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Concorde question

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Concorde question

Old 15th Jan 2011, 12:18
  #1101 (permalink)  
 
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Don't worry Dude, its the 'prattle' we're here for! And I echo your greetings to Landlady.

Thank goodness that dreadful paint job never flew - somebody might have been tempted to have a proper go at shooting her down!! (Not that they could catch her.)

Roger.
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Old 15th Jan 2011, 13:26
  #1102 (permalink)  
 
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Landroger

If you look here it suggests that it did fly on a limited number of flights.

"Afterwards, "Sierra Delta" started a promotion campaign in Europe and the Middle East. For the Pepsi commercial operation, there were a total of 16 flights (including the ferry flights from ORY) and 10 cities visited. Each flight, except the first and last ones, would have been occasions to go supersonic"
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Old 15th Jan 2011, 14:34
  #1103 (permalink)  
 
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If you look here it suggests that it did fly on a limited number of flights.
Don't want to be 'picky', but my photograph was of AS's 201 at Toulouse on the occasion of the party to celebrate the 20th anniversary of 001's first flight. If I understand correctly, the 'Pepsi' aircraft was 213 and belonged to AF. I don't think 201 flew with that Tricolour paint scheme. Can anyone throw more light on this?

CliveL
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Old 15th Jan 2011, 15:29
  #1104 (permalink)  
 
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Originally Posted by CliveL View Post
Don't want to be 'picky', but my photograph was of AS's 201 at Toulouse on the occasion of the party to celebrate the 20th anniversary of 001's first flight. If I understand correctly, the 'Pepsi' aircraft was 213 and belonged to AF. I don't think 201 flew with that Tricolour paint scheme. Can anyone throw more light on this?
Clive, you're right.
F-WTSB (201) was painted in that horrific scheme by students at Toulouse.
Since that was in 1989, and 'SB made his last flight in 1985, and was not maintained airworthy, he never flew with that colour scheme....
The 'Pepsi' aircraft was indeed F-BTSD (213), and leased from AF for the occasion.

CJ
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Old 15th Jan 2011, 16:24
  #1105 (permalink)  
 
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I'll get back in my box then
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Old 15th Jan 2011, 20:32
  #1106 (permalink)  
 
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A quick question for the technical chaps...

I remember that she had 3 channels of signalling for the flight controls - 2 electrical ( 1 main and 1 standby ) with the third being mechanical. How was the mechanical system 'de-coupled' from the electrical channels thus that any movement from the control column was 'ignored' by this channel ? Was it by somehow disabling the hydraulic jack that ultimately connected to the flying control units ? Was this mechanical channel ever used during service ?

Regards,

d
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Old 15th Jan 2011, 21:04
  #1107 (permalink)  
 
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Its a privilege to read so much knowledge. Thanks for taking the time to post it all.

Am just curious about the Emergency Descent/Rapid Depressurization profile that was used by Concorde.

TUC is so small at 60,000ft...I reckon that masks were not used at all times during cruise, so, what procedure was used?

How fast could the descent be completed to a safe altitude?

I dont think that any explosive decompression really puts the cabin altitude at 60,000ft instantaneously, but am just curious about this aspect of the Concorde.

Thanks for your time.

SEQU
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Old 16th Jan 2011, 00:28
  #1108 (permalink)  
 
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I went to have a poke around G-BOAD this afternoon at the Intrepid museum.

Am sad to say she's in a bit of a sorry state - paint peeling off in places which is no doubt due to being outside in the full weather of NYC. For example, there's still several inches of snow on the wings/elevons from the storm half a week ago.

Inside is no better - visible mould on some of the seats which are enclosed underneath a plastic display case type affair, printed on which are some alleged facts about Concorde, but at least one of them was completely wrong.

Such a shame. I have only been to see two of the preserved frames, this one and G-BOAA at East Fortune and I have to say the latter is a far better experience. At least someone seems to care about educating people about the aircraft and keeping it in good 'nic, which is not what you can say about the one in New York.
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Old 16th Jan 2011, 05:52
  #1109 (permalink)  
 
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How was the mechanical system 'de-coupled' from the electrical channels thus that any movement from the control column was 'ignored' by this channel ?
I'm sure Christiaan or Dude will have better explanations, but in brief :




In mechanical back-up control demands were fed to relay jacks which acted as force amplifiers so the pilot was unaware of control run friction. The autopilot also fed into these relay jacks. This meant that the control precision and ability to harmonise control forces given by the electrical control system was not degraded by mechanical system shortcomings.
In electrical signalling there was a dead space at the Powered Flying Control Units (PFCU) to allow for the difference between mechanical and electrical commands produced by autostabiliser activity. Variation of this dead space with flight condition gave the autostabiliser authority limits. Autostab. was not available in mechanical signalling when the PFCU servo valve was locked to the mechanical control system.
So the control column movements were never 'ignored' by either system, but the mechanical system never 'saw' the autostabiliser commands.

Cheers

Clive
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Old 16th Jan 2011, 08:41
  #1110 (permalink)  
 
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SpeedbirdConcorde
Hi again my friend. To further expand on CliveJ's superb explanation: Mechanical control inputs were fed to each of the 8 Powerd Flying Control Units (PFCUs), but in electronic signalling (either Blue or Green) these inputs were de-clutched at the PFCU input lever. When Fly By Wire' signalling is not available, the mechanical inputs (which as CliveL quite rightly points out) are driven by the Relay Jacks, now are locked to the input lever and can now move the input jack of the PFCU (known as the spool valve) and subsequently cause the PFCU to drive the control surface. (The body of the PFCU moved, the main jacks were attached at each end to structure and so obviously did not move). Hopefully this diagram will help visualising the process a little easier:

The diagram shows Green & Blue hydraulics supplied but the electro-valves (opened by the respective FBW channel) are both closed. You can see that the mechanical input lever is 'locked' to the PFCU input lever which will drive the SPOOL VALVE directly. When FBW is enabled, either the Blue or Green (never both together) ELECTRO-VALVE are signalled open, the ensuing hydraulic pressure then pushing the input clutch upwards and disengaging the mechanical input. FBW demands are now fed to the respective SERVO VALVE which will hydraulically send the SPOOL VALVE in the desired direction.
The Relay Jacks could be considered to be a little like a PFCU (you had 2 RJs per axix) but instead of the servo valves being driven by the FBW system they were driven by the autopilot and instead of driving a control surface, they drove the control runs. In manual flight the input spool was driven via a mechanical input lever, which would drive the RJ spool a little like Mech' signalling drove the PFCU spool. In A/P mode the mechanical input rod was de-clutched la PFCU, but (and here's the clever part) this input was locked to the body of the Relay Jack which when it moved, drove the pilot's control in sympathy. (Control column, yoke or rudder pradals). As the respective control(s) was moved by the Relay Jack, the corresponding FBW position sensor (resolver) would change position and generate the FBW demand. (As the surface moved there was a feedback resolver at PFCU level).
As far as the FBW channels themselves went; there were 2 electronic signalling modes, Blue and Green, sub-divided into 3 groups (Inner Elevons, Outer & Mid Elevons and Rudders). Each group was independently monitored, and a fault in say the Rudder channel alone, would result in the rudders ONLY changing lanes. NOW ( ), The normal control channel was BLUE, and if this failed you would drop the respective channel into GREEN and if this failed you would drop into MECH. The selector switches (1 per group) enabled you to select BLUE/GREEN/MECH in that order. If for some reason you were selected to GREEN, a failure of that signalling lane would not drop you 'up' into BLUE, but into MECH. Your switch would only be in this position if you'd had a problem with BLUE, however you would select this on pushback while you were testing the flying controls, otherwise you spent your whole life selected to BLUE. As far as BA went, I can never remember a time personally when all 3 groups dropped from BLUE to MECH, but very rarely you might get a fault that caused a single group to briefly drop to MECH. Just about one of the very few common mode failures to each of the 3 groups would be a failure of the respective FBW static inverter. This thing, which was rightly monitored up to the hilt, produced a 26 Volt 1800 Hz output. (1800 Hz was chosen as this is not a harmonic of aircraft mainline 400 Hz AC supply)
Best regards

Dude

Last edited by M2dude; 16th Jan 2011 at 11:10. Reason: Clarity; Oh for clarity
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Old 16th Jan 2011, 13:21
  #1111 (permalink)  
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Dude - that really brings back pain form the past! I remember knowing (just) enough about the flying controls to pass the ARB, but a diagram similar to that one was presented at one "Technical Refresher" day (remember those?) by one of our more chatty training EOs (could have been you?!) together with a coloured plastic overhead projector schematic complete with slidey moving jacks and PFCUs and things and it worked! I completely understood the system right up until the first pint of Brains that night...

Flying in mechanical signalling was a different experience - losing the autostabs was bad enough (and proved how good that system was). A mate on the fleet once described it as like trying to fly around on a supersonic dustbin lid. I think that description was too kind - the thing was barely controllable in that configuration. One of our skippers described an airtest when he was on the JS where the crew were trying a decel in MS: as the phugoids were diverging he thought he was about to lose his life so leant forward to restore things. Sadly the switches had been left in MS, so he had to move the switches up to "Blue" as well as then pressing the reset tits - a procedure which he described as almost impossible due to the ever more extreme manoeuvres. Recovery, fotunately, was instant. Resetting electrical signalling and autostabilisation always felt like slotting into a groove on the Concorde.

For that reason, I believe, flight in mechanical signalling was removed from transonic flight on airtests and altogether from Base Training. The simulator was the only sensible way of trying to fly like that...

And that flying control pre-flight check! Learning it was a conversion course rite of passage: one of the sadder parts of reading this thread was realising I'd forgotten it. Great times, great aircraft, great people. Nostalgia isn't necessarily a thing of the past... see you in March?
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Old 17th Jan 2011, 05:15
  #1112 (permalink)  
 
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NW1
Ahhh the Tech refresher days. Not being an EO it would not have been me, no. But the 'trainers' often used to come seek me out in the hangar and (over coffee, not beer I'm afraid) confer about various system quirks and nasties to use on you guys during the tech' refreshers. (So I guess can be blamed for a few of the 'stinkers', sorry ). And I definately know who you mean by describing him as a 'chatty' EO.... a truly great guy though.
Mech' signalling during decel'??, OUCH!! I would have thought that the 'supersonic dustbin lid' description would have been quite an accurate description of what must have been a very uncomfortable experience indeed. It was quite a vivid and scary description, I can just imagine trying to move the 3 switches up to BLUE from MECH and stabbing the reset buttons while your seat and the selector panel are seemingly going backwards and forwards, up and down in different directions!!. On the C of A renewal test flights I seem to remember that MECH was only tried fairly briefly at a very subsonic 300 KTS during the early stages of the flights, but even then it felt like the aeroplane was riding a sea of different sized golf balls and the outer wing sections seemed to flap about quite enegetically in a world of their own; it was pure bliss when we reset into BLUE. It really shows us all just how good the FBW and autostab really was, the fact that the aeroplane handled so beautifully throughout such an enormous envelope. Well done CliveL and ChristiaanJ and all you designer chaps..
Now NW1, I bet you can still really do the flying control check in your sleep (), but 'Great times, great aircraft, great people' is certainly a marvelous way to sum up such an amazing time of our lives. I still feel honoured and very lucky to have been a small part of it all for so many years.
And as for March... Yes I will be there; see you on the 4th.
Best regards

Dude
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Old 17th Jan 2011, 10:32
  #1113 (permalink)  
 
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Another pie-in-the-sky Q for you guys:

Concorde carried 100 fare-paying pax.

Hence, If you were looking to redesign Concorde today, to be more cost effective, you would I assume look to increase passenger loads?

Would this purely be a case of sticking everything in the photocopier and hitting the 'enlarge 150%' button? or could you have got away with expanding the cabin width or lengthwise without totally ruining the performance envelope? (a total redesign of the structure notwithstanding)

and which way would you expand? cabin width or length? or both?

Also, I assume a lot of the heavy analogue avionics kit would be replaced with lighter, microprocessor-controlled kit, giving more space and weight for fuel?

The Olympus engines replaced with more efficient ones given the march of technology?

So basically, if the British & French governments had another brain-fart and decided in 2011 to build Concorde2, what would you keep? what would you junk? and what realistically would we end up with in terms of pax numbers, performance, range, etc?

(you have an unlimited budget but need to make the thing a better economic prospect than if just presented with a fleet of de-mothballed Concordes).

Cheers,
Mike.
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Old 17th Jan 2011, 13:20
  #1114 (permalink)  
 
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Brit312 wrote:
Discharge valves

The same logic went for the engine starting ignitors which were used Lh or Rh per sector. This logic caused more problems with starting than any other although a way was found to over come this problem
Really alternate side Ignitors? All RR aero engines I have worked on always sparked up both sides every time, well the Avon, Spey 202, RB199 & the Oly 20202 (Vulcan) and industrial Oly did. Would this have made a difficulty with starting logic??

Was there LH & RH Ignition selector switch maybe?

I hope I haven't missed further comment on this since page 50 but just back off my Hols and raced through to the end.

Also on a tangent a bit; the roll out picture further on was that a Nimrod's tail in the corner of the Hanger??

regards
Howie
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Old 17th Jan 2011, 14:14
  #1115 (permalink)  
 
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Also on a tangent a bit; the roll out picture further on was that a Nimrod's tail in the corner of the Hanger??
Knowing the location and the 'extra' contracts Bristol's had at the time I think it is a 'Whispering Giant'.

Cheers

CiveL
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Old 17th Jan 2011, 16:26
  #1116 (permalink)  
 
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Originally Posted by CliveL View Post
Knowing the location and the 'extra' contracts Bristol's had at the time I think it is a 'Whispering Giant'.
Since it was me who took the photo, I can confirm that.
Filton was 'taking in' RAF Brittanias for major overhaul at the time.

Reminds me of a funny tale, not Concorde-related.

Years before (mid '60s) I'd bought an ex-RAF vacuum-driven artificial horizon in one of those surplus shops in London, dated by a War Ministry label to 1939. I'd already run it once with a vacuum cleaner (oh, the vandalism the young get up to...).
Since the Brit had some vacuum-driven instruments, there was a test bench in the Filton lab for such instruments. So I brought in my ancient horizon, had it tested.... and it still met the basic specs! They made them well in those days....

CJ
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Old 17th Jan 2011, 17:40
  #1117 (permalink)  
 
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For that reason, I believe, flight in mechanical signalling was removed from transonic flight on airtests and altogether from Base Training. The simulator was the only sensible way of trying to fly like that...
During the early years there was some doubt from the CAA that the aircraft could be handled in Mech signalling in the transonic region. Lots of meetings were held, and finally on a test flight the gentleman was invited again and one of the original training Captains flew the aircraft perfectly through the transonic area whilst descending in Mech Signalling. With that said it was a delicate area and control inputs had to be gentle and small so I understand


Was there LH & RH Ignition selector switch maybe?

Yes there was an Ignitor selector labelled LH--Both--RH, however the engines would be started using only one ignitor. This caused a few small but annoying delays as if the selected ignitor failed the start would have to be stopped the starter given a cooling period and then a further engine start using the other ignitor would be attempted, however it did give a running check that both ignitors were working.

This was not very popular with the crews and the ground engineers were persuaded to test the ignitors before presenting the aircraft for service. However due to the engine starting Fuel Pump switching, this resulted with a small fire in the hanger, and so the crews were back to starting on Lh or RH ignitors.

If I remember correctly the RR Conways on the VC-10 also had 2 ignitors per engine with a LH--Both-RH selector.

flying control pre-flight check! Learning it was a conversion course rite othat f
At one time there was a suggestion that BA adopt the Air France technique where the F/E did this check on the ground pumps prior to engine start, which did not go down very well with the F/E. It was fortunate that some one came up with the suggestion that this would wear the ground pumps out , and so this check stayed as apilot check after the engined were running [Thank God]

If you remember, if something went wrong with the Flying control check the F/E was always busy. This gave him a chance to think up a suitable answer or even better the pilots did the check again and it now worked.

But the 'trainers' often used to come seek me out in the hangar and (over coffee, not beer I'm afraid) confer about various system quirks and nasties to use on you guys during the tech' refreshers
No dude we never came to see you boys for the "Pilots Tech Refresher" as we always had to keep those lectures very simple as otherwise the pilots would go to sleep.

Now I have to admit coming across the hanger to consult with you boys when preparing for a new sequence of F/E "Tech Knowledge Checks". Not that we did not understand it, you understand, but mainly to make sure that we were correct before some clever line F/E informed you of your error. Very embarrising that, and I should know
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Old 18th Jan 2011, 05:28
  #1118 (permalink)  
 
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Good to have you back here again Howie
Really alternate side Ignitors? All RR aero engines I have worked on always sparked up both sides every time, well the Avon, Spey 202, RB199 & the Oly 20202 (Vulcan) and industrial Oly did. Would this have made a difficulty with starting logic?? Was there LH & RH Ignition selector switch maybe?

There was no automatic ignition selection logic as such built into the start sequence, but a manually selected L & R ignition selector switch. The reason of course to alternate L & R selection during starting was to detect otherwise dormant ignition failures if 'BOTH' was always selected. (Modern A/C with AUTOSTART do not have this problem, if an ignitor fails during the engine start sequence the other is automatically selected and an ignition status message is set on the lower EICAS screen). The ignition L/R selector switch was bypassed during engine operation by the auto-ignition system, where if the engine control unit detected a flame out (set at 58% N2) both ignitors would automatically fire up. The sequence would release onece the perceived N2 rose above 63%. The ignition system had several reliability issues, the first was the plugs themselves. Penetration into the 'can' was crucial; if it were more than about 130 thou', the tip would very quickly burn off. We soon learned that a penetration check was vital when fitting a plug and shims needed to be used to get the correct penetration. The other reliability issue was the ignition leads themselves; For the first 10 years of service they were a major pain until 'they' (Rolls-Royce) finally got it right. Also until Rolls modified the lead clipping, it could take 3 to 4 HOURS to change a lead. The dual channel HEIU itself was as good as gold, and seldom let us down, It was a very powerful 8 Joule 2KV beast, and you obviously treated it with utmost respect.

Best regards
Dude

Last edited by M2dude; 18th Jan 2011 at 06:28.
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Old 18th Jan 2011, 05:43
  #1119 (permalink)  
 
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ChristiaanJ
Years before (mid '60s) I'd bought an ex-RAF vacuum-driven artificial horizon in one of those surplus shops in London, dated by a War Ministry label to 1939. I'd already run it once with a vacuum cleaner (oh, the vandalism the young get up to...).
Since the Brit had some vacuum-driven instruments, there was a test bench in the Filton lab for such instruments. So I brought in my ancient horizon, had it tested.... and it still met the basic specs! They made them well in those days....
You young vandal you Christian. I'm just conjuring up the visual, a young ChristiaanJJ, vacuum cleaner hose in one hand and horizon in the other, the gyro whirring round at warp speed. (What voltage and frequency suction air did you use ? HAHAHA).
I seem to remember the Chipmunk used to use a cute little 'vaccy' gyro horizon. I pulled many of these apart during my RAF training. (Sometimes I even managed to get the odd one or two back together and working again).

Best regards
Dude
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Old 18th Jan 2011, 06:15
  #1120 (permalink)  
 
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Brit312
This was not very popular with the crews and the ground engineers were persuaded to test the ignitors before presenting the aircraft for service. However due to the engine starting Fuel Pump switching, this resulted with a small fire in the hanger, and so the crews were back to starting on Lh or RH ignitors.
The main problem with testing ignitors in the hangar was residual fuel. The LH ignitor sat right at the bottom of the can, and sometimes had a small puddle of fuel lying over it. This would produce a small 'whoof' of smoke out of the jet-pipe for about a second or two as the ignitors fired, but no more than that. The main danger was forgetting to trip the START PUMP C/Bs before you did the ignition check. If you did you had a guaranteed fire in the can (the pump would run as you know as soon as 'START' was selected and stayed running for 30 seconds after the start switch was returned to NORMAL) which was very messy (and scary as hell too). The only remedy was to grap a start truck, make sure the C/B is finally tripped and dry motor the engine until all the smokey stuff is gone. (It did no damage, but made a hell of a lot of smoke; the fire brigade were never best pleased). But provided the ignition checks were done correctly there was no ptoblem. (In nearly 30 years of doing ignition checks CORRECTLY, I never once saw a problem. Saw a few when people did forget to trip the start pump C/B however.
In any case as far as the 'ground engineers' doing the check of the ignitors, in my opinion if you are doing a pre-flight check, there is no point doing it unless it is pre-FLIGHT. Just about every other system on the aircraft got tested right up to when you boys arrived at the aircraft, but quite rightly you tested them again. (The whole point of 'us' testing systems was to pre-empting failures before they could impact the departure time).
No dude we never came to see you boys for the "Pilots Tech Refresher" as we always had to keep those lectures very simple as otherwise the pilots would go to sleep.
If you even bothered to read what I wrote "But the 'trainers' often used to come seek me out in the hangar and .....confer about various system quirks and nasties....". I never suggested that anyone but the trainers themselves wrote the tech refreshers; but several of the guys (not you, obviously) waited 'til I was back from leave etc to ask away over coffee about some specific system QUOTE quirks and nasties UNQUOTE they figured I would know about and could use in their refresher.
Or perhaps you are suggesting that I am hallucinating or worse?

Dude

Last edited by M2dude; 18th Jan 2011 at 06:27.
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