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Heritage Concorde - Project Return to light

Report on how the Heritage Concorde team switched on the Cockpit lights of G-AXDN at DAS Duxford for the first time in 37 years.

Background: The project started when we attended our first core members meeting at Duxford late in 2012 in attendance were Graham Cahill, Steve De Sausmarez (Founder of Heritage Concorde), Ian Mosdell, John Dunlevy and Gaute Lund, we spent about 5 hours walking around the aircraft and discussing how Heritage Concorde could look to the future and for Steve to hand over operations to Graham.While we were in the cabin of the aircraft we must have been talking quite loud but a Duxford Aviation Society (DAS) volunteer approached us and asked for some history of our group, of course Ian, and John were more than pleased to give some history of both Heritage Concorde and G-AXDN. We were lucky in that the Chairman of DAS, David Garside was also on the aircraft, we were introduced and he allowed us a visit to the cockpit.

The conversation quickly turned to how Duxford Aviation Society (DAS) wished to improve the visitor experience which included powering the cockpit lights among other things (this had been attempted but had failed). Steve asked John if it was possible and we offered to do the job for free (as usual), after some correspondence we agreed a date for the work to commence. 

Heritage Concorde and Duxford Aviation Society were both in agreement that any projects involving G-AXDN have to be within the relevant Health and Safety requirements.In the case of the instrument lighting originally the power supply to the transformers would have been 115Volts AC at
400 HZ and considered to be a potential risk for the viewing public.(inquisitive little fingers e.t.c) 

On the 21st of March 2013 Heritage Concorde had planned another core members meeting and also planned to attend the DAS with a view to inspecting the wiring on the aircraft. We met with David Garside at 11am and had a brief discussion, by 11.30 am John Dunlevy, Ian Mosdell, Chris Giles and David Garside were in the cockpit of G-AXDN working to get the lighting switched on, it was quite cramped so the engineers were left to do their work. Before we knew it panels were being removed and wiring being inspected it was truly fantastic, John was so pleased to be reunited with the aircraft he spent so long working on in the early years. Below are the thoughts and notes written by John on the project.

Day one of work (21/03/13)

​​In attendance : Graham Cahill, John Dunlevy, Ian Mosdell, Gaute Lund


John Dunlevy’s report and thoughts on Heritage Concorde project “Return to light”


With kind permission of Duxford Aviation Society at IWM Duxford, Heritage Concorde core members were invited to be aboard Concorde

G-AXDN on the 21/03/2013 to bring about the Return to Light Project.

The DAS have decided that to improve the visitor experience it would be fantastic to have the cockpit instrument lighting plus the various crew station warning caption lights operational once more.

On arriving at the aircraft around 11.30AM John Dunlevy and Ian Mosdell began the detailed and comprehensive inspection of the circuitry and contactors associated with the main aircraft batteries DC supply, specifically Bus Bars, 1PP, 2PP, 3PP and 4PP, together with the Essential Main Split Components.Individual connectors on the instrument panels were removed to check for corrosion and overall condition.

We were both totally amazed to find that the connector’s pins/sockets were in a perfectly serviceable condition together with the associated contactors and wiring looms


In Main Battery "B" location, DAS fitted a suitable 28Volt power unit that replaces the need to fit either of the two main aircraft batteries.This unit was checked for correct connection to both Main Battery DC Busbars. With the complete agreement of the DAS volunteers present, David Garside and Chris Giles all relevant circuit breakers required to operate the various panel lighting, flood lighting and lights test facilities were tested for correct operation and serviceability before being pushed to arm. Again with the authorisation of the attending DAS volunteers the supply power was selected ‘ON’

As can be seen from the accompanying photographs the results were truly amazing for an aircraft that has not had its crew station lighting operational for nearly 40 years.
There are a few lamps that need to be replaced during our next visit but I have some spares to hand that can be of use.The DAS volunteers were totally delighted with the result and on special occasions can now safely show the result. The next stage will be to create a power supply to enable the operation of the internal instrument lighting which is normally supplied via 50VA, 100VA and 200VA transformers.
It is not intended to apply ground power to this aircraftbut for now DAS are delighted with the enhanced flight deck experience
A truly exciting day at the office again.
  John Dunlevy

John Dunlevy next to some of the wiring he installed when the aircraft was being developed.

The next stage
The Heritage Concorde team had been discussing the possibilities of how to safely return the instrument lighting back to life, with the help of Laurent and the team at Le Bourget and much discussion we decided that the safest option was to power the instruments using a 5v power supply to replace the job the original transformers did when the aircraft was in service.
Below is a production Component Location Handbook however, as a guide it has been found extremely useful for locating the lighting transformers on G-AXDN.John identified the associated transformers in various colours to clarify their purpose and location.Transformers 1,2,3,6,7,and 8 are the important instrument lighting transformers for Return To Light.Transformer 5 (Back lights the Pilots Roof Panel) is strangely located at the Flight Engineers Station and was connected to the 5V PSU as an added bonus.
Transformers illustrated as 5 and 6 (Left) can be seen in the photograph above. Transformers 7 and 8 are to the right out of shot. Below you can see all transformers
John meanwhile had calculated that the power unit to cope with the loads involved powering the instrument lighting on the Flight Engineers panels would have to have the following specifications;
5Volt DC single output, 90 Amps, 450Watts, Built in safety overload and thermal protection.
John also determined the cabling specification would be rated at 50Amps.The power unit was ordered from the U.S.A. and 15metres of cable plus a numerous variety of cable end crimps and cable ties purchased.
Once the power supply had arrived we arranged another visit to Duxford to look at the wiring and install it in the aircraft.
(Day two of work) 8th May 2013
In attendance : Graham Cahill, John Dunlevy, Gaute Lund
John spent most of the day gaining access to the transformers which were buried behind the engineer’s desk and document storage panels. During the removal of the engineers desk and document panel we found a Flight test document last seen in 1976 (pictured below) which had slipped behind the document storage compartment, this was handed to DAS.
After quite an effort the transformers were exposed.
The existing transformers were stored by DAS for re installation on a further visit to make safe the 115 volt supplies in case in the future the aircraft were to have ground power applied.
John spent quite some time inspecting the wiring on the aircraft and cleaning various connectors to make sure it was safe to apply power to the instruments, most of the plugs were removed from the instruments and cleaned, the wiring was found to be in excellent condition. A visual check was made to the wiring to ensure safety.
Inspections included testing the insulation on the wiring, visual inspection of the plugs, continuity checks on the lighting circuits and a general condition inspection. John was more than pleased with the condition of the wiring.
After fully testing the wiring the new power supply was temporarily connected to the engineers panel lighting and this was the result. We found that the fuse protection boards John had supplied were excess to requirements because we had found the original lighting transformer output side fuses (all rated at 5amps) to be serviceable in operation so the fuse boards were not installed. They remain available for any future use for any failures as original specification fuses are unlikely to be obtainable.

It was close to the end of the day (5.30pm) so we removed the power supply and re assembled the aircraft ready for cockpit visits. The DAS volunteers were more than happy with the progress that day.

(Day three of work) 4th June 2013

In attendance : Graham Cahill, John Dunlevy


Graham Cahill’s account of the day


Today John powered up the remaining panels on the engineers station and I spent the morning meeting with the DAS volunteers discussing other issues, my afternoon was spent preparing access to the centre console transformers (With the guidance of John) in readiness for our next visit.

It was a true pleasure to spend the day working with John and he spoke often about the history of the aircraft and how he loves them so much.

Access was a problem and I understand how the engineers had such a love hate relationship with this aircraft, G-AXDN’s cockpit seems significantly smaller than the production cockpits because of all the extra equipment and different seats so it was very cramped by the time we had he tools, light, fan etc in with us. John soon had the engineers panel lit up but he could only light the panels individually we will complete the panel on our next visit.

Here are some of the photos taken today.

Access to the centre console transformers was difficult, the Pilots and co pilots controls were just perfectly positioned so access to the screws was restricted (to say the least) in the picture below (Left) the arrows indicate the position of the centre console transformers which are buried behind the console instruments.

You can see the transformers in the following pictures below.

Click to enlarge

We remove the side panels to the center console (each panel is held on with 10 bolts) to gain access to the transformers

Once the side panels were removed the transformers were more visible as shown below

Here you see the transformer mounting bracket viewed from the Co pilots side

Here you see the transformers on the mounting bracket viewed from the Pilots side

I’m looking forward to our next visit, I really can not wait to see the whole cockpit lit up. It was a really fantastic day. We tidy up and go home for this visit.


Graham Cahill.

(Day Four of work) 3rd July 2013

In attendance : Graham Cahill, John Dunlevy


The day started with a short meeting with David Garside of DAS and then straight to work on the aircraft. John completed the wiring to the engineer’s panel while Graham under John’s instruction gained access to the transformers for the Pilot and Co pilot’s instrument lighting. DAS construct a shelf for the power supplies and fit it. Great work DAS!

It was soon time to test the wiring so we turned the lights out on the flight deck and connected the power supply the results were truly spectacular.

The two transformers for the Pilots and Co pilots instruments lighting were prepared for re wiring on our next visit, we needed to supply another 5 volt power unit for the main instrument panels to be illuminated and we will do this for our next visit.


It has been a very good day we pack up and go home, we have some work to do before our next visit.

Home work

Once again John calculated from his drawings that the second power unit required to power the Pilots dash panels and centre console would have the following specification;

5Volt DC single output, 60Amps, 300Watts. Built in safety overload and thermal protection

Substantially less power required than for the Flight Engineers Panels.

This power unit was ordered from R.S. in the UK.

(Day Five of work) 30th July 2013

In attendance : Graham Cahill, John Dunlevy, Philip Cairns


The task for the day was to get as much of the pilots and Co Pilots instrumentation lit as was possible, install the second transformer wires to the instruments and find the third transformer. After a meeting with DAS we went straight to the aircraft and Philip and Graham were working on other things for the morning. John was in the cockpit all morning preparing the job. In the afternoon Graham joined John while also checking on Philips progress. The wires were connected for the pilot and co pilots instruments and found that some of the instruments failed to light, upon investigation we found them to be disconnected and strangely the instruments were capped off as if they had been serviced or stored which is strange as the aircraft had been flown in to Duxford Perhaps some of the instruments were removed for other aircraft in the fleet or loaned. We found that some of the instruments were from production aircraft and the plugs would not fit.

We reconnected as many of the instruments as possible, after checking part no's we found that some of the instruments in the test equipment on display at the Fight Test Observers Panels in the rear of the aircraft were correct for the Cockpit so we interchanged them and connected them.

We then removed the A.F.C.S.(Autopilot control unit) to find the last transformer, the autopilot is removed by accessing a panel on top of the centre instrument panel and pulling a quick release handle. The autopilot was remove with some encouragement and we could see the last transformer using a Borascope and camera.

Summary of the day.Another fantastic day most of the instruments are now working and now we have found the last transformer we will be able to complete the job. The final wires for the pilots and co pilots side need connecting and the third transformer needs looking at. The production instruments that remain need further investigation to make them illuminate.

(Day Six of work) 13th August 2013

In attendance : Graham Cahill, John Dunlevy, Ian Mosdell


Graham was late today because of traffic jams due to an accident however John got on with the job. Ian was working elsewhere on the aircraft.

The plan for the day was to wire the final transformer so the centre dash and console could be lit, complete the wiring for the Pilot’s and Co Pilots Instruments and investigate further the instruments that were not working.

As said previously some of the instruments were found to be capped off we wanted to investigate these and see if it was possible to re connect them so John started the day with this task. The Co Pilots ADI and the Icovol were failing to illuminate also the Automonitor on the engineers panel was not lit.


Upon removing the Automonitor we found all the plugs had been removed and the instrument sockets were blanked off. The automonitor was an instrument that was tested vigorously and designed to be installed on production variants but BA requested that individual indicators were preferred by their crews. We would need to find a way of lighting the unit on a future visit.


We removed the A.F.C.S.(Autopilot) and also the ADI and Nose switch on the co pilots side and gained access to the third transformer which was held in with four screws, John was just about able to remove the cover plate and wire from the transformer and the wire was crimped and connected to the transformer. The results were spectacular!

The centre console lit just like the aircraft was about to depart to New York.



The next step was to start putting the aircraft back together but before that John inspected and cleaned the nose selector switch

to ensure it was in good condition. All connectors and pins were checked and cleaned using cleaner spray. The autopilot was replaced along with the Pilots center console panel and the rest of the instruments were replaced on the co pilots side.



For the first time we would see the results of our hard work. The power was switched on and the results can be seen left.


It was late and we almost got locked in the hanger so we packed up and left. What a productive and exciting day!



(Day Seven of work) 20th August 2013

In attendance : Graham Cahill, John Dunlevy, Gaute Lund


We needed to neaten up the wiring and finalise the position of the power supplies, in addition we wanted to look at the remaining instruments that failed to illuminate.

Graham spent some hours in a meeting with DAS while Gaute and John continued with the work.

The Auto monitor, Icovol, Rate of climb, the co pilots Artificial horizon, the Mach Meters all needed attention.


We removed 2 x Sideslip indicators, one Mach meter, rate of climb from the Fight Test Observers Panels in the rear of the aircraft and after checking part numbers installed them in the cockpit replacing them with the blanks where possible. It was just stunning to see a working Mach meter in the cockpit both had been removed many years ago.


It was getting late, John had completed the wiring loom for the lights and connected them to the power supplies but unfortunately the ground connection was found to be unsuitable, John was not happy with it so we disabled the lighting until our next visit and tidyed up ready for our next visit. I would like to thank Gaute for his help that day, under the supervision of John he installed most of the missing instruments. Without his help we would not have achieved so much.


(Day Eight of work) 27th August 2013

In attendance : Graham Cahill, John Dunlevy


We agreed to make an extra quick visit to complete the project so DAS could use the lighting for some upcoming corporate functions so we attended as soon as we could to do this.We soon fixed the ground connection issue and added 2 extra for safety, although the instruments were only running at 5 volts the ampage consumed was substantial so the ground connections had to be correct.


To test out the wiring and make sure no issues would arise we powered the instruments for a total of 5 hours that day, we were pleased to see the power supplies doing their job exactly as expected.


To the left you can see John's immaculate wiring and the extra ground connections made to ensure the wiring was going to do a great job for years to come.

We continued to work on putting panels, screws and indicators back in place for the rest of the day. In addition some of the instruments were covered or blanked off from when the aircraft was flown into Duxford so we removed the “In Op” stickers or tape from them so the instruments could be seen fully. The attention to detail paid by John was second to none.

We connected the 28volt power supply which runs along side the 5 volt supplies so we could illuminate the entire cockpit and here is the result.

To the left you can see the captions and instruments are illuminated. Right a full view of the Cockpit with both 28v and 5v on.


Below (Left) you can see some of the instruments which were blanked off with tape on the engineers panel.                                

                                                                Right after we removed the tape


(Days Nine and Ten of work) 1st and 2nd October 2013

In attendance : Graham Cahill, John Dunlevy, Ian Mosdell


One of our core members very kindly donated quite a large stock of spares to us which included an Automonitor and an ASI. We had planned to visit the aircraft again to try to make some of the non functional instruments light up on the Co Pilots side so thought it was a prime opportunity to donate and fit these instruments into AXDN. We swapped the automonitor and fitted the ASI to the pilots side of the aircraft, because the ASI was production and the plugs would not fit John Dunlevy made a custom wiring loom to adapt the unit. Two more instruments were now working.


On the co-pilots side the ADI was still on our list to illuminate, the VSI and Mach meters are missing so we intended to construct illuminating models to replace the photographs currently in place and we ordered a similar ASI from the USA.


Left - Experimental dummy Mach Meter

Middle - The ADI Ready for testing

Right - The ADI now illuminated


John Dunlevy once again constructed wiring looms to suit and the ADI was installed and working on the Co-Pilots side Outstanding jobs to complete .

VSI and Machmeters 3D illuminated models to construct

Await arrival of ASI from the USA and fit on our next visit

Construct 3d non illuminating models of Sideslip (x2) Mach meter (x1) for the monitor position in the rear of the aircraft


Above you can see the Cockpit as we left it after this visit. It was late again and we pack up and finish for the day.


While away from the aircraft


While away from the aircraft dummies are constructed for some of the missing instruments as follows

For replacement of instruments removed from monitor station and put in cockpit as follows

Sideslip x 2

Machmeter x 1

Above Left - Various pictures of the dummies.  Right - Dummy 3d illuminating Machmeter next to old paper dummy.


The ASI arrives from the USA (Left) it looks similar to the ASI in Concorde, the ASI is marked “NOT A CONCORDE INSTRUMENT” so in the future it will not be confused as original.

The plan is to install all of these on our next visit.


We contact Brooklands and speak to Gordon Roxburgh who very kindly supplies two missing instruments for the engineers panel, a discharge valve instrument and a differential pressure instrument. We plan to install them on our next visit.

We would like to thank Gordon and his team for the support during this project the results will be fantastic.


Left you can see the instruments Brooklands supplied.


Right you can see where they will go in the engineers panel.


(Day Eleven of work) 22nd November 2013

In attendance : Graham Cahill, John Dunlevy, Ian Mosdell, Philip Cairns, Tony Morrish


We attend a meeting with DAS 10am to discuss progress then off to the aircraft to continue work.

John starts work by installing the replacement ASI to the Co Pilots side, he makes a wiring loom to adapt the instrument to connect to the aircrafts existing wiring, the instrument is installed in the aircraft.

He then installs the 3D illuminating models which have been constructed by making wiring adaptors to connect to the existing aircraft wiring.

The overall effect is fantastic

Left you can see the dummy instruments installed

Above you see the total effect

Below the Pilots side instruments 


John installs the instruments loaned to Duxford by Brooklands these are the final instruments to be installed in the aircraft.

(We would like to thank Brooklands again, in particular Gordon Roxburgh for the support they have given Heritage Concorde and DAS in this project.)


Left you can see the instruments Brooklands supplied are installed.


Right you can see how it looked before on the engineers panel.


Graham installs the dummy replacement 3D models in the monitor station which replace the instruments removed for the cockpit. This improves the display for the visitor walk through


John makes some final adjustments to the wiring loom so DAS can cover the power supplies and to hide the wiring.The project is completed and we take final photographs of the end result.


(Day Twelve of work) 27th March 2014 (Follow up visit)

In attendance : Graham Cahill, John Dunlevy, Ian Mosdell


We revisit DAS to continue the work on Project Salute, John Dunlevy is required to make various selections for the nose moves in the cockpit but for the most part is free to do what he wishes for the day.


He makes a wiring loom for the Icovol that has been intermittently working and we remove the Icovol from the Monitor station in the cabin of the aircraft. He installs it in the cockpit and it illuminates no problem.



John then investigates the audio warning system and slowly the cockpit sounds are heard in the hanger.

By the end of the day John has most of the audio warning system working and now when the 28v is applied to the aircraft the cockpit rings as if she is about to depart on a flight.

This was a nice surprise at the end of a hard day on the aircraft.

Video of audio warning work onboard G-AXDN at DAS Duxford

Video of cockpit nearly finished onboard G-AXDN at DAS Duxford

John has also replaced some filaments in the gear indicators so they light up nicely now.

It is close to the end of the day and DAS are preparing for a private function so we pack up and leave.

Another project completed by Heritage Concorde

We would like to thank Duxford Aviation Society for the hospitality they offered us during our visits. I have to say they have a wonderful team down there most of whom are unpaid volunteers who do their jobs for the love of the aircraft.

We would also like to thank Brooklands and Gordon Roxburgh who supplied help during the project and instruments for the flight deck.

We encourage all people reading this to put a little extra in the collection boxes on the aircraft when you go to visit so projects like this can continue and improvements be made.

Document Authors John Dunlevy, Graham Cahill

ALL project pictures © Heritage Concorde 2013 (Graham Cahill, Gaute Lund, John Dunlevy)

No copying or unauthorised publication please.

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