E175 Inaccurate Fuel Burn

Hey guys,

I don’t know if this post should go on here or on #general, but I’ve noticed that the E175 has a highly inaccurate fuel burn rate. For example, on my last flight (KSEA-KABQ), I had the amount of fuel for my trip calculated by SimBrief. I put that fuel figure into the Weight and Balance settings, and I also added an extra hour of fuel on top of that. The flight was normal during cruise and seemed to estimate the fuel time remaining correctly. However, as I came to my phone right before the final leg of the flight, I noticed that I had 100 pounds of fuel left (approx. 1 min. because of how I managed the speed). Needless to say, I had to divert, and glided into the airport with no fuel remaining.

A couple of my other VA friends have had the same exact issue.

I’ve also searched up this topic, and it seems many people agree that fuel burn rates are incorrect. It’d be great if IF devs could work on the Embraer family in the near future, as that would be a great help to the people who fly the plane on a regular basis.

Thanks

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The Embraer-series is an old model that needs a rework, so no surprise to see that things arent as they should be. Remember to vote for the rework if you want it:)

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It really is an old series of aircraft. Glad to see that someone wants the rework too :)

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if you’d like to cast a vote go here

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You can burn less fuel by step climbing.

The Embraer aircraft in the app are old

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Just did! Thanks for linking that post. I didn’t think to search that before posting this.

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Thank you. Even with step climbing, I still end up with less fuel that I expected. I’m going to give it another try though on my next flight :)

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Did you follow the Simbrief with regards to the speed, FL and weight of the aircarft? if you went too fast, climbed too quickly or had different weight settign then the fuel burn would be drasticaly diffrent. Saying that it IS an older airvcraft and needs to be re-worked…

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Yes, I followed the SimBrief data exactly as it told me.

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Hello!
It’s obviously something we need to look into if it’s inaccurate.
However, we need some data to be able to do so. Anyone sitting on some accurate fuel data for the E175?

This is what have right now (Based on N1% & altitude):

image

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@Vari2ty you still around bud? Maybe you could assist here.

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Was planning on doing a flight or two on the E175 tonight and comparing it to data on simbrief. Will post results in this thread.

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Step climbing is usually used with longer flights though.

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Indeed the E190’s (and most other planes) we use are inaccurate on their own for simbrief. However, we’ve done the following:

  • Created a custom simbrief fleet with appropriate passenger limits

  • Run extensive testing to confirm performance factors (for example, with a jetBlue passenger load, we’ve found that the E190 runs on a simbrief Perfomance Factor of -9, but it is still a bit squirrelly)

For example: (and I’m adding you to this @schyllberg so that perhaps you can make use of some of our data here)

Our simbrief fleet is setup like this:
image

Our A320 is setup like this:

image
Note the performance factor of -15
We’ve changed the weights to match exactly what IF says and also changed the maximum pax to what jetBlue uses-including recently changing our A320 to hold 162 pax. With that in mind however, changing the pax number in simbrief doesn’t particularly matter as the simbrief weight for pax of 230lb doesn’t match up to the IF pax weights for the same number of pax.

The trick to this is to setup your pax and cargo weights FIRST in IF-like this:
image

Notice we’ve taken all the fuel out, set our passengers and cargo to get a Zero Fuel Weight of 132,070 lbs. We then take that ZFW number (rounding up to 132.1) and set it in SB as seen below:
image

The ZFW is the ONLY weight we touch in SB, we leave the pax and cargo settings alone/in auto. If you’re at a big/busy airport like KATL adjust the sliders for taxi time accordingly. (15min=300lb for our A320)

Also notice the climb/descent profiles. We climb out as prescribed by simbrief, 250kt to 10K, 300kt above 10K, .78M from 280 to cruise alt, then .80M for cruise and then the REVERSE of that in the descent. We also use the simbrief TOC waypoint and set it in In Flight Assistant’s VNAV but not their TOD as there are often crossing/speed restrictions on the arrivals that SB seems to ignore. 🤷‍♂️

image

Generating our flightplan gives us our fuel load of 16188lb, so we load as close to that as possible and again, mind you-the taxi times matter.

I was able to get 16197lbs loaded but generally, within 50-100lb will work.
image

If you take off at the SB takeoff weight using ~90-95% power (more weight=more power) you’ll have burned ~300lbs taxiing, rotate and climb out sensibly (eg: no yanking and banking or rushing to cruise altitude!) at V2+15 or so to 1500’ AGL, then reduce your thrust, pitch down and accelerate to 250kt settling in at around ~2200-2400 VS til 10K, reducing VS to accelerate to 300kt above 10K and you climb at a VS to hit the SB top of climb waypoint at your TOC, then you’ll be within +/- 200lbs of the simbrief calculations for fuel burned and within +/- 400lbs of fuel remaining on each of your waypoints going forward.
For example as shown here, at the waypoint OTK you’d have between 12.3 and 11.7 remaining fuel and you’d have burned between 4.0 and 4.2
image

A few side notes to this

  • The numbers at each waypoint are very close on -15 but in the high drag configuration when landing the burn can go up a bit more.

  • For some reason IF always has a touch more remaining than has been burned even when the fuel is within 50lb or right on the money-for example if I taxi and burn my 300lb allotment, I should have roughly 15897 left, usually it’ll be 75-100lb more. Dunno why this happens.

  • You may be or SEEM behind the curve for a few waypoints on a longer flight and/or see the red warning for ETD/FUEL, the red WILL go away and you will likely catch up/be close to the simbrief numbers a few waypoints down the line.

  • If you cruise at less than FL280, you MUST pay attention to the IAS indicated at each waypoint and fly it at your cruise level.
    See the pic here: image

  • You can indeed set stepclimbs on longer flights.

I know this might seem complex, but with having the aircraft plugged into SB, it only takes a few minutes to setup.
If anyone has any questions or would like some copies of our aircraft numbers, please don’t hesitate to reach out.

I also must give credit to @Aquila for the info on how to set this all up.

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Very in-depth and good explanation. I’ve always followed SimBrief data to the tea, including step climbing if necessary and I’m usually good about cross-checking my fuel amounts against SimBrief’s data, no matter what aircraft I use. For many of the aircraft families, fuel quantities are comparative to SimBrief’s fuel figures, give or take a few hundred pounds. It’s just that the E-series never seems to match the data I find on the website, regardless of how many times I redo a flight with minor differences in the fuel balancing. Nonetheless, it can be concluded that the Embraer family needs a rework, and I think that’s what the devs are planning to do :)

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Glad you liked it. Some other A/C-the A321 is about -26, The DC10 I can solidly tell you is a huge minus -43 iirc, the A346 is a huge fuel hog w/ a plus factor that I can’t recall. The 777-200ER is either a zero (meaning SB Numbers work) or a -2 iirc. We have a fleet chief (@maestro) at virtualBlue who tests all aircraft and codeshare routes literally just to figure this stuff out for simbrief. Any data you’d like I’m happy to share.

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Also, on the topic of the E series-even when we’ve used one performance factor one time, sometimes with a head/tailwind it doesn’t match up the second time round. 🤷‍♂️

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Yep, I’ve noticed that exact same phenomenon as well. It’s safe to say that I can’t trust the E-series with long regional flights. 3 hours is the absolute most I will go without stopping over at an airport that is along my destination route. And yes, I will for sure ask for any data if the need arises. Thanks again.

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