".

CJ

1) How many Concorde airframes were built?

22 total. 2 test, 9 BA, 9 AF, 2 spares (1 BA, 1 AF).

2) As far as the British constructed aircraft went, name the destinations that were served?. Regular flight numbers only, excludes charters etc.

JFK, Dulles Intl., Barbados, Miami, Bahrain, Singapore.

3) What was the departure time for the ORIGINAL morning LHR-JFK Concorde services? (Not called the BA001 then either).

No idea.

4) Further to question 3 above, what WERE the original flight numbers for the BA001 and BA003? (The morning and evening LHR-JFK services?).

No idea.


13 tanks, 2 main pumps each (except tank 11 which had 4 pumps) = 28
Main and aux engine feed pumps (3 per collector, 4 collectors for a total of 12)
Fuel pumps from aux tanks to mains = 4
Fuel dump = 2


BAC 221. Flying test bed for the wing design.






Filton.


27 L/R, 09 R.

Oh I certainly vividly remember as teenager witnessing AF doing all sorts of training approaches, including touch and go & 3 engine takeoffs in Casa !