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I have a different question. Does anyone know what happened to the engines on Concorde? I know the airframes are about, but all seem to be sans engines.
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I think they mostly still have their engines, except AD in NY. Our AC at Manchester certainly does.
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AB had them removed for balance reasons, given that it has no interior.
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Would the lack of an interior make that much difference? Museum Concordes have no fuel in the forward tanks (or, of course, any tanks), and are therefore in danger of becoming 'tail sitters'. Our AC at Manchester has (I'm told) ballast loaded in the forward fuselage to prevent that happening.
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It must make a fair difference: On average, much of the 'interior' is ahead of the CG and remember AB has no cockpit, which is a fair chunk of weight a long way forward,
I vaguely recall that AB was filled up with old 'High Life' magazines initially. |
If memory serves, the Concorde at the Seattle Museum of Flight has engines (or at least something that looks like engines).
It also has an interior and flight deck - visitors are allowed to walk through the passenger portion of the aircraft (can't comment on the completeness of the flight deck since there is a big chunk of Plexiglas preventing close inspection). |
Every time I taxi past 'AB in Heathrow I really feel sorry that somehow it hasn't become a centrepiece for one of the terminals, I half expected T5 to have it hanging off the ceiling. Are there any plans to bring it in from the inclement UK weather or is this an issue of elf n safety? It would be great if it were moved, if only not to distract me from heading up a non-code F taxiway.
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AICU its boards and the interconnect wiring
Originally Posted by ChristiaanJ
(Post 5892328)
Mine is one of the 202 development units, and 'knitting' is too kind... 'kludge' describes it better. I'll post a photo, if you like.
That myth was amplified substantially by BA removing those "secret" AICUs from the aircraft after the final delivery flights. The way I understood the story was that they tried to collect as many reasonably reliable spare AICUs for the last few delivery flights, so as not to have to suddenly cancel a flight. The AICU was right at the top of the list of "unscheduled removals". IIRC the tea maker was second... The one I know about is the ADC/DAC board (analog-digital and digital-analog converter board). The supply of either ADCs or DACs ran out literaly worldwide, and the board had to be redesigned, requalified and recertified with more recent components, and a new batch manufactured. The cost, for the replacement of that board alone, came to about 3 million euros. Somebody passed me a photo taken at Casablanca of a table full of AICUs waiting to be programmed... of course every software mod had to be programmed into all eight computers! "... 'burning' each individual logic gate with a 9v battery." I believe you, thousands wouldn't... Didn't you have at least some sort of programming unit? I went through a similar exercise around 1976, but at that time at least we had a programming "suitcase", that let you copy the original in RAM, modifiy bit-by-bit with a keyboard, then 'burn' the PROM (or EPROM, by then) 'automatically'. Still took half the night.... Funny in a way how these things have stuck in our memories... But then, yes, Concorde was unique. I've said this elsewhere, but I don't mind repeating it... in those days, there were two programmes to be part of. One was Apollo, the other was Concorde. And I've had the chance to be part of one of them. The inter board wiring was random, no harness arrangement other than for power supply. Cross talk was even considered by the design engineers then. Wire wrapped in 30awg OFHC single core cables. I could go on about a lot of things used in the system as it was also my job to keep a record of all the components and which board they were used on. This also applied to the Sensor Unit, The Test Unit, The Management Control Panel. We were busy Bees in the DO for a few years on AICS. Happy Days |
Originally Posted by grumpyoldman
(Post 9933310)
The inter board wiring was random, no harness arrangement other than for power supply. Cross talk was even considered by the design engineers then. Wire wrapped in 30awg OFHC single core cables.
Days The inter board (backplane I surmise) random wiring may be what allowed it to work. "Way back when" I used wire wrap proto boards (socket for each IC) and found out the hard way that neatly bundled routing, Manhattan no direct cross country, greatly increased crosstalk compared to random 'rats nest' routing. I once made everything start working by dropping a single ferrite bead over the clock driver pin (before adding the wires) to slow edge rate enough to damp reflections. This was with a 66Mhz clock which is the upper limit for wire wrap. |
Originally Posted by Thridle Op Des
(Post 9907733)
Every time I taxi past 'AB in Heathrow I really feel sorry that somehow it hasn't become a centrepiece for one of the terminals, I half expected T5 to have it hanging off the ceiling. Are there any plans to bring it in from the inclement UK weather or is this an issue of elf n safety? It would be great if it were moved, if only not to distract me from heading up a non-code F taxiway.
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https://youtu.be/fqOcYhzWUZY
I am ignorant of Concorde operations. I am an aircraft accident investigator, however, after many years of PIC international operations. With respect to the above site, I'd be most grateful if the following points were to be confirmed in regard to AF4590: * A spacer was not installed on the LH undercarriage * The a/c was above its MAUW and outside its C of G limitations * The take off was commenced with a downwind component * The T/O run was commenced over tarmac still under repair * No runway inspection was conducted, as required before any Concorde T/O * No extra protection to fuel tanks had been provided, as had been done by BA * The FE completed engine fire and engine shutdown without consultation with PIC If the above is true, then the accident was unavoidable and I am astounded that the French authorities had the gall (Gaul) to blame Continental Airlines for FOD that should have been detected had the runway inspection been conducted as mandated. Shame! |
Originally Posted by Casper
(Post 9972671)
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TD Racer , Had the privilege of bringing home to LHR from SEA the engineers who de-commisioned her . Was able to make them and their other halves comfortable as a thank you . Some had worked on Conc. for the whole of her BA career , and were retiring with her .
No mention of removing engines whilst chatting with them . However after decades of keeping her running , it was sacrilege for them to drain all fluids , cut pipes ; allowing air /moisture into hydraulic / fuel / oil lines . Disconnecting all electrics , cutting through many wiring looms , removing sections . They were told to make impossible to renovate back to flying condition . On her delivery flight , via Toronto IIRC . The Canadians graciously allowed her to take a Northerly route over the Tundra with NO speed restictions . It all happened at the last minute , and the last sector had 30 , or was it 70 ? empty seats . A lost opportunity . |
Casper, I'm not aware of any fuel tank protection by either BA or AF prior to the accident.
Overweight & aft GC was due too much fuel as well as captain authorising baggage to be loaded (in the rear baggage cabin) when the aeroplane was already about 5 tons overweight. Something else germane to the accident was that the fuel tanks were overfilled leaving no airspace to absorb any shock waves on the basis this extra fuel would be burned off during taxi, but the change of runway (to a downwind one) meant a much shorter taxy so it wasn't burned off and the FE didn't ask for a delay while it got burned off. They just 'went'. Worse - realising they had a rearward CG, fuel was being transferred from tank 11 (in the tail) to the wing tanks DURING THE TAKE OFF ROLL. an absolute no-no in Conc ops. The idea being as fuel was burned off from the wing tanks and replaced by fuel from tank 11, the CG would move foreward. The result was the wing tanks were always overfull even though they were supplying fuel to the engines, so when one tank was hit by a big piece of tyre the shock waves travelled up through the fuel, bounced off the top surface of the tank, having found no gap of compressible air to absorb the overpressure, and travelled back down and burst the tank floor from inside. |
Casper
You might find it useful to read the BEA accident report (in English) f-sc000725a which has all the information you are looking for |
Originally Posted by a330pilotcanada
(Post 9858539)
Good Evening Stilton, M-2 Dude and others.
I am having a nostalgia evening as 20 years ago today I had a flight in G-BOAC from CYYZ to “no-where”. Actually, it was down to New York out over the ocean for around 30 minutes at FL 550 and Mach 2. For one in the “industry” it was a real treat to be able to have a flight in such an iconic aircraft. Things I will always remember going out of “reheat” (a more elegant description then afterburner) after noise abatement from being pushed back into one’s seat to being momentarily weightless, the brilliance of the sky at FL 550, the cabin windows being hot at Mach 2 and seeing the gap between the flight engineers panel and the bulk head at Mach 2 due to the aircraft heating. I could go on about the engineering, observing the crew coordination from the cockpit visit (sadly pre-9/11) and there is a certain story about how our group sweet talked our way into the first-class lounge in YYZ and drained all the bubbly British Airways had in the fridge that day but……. Reading the thread on this aircraft has been fascinating and thank you to all that has contributed to this wonderful story a sincere thank you. Anyway the captain then says "never mind, we'll be in JFK 5 minutes early because of the "issue" - you can stay up for the whole flight if you can explain why". After some serious cogitation, I sussed it out - any body else want a crack at it - and why wasn't an attractive option? |
I understand from that excellent interview that refuelling automatically cut off at about 83% of full tanks for safety reasons: to provide an air space that would absorb any shock wave travelling through the fuel caused by the impact of a foreign object striking the tank. What I don't understand is why there was a facility provided to over-ride this protection, and under what circumstances it was authorised.
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@Lancman
Not so on several counts 1. The phenomenon of structural damage arising from internal pressure waves in fuel tanks was unknown when Concorde was designed. Consequently the design made no specific provision for it. 2. 17% ullage is ludicrous on an aircraft for which fuel capacity is of vital importance. The correct value for tank 5 on Concorde is 6%. 3. Tank 5 was filled to 94% capacity at start of roll which would have been normal for any long distance flight. No more fuel was added to it; on the contrary, a very little might have been pumped into tank 1. The fuel transferred forward from tank 11 was put into the engine feeder tanks 1 to 4. This of course was not enough to compensate for the demands of OL593s operating at TOP with afterburner, so these tanks were running down and would have been topped up (tanks 1 & 2) from tank 5 at some point. 5. What actually happened was that the take off acceleration threw the fuel to the back of the tank so that the free surface volume was confined to a small zone in the upper forward region of the tank. When the rubber struck the rear part of the tank undersurface the fuel above it was constrained by a solid wall, which was enough to generate the reflected shock waves. |
@ CliveL
Thanks for that detailed and very interesting description of the fuel handling on Concorde and I agree that 17% ullage does seem to be very high, I've never come across a figure that high, ever. But your paragraph 5 seems to indicate that it was a jolly good idea from a flight safety point of view. The risk of tank rupture was increased because of the limited free surface volume. I'm just interested in what the circumstances were that allowed this restriction to be over-ridden. |
Originally Posted by Lancman
(Post 9988907)
. I'm just interested in what the circumstances were that allowed this restriction to be over-ridden.
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@Lancman
There a a lot of misinformation sculling around on this. The final report states that the overfill was 300 litres (237kg) put into the engine feeder tanks 1 to 4. These tanks are grouped to have approximately equal moment about the CG so if it was, as seems likely, 75 kg in each there would have been negligible effect on the CG. There was no overfill into tank 5. It is all a long time ago, but as SSDriver says the overfill capability was probably there to cater for extended taxi or waiting time operations. In this particular case the dispatcher ordered 2000kg rather than the standard AF allowance of 1000 kg to be loaded for taxiing presumably because he/she believed a more distant runway would be used because of maintenance work, but in the event the pilot asked for and was given the usual runway which meant that the aircraft was overweight for take off because only 1000 kg of taxi fuel was used. [Plus of course the additional baggage] |
@ CliveL.
Thank-you for your replies. As you say, it was all a long time ago. |
Originally Posted by CliveL
(Post 9989093)
The final report states that the overfill was 300 litres (237kg) put into the engine feeder tanks 1 to 4. These tanks are grouped to have approximately equal moment about the CG so if it was, as seems likely, 75 kg in each there would have been negligible effect on the CG.
There was no overfill into tank 5. And as the extra baggage was in the rear hold, and Tank 11 was full, that would explain the rearward CG and the desire of the crew to get fuel out of tank 11 ASAP and into the wings, Did it all go to tanks 1 to 4 via the forward trim tanks, with none going to tank 5 ( the 'accident' tank)? |
If the intent was to get the CG forward, what would be the point in transferring fuel to anything other than the forward trim tank? In particular why to the engine feed tanks which are arranged to be CG neutral?
However, the BEA report says: It has been established that the aircraft began taxiing with tanks completely full. Before line-up, the crew carried out fuel transfer so as to bring the CG to 54% for takeoff. During this operation, the fuel burnt from the feeders during taxiing was replaced by the fuel contained in tank 11. As a result of the transfer, feeder tanks 1 to 4 were full before line-up. In addition, main tanks 5 and 7, which had not been called on during taxiing, had remained full. Between 14 h 41 min 55 s and 14 h 43 min 10 s, the time when the tank ruptured, the quantity of fuel burnt by each engine is estimated at 219 kg (15 kg between 14 h 41 min 55 s and engine power-up, 204 kg between power-up and the rupture). This was therefore the quantity of fuel taken from each feeder tank. The transfer of fuel from tank 5 to feeder tank 1 deliberately only starts when the level in the feeder reaches 4,000 kg, that is to say 198 kg less than full. This leads to estimate that 219 kg – 198 kg = 21 kg was the quantity of fuel taken from tank 5. |
Because the forward trim tanks were already full so not an option to put it there, unless there is a route from there to tank 5, in which case it might be being transferred to the trim tanks from tank 11, and on to tank 5? The only place to put fuel (if all tanks are brimmed) is into a tank(s) which are being emptied by feeding the engines. If there is no route from the forward trim tanks to tank 5, then perhaps in normal ops tank 5 would be topping up the feeder tanks as the engines drain them, but topping up the feeders from tank 11 meant tank 5 remained full?
The objective is to get it out of tank 11 ASAP to try to get the CG further forward. |
Tanks 5 and 7 inlet valves have an ‘override’ position, do they not?
During the t/o roll, while the trim transfer pumps in 11 will be off, the de-air pump would allow flow through the trim transfer pipes to any tank with an open valve. The valves *should* be closed, unless someone had been creative with any override selections and failed to return them to normal. |
Originally Posted by EXWOK
(Post 9989964)
During the t/o roll, while the trim transfer pumps in 11 will be off |
@SSDriver
You are quite right; I should have checked that :O A simple check of BEA's figures shows that they were assuming transfer into the feeder tanks. Their sums say one needs to transfer about 700kg to make a CG shift from 54.2% to 54% (starting with a ZFCG of 52.4%). However, the engineer's panel after the crash showed that he had dialled in the loadsheet ZFCG at 52.3% so the fuel system would have transferred only 350 kg. I can't see anything to suggest otherwise than that fuel transfer was stopped when TO began and that tank 5 remained at 94% total capacity throughout We crossed in post, but where did you get the information that transfer was continued through take off? I didn't find anything in the official report |
CliveL
From this video. Have you not seen it? Ignore the garish sensational 'cover'. John is a highly experienced BA Concorde captain. |
I’m not sure we *know* the tank 11 txfr pumps were on.
The 5/7 inlet valves were in the override position. Even if the T11 txfr pumps were off, the de-air pump would pump fuel to the trim txfr pipes and hence to 5/7. All assuming I remember the report correctly. The nub being, if you ‘hide’ fuel and forget to return the 5/7 inlet valves to normal, you will still feed 5/7 even if the 11 pumps are off. |
@SSDriver
Yes, I had seen the video, but although he states things with apparent confidence his view is not supported by the formal report. Consider the final report wording quoted in my post 2025: Before line-up, the crew carried out fuel transfer so as to bring the CG to 54% for takeoff. During this operation, the fuel burnt from the feeders during taxiing was replaced by the fuel contained in tank 11. The BEA went to some trouble to establish the amount of fuel in tank 5 at the time of rupture. The process they describe makes no mention of any transfer from tank 11 into tank 5, or indeed any transfer of fuel into that tank during the take off run. In fact they concluded that there was a reduction of 21 kg as a result of normal transfer from tank 5 to tank 1 when that tank became depleted. |
To the top for users that have expressed an interest in the thread. What great reading this thread provides.
Thanks to all that have contributed. |
Excellent thread and may it continue!
I have a question I don't think has been previously posed. In terms of the BA fleet, what was the typical fleet rotation routine? Out as BAW1, return as BAW2, then off to the maintenance area, with a new airframe for BAW3 and 4? Essentially, was there a pattern (presumably to keep the cycles even across the fleet?). I appreciate this may have changed after 'fleet reduction', so to speak... Thank you! |
During my 27 years as a licensed aircraft engineer on the Concorde fleet I can not recall any type of rota for flying the aircraft. Whilst in theory it would be nice to equal their flying hours it was not possible as A/C engine hours would often dictate. The engine was made up of different modules & when that module became time x then the engine was changed & went away for the module to be replaced/overhauled.
You would often face a situation where you tried to limit flying hours of an A/C so you could change an engine to coincide with a service check. Also bearing in mind the delivery dates of each A/C G-BOAC was the first due to it having the BOAC reg. followed by OAA,OAB,OAD,OAE . OAF, & OAG both arrived later. OAC returned to Filton under warranty for a while & OAG was laid up for a long time before being recommissioned . Whilst we had 28 engines on the wing through out the fleet there were only about 8 spare engines. Don't know about Air France Engines. Like all engines they suffer from ingestion of FOD & oil leaks etc. so engines never really went to their full time x hours. As a flying spanner on several charters you always prayed for G-BOAD as it was always the most reliable of the fleet. They all had their own characteristics. Most Captains had a favourite A/C |
Thanks Mexican! I am pleased to have tempted you into the thread. I would be intrigued to find out if there are any other favourites that our friends here could declare. The cynic in me makes me wonder if they chose AD for the ITVV video for the reason you say! :P
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Favourite: OAF for fuel burn and subjective personal preference.
OAC second for the reg!. OAD was indeed the schedulers' favourite for long charters although I have to say that I didn't have fewer or greater tech issues with it c.w. the others. Def. not a favourite on BGI because it burnt a bit more fuel than some others (e.g. Fox and Golf). |
OAC was the first off the Filton line, and therefore the heaviest (they learned to add lightness as production progressed!). That would have had an effect on range and possibly CG for that aeroplane. It also had a wing repair (following an engine fire I believe) which added even more weight.
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Regarding the fuel burn differences would you have a ballpark number to quote?
.1%? 1%? More? |
Concorde at Kia Tak.
"BRITISH AIRWAYS Concorde at Kai Tak (1996)" on youtube.
It's been many years since I flew into Kai Tak. If memory serves me correctly, landing on the Southern Runway, it was a mandatory go around should the extended centre line be crossed on approach. In this clip the aircraft executes a shallow left turn on short final, proving to me at least, they went through the extended centre line. Was BA or Concords exempt from this rule? |
Hopefully this falls within the limits on commercial activity on PPRune, I have no connection with this other than being a satisfied customer a few years ago. If not, mods please be gentle with me...
The Concorde flight deck DVD produced by ITVV featuring Senior Flight Engineer Roger Bricknell, who also gave a fascinating talk on Concorde at the RAeS a few years ago, is soon going out of "print". So if you want a copy, you'll need to get an order in soon, or get a copy at an air show. I doubt anyone else will reproduce it soon. It's an excellent and in-depth video, well worth it if you didn't manage to fly in her and interesting even if you did. |
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