Insufficient Fuel

[Guest Oz747]

Hi,I have been flying the PMDG 737NG for some time now and recently I have been getting the "Insufficient Fuel" warning about 10 minutes into my flights. It then remedies itself as the flight goes on.As an example, today I was flying YSSY-YPPH in the 738 winglets model. I was using the KAT1 SID off Runway 34L at YSSY joining H44 at KAT.I had my payload worked out and loaded 29,960lbs of fuel. I expected to land at YPPH with about 2,800lbs. I set my reserve figure in the FMC to reflect that. During the climbout the FMC showed Fuel at YPPH would be 7.4! I rechecked my calculations and the 7.4 didn't make a lot of sense but I went with it anyway. At least if I made an error that large I wouldn't run out of fuel!When I had reached cruise FL360 I got the "ding dong" and the "Insufficient Fuel" message. With a sudden change it showed Fuel at YPPH would be 0! I did some fuel burn calculations and it worked out I would land with about 3,100lbs. So I continued.As I continued the flight, the 0.0 changed varied over the next 30 minutes to 1.3, then 0.7, then 2.0, then 0.7, then 3.0. During this time the fuel flow figures never changed, IAS, TAS, G/S nor winds changed, nor did the Cruise N1. Everything was as stable as I would have expected.Eventually the Fuel at YPPH stayed at 3.0 (varied 3.1 to 3.2).I landed at YPPH with 2,900lbs of fuel. Pretty much as I had planned.Can anyone suggest anything that might be causing me to get these erroneous messages?In addition, I have been reading these Forums for a long time (this is my first AVSIM post) and I would like to thank everyone who offers their assistance so freely.James

[bobbyjoh 11]

Hi James,We all have had this happen. First do you have all the patches? This issue was vastly improved with the latest patch. Having said that, there are still times when you may experence it again. What is happening is that if you get too close to a low fuel balance like you 3K pounds of fuel at destination the updating of the FMC fuel calculation logic is alow to recalculate the actual usage and displays the insuffiencent fuel message.I usually have a little more fuel than you do at landing, my calcuations keep it around 5-8K pounds. A lot of airlines today are reducing the amount of fuel they carry, but since the PMDG calulations are slower for this item I don't like to see so I keep it a little high. In the RW you would not see this with 3000 pounds of fuel at landing.If you know you are correct in your fuel planning then just wait for a few minutes and it will correct itself and turn the message off.Bob

[Guest Ross]

Oz, thats a pretty slim reserve. Remember that you should carry enough for some holding and at least one missed approach then a divert to your alternate destination. My total reserve figure including holding and alternate fuel is NEVER less than about 7000lbs. I FSBuild 2 for my fuel planning and a couple of weather sites for en-route winds, I find this to be very accurate.

[Guest Oz747]

Bob and Ross,Thanks for your reply.I have all the latest patches installed.Maybe my reserve is a little thin. I got that figure for landing fuel from somewhere but can't remember where.Today I tried the return flight from YPPH to YSSY with extra fuel. Once I was on cruise it was telling me that Fuel at YSSY would be 10.4. I had planned it for 6.0. A few minutes into Cruise I got the "Ding Dong" and the "Insufficient Fuel" with the Fuel at YSSY showing as 0. I cleared it and within 30 seconds it changed to 3.8, then over the next 20 minutes it went through the following figures 3.9, 6.5, 7.0, 0, 3.8 and 3.9, then 7.0, 7.4, 3.8 then 7.7. About 2 hours into the flight it has settled at 3.8.I landed at YSSY with 6,300lbs of fuel. Pretty close to what I had planned.It has only started doing this recently. Never had this problem before.I'm dreading a reinstall but it might be a way to get rid of the problem without knowing why it actually occured.James

[bobbyjoh 11]

Hi James,I am one of these people who hate that reinstall routine. If you are not getting some kind of error message than your current install should be very stable.When you load fuel, where are you placing it? For example like Ross, I use FSBuild on every flight to compute my fuel loads. Then I have a table that goes from 1700lbs to 46057lbs. Everything from 1700lbs to 17257lbs is loaded only in the two wing tanks. Once the fuel load requriemtns are above 17257lbs I load the wings to 100% and then start loading fuel into the center wing tanks, where the fuel burn starts.Next point what wind are you placing in the FMC? I also use ActiveSky 2004. When you load the flight plan it will give you the average route wind. FSMeteo also will do this for you. That wind is then inputed into the PMDG FMC. Not having an accurate wind in the FMC may be the cause of the changing fuel at dest. quanities.Hope these things help.BobKDEN

[Guest Oz747]

Bob,Thanks for your reply.Today I got to thinking what I had done just before I started having this problem. It started happening after I had installed Active Camera 2004 V2. So, with nothing to lose, I uninstalled Active Camera to see whether that made any difference.I loaded up my planned fuel for a trip YSSY-YMML and never had a problem. No "Ding Dong", no "Insufficient Fuel". An uneventful flight. So, even though this makes absolutely no sense to me I have left Active Camera off and in the further 2 flights I have done not a problem. Co-incedence? I don't know but for now AC can stay off as it saves me a reinstall. I'm happy with that. :)Thanks again to you and Ross for your suggestions and help.James

[crvm 0]

It might be that the sim winds are effecting FMS fuel forcasts giving you the message although I have heard the real one will do this too every once in a while.Best Wishes,[h4]Randy J. Smith[/h4]http://www.rawbw.com/~bdoolin/shinault/southparkcartmad.gif[h3]PMDG 747![/h3]Caution! Not a real pilot, but do play one on TV ;-)ASUS KV8 DLX | AMD 3200 64 | 1 GIG PC 3200 DDR | GIGABYTE 5700 ULTRA | ViewSonic VP192b 19" |

[zubart 5]

James,Are you accelerating MSFS speed, you know, 2X or 4X, etc..? This will cause the kind of errors you discribe in your post.Floyd

[Guest Anticyclone]

Hi James,Active Camera does not look for any gauge information. Nowhere in the programmation code there is a pointer to FS gauges.Reinstalling AC2004 would take you a minute.Regards,

[Guest Oz747]

Randy,I have just been using the wind setting in FS since I started having this problem so the winds are a constant 258*/25. They never change from that.Serge,The removal of Active Camera resolving the problem made no sense to me either but all I know is that since I uninstalled it, it has solved the problem. As I said in an earlier post I am sure it may just be coincidence and I in no way want to infer that Active Camera is anything less than an excellent product.Floyd,No I don't run at anything other than x1.I did 2 flights today, one of 1.5 hours and the others of 3 hours and in both cases they were flights that went without a problem. No "Insufficient Fuel" warnings in either. In one I setup to have 3,000lbs on landing (so I expected a warning) and the other with 6,000lbs on landing and again all went well.I will reinstall Active Camera and see if it makes any change.Thanks everyone for your assistance.Regards,James

[TRAVAIR 0]

James, just so you know, both Virgin Blue and Qantas have a min reserve/landing fuel of 2400KG's. (About 5000lbs - roughly:P).I initially thought your problem would have been due to winds as Randy pointed out, but as you have said they were constant.I have just reinstalled FS2004 and ALL of my scenery and A/C. It is now running better than ever.