View Full Version : Flight Instrumentation - Concorde...

5th Mar 2009, 11:36
I was recently watching a 'You-Tube' video of Concorde and was wondering -

The old analogue panels really show the age of the technology even though it managed to stay at the forefront for a long time. I wonder if they remained the same until retirement?

Can anybody help here please??

Cheers fom OZ....:ok::ok:

5th Mar 2009, 12:03
Search for concorde cockpit photo's and you will see the museum examples.(They remained as built)

Electro-mechanical instruments are still used in lots of older (pre 1990's) airliners and freighters.

Our A300-B4 freighters have the original instrumentation. The NAV kit has been upgraded with GPS based FMCs and some of them have EHSIs fitted.
The reliability of these instruments is not as good as EFIS but the cost of refitting these A/C would be more than they are worth.

Hope this helps.

5th Mar 2009, 12:31
It was a long time ago, but when I worked at GEC Avionics I came across some old circuit boards in a cupboard. When I asked what they were, I was told they were circuit boards from Concordes avionics, but were at that time obsolete. The boards I found were basically 2nd generation computer components. Such machines used discrete components, like transistors, very little more complicated than that, and were probably analogue computers.

The replacements were 3rd generation technology, i.e. all the discrete electronics were replaced with with integrated circuits, like op-amps, discrete logic chips and likely the odd early microcontroller or even an 8-bit processor. The change reduced the size of the avionics, plus its power requirement. Reliability no doubt was improved as well, and being digital were also going to be easier to setup and calibrate.

This was in 1986, which if you think back was when 8-bit home computers were new and expensive toys. Programming and design work was carried out on huge Vax mainframes. We had a couple of BBC Micros that we were tinkering with to see if it would be possible to ship software updates for Airbus via a modem link, rather than flying people back and fore with EPROMS in their baggage.

5th Mar 2009, 12:36
I meant to go on but submitted by mistake! Anyway...

Display technology was still basically small modules with dials. Externally they looked all the same, but the modern stuff the needles were being moved by servo-motors controlled by this newfangled 3rd generation computer tech'. I was involved at the time with a new plane called the A320, and this meant glass cockpits and fly-by-wire was only just making a major break into the commercial market.

So for Concorde although the computing part of the avionics was massively upgraded at some point, it is likely that most of the dials and switches did not need to change. It would be difficult to perceive much difference just by looking, as most changes were behind the scenes.

5th Mar 2009, 16:42
I did Concorde flight test support for the Elliott/SFENA AFCS at Fairford and Filton from 1969 until 1974.
These last few years I've been sticking my nose back into Concorde documentation, systems etc., among other things to help out with the restoration of the flight sims at Brooklands and Toulouse.

The vast majority of the Concorde panel instruments have remained unchanged from the original production fit in the early/mid seventies until the final flights in 2003. True in particular for the 'iconic' ones, like the ADI, HSI, ASI, Machmeter, VSI, engine instruments, and suchlike.
Most go back even further: the cockpit of the first preprod (Concorde 01) aircraft which flew end 1971, already looks very familiar compared to a production aircraft.

There were changes and updates, but they concerned relatively minor items.
The main one was the TCAS (the only 'glass' instrument) which became obligatory somewhere in the nineties, and led to a few instruments being shuffled about.
IIRC the clocks were updated at some point from semi-analogue to fully numerical displays.
The weather radar was updated at BA to preserve commonality with the rest of the BA fleet.

You really needed to be an insider to notice the differences over the years.

The SFENA ADI and HSI (the two "big 'uns") on the A300B are to all extent and purposes identical to the ones on Concorde. You had to look at the identification plate on the back to know which one you had in your hands.

So for Concorde although the computing part of the avionics was massively upgraded at some point....Negative!
In particular the AFCS (autopilots, autostab, autotrim, artifical feel etc.) computers that were in place at the end of service in 2003 were the same as those installed in 1976. And everything was fully analogue.
About the only digital "stuff" on Concorde was the core of the INS, and the AICS (air intake control system).

The latter was an amazing piece of work. It was designed in a hurry by the BAC Guided Weapons division around 1972 or so, before any aircraft-qualified microprocessors even existed. Imagine a few boards full of TTL logic chips for a CPU, forty-two 512-bit PROMs for program memory and look-up tables, a minute amount of RAM, and a huge ADC and only slightly smaller DAC.
There were eight of them on board, and it was the top scorer for unscheduled removals.
Never upgraded... it would have been far too expensive for a fleet of only 16 aircraft.
When at some point it became totally impossible to source ADCs for repairs, the ADC/DAC board had to be redesigned to accept a different model, requalified and recertified. In all, including the manufacture of a new set of spares, the bill came to over 2 million, and that was only for a single board.

I've had the rare chance of flying on one of the last flights before retirement, and seeing, during a very brief cockpit visit, that everything I had helped develop thirty years earlier was still doing its job, unchanged....!


PS: Oh and... MacBoero, Concorde was fly-by-wire as well (there was a mechanical back-up, but it was almost never used in anger). But at that time we still called it "electrical signalling". And since you worked on the A320, did you know the first tests with a side-stick were done on.... yes, a Concorde!

12th Mar 2009, 18:01
I didn't know sidestick tests were done on Concorde. Was that testing for Airbus, or a rejected idea for Concorde?

12th Mar 2009, 18:17
I didn't know sidestick tests were done on Concorde. Was that testing for Airbus, or a rejected idea for Concorde?It was strictly testing for Airbus when the A320 started to loom on the horizon.

Not sure which aircraft it was (can look it up if you're interested), but it was either F-WTSA (02) or F-WTSB (201).

It would have made little sense to retrofit it on Concorde, too far into production already.

But since Concorde was already flying at that time with mature fly-by-wire/electrical signalling, it was a logical choice for the tests. It was fitted only on one side for the trials, the other side retained the conventional controls.


PS : according to a quick check on other sites, it was F-WTSB (201), the French certification aircraft, now on display at Toulouse Blagnac.

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