£1000 to make a Spitfire aircraft fuel tank gauge. Can it be done cheaper?

Just started watching Spitfire factory on channel 4. I saw that making your own Spitfire fuel tank gauge system would cost around £1000. The part looks relatively simple. With the right machines etc could it be done cheaper and would this part have to be made of aviation grade aluminium?

Most of the cost will be tied up in paperwork. Both getting approval for the replacement design with substitute materials for those no longer available and traceability documents for the new parts. A fuel gauge will be very much a safety critical part, so subject to the most stringent regulation.

What do you think 'aircraft grade aluminium' is??

A much abused term!

Aircraft grade alloys will meet certain specifications and have traceability documentation verifying origin, conformance and batch.

I think around £1000 is a bargain price, as Stuart says most of the cost is in paperwork as an example a certificate of conformity for a piece of metal will add about £30 to the bill, you may need a couple of springs, about £1.50 each plus again £30 for c of c, it doesn’t take long to run up a fair old bill. Problem is it’s £30 for two springs or two thousand springs, same for a bar of brass, one length or fifty lengths from the same batch, the price is the same.

We used to mark up our own gauges at Boscombe Down for the Flight Test Instrumentation installs. Lots of matt black paint, lettraset and swearing. As mentioned, it will be the paperwork that generates the pennies.

Cambridge just paid 2.5 million for a roundabout so £1000 for a spit fuel gauge is nothing. There was nothing wrong with the old one either

regards Martin

Making parts for old aircraft is not easy, especially if they need to be covered by a CAA (Civil Aviation Authority) airworthiness certificate.

The design has to be as per the original, the materials have to conform to the original specification; 'better' materials cannot be used. All materials need to be certified and provided with approved certificates of conformity traceable through all stages of manufacture etc etc.

Cheap it is not.

Brian

As the saying goes, if you think safety is expensive, you should try having an accident.

Here's another way to think about it - which scenario would you rather be in?

You are a pilot flying a precious and priceless Spitfire in 2020 on a long flight. You are close to the destination, and you suspect you are probably getting low on fuel from your knowledge of flight time elapsed and the usual fuel consumption per hour. There are no closer alternate fields to land on. Headwinds are increasing so your consumption rate is rising. You know it will be a close thing to get onto the field. It is VERY important to know exactly how much fuel you have. Your survival and the aircraft's survival depend on knowing the fuel status.

Scenario 1: someone fitted a 10 UK pound fuel gauge to the aircraft, with minimal reliability engineering and a quick works / does not work QC check. Mean time before failure is not specified. Service life / replacement at X hours is not specified. Some automotive components were used, to keep costs low. Only key components are traceable back to raw materials, but many components are not traceable.

Scenario 2: someone fitted a 1000 UK pound fuel gauge to the aircraft, with well designed components intended for aircraft use, and the whole system thoroughly tested for reliability and quality control. The components come with a manufacturer's service and inspection plan to ensure the unit works and keeps working safely for its' service life, which is also specified. Every component is fully traceable back to raw materials. Hundreds of people have inspected and signed off on every stage of the unit's design and construction and testing.

A no brainer, really.

Edited By Jeff Dayman on 13/10/2020 02:09:12

Way back when, a colleague and family was flying in a 767 that had fuel gauge issues, and glided into Gimli Manitoba. They got on at the stop in Ottawa, and were flying out to see parents, etc.

It had zero working gauges (allowed at the time) and the tanks were not properly dip-sticked.

So, maybe a known-accurate fuel gauge, with the associated cost, on a priceless aircraft makes sense, despite the initial "wait a sec- I could give them a bargain and make 2 for that price" thought!

If you fit a 1000 quid part and the plane crashes it costs a million quid and the government clergy get 900 quid

If you fit a 10 quid part and the plane crashes it costs a million quid and the government clergy get nowt

Which system do you think the government clergy will prefer in a plane?

Free welfare for life is a powerful incentive

If you had not got enough fuel would it have made any difference ? Knowing that you have just run out of fuel ain't going to make life any better.  You would have still not made it to the airfield & you admit there is no alternative airfield.

Edited By Sam Longley 1 on 13/10/2020 09:00:44

Safety costs. Speaking as a passenger I don't begrudge it. It's only through an unrelenting focus on quality than air travel is as cheap and safe as it is.

Good point, except it ignores when the pilot gets to know he has a fuel problem. A reliable fuel gauge gives plenty of early warning so the pilot has more time to think. A dicky gauge is more likely to spring a crisis on the pilot. As most air accidents are caused by pilots getting it wrong, especially when confused by conflicting instrument readings, it's safer to fit gauges that work.

Dave

Apart from the quality/certification costs mentioned above, there's also the simple fact that producing a one off or in very small numbers tends to result in very high unit cost.

I would have thought that second hand gauges would be available. Still need testing and certifying but a lot cheaper than making one.

Brian

Even though he might have a second hand one it would still be stripped and parts checked/replaced and then tested for reliability, finally it would also need to be certified.

I spent several years as a volunteer at Duxford working on the Museums then Mary Alice B17G, we were restoring her to a static exhibit but were still required to maintain the work exactly as if she was to fly again, with exception of the engines everything else worked.

Martin P

Relying on fuel gauges in a light aircraft is a mugs game anyway. You check what's in there by looking in the wing. You know what you have when you start and you know what your burning. Then you know how long you have left. They're handy to tell you if its leaking out and thats normally about all.