Changing fuel gauges.

[bubba070]

We have an aircraft that has part of the fuel indications in US gal and others in Imperial gallons. I have asked for it to be changed but have got an answer back that it cannot be changed due to the original STC being approved under the current configuration. Is this for real? Can we not swap the gauges out so they all read the same?

[CamAero]

What type of aircraft is it?

That kind of optional change is usually found in a Service Bulletin.

Check ATA Chapter 28 of the SBs.

It also could be listed as 'option' on the aircraft's original Equipment List.

Using data provided by the type certificate holder, ie, Service Bulletins or options listed on the Equipment List do not require an STC or the filing of a Major Mod & Repair Form. Just obtain the parts and fill your boots.

However, if you say it was incorporated by STC, you need to have the STC information. Take the info, secure the required parts and remove the STC by returning the aircraft to stock configuration and make the appropriate log entries. Then you need to file a Major Mod and Repair Form with TC to show the STC is no longer in effect.

CA

[bubba070]

Hi Cam

The aircraft is a Turbo Otter with the Walter conversion.

[Heliian]

Which gauges are in which units? I'm not too familiar with the particulars of that conversion but if it's all as per the STC then there is no quick fix.

[bubba070]

There is a header tank gauge that is in US gallons. The original triple gauge for the three main tanks is in imperial gallons and the fuel flow and pressure are in US gallons.

[CamAero]

So the flow, pressure and header-tank gauges were part of the Walter conversion?

If that's the case, I am sure that the DHC-3 main quantity gauge was optional in either US gallons or Imperial. Uncle Sam wouldn't have wanted to be converting.

You just need to find the data.

Could be worth a quick call to Viking.

[Gos]

Imperial Gallons gauges are the original one from the original type design. So You would need a other STC just to change it and it may not exist at all.

The us gallons gauge for the extra tank and us gallons fuel flow meter are all part of the engine mod which is part of a completely different STC.

ALso probably that you would have to change the probe IN the tank if you want a reading in US gallons.


As i say this is probably 2 differents STC. For sure a quick call at Viking would get you all the answer you're looking for.

[black hole]

Some of the Otters that I flew had US gallon guages (triple). Check around, they should be direct replacement.

BH

[bubba070]

I have flown plenty of Otters. Some have had the fuel gauges in US gallons, some in imperial and others in lbs. It has never been an issue changing the gauges. This is the first Water Conversion I have flown and was a little surprised when I was told it could not be changed.

Thanks for the help

[CamAero]

Imperial Gallons gauges are the original one from the original type design.

I highly doubt that Otters sold to the US military were configured with Imperial Gallon Fuel Gauges.

ALso probably that you would have to change the probe IN the tank if you want a reading in US gallons.

Umm - No.

Units of measure are just markings on the face of the gauge. The needle has no idea what it's pointing at.

Might as well be barley-corns for all the internals of the gauge cares.

Furthermore, the DHC-3 uses floats, not probes.

[Gos]

@CamAero.....

Military aircraft are on a other planet in aviation world.


and I was refering at any device who can mesure fuel and is IN the tank when I said fuel probe. Also it can be something more than just replacing the gauges if you want a good reading of the fuel level. US gal, imp gal or lbs are all different and in some case a level pretty easy to read in certain units can be impossible to read in a other one because they are too far apart. For sure it's probably not the case from us gal to imp gal. But still, if a good thing to have the exact reading of fuel in the tank.

[CamAero]

The floats won't make a difference to the reading on the gauges.

Even if the measurement is by weight, the innards of the gauge still do not care what kind of a symbol the needle points to.

I can assure you that DHC wanted to sell Otters all over the world.

There will be a provision for US Gallon Gauges.

[all_ramped_up]

Might as well be barley-corns for all the internals of the gauge cares.

My Otter burns 0.625 stone per moment and that's the way I likes it!