Exwok,

Thanks for explaning that, makes perfect sense to me now. I thought it was some sort of Standard Procedure as opposed to an Irregular Ops Procedure.

Regards,

Steve.

Fuel Saving Landing

Requirements:

• Manual landing, at VREF, only
• Minimum of one autothrottle operative at start of approach
• Contingency power available
• Specific fuel distribution achieved
• Record in Maintenance Log

Not permitted with:

• Slippery runway
• Precipitation covered runway
• 3-engine ferry
• 2-engine approach and landing
• Reduced noise approach
• Fuelled with wide-cut fuel
• Secondary nozzle locked out
• Brake unit isolated
• Total loss of Electric Trim
• Total loss of Pitch Stab
• Total loss of Electrical Signalling
• Suspected tyre failure

Notes

3-engine landings were permitted. For all landings the landing gear would be lowered earlier than normal to ensure the brakes were stone cold to start with, maximum reverse thrust would be used on landing, and braking modulated so as to use (nearly) all of the full length of the runway. Landing performance figures at 130,000 kgs were in the performance manual for most runways. Any runway for which this procedure had not been pre-authorised required some rather tedious calculations, using the generalised basic data and graphs found in the performance manual.

If manual performance calculations were necessary, the F/E and I usually seemed to find that another problem that required our urgent and undivided attention had come up, and we would reluctantly be compelled to hand over all the manuals, charts and graphs for the F/O to perform the calculations! ;)

If the aircraft had an AFT ZFW CG (perhaps loaded with a lot of heavy bags in the rear hold), and given the specific fuel distribution requirements for a fuel saving landing, it was possible that the landing weight might have to be reduced below 130,000 kgs, in order to achieve a landing CG of 53.5%.

After landing, record the actual landing weight in the Maintenance Log using code 2899XXOO, sign it, and then leg it swiftly, to avoid M2Dude and the boys, who somehow always managed to imply that you were responsible for anything that had gone wrong with their pride and joy since they last handed her over to you! :p

Reasons

The clue is in the name! A possible saving of roughly 5,200 gallons of fuel, nearly 19,000 kgs, which need not be jettisoned, thus reducing the time spent in the air before re-landing, fuel costs and pollution.


Best Regards

Bellerophon

Engines
 

My physics has pretty much rusted away so can anyone help me with this, The frequent statement that the intakes accounted for approx 80% of the engine power when supersonic. I quite understand that the intake air has to be slowed to subsonic before it meets the first compressor disk but saying that the intake produces 80% of the power almost implies that you could turn off the fires and still have 80% power. Obviously that cant be right! and another thing I dont understand is how shock waves slow down the intake flow, so any help with that would be useful to me. Any aerodymicist/physicists out there?

Thanks and keep up the super remeniscences
rod

jodeliste,
That question already ended up in a separate TechLog thread... LOL.

Concorde engine intake "Thrust"

Have a look there first, then if things still aren't quite clear, feel free to ask more questions!

CJ

Bellerophon
There were no specific airframe inspections associated with a fuel saving landing (the possibility of which EXWOK eluded to) ; the 2899XX00 log code would however trip a flag that required the landing vertical and longitudinal accelerations to be analysed on the QAR readout. (The vertical G was also locked into the memory of the AIDS management panel, and was there until the next landing). And would I or anyone within Concorde engineering blame you guys for 'bending it'?.... :ugh:
(Only joking everybody, the most important thing after any minor incident was for us all to sit down and have a thorough post landing chat, so that everyone was clear as to what happened, and the cause of the 'bump in the night' could be nailed and remedied ASAP).
Leg it indeed..:= (chuckle).

Dude :O

M2Dude & Brit312:

FWIW the LP Cock to shutoff was added to the precautionary engine shutdown C/L - but I think this was after (and because of) the AF inceident.

But I had understood that their engine failure that day had been due to a problem with the engine which caused enough vibration to damage the fuel pipe leading to the leak. I don't know if they ran the Fire / Severe Damage C/L, but that C/L always involved shutting the LP Cock as part of the Cleanup Items. Maybe they did "only" run the Precautionary Shutdown C/L - I have no idea, but the LP Cock position (which turned out to be key to the near loss of the a/c) would depend on it prior to the addition of that step in that latter drill.

I do remember there was always controversy in training circles about the Cleanup Items and when or where (or even "IF"?) they should be run: but IF the AF flight had run the Fire / Severe Damage drill and IF they had run the Cleanup Items soon afterwards, then their situation would not have been so dire.

No critisism of anyone intended (AF crew or forum posters), it's all such a long time ago now, but the nuances involved in Precautionary Shutdown / Fire - Severe Damage / Cleanup Drills were far from clear-cut...

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 :O

Sorry M2Dude, but although I agree that the reasons for the premature withdrawal from service lay south of La Manche, the AF incident we're talking about was not due to "forgetting to select the LP cock to shutoff" in your quote
<<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>>
At that time the Precautionary Engine Shutdown C/L did not call for the LP cock to be selected to shutoff (that stable door was subsequently closed). So no procedural errors there.

You could argue that the severe vibration which kicked off the incident should have called for the Engine Fire / Severe Damage C/L in which case the Cleanup C/L would have seen the LP Cock closed - but when? And was this the drill called? IF the Precautionary Shutdown drill was used then it is not surprising that the LP cock was not closed. That's all.

Easy when looked at through a retrospectoscope....

And for what it's worth I think AM and CF were a pair of [edited to say: "allegedly not supportive of the Concorde operation"] who should not have been allowed any authority at all over this precious project....

NW1
I agree that my wording regarding precautionary engine shut-down was not quite correct my friend :ok:; with WW3 going on out there under the wing I think we can both agree that that check list ddi not in any shape or form cover the events ensuing.
And as for the AM/CF dynamic duo; I could not agree more; these two wankers/toss-pots/cretins etc (being a gentleman forbids me from printing here my real thoughts on these veritable slime buckets) I would not place them in charge of a broken down manure truck.:\. One had the avowed aim of destroying Concorde and the other, in a position to do some good did his master's bidding and was party in no small way to this madness. Pity 'skippy' did not have some balls too!!
Best Regards

Dude :O

Hmm, Dude, don't hold back on what you think of them, tell it like it is! :D

I've been following this fantastic thread since day 1 - what a tremendous source of information and inspiration!

Was fortunate to have a look around G-BOAC in Manchester today, and she's being looked after extremely well. There are a few photos here if anybody would like to take a look... and I'm more than happy to share them so feel free to download if you wish.

MobileMe Gallery

Thanks for a truly fantastic thread, all!

Landlady returns from the land of the pirate
 

Hello again chaps and chapesses,

Having consumed enough rum punch to ensure that the guys at the Mount Gay distillery in Barbados stay in business for a long while yet, I was very pleased to return from holiday to see the thread still going and of course, still very interesting. :ok:

The photos from pax-man, (thank you!), brought back my own memories of AC, for that was the Concorde on which I did a round-the-world trip in 1988 with the lovely Captain Jeremy Rendell at the controls.

They also reminded me - since she is at Manchester - of taking her up to Ringway a few times when BA would surprise shuttle pax by putting a Concorde on the route as a last minute a/c change.... sheer delight and 100 Concorde grins every time! I sat on the f/d a couple of times going in to Manchester as I am a northern lass and began my flying career there, so the place holds a lot of fond memories for me. On the approach, you could see cars parked everywhere, all the roads and motorways jammed with spectators. It seemed like the whole of the north of England were there to welcome her in.

I realise that I did promise - a while ago now - a bit more information with regard to the RTW trips, so I am off to dig out some old diaries in the hope that I can relate some yarns for you all.

Whilst in BGI I was offered the opportunity to see Connie in the special hanger which they have for her over there, but I simply didn't have time this trip. Maybe I am putting it off... I know that it will be a very emotional experience to touch the galley tops again.... I am back in Barbados again next March, so I will go then..... although I know I will be crying when I have to say goodbye to her. :{

Happy to be back on line (I don't go in for all this keeping up with forums/facebook/e-mails whilst on holiday!) and happy to answer any cabin-related questions you may have. :)

Warm regards,
LL x

Thanks for this amazing thread
 

Hi All, just wanted to say thank you to everyone that has posted in this thread. I am just humble SLF with a little bit of gliding experience who never had the privilige of flying on Concorde and only ever saw her flying once (in the seventies I saw her take off from Heathrow when she was painted in BA and SIA colours... I was very young!) Thank you all for sharing your passion with us all and keeping this thread so gripping.

I did once meet a Concorde Pilot, it was in about 2003 shortly after the end of her service had been announced. It was on a motorboat somewhere in the solent (Bembridge on the isle of Wight springs to mind) and he politely listened to me rabbit on about my gliding experience and my hopes to get an NPPL one day (Still haven't managed!) I knew that he was a pilot and when I asked what he flew he just quietly said, "Concorde". I nearly fell of my perch. Anyway a couple of minutes later I acidentally spilled a glass of wine down his trousers and I have never forgotten it - my wife tells me it was deliberate because i was jealous! It wasn't I promise. Anyway, sorry for waffling on, but if that pilot is one of the contributors here - I really am sorry about spilling that drink!

Thanks again for an amazing thread
D

You obviously weren't listening when he introduced himself.

(It's a joke guys - a joke.)

I'm sure there are plenty of self-effacing pilots, but maybe they don't post on PPRuNe....

And they're not from Yorkshire.... (that's a joke as well :rolleyes: )

Landlady,
I know this will sadden you... but better forewarned than discovering it on the day, no?

When they set up the Barbados 'Concorde Experience' on G-BOAE, they decided it would work far better if people could move one way, from the back to the front, rather than continuously getting in each others way.
Now, the two little service doors in the rear galley are not really suited as entrances for the public.
You should know!
Hence the decision was made to remove the rear galley (which they undoubtely kept in storage somewhere, if not actually on display) and to have people enter through the rear baggage hold door, through the baggage hold, and from there into the rear cabin.
(Much the same was done on Delta Golf, the Concorde now at the Brooklands, Weybridge museum.)

So, the only galley tops will be those in the forward galley. Snif....

CJ

Welcome back Landlady :)

Here's a question for you - how often did they surprise shuttle pax with Concorde as a replacement?

...and for the rest of you, roughly how much in terms of fuel would a shuttle flight in Concorde cost BA versus say a B737 or A320?

(i.e. it was obviously done for PR sakes as much as anything, but was it really costly?)

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...

Flight Directors
 

I have read somewhere (could be on this thread) that Concorde's flight directors were only used in the climb above a certain altitude.
If that was the case, what was the reason? and was there a specific altitude above which the FDs would be used?
I presume that on the descent they could be used all the way down to the landing as they would be linked to the ILS.
Regards
Nick

They weren't used for take off because there was no relevant mode. The initial climb was to hold 250kts after takeoff until a predetermined time for noise abatement (a little over a minute ex-LHR, less ex-JFK) and then start to accelerate after the NA thrust reduction.

It was a balancing act and different for each departure - the RoC actually went up the faster you went so you were easing up, maximising the acceleration, while ensuring you (just) made the SID alt requirements.

So, apart from a few seconds holding 250kts, there really wasn't a mode that would work in pitch; you would have to take vert speed and be constantly asking the NHP to select different VS's and HDGs and they had quite enough to do already. No benefit, so don't use it.

Once you'd got to Vmo during the SID (it was 400kts at that point) you could use Max Climb mode (see earlier discussions) and that was generally when the FD was engaged.

It was permissable to engage the AP at an early stage, in which case HDG mode and Pitch Hold would be used, but it was more effort than hand-flying, less accurate and less fun so that was a rare event.

On approach, if an ILS was being flown, you are correct that the FD could be used, although for a typical approach it needed to be off at 300'. This was because wherever possible we flew a 'Reduced Noise Approach' (again, see earlier comments) which consisted of holding 190kts to 800' then reducing to final speed to be stable by 300'. AP/FD had to out by 300' in this case, owing to the very tight pitch control required for which it wasn't certificated (although it could carry out a very good coupled approach and landing if given a more stable approach).

In summary - a very 'hands-on' aeroplane. And all the better for it :E

Fuel: Conc vs 737
 

For those who wanted to know what the difference in fuel burn between a 737 and Concorde LHR-MAN........I don't know! (Never had the pleasure of flying the 737).

My best guess - at least 200% more. Probably higher.

A comparison:

Typical Concorde taxying fuel burn: 6500kgs/hr

Typical 777-200 cruising fuel burn: 6500kgs/hr

Of course, as we've already discussed earlier, the magic thing about Concorde was that once you'd got to Mach2 its efficiency was outrageously good - better miles per gallon than a 747. An option not available, however, between LHR and MAN.

Edited to add: a slow taxy out at LHR would almost definitely consume more fuel than the 737 would burn for the sector.

Fuel comparison
 

No experience on 737, nor, sadly, on Concorde but do recall an occasion when travelling from Compass Centre on northside of LHR to T4 on the south side in the BA001 crew's van when we got to comparing fuel figures.

Turned out that they would burn slightly more fuel getting their 100 pax from T4 to 1000' agl than we would use to get our 180 pax on the 757 all the way to Amsterdam!

Typical burn on a 757 LHR - MAN was 2200 kgs or 2000 kgs on an a/c with the much more efficient E4 engines.

I have to admit that some of the subsonic fuel burn figures for Concorde were truly eye watering, and without massive engine and airframe modifications there was precious little in service that could be done to improve things. Paradoxically improvements to the supersonic efficiency of the powerplant were easier to implement, and several modifications were implemented, tried or proposed to improve fuel burn:
Way back in the late 1970's we did a major modification to the intakes that increased capture area by 2.5% and gave us typically a 1.6% improvement in trans-Atlantic fuel burn, and although this was our biggest performance improvement modification, there were more:
The famous elevon and rudder trailing edge extension modifications (that due to poor design, produced in later life the water ingress induced honeycomb failures) together with the re-profiled fin leading edge modification, I never saw the performance gains quantified (anyone have any ideas?).
Can anyone here remember the riblet trial? In the mid 1990's Airbus supplied 'stick on' plastic riblets, applied to various areas on the under-side of the wing on G-BOAG. These riblets had very fine undulations moulded into the surface; the idea being that as the air flowed through and around the riblet patches, boundary layer turbulence, and hence induced drag would be reduced. Now, the performance gains (if any) were never quantified, mainly because the riblet patches either peeled off or the surface deteriorated with the continuous thermal cycle. (I was over in JFK when the aircraft first arrived after having the riblets fitted, and as the crew were trying to proudly show me these amazing aerodynamic devices, they were sadly embarassed, as several had dissapeared in the course of a single flight).:ugh:
There was one modification, proposed by Rolls Royce in the late 1990's that did have quite a lot of potential; this was to increase the engine N1 by around 1.5%. This would have had the effect of increasing engine mass flow and therefore reducing the drag inducing spill of supersonic air over the lower lip of the intake. Depending on the temperature, the performance gains were in the order of a 1.5% improvement in fuel burn at ISA Plus upper atmosphere temperatures ('normal' LHR-JFK) to none at all at significant ISA Minus temperatures (LHR -BGI). The modifacation had been trialed on G-BBDG before her retirement in the early eighties, and was proven in terms of performance enhancement and engine stability. In order to keep TET at the pre-modification level, there was a small increase in N2 commanded also. (The higher N1 required an increase in primary nozzle area, reducing TET). The main reason for the modification not being implemented was one of cost; The Ultra Electronics Engine Control Units were analog units, and the modification was a simple replacement of two resistors per unit. However because ultimate mass flow limitation was also controll by the digital AICU (built by British Aerospace Guided Weapons Division) the cost of getting a software update for this exremely 'mature' unit was found to be prohibitive.
A certain 'brainy' SEO and myself were working on a modification to improve fuel burn on ISA minus sectors. The idea was to force the autopilot, in Max Cruise at low temperatures only, to fly the aircraft close to Mmo, rather than at Max Cruise speed of Mach 2 - 2.02; this would have given us gains of up to 1%, depending on the temperature. The basic electronics involved for the modification were relatively straightforward, but it was never pursued due to the complexity of dealing with temperature shears and the cost of certification. :{

Dude :O

Sincerely, this thread just gets more interesting.




Was any consideration given to the fitting of a Head up display ?




With such a manually flown Aircraft it would seem to be a natural for such an aid.




I realise the technology was in it's infancy at the gestation of the Concorde project but was there ever a proposal or even testing of such a device ?

Flattery will get you nowhere....
But I agree, post after post has either an interesting question or an interesting answer!

I don't think it was ever considered... which may be a tribute to the 'fit' of the SFENA 'clock-work' primary flight instruments of the time.... which was carried over to the next generation such as the A300 and A310.
AFAIK, even today, only very few commercial aircraft types have HUDs installed.

Not really true, basic HUDs alreay existed well before Concorde flew.

On Concorde? Not that I know.
SFENA (the firm I worked for) did work on a very limited HUD, basically just for runway alignment during take-off and roll-out, and IIRC some were installed on early A300s and A310s, but the idea never really seems to have caught on.

CJ

Thanks Christiaan.




Yes I think the Mercure had a HUD if i'm not mistaken.

Was the first HUD installation on a commercial airframe (Thomson/Sextant). Certified to CATIIIb.

One of your earlier posts makes reference to the three engine ferry case, so I assume it was an authorised procedure?

Can one of your number remember the technique, the limitations and any comments on the rotation/acceleration/climb. I'm curious about the handling implications.

stilton, Brian Abraham,

Just Googled this to confirm a less-than-certain memory.....
Today, only the 737 (later variants) has a HUD fitted.
Not sure if it's a standard fit, or a customer option.

CJ

PS : off-topic, but the Mercure was a nice aircraft, even rarer than Concorde (incl. the prototypes only 12 built).
One is at the LBG museum, looking immaculate, and being kept "alive" by volunteers, but of course out of hours.

Concorde had a very advanced HUD fitted. It was a spring-loaded wire frame (a bue transparent plastic thing on 'OAG) which you could flip up in front of you to help judge the landing attitude. With final attitude about 11 degrees and secondary nozzles scraping the runway at (from memory) about 12.5 degrees attitude control was key.

Three-engined ferrys were approved. Went through it on the sim, and this is only from memory but you set full re-heated power on the symmetric pair, and the assymmetric engine at 75kts. "Power Set" was called slightly later than normal (130kts). Any re-heat failure before V1 = RTO.

There were loads of complex additional issues to go through at planning (the 3-engine ferry manual wasn't the thickest on the fleet - but it was thick enough!) and I don't think I'd have been too keen on doing one (I was never asked, and I don't know of any Concorde having done it - more "seasoned" fleet members may know better!): I think it was a slighly more critical proposition even than doing it on a blunty, and most guys I know have reservations about it on their fleets too...

LOL...
Wasn't that the same thingmabob that was used to set your 'throne' to the exact eyeheight?

I knew it existed, but somehow never saw it. How and where was it stowed when not in use?

CJ

NW1 and ChristiaanJ
Ahh yes, the super hi-tech 'HUD'. It was right up there with the 'eye level datum' indicator and not to forget, the reheat capabiliy indicator in terms of sophistication. (Extremely reliable though :rolleyes:).
As far as 3 engined ferries went; well NW1, not sure if you'd call me seasoned or just just clapped out and wrinkly, but it did happen a very few times in days of yore, mostly from SNN back to LHR. There were at least two; OAF in 1980 when she had the infamous LP1 blade fail (and Monty Burton's immortal words during the 'event' "what *** ing drill?). The second one that I can remember was OAA in 1991 when there was another far less serious compressor blade failure. In each case for the ferry flight, the broken engine was 'swaged' to prevent it windmilling and the aircraft would be flown back to the LHR garage by a management crew. There was however another required ferry measure as well as the engine swaging, this measure was to prevent the good engines going into contingency, due to the very slightly flamed out dead 'donk'. This procedure required the Engine Speed Unit to be removed from the electronics rack and a special jumper plug fitted in it's place (without the jumper fitted the start switch would never latch in. In this case also the E/O would also need to manually disengage the start switch at 25% N2). I have to admit that I never in my life ever saw this jumper plug, and in the cases that I can remember the aircraft departed SNN with the three engines at contingency. I remember that the case of OAA back in '91 most certainly was; I was flown out to SNN equiped with a pile of circuit diagrams and test boxes to investigate what we all thought was just a surge related engine shutdown. only to find a slightly more hairy state of afairs, with a very broken engine indeed. As a matter of interest, this particular failure was the only one ever in the history of Concorde in BA attributed to the engine having run for a protracted time in rotating stall. (This had happened on the previous day). A lot was learned by both BA and Rolls Royce after this event, and this failure never occured again.

Dude :O

You can't just leave it there Dude!

Would you be so good as to explain what happened and why? It certainly doesn't sound healthy....

Oh darn it Feathers, if you insist (LOL). :bored:
First of all, what is rotating stall? All gas turbine engines are prone to this to some degree or another, the Olympus was particularly prone (so we discovered to our cost). What happens is that extremely LOW figures of N2, small cells of stalled air rotate around the anulus of the early stages of the HP compressor (at approximately half the rotational rpm), resulting in parts of the airflow becoming choked and highly distorted. This often results in the combustion process being disturbed to the extent that combustion instead of occuring in the combustion chamber, occurs in the turbine itself. This of course results in massive overheating of the turbine blades and stators (and is what is suspected occured in the #2 engine on G-BOAA in 1991.
To prevent running in rotating stall, the Olympus automatic fuel start schedule would accelerate the engine quickly to around 67% N2 before dropping back to the normal idle figure of around 65% N2. (The stall clearance N2 figure was ambient temperature dependant, the higher the temperature the higher the N2 that was required and hence scheduled by the automatics).
What had happened on G-BOAA was an engine starting/accelerating problem, where the N2 ran at a sub-idle of around 40% N2 for several minutes. This was enough for the malignant effects of rotating stall to take hold, and the resulting turbine blade failure over the Atlantic the following day. In all fairness to everyone involved, none of us, including Rolls Royce realised just how potentially serious this phenonomen was, and salutary lessons were learned by one and all. (The following year Air France had a similar failure; their first and last also).
I flew out to Shannon on a BAC 1-11, that was sent to fly the Concorde passengers back to London. As I and my colleague were coming down the ventral door steps of the 1-11, a chirpy Aer Lingus engineer asks 'have you guys come to fix the broken engine?, there are bits of it lying in the jet pipe'. Now up to now, from the information we'd been given in London, we thought that we were going to be looking at either an intake or engine induced surge, a few systems checks and boroscope inspections and we'd all be on our way, so we naturally thought the Aer Lingus guy was joking. He was most certainly was not; as you looked into the jetpipe (through the secondary nozzle buckets) you could see a large quantity of metal debris, accompanied by a strong smell of burnt oil. I remember this day well, it was the day that the first Gulf war ended; how ironic.
The aircraft departed on three engines, flown by a management crew late the following day, my colleague and I returned to London by Aer Lingus one day later. (No passengers whatsoever are permitted on ferry flights, even expendable ones like me).

Dude :O

Odd question this which requires a bit of background to give authenticity.

When I could afford to fly R22s from an airfield neat Stratford on Avon the Heli company’s owner’s son attended some kind of auction of Concorde parts and came back with part (or all) of a Concorde rudder which was duly mounted on the hanger wall.

I gazed long and hard at it (closest I ever got to the supreme lady) and noticed a series of mysterious ‘bolts’ sticking out of the rear edge of the rudder. One of the helicopter engineers present rubbed his beard thoughtfully and surmised they may be ‘static wicks’ – but nobody present was really sure.

All this of course went straight over my head but whilst they were all on tea break I managed to chip of a couple of flecks of deep blue paint from the rudder and stash them in a match box. (Back in Birmingham later that evening I sat with friends in the garden of the 'Rose and Crown' and we all touched reverentially those paint chips that had been places we could only dream of – but I digress).

What were those bolt like things on the trailing edge of the rudder?

OK Dude, thanks very much for that. Extremely interesting, I assume that there must have been some sort of fuel control failure for a sub-idle N2 to establish with the engine lit.

I've never heard of this phenomenon before, although I know that some fairly odd things can happen in helicopter rotors where the air below the rotor can be pulled around by the passing blades which sounds vaguely similar.

What steps were taken to prevent his happening again? Modification of the fuel control scheduling or something else?

Cron
Sounds like the helicopter engineer's guess was right, they'd be the static wick mountings.
Feathers McGraw
Yes there was, that was the problem alright Feathers. I'd only heard an engine stuck in rotating stall during startup once; even on the flight deck it sounded like a tom cat with his gonads trapped in a vice, and we shut the thing down straight away. (The engine, not the tom cat :ok:).
It was mainly a case of increased vigilance during engine start; it was always noticable to see rotating stall clearance on startup as the N2 went past normal idle and then rolled back. As far as modifications go, I'd designed a modification to detect and alert the crew if rotating stall had not been cleared on startup, but it was felt to be too costly and complex, when increased vigilance by all could prevent the nasty event happening in the first place. (I suppose only one BA occurence in 27 years is not so bad, and if the automatics did their job you had no problem anyway). But now at least EVERYBODY was aware of the malignant consequences of not clearing rotating stall on startup; it was no longer just a phrase that we all learned in training, but scary reality.

Dude :O

Does anyone know what happened to the pilots that featured on the ITVV Concorde video?
There's a preview here (I think it only lasts for this Sunday though)
ITVV British Airways Concorde Preview :: ITVV

Rotating stall.
 

Sorry Dude, I'm behind on this again. :uhoh: I must be in the hard of thinking class on this. Would you just confirm - or jump all over :eek: - what I am visualising here please?

Due to some quite esoteric disturbance in the area where fuel first hits compressed air, the flame front either detaches from the nozzles or establishes some way downstream? As far, indeed, as the turbines with a very hot (too lean?) mixture that damages the blades? Is that anywhere on the right track? :)

The closest analogy I can think off is with a plumbers blow torch, where the fuel pressure/temperature is disturbed while lighting it. The flame detaches from the burner and exists - usually briefly - up to an inch from where it ought to be, often with a very harsh, high pitched roar. I've seen it happen with my oxy/acetylene torch on light up as well, but only briefly and it usually goes out.

Roger.

Landroger
Good to see you here again Roger, I'll try my best to give you my take on rotating stall. (I worked very closely with Rolls Royce in the Concorde days, and everything I know about the process is thanks to them). Turbine engine combustion is a precise and delicate affair, particularly during start, and too much or too little fuel can cause severe problems. With rotating stall, the rotating cells of stalled air. if they manage to take 'hold' can cyclically choke the flow into the latter compressor stages (it's the cyclic nature of the cells that is the real problem, hence the 'rotating' stall term). The cells as they 'hit' the compressor blades (the cells are rotating at half shaft speed in the opposite direction of shaft rotation) can cause blade vibration and can also cause minor surges within the engine. The combustion fire literally can burn in the turbine section, but any distortion to the combustion process will result in local overheating, due to poor air/fuel mixing etc. In some engine types, damage can be also be caused to the HP compressor blades (due to vibration) but with the Olympus the main danger was to the turbine blades and stators. It's difficult to relate to any common analogy for this lot I'm afraid Roger.
Rotating stall was avoided in the Olympus by starting the engine with the primary nozzle driven wide open, and controlling two parameters; those being the opening rate of the fuel valve and the rate of rise of exhaust gas temperature. (During the start sequence, once ignition had occured the EGT rise was held to 6 degrees per second, right up until rotating stall clearance at 65% temperature corrected N2 ). So the engine accelerates without let or hinderance right through the danger zone, but was prevented from dipping below 65% temperature corrected N2, where the danger zone starts again. (Absolute minimal idle for the Olympus 593 was set at 61% N2).
I sincerely hope this blurb helps Roger, if not then feel free to ask again or PM me.
Regards

Dude :O