Posts about: "Air France 4590" [Posts: 59 Page: 1 of 3]¶

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
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

bizdev ,
So far this thread has been about facts , and stories and anecdotes about Concorde.
While the accident is certainly a subject worth discussing, I've seen enough forum threads on the subject to know they invariably end up with many opinions, but very few facts.
So may I respectfully suggest that, rather than diluting this thread, you open a new one ?

CJ

I agree with that. This thread is so good because everyone involved either designed,operated or flew her; together with onlookers such as myself who are grateful that you are all willing to share your unique experiences. If we get on to the crash we will have all the people with other agendas posting here.
Regards
Nick

Re the Concorde disaster and bizdev 's question, I've opened a separate thread on the subject.

Concorde Paris crash, questions, facts, opinions

Can we post any specific questions and discussions on that specific subject over there, please ???

CJ

Two names...

Barbara Harmer at British Airways.
The first female Concorde airline pilot.
She became F/O on Concorde in 1993.
After the end-of-service, she continued to fly 777s with BA.
.
B\xe9atrice Valle at Air France.
After a long career as a pilot, she finally was selected for Concorde... and then the Paris crash happened.
But she persisted, and in the end she did 35 return flights CDG-JFK before the final end-of-service.
She then became captain on 747s.

Apart from Jacqueline Auriol , well-known French 'aviatrice' and test pilot, who flew once on the Concorde prototype, I do not know of anybody else.

And no, there is no record of any female F/Es.

CJ

Hi again Stilton. We really need one of the flying folk to answer this one fully, I am not sure what drill there was for this scenario, but I'm sure there was one. The Concorde flying manual had a drill for everything, from a four engine flame out at Mach 2 to a blocked toilet (ok, maybe not the loo thing ), and one of my winged friends EXWOK, Bellerophon, SEO Brit312 would remember one.
As far as your point about moving the CG further aft; you never had oodles of fuel to play with , and I'm sure that the guys will mention about handling the aircraft on approach with the CG too far aft. (After landing four tonnes of fuel were transferred from Tanks 5 & 7 into the empty fwd Trim Tank 9, 'to aid ground stability'. ie, help stop the aircraft from trying to sit on it's rear end as the passengers got off).
As far as your visor query goes, well the visor is either up, or retracted into the nose. The nose itself (which I suspect is what you are really referring to) would already be at the fully down 12 1/2 degree setting for landing anyway.
Oh, and back to the ground stability issue, was Concorde ever sat on it's tail by accident? Oh yes, just once to my knowledge. In May 1977, aircraft G-BOAA was returned to Filton for some modifications that were required, and part of these 'mods' was some improvements to the main trim-transfer pipes connecting the three trim transfer tanks 9, 10 & 11, as well as the trim tanks 5 & 7. Now the flow into tank 11 (the rear tank) had to be checked, but there was insufficient fuel at the front of the aircraft for stability. This shortcoming was passed on to the BAe manager in charge of everything, who stuffily refused to listen, and INSISTED that these transfer checks were carried out, 'do as I tell you, I am the manager here'. The man's sole concession to any sort of common sense was to allow a BAe employee to sit on the flight deck 'and watch the CG indicator', what the point of this was, well your guess is as good as mine. The name of the guy sitting on the flight deck was... John Thomas. (Hilarious I know, but true). So in goes the fuel, and in a very short period of time, John Thomas notices that the roof of the Filton assembly hangar seems to be slowly getting closer, and closer, and BANG!! The aircraft nose is high into the roof section of the hangar, but fortunately because the hangar is so huge, the nose did not hit anything, it was just stuck up there, complete with a very worried/terrified John Thomas who is sitting terrified in the captain's seat, staring at the hangar roof. The rear of the aircraft however was not so lucky. The right hand inner elevon came down on top of a hydraulic rig, damaging the elevon badly, as well as FLATTENING the rig. The opened #3 engine bay door came down on some large access steps, tearing the corner of the door. (not much left of the steps either). The rear fuselage, in the area of the hydraulic tanks, was holed quite badly by some access staging, entire spectacle coming to a very 'grinding' halt.
So now we have this Concorde G-BOAA, due to be returned to BA the following day, sat down on top of a lot of equipment, it's nose high in the air with a terrified John Thomas requiring a change of underwear. (The brilliant manager of course was nowhere to be seen). The aircraft was eventually returned to it's rightful attitude by someone WITH some sense instructing Mr Thomas on how to slowly, a little at a time, pump the fuel from Tank 11 forward into Tank 9.
And was OAA returned to BA the following day? errr no. The best skin repair man that BAe had to offer was sent from Weybridge to sort out the holes in the rear fuselage (he did an amazing job) and the crunched bits of aeroplane were repaired or replaced. OAA flew back to Heathrow four short (??) days later.

Dude

See post #328 for the rest of the story.
In "Concorde - The Inside Story" by Brian Trubshaw there is actually a photo of what is almost certainly the same incident.

But there is another story....

After the first-ever landing at Bahrain, a crowd of Very Important Persons was allowed to visit the aircraft.
Of course they had to see it all, including the rear cabin.
Since the aircraft hadn't been refuelled yet, the inevitable happened... the aircraft started slowly but inexorably tilting backwards.
A very undignified stampede towards the front resulted, just in time, so the aircraft did not actually sit on its tail.

But there was a sequel. The incident had been watched by the airport manager, who promptly decreed that from then on a tractor would have to be chained to the nose gear whenever the aircraft was on the ramp.

Urban legend has it, that from then on there was a new item in the pre-taxy checklist for Bahrain.

CHAIN REMOVED FROM NOSEWHEEL - CHECK

CJ

Good question Roger, the short answer to that is 'no they didn't. Radiation (in millirems) was logged after each flight, the data coming from the onboard radiation meter developed at the Harwell nuclear research centre in Essex. (A counter clocked the overall dose and an analog dial indication showed the dose rate). Although the dose rates in Concorde were higher than in a subsonic aircraft, because the sector times were over twice as short everything kind of cancelled out. The indicator itself
I do remember that when the Three Mile Island Pa accident happened in 1979, some spikes were seen on the radiation meter on the IAD-LHR sector, and occasionally throughout the years we got minor spikes when overflying the Atomic Weapons establishment at Burghfield in Berkshire. (All we did in that case was to telephone the duty officer at Burghfield who would say 'thank you' and log the event).

As far as the 'B' model goes, well yes it is a little frustrating to know that the full potential of this wonderful design was never fully realised, but as I said before, 'the 'A' model itself was still totally amazing.

Dude

I'll certainly look out for one Christiaan, but the hospital where I remember seeing it has been closed for seven years and I noticed the developers had moved in the other day!

Out of pure, vulgar interest in my field, the hospital was Atkinson Morley's Hospital in Wimbledon. This hospital is where Stirling Moss did much of his rehabilitation after his near fatal crash and huge numbers of patients benefited from pioneering neurosurgery . Most importantly from my point of view, AMH where the original prototype CT (Computed Tomography) scanner was installed and all the early clinical work - done by Doctor James Ambrose - was done. This machine is the one that can be seen in the Welcome Medical Gallery in the Science Museum and I used to work on it!

Roger.

The reason for 9L being used was because there was a blanket ban placed on the aircraft taking off from ANY runway undergoing construction, post Gonesse. (I seem to remember that the restricion was placed due to crown life issues). Oh, and Brit312; I knew that this all happened long after you put your last HP valve switch to SHUT, that is why I made the coment.
And Dixi188 has kinda answered the trick part of this question too, regarding 10/28 Left & Right. (As well as the 'correct' cross runway QDMs). Nice one Dixi
Answers in total in a couple of days guys, and keep 'PM'ing away about this, I'm happy to carry on answering.
Regards to all

Dude

OK guys, here are the answers. If you disagree about any of them then fire away, the old memory certainly 'aint perfect.
As many of you have guessed, there were 22: The 14 production airframes, the 2 production series development aircraft (201 & 202), the 2 pre-production airframes (101 & 102) and the 2 prototypes 001 & 002. PLUS, the major fatigue test specimen at the RAE Farnborough and the static test specimen at CEAT in Toulouse. The CEAT tests actually tested the wing to destruction; I seem to remember it was something like a 200% overload before the wing failed at the root. And great but rather sad pictures VOLUME , never seen these before.
OK, from MY memory , we have: London LHR (duhhh!!), Bahrein BAH, Singapore SIN, New York JFK, Washington IAD, Dallas DFW, Miami MIA, Toronto YYZ, Barbados BGI, and Riyadh RUH. As well as charters being ommited, so are some of the special 'surprise' shuttle appearances that Concorde would make, substituting a subsonic to and from destinations such as Manchester and Edinburgh.
11:15
The BA193 and BA 195.
OK, there were 12 engine feed pumps (3 per engine) 8 main transfer tank pumps (2 each for the transfer tanks 5, 6, 7 & 8), 4 'A' tank pumps (2 each for 5A & 7A), 8 trim-transfer tank pumps (2 electric pumps each for tanks 9, 10 & 11 PLUS 2 hydraulically driven pumps for tank 9), 4 electric engine start pumps (there was a single electric start pump per engine that delivered fuel to it's own dedicated start atomiser in the combustion chamber. The pump automatically ran when the engine HP valve was set to OPEN and would continue running for 30 seconds after the DEBOW switch was returned to the 'normal' position), 4 engine first stage pumps (a single mechanically driven pump per engine), 4 second stage pumps (a single pneumatically driven pump, sometimes termed 'the turbopump, per engine. This would cut out at around 20,000'), our scavenge tank pump (triggered automatically when there was 7 US gallons in the tank; pumping it back into tank 2. This pump was identical to an 'A' tank transfer pump), and FINALLY, a single de-air pump for tank 10. The pump would drive the fuel through a mesh, removing air bubbles from the fuel. Tank 11 used the L/H trim pump for de-air (similar principle)and would be switched on during take-off. This is why the tank 5 trim inlet valve being set to over-ride OPEN would result in the tank being highly pressurised in the case of the Gonesse disaster; the pump would obviously pressurise the L/H trim gallery and any tank on that side with an open inlet valve!!!
G-AXDN, aircraft 101. (A production wing, fuselage, droop nose and intakes, but with the short tail section and secondary nozzles of the prototypes.
Ready ChristiaanJ? There were 18....Yes, the single SFENA standby horizon, 9 INS gyros (one per X,Y and Z platform in each of the 3 INUs), 8 autostab' rate gyros (one per axis for each of the 2 autostab' computers PLUS a monitor gyro for the pitch axis). The radar by the way used attitude signals from the INS.
9. One per main wheel plus the single 'in flight braking' nose wheel brake.
Mach 0.7!!! Between this and Mach 1.26 the intake surfaces were positioned as a function of engine N1 if the engine was shut down for any reason. (Otherwise of course the intake surfaces were fully up). You needed a sub idle N1 of 57% and below for all this to happen, and it was to assist relight performance and reduce buffet. Between Mach 1.26 and 1.32 the ramps were driven down slightly to about 5%, full supersonic scheduling itself commencing at Mach 1.32.
Already brilliantly answered by Brit312 (as well as the FSLabs diagram). Yep, Geen GO, T/O monitor armed, fuel flow and P7 at or above datum, A/C on ground, reverse not selected and CON light not on. Amber CON (Reheat selected and not detected, N1 OK or reverse selected and primary nozzle (Aj) not at minimum. Blue REV; steady buckets at reverse, flashing buckets in transit.
Fairford, followed by Brize Norton, and then a host of airfields from Prestwick and Shannon to Chateauroux.
OK, probably no surprises now:
Landing - 27L & R, 9L & R (prior to LHR mag' deviation update were 28L & R & 10L & R) together with 23/05.
Take off - 27L (28L), 9R (10R) and 9L. (10L never happened as take offs on this runway only occurred in 2003).
It was FedEx, they planned to operate two stripped out aircraft, leased from BA, between Shannon and JFK as high value parcel carriers. The idea was that parcels would be flown in from all over Europe by small FedEx feeder aircraft and the parcels transferred to Concorde which would then speed on to JFK in around 2 1/2 hours. It never happened because of a combination of economics appraisal by FedEx and BA deciding that it could would not release the aircraft anyway.
A/C 101, G-AXDN first flew on 17th December 1971 with FIXED INTAKES!! (101 was going to be the launch vehicle for the new digital intake control system, but the 'boxes' were still being designed). This placed an operating limit of Mach 1.5 on the aircraft, limiting her ability with such a restricted flight envelope. She returned to Filton in late 1972 for installation of the system, as well as the new Olympus 593-602 engine. (The engine, very similar to the production Mk 610 version, used a quite revolutionary annular combustion chamber, and eliminated at a stroke the thick smoke exhaust that had up to then been Concorde's unwanted visual signiture). The aircraft flew more or less smokeless on 15 March 1973, achieving Mach 2 soon afterwards. As ChristiaanJ pointed out, the British prototype 002 had a similar gap, actually significantly higher, of 19 months. (The French aircraft 001 had an even longer gap of some 20 months).

I hope you guys had fun with this one, regards to all

Dude

jodelistie
First of all Rod, welcome to our Concorde thread, and thank you very much for your kind words.
Now as far as the rumour goes, I'm afraid that it is nonsense, however the truth is an even more complex story of collusion, betrayal and intrigue. You may read that 'Concorde was retired by BA and Air France purely due to economic reasons', however that is not quite the case (and as far as THIS side of the English Puddle goes, is total poppycock!!). Now BA lost a huge amount of her regular traffic as a result of the 9/11 tragedy and also as a result of the 2003 Iraq war, but things were improving nicely. In her 27 years of operation, Concorde had survived countless dips in her traffic, only to return stronger as market conditions improved.
It is early 2003, and French Concorde traffic to the USA has almost vanished, down to single digit loads. This is due mainly to total French opposition the impending US/UK invasion of Iraq, and US businessmen using BA Concorde almost exclusively. (French business seems to be boycotting the US altogether, so their contribution to passenger loads virtually ceased). Due to the apalling loads, AF are losing absolutely MILLIONS of Euros, at a time when the carrier is trying to privatise itself ... but there is more:
In the same February, AF very nearly lost ANOTHER Concorde, yet again largely down to total incompetence and lack of adherence to established procedures. Aircraft F-BTSD was flying between CDG and JFK when there was a failure of the reheat delivery pipe that runs from the engine 1st stage fuel pump to the reheat shut-off valve. This failure, although not particularly serious, led to a chain of events that very nearly resulted in the loss of the aircraft, and all those onboard. (Air France engines were overhauled seperately to BA, who never experienced this particular failure). What was required in the case of this failure was a precautionary engine shut-down, closing off the fuel supply to the engine totally, and a descent/deceleration to subsonic speed, carefully monitoring fuel consumption all the time. Unfortunately the crew 'forgot' to shut down the fuel LP valve, and this resulted in the fuel continuing to gush out of the failed pipe at an alarming rate. (Oh, and also they forgot to monitor the fuel consumption). Only after the crew FINALLY noticed that they were still losing fuel did they remember to close the engine LP valve, but it was almost too late. The aircraft just managed to land in Halifax, with barely enough fuel left in the tanks to taxi!! So, herer we are, AF are horrified that they have come very close to yet another disaster, knowing full well that yet again human error was a major factor.
But there is more....
One week later another AF aircraft loses part of a rudder panel due to de-lamination of the honeycomb surface, not particularly serious in itself, but it put even more jitters up the trousers of AF. (Rudder failures had happened to BA aircraft many years previous to this, but BA had purchased brand new and improved rudders from Airbus UK in Filton, but Air France chose not too).
So it seems that the chairmen of both Air France and Airbus (who regards Concorde as a waste of its valuable resources) have a 'secret' meeting to plan what was effectively the murder of Concorde. There is no way that AF want BA to carry on flying Concorde while they have to cease operations, so the plan is for Airbus to make a huge hike in their product support costs; these costs would have to be borne by BA exclusively, which they both knew would not be possible. If these support costs were not met, there would be no manufacturers support, and without this there would be no type certificate, and without this, no more Concorde.
Their (AF & Airbus) hope was that BA would not challenge this move legally, and sadly for the world of aviation they did not. At a meeting, BA AND AIR FRANCE!!!! were told by Airbus about the hike in product support costs, and BA would also have to cease operations. BA were not even allowed to continue until March 2004 (the Barbados season was nearly fully booked already), and so would have to cease operations in October 2003.
But the British were far from blameless in all this; a now retired very senior British airline person had always obsessively HATED Concorde, so the French conspiracy was a very early Christmas present for him; he finally got what he had always wanted. The 'end of Concorde' anouncement by both airlines was made in April 2003; AF had got what their executives wanted and finished flying in May, reluctantly leaving BA to fly until late October. If you want a full (and extremely well informed) explanation of what happened in that whole debacle, the article by Don Pevsner is worth reading. It can be found at this website:
THE BETRAYAL OF CONCORDE
There is absolutely no doubt in my mind that without the truly disgusting events in France in early 2003, Concorde would still be proudly flying for BA. (And with modifications and enhancements would fly safely for many more years).
quote** "in the hands of true professionals, Concorde was the safest aircraft that ever flew. and in the hands of BA crews at least, she was always just that..*

Oh and yes you were correct, the Olympus (the world's first ever 2 spool engine) was originally a 'Bristol-Siddeley' design, before BS were absorbed into Rolls-Royce. Stanley Hookers book is in my view totally superb, a true classic.

Dude

I have to admit I had to look up my old manuals to ensure I was correct , and I can now confirm that in Concorde's Precautionary Engine Shut Down Checklist there is no item requiring the crew to shut the LP fuel cock, so they did not forget they stuck to the checklist

Now I do not know what event happened to require the engine to be shut down, and if it was for fuel loss then yes the crew should have been moitoring the difference between fuel on board and fuel used figures and I am sure they were. However if they were also slowing and descending then the fuel system would be quite active and the difference between fuel on board and intergrated fuel left could vary very much during this phase of flight as the fuel cooled and you found that the gauges were still showing a few hundred Kgs each, even though the pump low pressure lights were on

It would not have been until they had settled down at Mach 0.95 with fuel transfer still that a proper appraisal could be made of the difference between the two fuel remaining indication and now the loss of fuel in the appropriate collector tank.

Not sure where they were when they started their subsonic diversion but believe me even with everything going for you there would not have been huge amounts of fuel left, by the time the aircraft got to Halifax

Perhaps if there is any blame it should lie with the people who wrote the checklist, by not putting an item in to cover such a case as this

It seems to me thet poor old Air France are blamed when

1] They deviate from the checklist as was suggested in the crash

OR

2] Stick to the checklist as in this case

Now you might say what about airmanship, well they did use it, perhaps a bit earlier would have been better, but easy to say without knowing all the facts.

Brit312
mm I guess they were not to blame for flying for over one hour with a red throttle light on (the engine is under no electronic control), resulting in the severe engine overspeed (N1 overspeed protection amplifier already disabled) and the subsequent scrapping (on the orders of Rolls Royce) of the entire rotating assembly of the engine. Or for omitting TWO intake trunnion blocks during a ramp actuator replacement, and then the E/O continually and cyclically operating the intake lane selector switch, following a spill door runaway, until he manages a double engine surge and near destruction of the 'forgotton parts' intake and engine also. I suppose they are not to blame for the experimental tripping of the LPOG circuit breaker by the E/O, during an engine power mismatch, resulting in serious damage to the engine and intake due to the resulting massive over-fueling surge. I suppose again, that they were not to blame for ignoring for over 6 months a simple electrical load defect, eventually resulting in a not too minor fire in the electronics racks that had to be extinguished by the crew with extinguishers. And yet again, I suppose they are not to blame for putting skydrol into Concorde hydraulics systems, almost resulting in the loss of the aircraft, as well as a 9 month grounding while all of the hydraulic components were replaced. And it was not Air France that hammered Fox Delta twice into the runway at Dacca, resulting in so much airframe distortion that the aircraft performance was seriously compromised (and eventually broken up). And of course they were not responsible for the technical and operational failures, including the (forgotton AGAIN ) missing spacer and overweight take-off etc.) on 25th July 2000. Silly me.
And although I might have said 'precautionary engine shut-down', we are talking about a quite an eventful episode here indeed, you can NOT excuse the further mistakes made on that day, 'just because they are poor old Air France. With the greatest of respect Brit, there are 3 crew members on that flight deck, do you not think that the loss of over over 5 tonnes of fuel over a period of time might just be noticed????? The subsonic 3 engined leg was carried out for quite a time before it computed to them that they were still losing fuel. There is no excuse for flying with your eyes closed, I'm sorry.
For goodness sake, this is probably the biggest single episode that was behind the demise of Concorde, poor Air France my eye!!!

Dude

NW1
I do remember well that the AF incident was as a result of severe vibration, that was what I was (not very elequently) eluding to in my previous post. The engine shut down was due to these vibrations, not because of any fuel loss. According to Rolls Royce the fuel pipe fracture ended up being as a result of an engine build failure, on the part of the AF sub-contractors. However my 'eyes closed' comment still holds here I'm afraid, it's basic situational awareness folks. And I'm not jumping to any conclusions here , I helped investigate the first of the serious errors (the experimental c/b tripping/overfuel surge incident) when I was still at British Aerospace in early 1977 and learned long ago to get my facts straight as far as possible in these things.
As a grotty old engineer I tend to lack the subtlety and diplomatic skills of you guys, but this coming at the end of such a long catalogue of gross errors, this possibly last straw in the life of Concorde was in my view also the very last straw in terms of these serious procedural failures too.
There are so many events in Concorde's history that we would like to 'roll back the clock' on, but this extremely pivotal one has to be just about at the top of a very big pile (save of course for the Gonesse tragedy).

Dude

I seem to remember a time when there had been a 737 related incident and all 737's were grounded or need some specific check to be done and Concorde was being used quite regularly. It might have been after the Manchester British Airtours disaster or possibly Kegworth... Apologies if this is wrong but it is in my mind from somewhere...

Have a quick look here:
Concorde FAQ
(Scroll down to "How much does a Concorde cost?" and "Did Concorde make a profit for the airlines?".)
IIRC, break-even was slightly over 100 airframes.

You are making the usual mistake of confusing development costs and operating costs.

The development costs were covered by the governments, so it that respect, yes, Concorde was a commercial disaster. Even so, the Concorde project paid for much of the groundwork of what was later to become the European Airbus consortium, so it certainly wasn't all wasted money.

BA and AF bought their first aircraft, much like all those other airlines that chickened out would have done.
Maybe they got a bit of a discount as launch customers, but they certainly paid for them!
BA and AF were never expected to pay for the development costs... you could say that was not their problem!

BA's operations were in the beginning subsidised, until they "bought out" the government, and revised their cost and pricing structure.
After that, overall, the BA Concorde operation was profitable until the end. Maybe the bottom line of the operation wasn't huge, but it was certainly positive and no myth.

AF's operations, for various reasons, were less of a success story....

CJ

I've got another question about the lady if I may. It was touched on before - about the deicing on her. Having watched a few Air Crash Investigation programs on TV (so, yes, completely NO knowledge about aircraft from any experience at all!), it seems that there are restrictions about how much ice can be on a wing and the aircraft still allowed to take off.

From what I've been told on concorde, how the wing was so radically different from subsonic craft, what limits were there for ice on her wings - was she as affected as other aircraft?

One other thing I was wondering about - how much of concorde is now still under the protection of patents / copyright etc? I suspect not much, as the information posted here is showing quite intimate parts - or are these all publicly available documents anyway? This isn't to question whether the information in this thread is in anyway secret - just wondering how much of the information about concorde is actually still under wraps and can't be told?

Lastly (its late!) is it actually possible for a supersonic aircraft to achieve *higher* fuel efficiency than subsonic aircraft? Only reason I ask is that with all the drag numbers quoted previously it seems that the fuel efficiency climbs higher the faster you go when above mach 1? Or am I just completely off-base with that?

Thanks for this WONDERFUL thread. I've had the wonderful opportunity to see G-BOAF at filton just before she closed, and just wish I still had the chance to fly on her. m2dude - if you have it within you to post your theories about why what happened in 2003, I'd love to hear it.

- DavvaP.

Well I have to say this is a brilliant thread.

I stumbled upon it by accident and been catching up on it when I had a spare moment and have found it completely riveting and it has whiled away many hours over the past month.

I\x92m ex-RAF and spent the last ten years working as an engine bloke on the T aeroplane & RB199. We were always told there were many parallels with Concorde & the Olympus 593 \x96 TBT/T7 Gauges, Optical Pyrometers, EPC Coils on-engine FCU\x92s, Vapour Core Pump for reheat fuel as well and the like. I attended the RR Manufactures course for two weeks at the Patchway Works and spent a day at the Concorde Museum seeing the similarities with the Electronic Control Units too though Lucas Aerospace made the MECU\x92s or GR1/4 (& DECU\x92s on the F3\x92s).

Also while on the course the distinguished RR Instructor Gent filled up in with various snippets of Engine History too such as the Vaporisers which were fitted to RB199 & the later models of Olympus 593 were originally Armstrong Sidderly designed for the Sapphire, also I learned the whole 15 Stage Sapphire Compressor was lifted completely and fitted to later Avon\x92s as it worked better.

I was at Leuchars in the early 80\x92s and the Open Golf peeps all arrived in one of these magnificent lady\x92s \x96 the visit was notable for several things; someone fired off an escape chute!!! \x96 What does this little handle do on the Main Oleo ??? whoosh ! and after the dusk take off the pilot beat the place up several times in full reheat !!!!

My last place of work before I was de-mobbed was at the RAF Marham Engine bay and I had the good fortune to meet an RR Technician called Phil (second name escapes me) but he was part of the team of RR Controls Engineers during the Hot & High Trials. He said they used to modify the three \x93Amps\x94 for each Engine control \x96 Lane1, Lane 2 & Reheat on the fly and the aircraft often flew with different schedules installed on all four engines \x96 I think the aircraft at Duxford has these still fitted in the racks (??M2Dude??) but that\x92s another Tonka thing too; three control lanes. Were all these Amps combined into one black box??

They are always Amps in RR Speak?? The Spey 202 had \x93Amps\x94 in its reheat system too.

I was lucky to find a job with the TVOC in 2001 until they ran out of money (as they do) and worked to have their flight worthy Olympus 20202\x92s tested at RR Ansty but left before that happened. In fact I don\x92t know if it did happen though it was a CAA requirement. While I was there we were working with Alan Rolfe & Mike Batchelor of the RR Historic Engine Department were offering support too. (593\x92s were their responsibility also !!! Historic !!!) but I think that was unofficial until there was an agreement about the costs.

After that I worked in industrial applications of Olympus (and Avon) and worked on many installed Olympus in power generation but based on the 200 Series \x96 I think the 300 was thought to be too fragile. But I did have a good look at Olympus 2008/003 Still in good working order in Jersey on the Channel Islands with it\x92s Bristol Sidderly Name plate on it. They didn't have Inlet Guide Vanes as the 300's had but just 6 Forward Bearing Supports, hollow with anti -Icing air blown though, controlled by a Garret Air Valve.

I never saw a DEBOW sort of function on the Industrials but there is a critical N1 speed which has to be avoided because the LP Turbine Disc can fail. The Trouble with that speed range is that it is right where the usefull power is produced!!! Was there any Normal Operating Range RPM's which had to be avoided on the 593 ?

Again thanks very much for all the fascinating information here\x92s to another 42 pages!! Sorry to have rambled on so much

Howie