Primarily for general aviation discussion, but other aviation topics are also welcome.
#1796291
Since our Annual (April 2020) both the Autopilot and R fuel gauge are inop. They both worked well before annual and there is some tension ascertaining cause and effect (Much fiddling with aileron cables and tanks out at annual).

Engineers have been consulted and just resulted in much tooth-sucking. Quick look at gauge fails to determine problem, so it's a 'tank out' job.

Problem is group groundswell , while happy to get A/P fixed sooner rather than later(usually a struggle as I'm the only group member that uses but our new member BA A320 F/O hopefully will want to use it) , is 'I don't give a toss about fuel gauges, they're inaccurate anyway', leave it till next annual (April 2021)..

And its looking as though I'm going to be in a minority to get fuel indication fixed anytime soon.

I don't subscribe to the 'the gauges are inaccurate anyway, so I don't give a terpenny ferk ' theory: There is a world of difference between an inop gauge and an inaccurate gauge which at least moves and indicates the presence of fuel slopping about in the tank. And yes, I dip the tanks before flying.

We don't have electronic engine management / fuel flow monitoring systems so its a bit hit and miss.

I find I'm spending a disproportionate amount of time logging time on dud tank, counting down fuel usage etc while there's plenty else to do esp. flying IFR.

How long do forumites leave a zero fuel tank quantity reading before getting it fixed?

(Not diagnosed yet: Sender/wiring/Gauge itself?)

Or are you happy (unlike me) to see 'INOP' stickers plastered all over the place for long periods?

Am I being oversensitive? : In 25 years of flying the old girl I've never seen an 'INOP' and now all of a sudden they're all over the place .

Peter
Last edited by PeteSpencer on Tue Sep 15, 2020 12:04 pm, edited 2 times in total.
#1796302
I only use fuel gauges to cross check if my fuel calculations are correct (calculations done in minutes assuming worst case fuel burn) and i switch tanks to manage load imbalance to minimum and minimise force i need to apply to ailerons (so if it is just me flying, left tank is used first)).

Assuming source of the fault is known and it will not affect flight safety by causing fire/other electrical issues i would only make sure i have always at least 30 minutes of fuel left in each tank individually and go flying as normal however i do have a fuel flow meter to ensure my fuel burn calculations are correct.
#1796308
Early Rans S7s have direct reading tanks, no not a sight tube, but you can see the translucent ends of the fibreglass tanks in the wing roots. Difficult to get an accurate reading in flight, particularly as fuel diminishes and sits in the rear of the tanks and the pilot sits well forward.

Top Tip - Unsure if you've got much fuel left? Push the stick forward and it all comes sloshing forward to where you can see it.

Until, going for a short local 15l in the right, 10 in the left.

Take off, is there a slight smell of fuel? Look around can't see anything leaking or disappearing into the slip stream. Push stick forward, plenty in the left, not so much on the right. Engage ageing brain to convince myself that 5 mins ago there was more in the right than the left. Another brain cell says "TURN BACK NOW!!" Apply left aileron and as the right wing rises, a significant quantity of fuel comes out of the wing root and onto my lap.

Each tank has a forward and rear take off point, and some kind person had in the recent past fitted chunky good quality black rubber hose to the right front giving no cause for concern for its condition. Unfortunately somewhere out of sight they had connected it to the original 25 year old plastic tube (which cannot be seen until you cut a hole in the wing to effect the new connection to the tank outlet) which had finally given way.

OK, perhaps a failed fuel tube emptying your tank is a rare occurence, but there are enough variables in flying to make it sensible to eliminate those that you can. Even an inaccurate gauge will hopefully tell you if a tank is rapidly emptying.

Suggest you tell the reluctant shareholders to cough up or take up knitting.
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#1796309
I am trying to recall if I have ever had an aircraft fuel gauge that was worth the effort of looking at. The Yak had two columns of lights that disappeared at a fearsome rate. Basically you were in danger of running out shortly after taxiing from the pumps.

Since then nothing that could be described as functional. But the RV now has a very accurate engine monitor that gives you the choice of readings from each tank's sender, or a virtual fuel tank that is deadly accurate, driven by the flow meter. This will inform us to the nearest litre or so exactly how much fuel remains, it just doesn't tell us in which tank that fuel is hiding.

I must admit I wouldn't like to be part of a group that is adverse to spending money on the aircraft it owns. We are custodians and it's our job/duty to leave the aircraft in better condition than we acquired it.

Rob P
#1796318
[quote="PeteSpencer"
How long do forumites leave a zero fuel tank quantity reading before getting it fixed?
[/quote]

The fuel gauge on my Moth hasn't worked for years. I think that the float has become un-bouyant (if that's a word). I've just got used to always dipping the tank.

In my Arrow the fuel guages 'work' but I would never trust them. I once ran one tank down to splutter-point and I was amazed how far off the end of the scale the needle got before that happened. So I regard the fuel gauges as just part of the 70s period decor, to be honest.
#1796319
Our old analog guages on the RV failed last year. Bizzarly it was the guage itself that failed and both senders were fine. We cleaned the resistive track up on senders and fitted both a fuel flow meter and red cube and new digital guage and calibrated. Both of these have proved extermely accurate and are with in 2-3 litres or so of being spot on. Coupled with dipping the tanks and knowing the aircrafts consumption I'm not sure we could improve.
It is very reassuring to know you have accurate guages but also helps confirm your mental arithmetic backup plan.
I
Rob P, Highland Park liked this
#1796328
I agree accurate dipping/fuel consumption knowledge is essential:
After yesterdays flight following top up I dipped the tanks:
Showed 71 L remaining against my calculated 68.5L so not a bad discrepancy and in my favour.

But still a faff and one has to ask if fuel gauges are so 'kin bad, why are they fitted at all.

Peter :roll:
#1796337
PeteSpencer wrote:I agree accurate dipping/fuel consumption knowledge is essential:
After yesterdays flight following top up I dipped the tanks:
Showed 71 L remaining against my calculated 68.5L so not a bad discrepancy and in my favour.

But still a faff and one has to ask if fuel gauges are so 'kin bad, why are they fitted at all.

Peter :roll:

probably when they were fitted they weren't that bad but with average age of the GA fleet things have deteriorated. The resistive wirewound track on the sender will now be dirty and also the spring that rubs on it is probably worn as well. our aircraft only 14 years old but the difference in readings after cleaning was very apparent with dead spots gone as well
#1796347
David Wood wrote:
PeteSpencer wrote:
But still a faff and one has to ask if fuel gauges are so 'kin bad, why are they fitted at all.

Peter :roll:


Err, like the heater/demister, the fan, the instrument lights... one could go on! But hey at least it has an ashtray.



And a fag lighter socket. :wink:
#1796387
Rob P wrote:I am trying to recall if I have ever had an aircraft fuel gauge that was worth the effort of looking at. ....<big snip>
Rob P

You have flown with me, Rob, and mine was pretty reliable! Cork on a wire!


(Image shamelessly stolen from the internet, and it's a J3 Cub but it has the same cork/wire fuel gauge principle on the front tank as I do on my Taylorcraft) :D
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