fixed External Fuel tanks and Hot vs Cold starts

[Antix70]

Make a mission with two Apaches in it.

One of them Hot Start with a fuel tank on the inboard pylon, either side

Set the other to Cold Start with matching fuel tank setup.

Enter your external fuel quantity of 230 gallons, and you can not select R AUX or L AUX on the fuel page if you are in the Cold Start slot.

However you can select either in the Hot Start slot.

Edited August 22, 2023 by Antix70

[NeedzWD40]

For a cold start, you have to specify total external fuel in gallons before external tanks can be used.

[shagrat]

Just looked at a "conversion table" for aviation fuel... You imperial guys do take a lot of drugs, don't you?

Are we talking US gallons or Imperial, I guess US? Then 50 lbs is 7 Gallons, but 100 lbs is 16 Gallons and 200 of course is 30 Gallons not 32 and 300 lbs is 46 Gallons? Why is even the fuel handled in different measurements in the same(!) aircraft?

Doesn't that beg for mistakes endangering service members?

And even if nobody cares about the monkeys operating the controls, the aircraft isn't exactly cheap, either.

[Raptor9]

32 minutes ago, shagrat said:

Why is even the fuel handled in different measurements in the same(!) aircraft?

Refueling facilities and services operate by volume, not weight. And since the external tanks don't have a fuel sensing probe to calculate the fuel quantity, the refueling personnel can only tell the aircrew how many gallons of fuel they've pumped into each external fuel tank.

Different fuel types have different densities, therefore slightly different weight per volume. If the fuel type is set to JP-8 on the FUEL page, the aircraft performs the conversion for the crew, but the crew still needs to input how much fuel (in gallons) has been pumped into the external fuel tanks.

However, since the external fuel tanks in DCS AH-64D are always loaded and then filled with 230 gallons of fuel, just multiply 230 by how many tanks you have installed, and input that into the FUEL page. Easy. Now, if you want to figure out if you can physically take on the weight of the additional fuel, given the environmental factors, just multiply the total number of gallons you plan to take by 6.7 (the weight in pounds of each gallon of JP-8).

32 minutes ago, shagrat said:

Doesn't that beg for mistakes endangering service members?

And even if nobody cares about the monkeys operating the controls, the aircraft isn't exactly cheap, either.

Professional aviators aren't stupid, nor are they like the fighter pilots in the movies with the cool sunglasses and the scarf waving in the wind, hopping into their cockpit and simply taking off into the sky. If an aviator spends years learning complex aerodynamics, procedures, weapon systems, munition ballistics, tactics, etc, simple arithmetic is not going to be a hard thing for them to do, nor is something so rudimentary as performing fuel calculations prior to takeoff going to be what causes them to crash.

[NeedzWD40]

59 minutes ago, shagrat said:

Doesn't that beg for mistakes endangering service members?

@Raptor9 has already answered sufficiently, but take a gander at the AH-1F manual (distro A, TM 1-1520-236-10) and note that the back section is filled with charts, data, and formulae for the crew to utilize as part of pre-mission planning. I'm not sure how easily it's found as I have a hard copy of it, but the Aviator's Handbook (FM 1-400) is a pocket guide to assist aviators with everything from planning, procedures based on environment, fire support calls, survival, to fuel types converted to civil equivalents. These are all made for aviators (and crew) that have gone through a rigorous multi-year training program to ensure a baseline competency. Consider also that the US Army has a vast number of aviators that were previously enlisted crew on the same airframes they fly and as a result they also have a deeper technical understanding of the aircraft.

All this means that the larger problem becomes one of typical human factors like complacency, in which case it wouldn't matter what kind of automation or fail-safes are put in place as people will bypass those anyways - like using a sledge hammer to pound a threaded bolt into a computer cover on a USN carrier (true story).

[shagrat]

vor 1 Stunde schrieb Raptor9:

Professional aviators aren't stupid

That's not what I meant, or was remotely implying, but from most if not all accounts I came across, after let's say 3-4 months into deployment fatigue and constant stress all take their toll.

What puzzles me, is these simple things, that under high stress levels and urgency, combined with fatigue isn't this little detail something the designer of an aircraft want to omit?

I mean, yes you can do the math, but why add this risk, instead of consolidating measures. Just because you can simply do some arithmetic to get things going, it does not have to be a good idea. I always thought, especially in military aviation the goal is to minimize the risk and give the guys the best chance to achieve the mission goal.

No offense meant, just my personal thought on "on-the-fly" conversion under high pressure.  

[shagrat]

vor 50 Minuten schrieb NeedzWD40:

note that the back section is filled with charts, data, and formulae for the crew to utilize as part of pre-mission planning. I'm not sure how easily it's found as I have a hard copy of it, but the Aviator's Handbook (FM 1-400) is a pocket guide to assist aviators with everything from planning, procedures based on environment

There's a lot of the generic declassified stuff available (even from Amazon) and for "mission" planning (in DCS) I actually prefer the trusty CR-3 most of the time.

With multicrew it's even viable to hand over controls and grab paper charts and recalculate some legs, but why would you not consider to simplify those tasks when designing the system? At least the option to enter both volume and weight... Well, in the end it is how it is. Guess, today the developers of the Apache systems would do a lot of things differently, anyway.

 

[Raptor9]

38 minutes ago, shagrat said:

No offense meant, just my personal thought on "on-the-fly" conversion under high pressure.  

No offense was taken.  But I think you are over-estimating how complex of a process this is, or when the process is being undertaken. Aircrews are not doing fuel volume->weight conversions "on the fly". They are sitting on the ground and simply inputting the number of gallons that the refueling personnel have pumped into the external fuel tanks, which the avionics automatically adds to the total fuel weight, based on the selected fuel type.

21 minutes ago, shagrat said:

At least the option to enter both volume and weight... Well, in the end it is how it is. Guess, today the developers of the Apache systems would do a lot of things differently, anyway.

If the fuel input was required to be in pounds, then that would require the aircrew to perform a manual conversion. This method removes that step, and let's the aircraft do it. The developers of the Apache wouldn't change this, because doing it how you would suggest would make it more complicated and add greater chance of a mistake. I don't think the video game experience of a real-life aircraft is an adequate determination of what a real-life aerospace company would or wouldn't do.

Also keep in mind, that this is just for the external tanks, which are only intended for long-range ferry flights. So even though the 230-gallon ERFS tanks have been used on some combat missions in the past out of necessity, it is not something that you would use on long-term deployments where crews are suffering from chronic fatigue. Further, the fuel is still getting pumped into the internal fuel tanks which do have their own fuel quantity sensors so you know exactly how much fuel you have internally for several more hours, and there is also a sensor in the external fuel tanks that indicate when the tank is empty. It's not like the aircraft is going to suddenly flame out because the aircrew thought there was still fuel in the externals.

The only calculations the crew will need to do is for aircraft performance planning for how much weight they are taking on, and how that affects their range or station time. But that is something that the aircrews already do every day from the first day of flight school and throughout the rest of their career. This isn't rocket science, or something that is only done every once in a while, this is part of the job and is second nature.

[Nealius]

Tank is labeled 230 potatoes so I just put 230 potatoes into the system. No thinking required. 

[Antix70]

On 8/20/2023 at 12:39 AM, NeedzWD40 said:

For a cold start, you have to specify total external fuel in gallons before external tanks can be used.

Yeah, 230 gallons were set in the Fuel page right before clicking on R AUX.

NO EFFECT. It still doesn't work.

 

The R AUX does not work in the mission I'm attaching to this post

You will get R EXT XFER FAIL caution

DESERT_STORM_PRACTICE.miz

Edited August 22, 2023 by Antix70

[Antix70]

But R AUX DOES work in both HOT and COLD starts in the mission I'm attaching to this post, but for the life of me I can't figure out why.

FUELFOLLIES.miz

[NeedzWD40]

3 hours ago, Antix70 said:

The R AUX does not work in the mission I'm attaching to this post

You will get R EXT XFER FAIL caution

I cannot replicate, the right aux registers and ~4040lbs total fuel is reported.

[Lord Vader]

Hi @Antix70

I too cannot replicate what you are referring to. 

I suggest you run a repair on your DCS World installation. If the problem persists, share your track file with the issue for further analysis.

[BIGNEWY]

Folks please do not derail the thread, keep it to helping the issue. 

As mentioned above we are unable to reproduce this, please attach a track replay example, not the mission, we need to see what is going on. 

thank you

[Antix70]

Two tracks for you.

The failed one from the Desert Storm practice mission

And the successful one from the FuelFollies mission

R AUX XFER Fail.trk R AUX XFER Success.trk

[Antix70]

It's worth noting that there were six of us in the Desert Storm Practice mission, all of us got the R AUX XFER failure.

Upon changing the mission to use HOT starts instead, the R AUX was successful after the change to HOT starts for every aircraft in the mission.

Edited August 23, 2023 by Antix70

[Antix70]

I have created some confusion here. In my original post, I suggested that you make a mission with two Apaches in it, and equip them with fuel tanks. And run through the steps.

The original failure was discovered by 6 of us in a mission, DesertStormPractice.mix, made by one of the folks we were doing a mission with and hosted on my dedicated server. When we tried to set up the fuel page, we all got the XFER failure message as shown in my track file above.

Afterward I read some posts here, I followed my suggested steps and created the FuelFollies mission, and to my surprise R AUX XFER works just fine.

I don't know what is different in that mission versus the one I made using the steps from the original post. And it now appears that you (NeedzWD40) are now able to get the XFER to work in the DesertStormPractice mission, even though six of us got the failure, and still get the failure each time we run the mission.

Could it possibly have something to do with the dedicated server it's running on? Even though just moments ago, to make the track files, I ran the missions by clicking MISSIONS on the DCS menu, chose MY MISSIONS, and loaded each file from that dialog.

It's all very confusing on my end here...

[NeedzWD40]

I do think there may be a bug here, but I don't think it's at the server level. Some variable isn't being cleared out at the game level: when I was able to replicate your failure in the track, I noticed I kept getting the "FUEL XFER FAILURE" caution, even when bags were removed. This was repeatable in the track each time I took control. I restarted the game and tried again, taking control at the start as previously and got no failures and external tanks worked as expected. The only observations I have is that it almost looks like a double tap on the APU start button and attempting to use the external tank before the quantity is set. Those may be red herrings.

In the interim, what I'd try is setting the default external payload to empty, then equipping weapons and tanks after startup. It could be a weird glitch with having tanks on at spawn and I know I've equipped tanks after startup on dedicated servers with no issues.

[Floyd1212]

I just flew a mission with some guys with cold starts, and didn't use bags at all the whole time.  I died at some point and the second time I spawned in I got a "FUEL XFER FAILURE" warning immediately after I turned the battery on.  I died and respawned a third time, and got the same error right after powering up.

Again, no Robbie tank or external tanks used at all.

[Lord Vader]

Hi again

The "FUEL XFER FAILURE" bug is known but thanks for referring to it.

We'll look into this external fuel tank item a bit further. Thanks for your patience.

[Heli Shed]

Bump.

 

Any plan to fix this issue Vadar? 

 

Cheers.

 

[ShuRugal]

On 8/21/2023 at 2:53 PM, Raptor9 said:

Professional aviators aren't stupid, nor are they like the fighter pilots in the movies with the cool sunglasses and the scarf waving in the wind, hopping into their cockpit and simply taking off into the sky. If an aviator spends years learning complex aerodynamics, procedures, weapon systems, munition ballistics, tactics, etc, simple arithmetic is not going to be a hard thing for them to do, nor is something so rudimentary as performing fuel calculations prior to takeoff going to be what causes them to crash.

Real world aviators also use tools to help them check their data....  Any chance we can get an E6B added to DCS?  that'd be a neat kneeboard functionality.

[Raptor9]

The original bug reported in this thread is marked as fixed. Further, I am not able to reproduce it either.

Since the original topic appears to have been resolved, I am locking this thread to prevent any further confusion regarding the issue at hand. If anyone has any bugs or wishlist threads to post, please make a unique thread for it.