Posts about: "Andre Turcat" [Posts: 12 Page: 1 of 1]¶

Ozgrade3,
I would say those books already have been written... from the autobiographies of Turcat and Trubshaw, through the books by people like Brian Calvert, Christopher Orlebar and others, to the Haynes "Concorde Owners' Workshop Manual" (!), that's come out recently.

I've written some bits and pieces, but it's more for my offspring, to explain what all that Concorde junk and documentation in the shed is all about, so they don't all thrash it when I'm gone... I don't think my story would interest a larger public.

As M2dude says, we just like to share some of our experiences with those who are interested.

From the thousands of hours of windtunnel tests, test flying with aircraft like the Mirage IV, HP 115, BAC221, etc. etc. they already had a pretty close idea of how the aircraft was going to fly.
IIRC, Andr\xe9 Turcat remarked after the first flight of 001 it flew pretty well like the simulator, or if anything somewhat better!

There were two development simulators, one at Toulouse and one at Filton, that were used by the test pilots and by the engineers. These were "tweaked" whenever more data became availble before the first flights, and then updated with flight test data.
For airline crew training , two new simulators were built in the early seventies, again one in Toulouse (later moved to CDG) and one in Filton.
In the best Concorde style, they were designed and built by two different firms....

I don't believe anything of the development simulators has survived.
As you will know, the "cab" of the British Airways Filton simulator was salvaged and taken to Brooklands, where it's now slowly being brought back to life.
The Air France simulator at CDG, minus motion system and video display, was taken back to Toulouse, where it's slowly being restored, to go on display in the planned Museum at Toulouse.

CJ

Shaft109 ,
Thanks for your link for a start...

But it also lead me to this one ... a true gem.. I hadn't imagined it still existed.

Trubshaw on tests

The cutting of the cake after 002s first flight... many familiar faces, including Andr\xe9 Turcat, and John Cochrane, of course
Brian's comment about the "damn furriner" and Turcat's grin alone makes it a "must-watch"

CJ

My "Concorde Story" really started around April 1968.

I'd only just finished my aeronautical enginering studies and had already been sending CVs all over the place... when I received a letter from the French firm (SFENA) that was building the French half of the Concorde automatic flight control system, to meet them for an interview : they needed a "flight test support engineer" to take care of their equipment in the UK (Fairford and Filton).

"No experience needed".... since everything in Concorde was new anyway....
My engineering degree, which included a fair amount of electronics, was considered enough... I could learn the rest "on the job".
What clinched the deal at the time was that I was aleady pretty well bilingual Dutch/English, and spoke enough French to get by, whereas in those days most of the French engineers in the firm had very little if any English.

So Dec. 1st, 1968, I moved to Paris, after delivering wife and new-born daughter to mother-in-law in London.
Some nine months of intensive study followed, before my move to Fairford and my first encounter with Concorde 002.

During my "indoctrination", the firm thought it would be a good idea to at least have a personal look at what I was going to work on, and also meet my 'counterparts' at Toulouse I was to be in continuous contact with.
So, sometime end January 1969, only a few weeks before the first flight of 001, I first set eyes on a real Concorde, still buzzing with final preparations.
With all our stuff being in the "pointy end", that's where we went, of course, and I spent half an hour or so in the left hand seat getting familiar with the cockpit lay-out and "our" systems..... the same seat where Andr\xe9 Turcat would be sitting a few weeks later during the first flight.

After that came five years of Concorde at Fairford and Filton, until the development flight test support largely came to an end, and was taken over by our 'product support' department, and I returned to France.

In my case, I wouldn't yet have called it a "love affair" in those days, more an intensively satisfying job.
It was really not until afterwards, that I started to regard those "Concorde days" as the best time of my professional career, and that I started to realise she'd gotten "under my skin".

And I can call myself lucky.... I've "met" 002 again 35 years after last seeing her in the Fairford hangar.
And I've also sat again in that self-same left-hand seat on 001, more than 40 years after that first time.
And I've had the chance of flying once on Concorde, even if in the end she retired just before I did.

landlady is right. We were there, at the right time, and the right place.
I think that says it all.

CJ

Mike ,
No, sadly there is no known footage of a real Concorde barrel roll.

But it's been done.... repeatedly.
Confirmed not only by Brian Wadpole, but even by Andr\xe9 Turcat himself.

Who, by the way, stated that "what annoyed me the most about it all.... was that I never had an occasion to do it myself....".

CJ

A pot pourri of responses after my Christmas reading!

This actually is interesting in that the n umbers show one of the fundamental features that made the Ol 593 such a good choice. If you look closely at the TO and cruise values you will find that at TO the overall compressor pressure ratio is 13.5 the compressor exit temperature 460 degC and the turbine inlet temperaure is 1152 degC. In cruise the pressure ratio is 10.5, the compressor exit is 565 degC and the TET 1100 degC.

Somebody, I can't find the exact post, was asking whether the elevated cruise total temperatures affected engine life, and here we see why this is so. As Christian said in another posting, when you compress air it gets hotter - from 21 degC to 460 degC at take off and from 127 degC to 565 degC in cruise. A fundamental limit on engine operation is the turbine entry temperature. Not only does it affect the maximum TO thrust you can get but also the continued exposure to cruise TETs has a very big effect on engine fatigue life, and engine manufacturers have shown extremes of ingenuity when developing new materials and ways of cooling the blades to increase allowable TET.

The problem with supersonic operations is that you start from an elevated intake delivery temperature so that when the flow exits the compressor it is already very hot 565 instead of 460 to be exact. But the maximum temperature one can stand for fatigue reasons is limited, therefore the amount of fuel you can pour in must be limited also, and the thrust you can develop per pound of airflow is roughly proportional to the fuel input/temperature rise. To get any sensible cruise thrust then one must squeeze the cruise TET as high as you dare for fatigue reasons but also you need to keep the compression ratio down so that the temperature going into the combustion chambers is as low as you can get away with. This tend to drive engines designed for extended supersonic operations to having a low pressure ratio. This is against the trend in subsonic operations where compression ratios have been steadily increasing along with bypass ratios.


The net result then is that the engine must be designed with a low OPR and must operate with cruise TET much closer to its TO TET value than would be necessary, or indeed desirable, on a subsonic design.



Actually, here, as on some other apparent carry-overs, one should look at the equipment supplier rather than the aircraft manufacturer to trace continuity. Here we have Messier supplying Concorde's gear and Dowty (OK they are now part of Messier) supplying the A330. And having worked on both, I seem to remember that the means of doing the shortening are quite different.

Quote:

Originally Posted by Brit312

The Britannia and now you are talking about the love of my life and yes I do remember the story of the nose and visor selector, but we have forgotten the most obvious. Where do you think they got the idea for the control column from

Yes, they both came out of the Bristol drawing office. One minor anecdote: the 'ramshorn' stick was a novelty to the Concorde flight test crews but they got to like it, or at least put up with it. All went well until it came to the time when Dave Davies, the ARB Chief Test Pilot, came to put his rubber stamp on the aircraft.

Concorde's seats, just like those on your car, could be moved back and fore to get your legs on the pedals and up and down so you could see over the bonnet (sorry, instrument panel). The control column of course stayed in one place, so the relationship of the 'horns' to ones thighs varied with ones height. Andre Turcat was about 6ft 2in, Trubbie and the others of average height. The smallest regular pilot was Jean Franchi at, I suppose, about 5ft 7 or 5ft 8. No problems. But Dave Davies was short like me and he found that he could not get full back stick and full aileron because the ramshorn fouled his thighs.


Consternation! Completely unacceptable! I don't know what arguments they used to convince him it was all OK really, but it got through certification. I would certainly be interested to learn from the pilots in this group as to whether it was ever a problem.

Quote:

Originally Posted by exWok

........which was one reason it was so important to touch down with the wings level - even a very small angle of bank could result in bucket contact as they translated to the reverse position. It was a surprise coming to Concorde to find it was even more restrictive than the 747 in this respect

I can't resist this one!. Has anyone ever noticed/wondered about the tiny bit of the outer elevon that has been chopped off? That was my first real input into the design as a young erk looking at variability of touchdown conditions and coming to the conclusion that if the pilot got into trouble and was trying to pick up a trailing wing with too much AoA as well then he was likely to hit the ground with the downgoing elevon. I persuaded my boss that this was so and we made a small adjustment.
In self defence I am going to plead that this was well before the days of the Type 28 nozzle, so the issue of buckets contacting the ground first never came up!

Quote:

As far as your point about the prototype engines; they were way down on thrust anyway, (even without the 'help' of the silencers), produced more black smoke than a 1930's coal fired power station.

To the point where an American Airline maintainance engineer, watching a prototype taking off and with full benefit of being located strategically for maximum sideline noise, remarked on what he described as 'visible acoustic radiation'

On another occasion, it was reputed that Stanley Hooker, watching a TO in the company of HRH the Duke of Edinburgh, remarked that "You know Sir that that noise represents less energy than it takes to boil an egg". to which he got the reply "Then I must congratulate you Sir Stanley, on producing so much noise for the expenditure of so little energy".

Quote:

Originally Posted by CJ

One example : in theory the aircraft did weigh 1.2 % less, so the lift was 1.2 % less and the drag was 1.2 % less, so the fuel consumption was less too, so did Concorde have another 50-odd miles range thrown in 'free' by flying higher and faster than it's low-down subsonic brethren?

There was an effect and in consequence the aircraft performance brochures were formally calculated for north/south flight. Pity really, it would sometimes have been nice to be able to fly guarantee performance demonstrations in the most favourable direction

That's enough for today!

CliveL

For the french speaking (or reading) people here, I just found a mine of very interesting informations about Concorde on this website:
Accueil
This site has a database of thousand of concorde flights with the following datas: Date and time of the flight, airframe used, technical and commercial crews, guests, departure/arrival airports and flight type (regular, charter world tour...).
On top of that, many infos and stories around Concorde can also be found there.
I can't resist to translate one of those stories (I'm far from being a native english speaker or a professional translator; so forgive me for the misspellings and other translation mistakes). It is a report about one of the biggest incident that happened to the prototype 001 during the flight tests:

Shock of shockwaves
We were flying with Concorde at Mach 2 since 3 month already on both side of the Channel. The prototype 001 did outstrip 002 which was supposed to be the first to reach Mach 2.
Unfortunately, a technical issue delayed 002 and Brian Trubshaw fairly let Andr\xe9 Turcat be the first to reach Mach 2 with the 001 which was ready to go.
The flight tests were progressing fast and we were discovering a part of the atmosphere that military aircrafts hardly reached before. With Concorde, we were able to stay there for hours although limited by the huge fuel consumption of the prototypes.
The Olympus engines did not reached their nominal performance yet and, most of the time, we had to turn on the reheat in supersonic cruise to maintain Mach 2.
The reheat is what we call afterburner on military aircrafts. Fuel is injected between the last compressor stage of the low pressure turbine and the first exhaust nozzle. This increases the thrust for the whole engine and its nozzle.
The 4 reheats, one for each engine, are controlled by the piano switches behind the thrust leavers on the center pedestal between the two pilots. Air was fed into the engines through 4 air intakes, one for each engine, attached 2 by 2 to the 2 engine nacelle, one under each wing. The advantage in terms of drag reduction was obvious.
However, tests in wind tunnel showed that, at supersonic speed, if a problem happens on one engine, there was a great chance for the adjacent engine to be affected as well by the shockwave interference from one air intake to the other despite the presence the dividing wall between the two intakes. So we knew that an engine failure at mach 2 would result in the loss of 2 engines on the same side, resulting in a lateral movement leading to a strong sideslip that would likely impact the 2 remaining engines and transform the aircraft into the fastest glider in the world.
This is why an automatic anti sideslip device was developed and installed on the aircrafts.
The air intakes are very sophisticated. At mach 2, it creates a system of shockwaves that slows down the air from 600 m/sec in front of the aircraft to 200 m/sec in front of the engine while maintaining a very good thermodynamic performance. In supersonic cruise, the engines, operating at full capacity all the time, were sensitive to any perturbation and reacted violently with engine surge: the engine refusing the incoming air.
Stopping suddenly a flow of almost 200kg of air per second traveling at 600m/sec causes a few problems. As a result, a spill door was installed under the air intake and automatically opened in such event.
To control the system of shockwaves and obtain an efficiency of 0,96 in compression in the air intake, 2 articulated ramps, controlled by hydraulic jacks, are installed on the top of the air intakes in front of the engines. Each ramp is roughly the size of a big dining room table, and the 2 ramps, mechanically synchronized, move up or down following the instruction of an highly sophisticated computer that adapts the ramp position according to the mach number, the engine rating and other parameters such as skidding.
At that time, it was the less known part of the aircraft, almost only designed through calculation since no simulator, no wind tunnel, did allow a full scale test of the system.
The control of the system was analog and very complex but it was not easy to tune and we were moving ahead with a lot of caution in our test at mach 2.
On the 26th of January 1971, we were doing a nearly routine flight to measure the effect of a new engine setting supposed to enhance the engine efficiency at mach 2. It was a small increase of the rotation speed of the low pressure turbine increasing the air flow and, as a result, the thrust.
The flight test crews now regularly alternate their participation and their position in the cockpit for the pilots.
Today, Gilbert Defer is on the left side, myself on the right side, Michel R\xe9tif is the flight engineer, Claude Durand is the main flight engineer and Jean Conche is the engine flight engineer. With them is an official representative of the flight test centre, Hubert Guyonnet, seated in the cockpit's jump seat, he is in charge of radio testing.
We took off from Toulouse, accelerated to supersonic speed over the Atlantic near Arcachon continuing up to the north west of Ireland.
Two reheats, the 1 and the 3, are left on because the air temperature does not allow to maintain mach 2 without them.
Everything goes fine. During the previous flight, the crew experienced some strong turbulence, quite rare in the stratosphere and warned us about this. No problem was found on the aircraft.
We are on our way back to Toulouse off the coast of Ireland. Our program includes subsonic tests and we have to decelerate.
Gilbert is piloting the aircraft. Michel and the engineers notify us that everything is normal and ready for the deceleration and the descent.
We are at FL500 at mach 2 with an IAS of 530 kt, the maximum dynamic pressure in normal use.
On Concorde, the right hand seat is the place offering the less possibility to operate the systems. But here, we get busy by helping the others to follow the program and the checklists and by manipulating the secondary commands such as the landing gear, the droop nose, the radio navigation, comms, and some essential engine settings apart from the thrust leavers such as the reheat switches.
The normal procedure consists in stopping the reheat before lowering the throttle.
Gilbert asks me to do it. After, he will slowly reduce the throttle to avoid temporary heckler. Note that he did advise us during the training on the air intake to avoid to move the thrust leaver in case of engine surge.
As a safety measure, I shut down the reheat one by one, checking that everything goes fine for each one. Thus I switch off the reheat 1 with the light shock marking the thrust reduction. Then the 3\x85
Instantly, we are thrown in a crazy situation.
Deafening noise like a canon firing 300 times a minute next to us. Terrible shake. The cockpit, that looked like a submarine with the metallic and totally opaque visor obviously in the upper position, is shaken at a frequency of 5 oscillation a second and a crazy amplitude of about 4 to 5 G. To the point that we cannot see anymore, our eyes not being able to follow the movements.
Gilbert has a test pilot reaction, we have to get out of the maximum kinetic energy zone as fast as possible and to reduce speed immediately. He then moves the throttle to idle without any useless care.
During that time, I try, we all try to answer the question: what is going on? What is the cause of this and what can we do to stop it?
Suspecting an issue with the engines, I try to read the indicators on the centre control panel through the mist of my disturbed vision and in the middle of a rain of electric indicators falling from the roof. We cannot speak to each other through the intercom.
I vaguely see that the engines 3 and 4 seem to run slower than the 2 others, especially the 4. We have to do something. Gilbert is piloting the plane and is already busy. I have a stupid reaction dictated by the idea that I have to do something to stop that, while I can only reach a few commands that may be linked to the problem.
I first try to increase the thrust on number 4 engine. No effect so I reduce frankly and definitively. I desperately look for something to do from my right hand seat with a terrible feeling of being helpless and useless.
Then everything stops as suddenly as it started. How long did it last, 30 seconds, one minute?
By looking at the flight data records afterward, we saw that it only last\x85 12 seconds!
However, I have the feeling that I had time to think about tons of things, to do a lot of reasoning, assumption and to have searched and searched and searched\x85! It looked like my brain suddenly switched to a fastest mod of thinking. But, above all, it's the feeling of failure, the fact that I was not able to do anything and that I did not understand anything that remains stuck in my mind forever.
To comfort me, I have to say that nobody among the crew did understand anything either and was able to do anything, apart from Gilbert.
The aircraft slows down and the engine 3 that seemed to have shut down restart thanks to the auto ignition system. But the 4 is off indeed.
Michel makes a check of his instruments. He also notes that the engine 4 has shut down but the 4 air intakes work normally, which makes us feel better. After discussing together, we start to think that we probably faced some stratospheric turbulence of very high intensity, our experience in this altitude range being quite limited at that time. But nobody really believes in this explanation. Finally, at subsonic speed, mach 0.9, with all instruments looking normal, we try to restart engine 4 since we still have a long way to go to fly back to Toulouse.
Michel launches the process to restart the engine. It restarts, remains at a medium rotation speed and shuts down after 20 seconds, leaving us puzzled and a bit worried despite the fact that the instrument indicators are normal.
Gilbert then decide to give up and won't try to restart this engine anymore and Claude leaves his engineer station to have a look in a device installed on the prototype to inspect the landing gear and the engines when needed: an hypo-scope, a kind of periscope going out through the floor and not through the roof.
After a few seconds, we can hear him on the intercom:
"!!!!! (stuttering) we have lost the intake number 4."
He then describes a wide opening in the air intake, the ramp seems to be missing and he can see some structural damages on the nacelle.
Gilbert reacts rapidly by further reducing the speed to limit even more the dynamic pressure.
But we don't know exactly the extent of the damage. Are the wing and the control surfaces damaged? What about engine 3?
We decide to fly back at a speed of 250 kts at a lower altitude and to divert toward Fairford where our british colleagues and the 002 are based. I inform everybody about the problem on the radio and tell them our intentions. However, I add that if no other problems occur, we will try to reach Toulouse since we still have enough fuel.
Flying off Fairford, since nothing unusual happened, we decide to go on toward Toulouse. All the possible diversion airport on the way have been informed by the flight test centre who follows us on their radar.
At low speed, knowing what happened to us and having nothing else to do but to wait for us, time passes slowly, very slowly and we don't talk much, each one of us thinking and trying to understand what happened. However, we keep watching closely after engine 3.
Personally, I remember the funny story of the poor guy who sees his house collapse when he flushes his toilets. I feel in the same situation.
Gilbert makes a precautionary landing since we don't rely much on engine 3 anymore. But everything goes fine.
At the parking, there is a lot of people waiting for us and, as soon as the engines stop, we can see a big rush toward the nacelles of the right hand side engines.
Gilbert and myself are the first to get off the plane and we are welcomed down the stairs by Andr\xe9 Turcat and Jean Franchi who came out from the crowd watching at the right hand side nacelle.
They both behave the same way, with a slow pace attitude, the same look, a mix of disbelief and frustration.
Andr\xe9 is the first to speak: "I can't believe we were not on this flight, really unlucky\x85". Yes, this flight was supposed to be just a routine flight\x85!
The condition of the nacelle is impressive. We come closer and everybody move aside for us with a look of disbelief and respect as if we were hell survivors.
The ramps of the intake 4, those 2 "dining tables", have completely disappeared leaving a hole where we can see the hydraulic jacks and the stub rod where the ramps were attached.
Indeed, only the ramps were missing, apparently ejected forward which was unbelievable knowing how fast we were flying. The ramp slipped under the nacelle causing some damages on it and on the hood of one of the elevon's servo control. Fortunately, the control did not suffer any damage.
What is left of the rear ramp seems to be blocked down inside the intake in front of the engine and we can see behind it the first blades of the compressor, or what is left of it, not much.
The engine swallowed a huge amount of metal but no vital parts of the aircraft has been damaged, no hydraulic leaks, no fuel leaks. I remembered at that time the stories of some B58 Hustler accident where the loss of an engine at mach 2 almost certainly ended with the complete loss of the aircraft. Our Concorde has only been shaken. This incident strengthened the trust I had in this plane. And I was not unhappy to have experienced this ordeal, especially when I saw the frustration on the face of Andr\xe9 Turcat and Jean Franchi.
But we had to understand what happened and how; and also why the ramp's fixing broke.
It didn't take much time to get the answers.
I unintentionally triggered the problem when shutting down the reheat of engine 3. The sudden stop of the fuel flow did of course stop the combustion and the back pressure behind the low pressure turbine. But, probably because of the modification made on the engine before the flight, the stop of the reheat has not been followed by the normal closing movement of the primary nozzle to compensate the pressure drop. So the low pressure turbine ran out of control, dragging down the low pressure compressor which reacts by surging.
Despite the opening of the spill door, the engine surge led to a sudden movement of the shockwaves in the air intake creating a surge in the intake itself. A similar surge happened in the adjacent intake 4 followed by a surge of the corresponding engine. This caused an excessive pressure above the ramps and the fixings of the intake 4 did not hold.
Since it was the first time we experienced a surge in the air intake, we had little knowledge of the stress it would create on the ramps. This led to miscalculation of the strength of the ramps's frames and they did brake.
Another mistake: instead of installing the motion detectors on the ramp itself, to make the production easier, they have been placed on the arms of the hydraulic jacks. This is why Michel R\xe9tif thought that the position of the ramps were correct. The hydraulic jacks did not suffer any damage and were still working normally even if the ramps were missing.
All the data recorded during this event helped us in redesigning the air intakes and the flight test program resumed three month later.
After this, we deliberately created dozen and dozen of air intake surge to fine tune the way to regulate them with digital calculator this time.
From now on, even if it was still very impressive, it was safe and their intensity was not comparable with what we experienced with the missing ramps.
However, a french president may kept a lasting memory of this, much later, during a flight back from Saudi Arabia. This time, I was on the left side, Gilbert on the right and Michel was still in the third seat\x85 But that's another story.
For me, the lasting impression of failing and being helpless during this incident made me wonder what a commercial pilot would have done in this situation. This plane was designed to be handled by standard commercial pilots and not only by the flight test pilots.
At that time, I was interested in taking in charge the management of a training center for the pilots of the future Airbus's clients. This event pushed me that way and I made it clear that I wanted to add the flight training on Concorde in this project. This has been agreed and I did it.
And the Concorde training program now covers the air intake surges and how to deal with them.
Jean PINET
Former test pilot
Member and former president of the Air and Space Academy

Goodbye Andr\xe9 Turcat !
Thanks

Good by, Sir!
Mort d?Andr\xe9 Turcat, le pilote d?essai du Concorde

FraserConcordeFan

... How exactly would you get the INS into memory mode so you could input the two digit code to activate the route section...

Concorde did have a facility to input a flight plan route segment into the INS and this facility was used on most flights. To explain this very briefly , let\x92s take a typical LHR-JFK flight as an example:

\x95 Press the amber REMOTE button on each INS CDU
\x95 Load the first waypoint (#1), usually Woodley, manually into an INS
\x95 Key WAYPOINT CHANGE and enter and insert \x930 to 1\x94 on each CDU.
\x95 Select DSTRK/STS and HOLD
\x95 Key WAYPOINT CHANGE
\x95 Key the DME catalogue number (from the flight log, usually 90 on a LHR-JFK sector) and insert
\x95 Key WAYPOINT CHANGE
\x95 Key the Route Segment number (from the flight log, usually 10 on a LHR-JFK sector) and insert
\x95 Cancel HOLD

Then the usual checking routine of:

\x95 Checking the lats and longs of the loaded waypoint lats with those given on the flight log
\x95 Checking the INS distances between waypoints with those given on the flight log
\x95 Checking the lats, longs and frequencies of the DMEs against the database guide

Return the displays back to WAYPOINT, cancel REMOTE, select AUTO and check the INS alignment.

Remember, with only nine waypoints available in the INS, this procedure would have to be repeated in flight, sometimes more than once. Takes much longer to write about than it did to do!


tomahawk pa38

... I'm just curious about what eastbound routings were into Heathrow...

The usual Eastbound routing on a JFK-LHR flight would be via track SN to 15\xb0W then on SL3 to BARIX to MATIM to PITEM to NIGIT and then OCK.


... and where the decel point was....

Let me just check we are talking about the same thing! The Decel Point was the point at the end of the cruise/climb, where we first throttled back and started to decelerate from M2.00 and then descend from, say, around FL 560.

The decel point was calculated in order that we would be just under M1.00 at the designated Speed Control Point , and so the Decel Point was obviously further back than the Speed Control Point.

The usual route was up the Bristol Channel, a bit to the South of our outbound route, crossing the Devon coast just to the North of Barnstaple, routing to a waypoint called MATIM, which is around 51\xb0N 004\xb0W.

In winter, on a JFK-LHR flight via SL3, the Speed Control Point was 110nm before MATIM , and we were required to be subsonic at this point. Typically, we would be just under M1.00, and around FL410, when we crossed the speed control point, having started down from FL 560 around 105nm earlier.

The decel point was of no real relevance to those living on and around the coast of Devon and Somerset, but the Speed Control Point was. The position and time at which we decelerated through M1.00 and became subsonic were always recorded on the flight log, along with the altitude and spot wind, in case of any future claims of boom damage due to a misjudged decel.

Best Regards to all

Bellerophon

Dedicated to the memory of Andr\xe9 \xc9douard Turcat (1921 -2016)

The reason that "birds nest wiring" was used for the backplane wiring on the AICU was indeed to prevent crosstalk.
I carried out a prom change at Cassablanca just days before the C of A flight, and used a prom blower that I carried out from Filton in my hand baggage together with boxes of proms, i remember the strange reaction by the customs man , until someone rescued me by telling him that I was taking them straight through to air side for Concorde. I programmed the proms by selecting the switches for the 8 bits of the line in the program for that particular prom, and then pressing the "blow" button that destroyed the fusible links in the input circuits of the prom. Of course all 64 lines of program in the prom that was changing had to be blown, even if only one line of program was changing. I carried out the programming on all 8 AICUs in 201, and the prom boards were laid out on a desk in the Air France office. Andre Turcat popped in to see what I was doing.

Hi, for some strange reason I have only just come across this thread, I have looked at some of the early posts and can answer a few questions.
I was a development engineer on the AICU in 1972 and put the first AICU together and got it working.
I am now a volunteer at Aerospace Bristol and we have this box in the archives, it was used on the intake rig by Roger Taplin, half way down the hill at Filton,
There are no secret components used in the AICU, TTL 54 series was used, and these are the milspec version of the 74 series TTL. they are better quality, reliability and better tolerance, and more expesive. They were not available to all countries.
I worked with Ted Talbot at the time and in 1990 he recruited me to be the design manager for aircraft conversions and my first job was to manage the design of the VC10 tankers. There was mention of the leggy girl at Tangiers, that was Liz Pedley, a Cambridge maths graduate systems engineer, she married a GW systems engineer. I worked with her on many a long night sorting out program problems. I was the one who went to Casablanca to do the program program change to the AICUs that someone mentioned being removed from the aircraft and lined up on a desk in the Air France office. While I was there Turcat came in and sat at the table to watch.
I used a prom blower to blow the fusible links not a 9 volt battery, just as Liz would have done at Tangiers (the same prom blower)
Regarding the 1990s modifications to the AICU pcbs for obsolete components, I was requested by John Churchill, who designed the replacement boards, to give him some help. I was amazed that the test specs were still approved by my signature, which meant they had not changed since I moved on around 1978 when I moved to Stevenage. In about 1974ish we bought all the remaining proms as they were stopping being manufactured.
I will try and read the rest of the threads to see if anything else has been asked.