Christiaan, Since you were discussing the scenario of a nosewheel not lowering and that the CG was over the main wheels may I suggest a rather (amusing at least) possibility ?!!
Why not? Let's admit that being faced with that nasty situation in reality would not have been amusing.... But kicking the idea around a moment, why not? It's what I did seeing the question at first.
With a nose gear jammed up but all other gear lowered normally could the Flight Engineer pump fuel rearward adjusting the CG aft sufficiently to allow the Concorde to settle back on her 'Tailwheel'. I realise there would be some damage, especially in light of what has been said about the occasional tailwheel contacts but I imagine it would be less than lowering the unprotected forward fuselage onto the runway.
Obviously depends a bit on the fuel remaining, but yes, I think one could have move the CG sufficiently rearward.
Of course some pax might have to move to the back of the cabin too !
LOL, don't you think they'd all would have moved as far back as possible anyway?
If the CG was adjusted this far aft would there be controllability issues ?
Possibly, but not enough that an experienced pilot couldn't handle it, I would think.
There could finally be a use for the 'full down position of the visor' landing in this attitude !
I don't quite follow you there...
One thing that promptly occurred to me for this 'no nose wheel' scenario is braking, since both engine reverse and main gear wheel braking act below the CG, so they'd both act to pull the nose down. At some point, stick fully back, hence elevons fully up, will no longer be enough to fully counteract that, so you'll have to cancel reverse and braking, and probably commit to an overrun. Your scenario of doing it as a 'three-pointer' on the tail might wel be the better one !
And while we're at it, what about ditching a Concorde? It's hinted at in the Safety Cards. It's been tried lots of times, with models in water tanks. It wasn't really feasible.......
I can only imagine the excitement and fulfillment that those posting here must have felt for the time that they knew her..... Those who maintained her, engineered her, looked after her must have enjoyed immense satisfaction by doing something that MATTERED in life.
There were the early days... At the time there were only two programs that everyone wanted to be on. They were Apollo and Concorde. I was a part of one of those
There were the years after that, when Apollo was cancelled, when only 16 Concordes ever saw service, and one felt the world was no longer going forward.
And for me, there indeed was that immense moment of satisfaction, when I finally flew on one of the last AF Concorde flights, and got my brief cockpit visit, to see that everything I had helped to develop long ago still worked exactly as we'd designed it, close to 30 years later !
In my experience on the receiving end, the amount of personal attention they gave each and every passenger was truly amazing, particularly considering the very complicated meal service offered from a galley with minimal storage volume and a tiny working space
I very much doubt CC had any time available, even for snacking on the 3-4 hour flights.
The two galleys were a fairly cramped environment, and the forward galley in particular suffered by being an extremely hot place to work in. This heat came not from the ovens, Bev' makers or such, but kinetic heat from the area surrounding Door 1 Left. There was precious little air conditioning ducting in this area (no passengers sat there you see) and this door area really make one sweat a bit. Coupled to all this, because of the short flight time there was precious little time for the crews to achieve a full three course meal, including wine/Champagne sevice. Speaking for BA, these six crew worked their socks off at a truly astonishing pace, but sat in your airline seat, all you as a passenger ever saw was a truly superb cabin service from a truly professional group of people. Oh, and the food was totally FIRST class, the wines even more so. (Hic! ). So to any ex Concorde cabin crew reading this thread, a genuine and sincere 'well done guys', you did the fleet proud
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.
Now you really have upset my Sunday as after many years being retired I have had to go up to my attic to get the Concorde books out so as to answer your question
Anyway as M2dude has said there were drills for everything on Concorde and if I remeber correctly the figure came to 194 seperate drills with 13 of them having a memory content. Never mind remembering the memory content it was hard enough sometimes to remember which drill had a memory content
Anyway I have found the drill for
"Landing with Nose gear not locked down "
To give just the essence of the drill you are asked to
Jettison as much fuel as possible
Set the C of G for landing to 53%--- sitting over main gear
After gear lowered select Standby lever to down position----- This ensures the gear jacks remain pressurized down on touch down
After lowering nose/visor on normal system seltct visor stby system to visor down---- this removes hyds from nose and visor system down jacks, so allowing nose/visor to raise if nose leg collapses
Brake lever to standby ---If nose leg collapse there is no ref anti skid signal and normal brakes would not work. Standby has no anti skid system and will work
Then on landing nose up attitude should be maintained and normal engine reverse selected as soon as possible remembering that engine reverse tries to pitch the aircraft nose up
Wheel brakes use gently and cease at 120kts
At 110 kts reduce attitude to touch nose wheel down gently
At 85 kts select engine reverse to idle power
At rest " Passenger Evacuation"
---------------------------------------------- So you can see this drill uses the nose up effect of engine revese to hold the nose gear off the ground for as long as possible.
I fear this explanation will gemerate more questios than it has answered, but off for a cup of coffee now as grey cell are hurting
I would first like to thank everyone in this thread for making it so informative and a brilliant read.
If I may I would like to pose a question, the answer to which I can't seem to find in all the books and manuals I have read, this relates to the procedure that was adopted on those ocassions when FL600 was reached.
As far as I am aware Cruise/Climb was carried out with AT1, AP1, FD1 or AT2 AP2 or FD2 and with MAX CLIMB engaged, MAX CRUISE would automatically engage as required. Was 60,000 feet set in the Altitude Select window and was ALT ACQ primed?
If not, what stopped her from continuing to climb past FL600 if conditions were suitable, and, if ALT ACQ was primed and FL600 reached and she then held that altitude what was the procedure if speed started to decay due to external influences? Was a gentle descent initialised using the pitch datum adjust until the speed came back and then MAX CLIMB re-engaged?
Hi Steve, good question. You could not prime Alt ACQ directly from MAX CLIMB/MAX CRUISE, but I'm sure the guys would confirm that FL600 was nonetheless set in the AFCS altitude window. If you did come close to FL600, then you would get an altitude alert audio and visual warning anyway, but the crew would obviously know anyway. The guys will have to confirm this but I think that ALT HOLD would be selected at this point, and the autopilot would now constrain the altitude by varying pitch attitude. You would normally be flying in nice cold conditions for this to occur, hardly ever on the North Atlantic, but on the LHR-BGI sector it would occur as often as not. (As usual, apologies to my all flying pals if I'm talking rubbish again ).
Thanks for the reply, I never knew you couldn't prime ALT ACQ from MAX CLIMB / MAX CRUISE.
I was thinking though that if you had ALT HOLD selected then the autopilot wouldn't be able to vary the pitch attitude and it would hold at the ALT HOLD level. Once there it wouldn't be able to use pitch to increase or decrease speed if necessary. I can see how the autothrottles could hold the speed back but if it were to get warmer then even at full power it may not be able to maintain speed at a fixed altitude.
I'm sure there is a simple answer which will leave us saying "oh yeah, how obvious, didn't think of that" Just strange it doesn't seem to be written anywhere.
First of all, THANKS to all you from Concorde family for this fantastic topic. Started reading last night and almost slept in front of computer trying to read everything!
As a Concorde fan for 10 years (since I bought FS2000), and passionate developer of SSTSIM Concorde and FSLabs ConcordeX (flight dynamics, weight and balance), it's simply awesome to have you guys and gal here sharing your memories.
Regarding the CG corridor, here's a fantastic graphic from online Concordepedia, aka ConcordeSST.com, Technical/Fuel System section:
Interestingly, it doesn't show a warning for CG>59.1% above M1.6, opposite to what M2Dude said earlier on the topic.
I got curious on the Max Climb/Cruise and ALT ACQ not being primed. How the levelling at FL600 was done? Manually?
Regarding the fuel tanks, specially tanks 6 and 8: did these tanks' lateral center of gravity change with quantity? Due to their completely assymetrical shape, I'd expect some change in it.
Operationial question: did BA use the 380kts descent profile? Have heard that only AFR used it, but Haynes' book says that BA started using it too.
There are many doubts regarding procedures as manuals and informations available on the internet are mostly from BA 1976 entry-into-service era. But i understand many things changed along the years, as I can see on a Aug 2000 manual I've got, with percentages showing differences from the 76 era, or even completely new tables.
Well, that's it, hope to be able to contribute on the topic, but mainly learn from you that flew the real thing.
BlueConcorde, Look at my post #260, second diagram, taken directly from the BA Flying Manual. There is a "first stage warning" (Mach/CG lights and gong) above Mach 1.6 and below Mach 0.45 for the aft CG limit. It's only in the "corridor" that there is a "second stage warning" (flashing Mach/CG lights and stick shaker).
1st stage warning then the F/E rectifys it by moving the fuel
2nd stage warning was considered a more dangerous exceedence and would be remedied by the F/E moving fuel and the pilot slowing or speeding up the aircraft depending on which limit had been triggered
The aft limit second stage warning was a flashing light and a stick shaker to which the natural response from the pilot is to speed up Now you can see from your diagram that above M1.6 increasing will not improve the siuation if the aft boundry has been infringed. Therefore to prevent an auto response from the pilot to a stick shaker [ push the nose down and speed up] the 2nd stage aft warning was not available after M1.6
Tanks 5 and 7 were operated as a pair as were tanks 6 and 8 Because of the odd shapes of the tanks when you were transferring from the set 5 and 7 the F/E had to pump fuel across the ship to keep lateral trim. Once they were empty and 6 and 8 were being used then again due to their shape the F/E had to transfer fuel across the aircraft to keep lateral trim ,but this time in the opposite direction . well it stopped him getting bored
Tanks 5 and 7 were operated as a pair as were tanks 6 and 8 Because of the odd shapes of the tanks when you were transferring from the set 5 and 7 the F/E had to pump fuel across the ship to keep lateral trim.
Right, do this everytime I fly on the sim!
Once they were empty and 6 and 8 were being used then again due to their shape the F/E had to transfer fuel across the aircraft to keep lateral trim ,but this time in the opposite direction . well it stopped him getting bored
Yes, so my not-so-trivial questions, aimed more for F/E and Ground Engineers are: 1) with the same quantity on tanks 6 and 8, for example, 10 tons, there would be a roll tendency? I suspect yes, but not sure. 2) Using valves 6/7 and 5/8 would make lateral unbalance gone or they just leveled the fuel height on each pair of tanks? (Assuming that all these 4 tanks had the same height, what sounds logical to me) 3) Is there any table with these tanks quantities to reach lateral balance or the F/E did fine tune just by making elevons level?
I have these doubts for a looooooooong time, as I never found the lateral arm of the tanks, just the longitudinal (in % MAC that is equal to root chord in Concorde). So I assumed in FSLabs ConcordeX that if all these 4 tanks were FULL and symmetrical as a group, there would be no imbalance, that means: different quantities and different arms gives the same momentum.
Due to this, I always keep 300~500 kgs more on the 7 and 8 (right) tanks than on 5 and 6, but I'm really not sure if it's a realistic value.
The fuel system was just FANTASTIC... and making it work engineer-less under any abnormal condition would be something VERY difficult, in my humble opinion.
BlueConcorde A hearty welcome aboard here from me also. (Sounds like you are doing amazing work on the FS-X Concorde). Brit312 has given you a good idea of just how hard the F/E used to work on Concorde, and juggling the fuel system was always his pièce de résistance. (Might also explain why a beer or several at the end of a trip was absolutely essential). I'd certainly let Brit312 answer the balancing bit, and I'm afraid I've no info on the lateral moment arms of the tanks. (I did have a rummage). As far as automating the system, I agree that it would be incredibly difficult even now, but with the technology around during the 1970's I would agree that it would say that it was just about impossible to do it with the same level of finesse as Brit312 and the guys..
I never knew you couldn't prime ALT ACQ from MAX CLIMB / MAX CRUISE. I was thinking though that if you had ALT HOLD selected then the autopilot wouldn't be able to vary the pitch attitude and it would hold at the ALT HOLD level. Once there it wouldn't be able to use pitch to increase or decrease speed if necessary. I can see how the autothrottles could hold the speed back but if it were to get warmer then even at full power it may not be able to maintain speed at a fixed altitude. I'm sure there is a simple answer which will leave us saying "oh yeah, how obvious, didn't think of that" Just strange it doesn't seem to be written anywhere.
Hi again Steve. At FL600 your aircraft is going to be relatively light, and your autopilot is set to ALT HOLD mode. As the aircraft continues to burn fuel it will 'try' and climb, but the ALT HOLD mode will of course slightly reduce pitch attitude to keep prevent the aircraft from climbing. The autothrottle in MACH HOLD mode can keep us from straying from Mach 2, large positive temperature shears were to my knowledge almost unheard of, and so any speed reduction was exceedingly unlikely. We really need a pilot's input here to further clarify the realities of LHR-BGI supersonic cruise; that's the way the AFCS was designed to do things however.
M2Dude has it all correct here. It only really happened regularly on the LHR-BGI route (low temps at crz alt, and light weight as you've burnt most of the fuel).
In the MAX Cruise mode the aircraft would sniff about vertically, gently climbing and descending to hold M2 (following the temperature changes), but with an overall general climb.
Heading to BGI you were climbing into very cold air, commonly down to less than -70degs, I saw minus 80 on multiple occasions. (Which was all very good news from a fuel point of view). So the climb was more definite and the likelihood of a subsequent descent lower.
It was pretty easy to spot when the aircraft was definitely going to 'stick' at FL600, and to select Alt Hold, with the already armed AT (with Max Crz mode) engagd in Mach Hold. Very occasionally one may have to subsequently make a subsequent return to Max Crz mode if warmer air was encountered, but I don't recall doing this more than once.
If you had very cold air and a lighter than average load, one would find that the throttles (no 'thrust levers' on Concorde!) were quite a long way back at TOD, maybe 10-14 degrees throttle angle. It was worth noticing this early - the decel/descent was initiated by reducing the throttles to 18degrees, normally this would be from full forward so it can be seen that reducing them by 4 or 5 degrees rather than the usual 18 could result in a disappointing rate of decel. At nearly 20NM a minute this could really screw your descent plan! (I think the record-holders went past BGI still just the wrong side of M1......)
I used to enjoy the last few minutes of the flight at FL600 - before the space station was manned and post-MIR there was a fair chance that at that moment we were the human beings furthest from the surface of the planet. In shirtsleeves, with a cup of tea (or something more palatable if one was in one of the comfy seats).
EXWOK's superb post above really characterises what Concorde was all about; An aircraft with 100 Champagne sipping passengers sitting in total comfort, the aircraft sat at Mach 2 - 2.02, 60,000' and wanting really to both climb and accelerate, but having to be restrained to prevent this and the engines poodling along and nothing approaching their maximum power. Seven cabin crew happily looking after their one hundred charges and three VERY lucky guys, sat at the front of this wonderful aircraft in shirtsleeve comfort and having really the best time of anyone aboard.
ANY fighter of the time would have to have been on full afterburner with the pilot in a sweaty flying suit and bone dome and only able to stay at anything like this speed for a VERY few minutes.
To EXWOK and the other guys (and gal ) I take my hat off, because you made it happen. Because of all you guys BA had 27 years of highly successful and TOTALLY SAFE Concorde operation. In the VERY few times that things did not go to plan, your skill and professionalism made the hairiest of moments seem like total routine. And stilton my friend, we are in debt to you for starting this thread in the first place. Keep asking away and we'll all do our best to give you as straight an answer as possible; it's really fun for us too.