I know exactly what you mean Clive and ordinarily I would agree with someone with vastly greater knowledge and experience, but it just looks too.........'classy' for a drain. The aperture is a rounded rectangle, very wave guide in nature and that vane is beautifully made, whatever it was made of. The only thing is, I'm a bit concerned the aperture is not covered in some way.

Somebody, somewhere must know what it is and now I'm fascinated. :)

engineers live their lives in an atmosphere of mutual jovial insult

Indeed, good sir. Having been exposed throughout a lifetime to various disciplines, including aerodynamics (djpil and I shared adjoining desks under AW's watchful glare in an earlier life at the Bend), I invariably upset various parties from time to time when I line select and execute the wrong set of social mores for the company in question.

Oh well, it's been anything but a boring life.

One of the guys on the Save the TU144 Facebook page says that the thing in that picture on the TU144 is connected to the Air Conditioning.

There is also a TU144 website now. Format donated by Gordons ConcordeSST

TU-144 SST - Flying Forever on the Internet

reverser incident 70s
 

hi guys, thanks for a very informative thread.
In the mid 70s I lived in a thatch cottage 31nm west of LHR at the bottom of a hill in the Thames valley.
One particularly grotty dark autumn evening our cottage started shaking, I rushed out into the dark expecting to see a car crash but realised it was a low flying aircraft. (I wasn't a stranger to low aircraft noise as we were in the Greenham Common circuit and the F111 had been based here when Upper Heyford was resurfaced).
I later read that droop snoop had an engine go into reverse in cruise.
The subsequent report in the horror comic was of it's following take off when it happened again on rotate.
What I remembered was some sort of award to engines or probably the whole crew and that she didn't get above three thou until crossing the Bristol coast.
questions...
Was it a simple electrical failure?
Was there any protection to stop it happening again?
Was there a significant speed loss when it happened?
Was there a problem with the adjacent engine?
Flying questions.
What was the engine out climb procedure?
Was there another double engine failure procedure as on the iron duck with immediate fuel dumping?
Was it just a coincidence that the flight was routed outside of CAS but along the Thames valley avoiding the high ground to the north and Membury mast?
Thanks
sorry if it has already been covered but have only got through to page 50...

Thanks for following up my question, johnjosh43, and also for posting the TU144 link; I shall take a gander tonight. :)

Green bean
Remember the Heros well, one of the pleasures of JFK especially having grown up on spam.....

Sonic booms
Experienced the trials in the sixties over East Anglia, one rogue one over Berkshire in the 70s, three or four from the French concorde whilst sailing across the channel and latterly annual ones from the French airforce.
The Concorde ones seemed much louder and frightening - first time I thought we had hit a mine (wouldn't be the first time although fortunately it didn't explode).
And contrary to a previous opinion they did do damage - odd window and a vase.

Concorde intake shocks question
 

First I would like to agree with others on the priceless content of this Concorde forum. The published books are gems in their own right but always leave more questions than could ever be answered without all your input.

Whilst looking for some engineering background on the intake flow I came across this paper which goes into some detail

https://docs.google.com/viewer?a=v&q...70XxfUcy8PWNyw

The author says for example "..pressure recovery at Mach2 was 95%, with 1% of the loss attributed to subsonic diffusion,0.5% to the 1st shock,, 0.02% to the 2nd and 3.7% to the 3rd and final oblique shock."

I was looking for mention of a normal shock as I always understood that was a prerequisite for finally getting to subsonic.

A normal shock is only mentioned in connection with an alternative design with a lengthened forward ramp.

So, was there one or not? Or is it just not that simple?

Thanks.

How about this:

http://i1080.photobucket.com/albums/...l1/Image19.jpg

In normal operation (centre picture), the flow in the upper half of the intake was supersonic with a normal shock as required to decelerate to subsonic conditions. In the lower half the flow was decelerated to just sonic by the cowl shock. If the engine demand increased the region of supersonic flow got bigger until it nearly filled the intake (right hand picture).

The small reversed "D" zone just below the bleed slot is the supersonic region. The bleed flow entered the bleed aft of the normal shock.

Thanks for the pictures which I will try to absorb.
In the centre picture it looks like the cowl shock is the 3rd oblique shock mentioned in the paper.
As you have said, the region below the reversed "D" is subsonic and there appears to be no plane shock as I understand it, so I'm still a bit mystified.
Maybe I should give up on this very complex subject.

@ peter kent

As you say, a complex subject!

Maybe the missing link is that a plane shock is not the only way to decelerate through Mach 1.0. If the nose of a body is blunt, or if the angle you are trying to turn the flow through is too big then the shock wave becomes detached from the leading edge of the body. The bit of the shock on the 'cusp' is then actually a very strong plane (normal) shock and the flow immediately behind that part is subsonic. In the case of a sharp surface with a large tuning angle this subsonic flow allows air to escape from the high pressure side of the surface to the low pressure side. This would be the case for example if the flow onto the leading edge of an intake hit it at too big an angle.

Supersonic intakes come in two basic guises - external compression and internal compression. The ramjet intakes you have been reading about are the latter type in which all the deceleration/compression takes place inside the intake. In these designs the final compression is through a normal shock situated at the minimum area 'throat' of the intake where the flow is close to Mach 1.0. This flow is delicately balanced and if some engine disturbance causes the shock to move into the converging supersonic bit of the intake the whole shock system can be expelled giving all sorts of problems (inlet unstart). Generally they are used for high Mach numbers where their higher theoretical efficiency and low external/spillage drag count for more than the additional control system complexity and performance requirements.

In external compression intakes (a simple pitot intake would be an extreme example), all the compression is done by a system of shock waves that sit outside the intake. These intakes are less efficient than internal compression intakes and they also spill a lot of air which produces external drag. Usually restricted to low supersonic Mach numbers.

Concorde's intake was a "mixed compression" design which had some features of each type. At low engine mass flow demands the flow coming on to the cowl lip could be at too great an angle to maintain attached shock waves so it behaved a bit like that described earlier. You can see this most clearly in the left hand picture where the lower efficiency and higher spillage can be seen in the graph of efficiency against intake capture (epsilon). In this state the intake behaved more like an external compression type and there was no appreciable final normal shock.

At high engine demand the angle of flow hitting the cowl was such that the shock waves remained attached and the intake functioned more like an internal compression design. Again you can see this in the right hand picture which shows most of the intake throat covered by a normal shock and in the graph where total intake flow (engine plus bleed) is constant.

On condition there was a bit of each, but since it was designed to minimise spillage you cannot see the detachment of the cowl lip shock at the scale of the diagram.

Hope this is helpful rather than additionally confusing!

PS: Looking at the centre picture again, it occurs to me that the curved shock running from the lip back and up to the reversed "D" would actually be normal to the approaching local flow which was being turned by the ramps and the isentropic compression. This would be the shock you are looking for to decelerate the flow to subsonic conditions. In other words the intake was functioning as an external compression design over this part.

593 smoke reduction
 

ref question from Joliste

As I was working my way from 1 to 85 I read the above which reminded of a paper I filed 35 years ago:
"Development of Pollution Controls for Rolls-Royce RB211 and Olympus 593 Engines" by A B Wassall. I have picked out stuff relevant to the question:


The engines of the day generated smoke in the primary zone and partially consumed it in the rest of the combustor.
It was easier to reduce the production than increase the consumption but leaning the primary zone had an adverse effect on relight capability which then needed its own corrective action as was done on the 211. Metal temperatures went up with the leaning (as intimated by Joliste)
The 593 did not have the leaning option as it had to maintain an over-rich primary zone at TO to ensure an adequate weak extinction margin when throttled back at completion of supersonic cruise when the combustor had to operate at A/F ratios over 180.
In addition to the smoke problem the combustor weight and pressure loss had to be reduced.
These other two requirements led to the annular combustor and vaporizers which also reduced the smoke substantially. These three benefits were expected based on Pegasus experience.

A couple of questions
 

Hi all, amazing thread! I hope I can add a couple of autopilot questions:

1. Did anyone ever use the IAS Hold button in the vertical mode, i.e. control speed with pitch instead of autothrottle? I always thought it might be used during climbout to maintain 250 knots under 10000 feet at full throttle.

2. How did the autopilot work in 'Go Around' mode and was it ever used, or were go arounds always done manually?

Thanks in advance,

Jim

The IAS hold in the pitch mode as used every flight as it was SOP for a decent.

Alt Hold engaged
Throttle back the engines to an intermediary point.
When speed came back to 350knts engage IAN hold to start the decent all the way at 350knts until a primed new altitude was reached, where the aircaft would level and the Autothrottles would come back into play

For sustained decent at M0.95, Mach hold would be used.

Question for British Airway Concorde Crew
 

I was doing some research for a little project, ran into a dead end.

I have seen the take off data card used by flight crews.

But, I can't seem to locate any images of the landing data card utilized.

So, wanted to ask. Did you have an official landing data card, similiar to the take off data card.

If so, do you perhaps have an image/scan of one? I've looked all over the internet, I can't locate anything.

If it was just written on a notepad then that explains everything.

I have an image of the Landing card used by Air France, just need to try and locate the one used by British Airways if there is/was a card/form. Any insight or help appreciated.

Best,
David

Any Concorde crews follow this thread anymore?

Been awhile since any replies. If you have any ideas on above question, would really appreciate the help.

Best,
David

From an occasional visitor:

I don't recall using landing data cards.... There may have been a version buried deep somewhere, but we generally just set the limits and did any necessary perf calculations.

Hope that helps.

EXWOK, Thank You for taking the time to answer my question.

This will save me some hunt time now.

Best,
David

Beautiful
 

Ladies and Gentlemen,

I would just like to thank the contributors to this thread - it is by far and away the best piece I've ever visited on the internet. Bar none. It has taken me months (and many arguments with a jealous girlfriend!) to get this far - I didn't want to ask any questions which had already been answered.

My experience; never flew on her but when I heard she was being decommissioned, I decided to make every effort to watch a Concorde take off and hang about for the final three consecutive landings at LHR. I have never seen so many grown men cry. I would have counted more but I think I got something in my eye..

As a Chartered Engineer working on a multi-disciplinary rail project, I am amazed that a project as complex as this was managed across the Channel in the 1960's; how was the Systems Engineering managed - who drove the requirements for the Jet, potential carriers, engineers or politicians?

CliveL - your input to this has been amazing - a quick question if I may; you say wind modelling played a big part in the development of the aerodynamics, how big did the models go? Did you have the luxury of testing a full-scale model? or maybe full-scale parts or sub assemblies?

Dude - its my understanding that you worked on the Maintenance Engineering of the jet, many thanks for your thoughtful remarks. Please keep those grey cells going! Was any maintenance every brought forward when it became clear a member of the Royal Family was to fly? How much input did the carriers have in generating the maintenance periodicities for the works? Did these change mid-life? If so, what and why?

ChristiaanJ - I am blown away by just how much cutting-edge (for the time!) kit was provided to get her up. In the railway, we try and steer clear from 'New and Novel' because of the increased assurance risk required. Did the onboard systems required extended testing to assure the authorities? Please forgive my memory, but I seem to recall seeing the test craft have many 'computers' in the passenger areas while testing - what did these record? How did the data support development?

Bellerophon - your post on 18th Dec 2010, 15:20 #875 had me in tears for about 20 minutes - wife to be thought I'd found out someone had died. hhmmmm..

As someone who's hoping to secure their PPL in March / April I found your piece extraordinary - can you confirm rough altitude above aerodrome (AKA QFE for us GA boys?) before instigating the 25° left bank to commence the turn out over Jamaica bay?

A thoroughly enjoyable and often moving read. Thank you all. Like a good book / film I think I'll come to read it from page one before long - who'd have thought missing out the APU would cause such a stir?!

Thanks from me too for this great thread!

Does anyone remember a Concorde passing a manned balloon? I have seen footage of it and it did not look planned. You can find more details in an old thread:

some years ago: Concorde passes balloon crossing atlantic ocean [Archive] - PPRuNe Forums

For sure not the politicians, who could not distinguish between their rectum and middle arm joint so far as aircraft systems were concerned :D
Once it was decided to go, I would say that the system requirements were largely driven by the difficulty of the task - more a question of finding out how to make it work than of optimising. The overall aircraft requirements were driven by the engineers, but criticised by the potential customer airlines in regular meetings.

Safety requirements were specified in a completely new airworthiness code - a sort of comprehensive set of special conditions, which were generally more severe than the subsonic codes of the time. Concorde, for example, was, AFAIK, the first civil aircraft to be certificated against the requirements that now exist as 25.1309.
But nobody really knew what to write for supersonic flight and, in particular, the transition from subsonic, so to some extent one made it up as one went along, using prudent common sense and engineering judgement. Fuel system transfer rates for example had to match a requirement that it should be possible to abandon the acceleration at any point and return safely to subsonic conditions - and the deceleration was much quicker than the acceleration!

Well some people might say we had four full scale models - two prototypes and two pre-production models :) Supersonic testing mainly at 1/30 scale; low speed 1/18. The biggest model was a 1/6 scale half model used mainly for icing tests. Isolated intake tests, IIRC, about 1/10 scale, but we did have a full scale intake operating in front of an Olympus 593 at Mach 2.0 in Cell 4 at NGTE Pyestock.

Faltahan
 

I take no credit for this interesting read. Hope it's not copyright.

http://www.svfw.ch/Archiv/ConcordeDev.pdf

My only connection with the bird was as an apprentice to "assist" the gents assembling the cockpit structure. Later on I sat in an office overlooking the fin assembly area, trying to get to grips with its (very particular) performance manual.

Toffeez: very interesting read ! As concluded by the author a real shame that airframe 19 was never constructed...

Departure without noise or boom considerations
 

Just for theories sake, if there were no noise, speed or boom considerations what would be the optimum profile for Concorde to fly after departure ?



In normal service I understand it had to comply with normal noise abatement departures, speed limits and remain subsonic until far enough from land to prevent the boom being a consideration.


But what if it could accelerate immediately, with no restrictions of any kind ?


I imagine you would stay in afterburner, accelerate to VMO and on to M2 in the climb ? or would airframe heating at lower altitudes prevent this ?



Lastly, was this ever done in testing, or for example leaving Barbados ?

I suspect that, given the Concorde's rather unusual fuel consumption figures, the most efficient climb profile was also the fastest one, since pretty much anything other than the M2.0 cruise-climb was fairly inefficient. From way back in the thread (here) the minimum time to hit M1.0 was about six minutes, and M2.0 came at 9 minutes (although a few posts later someone mentions that these figures may be wrong as the fuel transfer rate wouldn't allow such a fast climb).

Some questions from me, after reading through the thread:

- Someone mentioned that, as a result of Concorde's sustained supercruising across the Atlantic, the twenty-odd Concordes have more supersonic flight hours than all other aircraft combined. Does anyone know what the figures are?

- What was the minimum range for supersonic travel to be worthwhile? Obviously if you were only going a few hundred kilometres it'd make more sense to cruise at 29000ft an M0.95 rather than climbing all the way up to 40000ft+ and M2.0.

- What other aircraft are/were more efficient supersonic than subsonic? The modern supercruising fighter jets (eg. the F-22) are still more efficient at subsonic speeds. The original Tu-144 would certainly have been much more efficient subsonic (since it couldn't supercruise); I'm not sure about the later models. The SR-71 was more efficient at high supersonic speeds than at low supersonic speeds, but I can't find anything about subsonic fuel consumption. And that leaves the XB-70, which is just a big unknown.

@ stilton

see posts 883 and 884 ... december 2010!

FALTAHAN -

I can answer just one of your earlier questions - the one about the turn initiation off 31L.

As Bellerophon noted in a distant earlier post, we 'bugged' 20ft on the rad alt for this departure. As one climbed through 20' the DH light would go out and, subject to the gear being selected up, and V2 being achieved (that normally happened at about the point of lift-off), and a definite positive rate being achieved, the turn was initiated then. In deference to the low level we rolled gently, 6secs to achieve 25 degrees, but it's still a great testament to the handling qualities of this machine that we would initiate this turn - in any weather - at a height I'd be most uncomfortable if doing the same thing in a single-engined tourer.

So - in short - forget QFE; the answer is a height of 20ft.

Hope the PPL is coming along well, keep us posted.

@ FALTAHAN
 

I wonder if they are thinking "if only" on the 787 :}

Duck!
 

I just had my jaw flop open with EXWOK's post about them begining the turn off 31L at 20ft :eek: and wondered what the typical pitch attitude would have been at that point and troughout the turn?

Many thanks (again) for such a wonderful thread :ok:

It has been a fantastic and extremely enjoyable thread.

I'll second that Stilton !

Was lucky enough to catch the Concorde as she came into Schenectady Airport ( now Stratton ANG) on a solid overcast day. We heard her coming long before she popped out of the clouds at about 500 feet, perfectly lined up and ready to land on Runway 4. But she had other ideas, as she went gear up and flew by us at about 100 feet, and then climbed back up into the overcast sky. After circling around the field, the Concorde once again popped out of the clouds at the same exact spot and made a flawless landing.
After a short taxi and shut-down, we were allowed to take a walk-through before the charter flight(s) began. What a day to leave the camera at home...sigh

Recently, while surfing around on You Tube, I came across some footage of the Concorde flying the checkerboard approach into Kai Tak. What a thrill that must have been for the pilots, crew, and passengers.


Does anyone have any more details to share about that particular flight?

10 years this year. What a horrible and tragic thought.

Do you have more infos about this video like the date or the aircraft tail number? Can you give a link to this video? After watching it, I'll probably be able to tell you more.

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 André 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 Rétif 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…
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… 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…! 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 André 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.
André is the first to speak: "I can't believe we were not on this flight, really unlucky…". Yes, this flight was supposed to be just a routine flight…!
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 André 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 Rétif 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… 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

SNECMA reheat
 

I've always seen it mentioned as SNECMA reheat until the other day..

The ORIGINAL design for the reheat was done by SNECMA, but due to them getting into all sorts of trouble with the fuel injection system and flame stabilisation, Rolls-Royce baled them out, and it became a Rolls-Royce/ SNECMA design.
ref heritageconcorde.com

Does anyone have any details on the 'joint' development alluded to above?

Thanks.

Rolling Thunder,
There were quite a lot of Concorde flights to Kai Tak over the years. The first was Air France which was a checker board approach (got out of bed on a damp Sunday morn to watch it arrive). At one time BA had a deal with Cunard where you could fly Concorde to HKG and return on the QE2 or vv so there were regular arrivals in the summer for 2 or 3 years. Normally Concorde was required to take off on 13 presumably for noise reasons. The BA/Cunard flights usually departed around noon. On one occasion I saw a BA Concorde taxiing to the end of 31, so phoned home to tell my wife to go up on the roof as we lived close to the flight path but she was out so missed out on a great sight and a great noise! There may have been other 31 take offs but that was the only one I witnessed.

CV880;

I was doing Kennedy turns out of Toronto on the DC9 when fortunate enough to not only walk across the ramp (remember those days?), and be welcomed on board Concorde for a short tour of the aircraft but when our turn to taxi/takeoff came, we were next behind Concorde, on 31. The noise was unearthly; we could not speak to be heard. We sat in our DC9, awestruck at the magnificence that was unfolding before us, two very lucky airmen fortunate to watch this wonderful airplane, the sound of the afterburners "filling the windshield", take off and do the left climbing departure. The silence in the cockpit which followed was momentarily deafening!, the meaning of witnessing this airplane slowly coming into awareness. It was the late 70's and I was a young aviator wet behind the ears just starting with my airline; there was nothing merely 'technical' about what we had heard and felt in the belly - one encounters and sees many things in such a career, but the effect of that moment has never been topped.

You say it better than I PJ2. Was fortunate to be at the Oshkosh show when the aircraft was in attendance and giving flights to those who could afford the price. The big memory was standing at the barrier on the runways edge (insanely close it seemed to the runway) and happened to be standing at the point of rotation. A memory not to be forgotten, nor the noise and visceral vibrations within the body.

PJ2 does, in fact, speak well. I presume he meant to say 31L, not just 31. I also like the "left climbing departure". Very professionally spoken.

@flyboyike - if you haven't read it already, I can heartily recommend post #875 on this thread.

http://www.pprune.org/tech-log/42398...ml#post6129540

To my eternal regret, I never had a chance to get close to the old girl in her "lifetime", but I'll never forget the day she overflew my Mum's house at what can't have been more than a couple of thousand feet on her way back from Farnborough.

flyboyike - "31L", yes, thank you for the clarification!

Another 'feature' of the experience, (and those who have seen this phenomenal sight will recall), was the color of the exhaust - a slight 'greenish' tinge to the usual brown-black tint of turbojet exhaust; - it just added to that sense of the 'exotic' of what one was seeing and watching.

There wasn't a single part of our little airplane that wasn't 'in sympathy' with Concorde when the afterburners lit... the only thing I can imagine that takes one's breath as rapidly and involuntarily as that did, is the launch of a Saturn V, or the launch of the Shuttle, even from a distance.