Dry Operating Mass

[KingGhidorah 209]

Where did Majestic get the 18434kg/40639lbs DOM figure from?

 

One source says the airplanes empty weight is 36,500 lbs, another ~37000, and at least one piece of literature from Bombardier itself says the empty weight is 39,300.   A spread of almost 4000lbs in quoted figures seems pretty signifigant and makes me wonder what is most "typical".   I'm aware that any number used above the 37572 lbs listed in the aircraft.cfg is added in as payload in the mythical compartment known as "Operating Empty", station 0.

 

Has anyone come across any figures for real world airframes operated by real airlines to get some idea about what would be an appropriate number to use?

[ubersu 78]

Dry operating weight (not mass) includes hydraulic fluid, water, oil, etc... basically all up weight ready to fly excluding fuel.

 

DJ

[KingGhidorah 209]

Dry operating weight (not mass) includes hydraulic fluid, water, oil, etc... basically all up weight ready to fly excluding fuel.

 

DJ

 

That isn't quite what I asked, and if you would prefer to call it "basic operating weight" to avoid confusion, that's fine too.   I'm guessing that this plane doesn't carry 3000+ lbs of oil and hydraulic fluid   This is why I'm wondering if somebody could narrow this weight down a little, or at least tell me what is included in the default figure (40,639 lbs) that is used in the tutorials and what airline/airframe/customer configuration it is based on. 

 

It doesn't seem that we are only dealing with  trivial differences here.  The discrepancies amount to more than an entire baggage hold's worth of payload, and the line in the aircraft.cfg file that reads "empty_weight 37572.48   // This is in fact the DOM" raises some real questions about what is the appropriate figure to use in the load configuration utility.   

[ubersu 78]

What's included varies wildly and accounts for the differences that you see published. There is no real standard that I'm aware of, but the weight is generally considered to be the weight of the aircraft without fuel and passengers but with all the items that I mentioned and all consumables on board. However, it has been my experience that no two documents will agree on this seemingly simple number for any aircraft that I've bothered to look at in detail.

 

As far as the weights in the tutorials go I would suspect that Majestic would be the be the best folks to ask. I would use the weight given in the config file in the load configuration utility since that is the weight you're dealing with regardless of where the number came from.

 

DJ

[g_precentralis 191]

There's no "real" definite number as every aircraft is different. Different amount of fluids, different airline options, different interiors...

 

And it's not a weight, it's a mass, although I call it weight too - for sake of simplicity.

[KingGhidorah 209]

I went ahead and did some further checking into it, partially answering my own question, by looking at some sales brochures for used aircraft.

 

Ship 4022, built around 2000 is ex SAS, and ex Flybe.  It has 76 seats and 3 galley stations (1 front, 2 in the rear, called G6,G5, G3 respectively).  It was the heaviest I found.   It was quoted as a Basic Empty of 39,500 (rounded) and Operating Empty of 40,240 lbs.  So add in some TV dinners for the passengers, and you probably come up close to the figure used in the tutorial.

 

#4065, ex Flybe built in 2002 has an operating empty weight of 17, 503 kg (38,508lbs).  It has 1 galley component up front, and 1 in back. 78 seats.

 

#4354, ex Colgan listed an "empty weight" of 38,632.  Built in 2011.  It also has one galley unit up front and 1 in back.

 

As a guess, the 40639 lbs used in the tutorial and the default probably represents the very high end of empty operating weights.  In my simming, I think I'm probably going to scale down from the DOM figure, knowing what I just learned. 

 

If anybody comes across any more good figures for specific airframes, please add them.

[Jazzfan 57]

Hi KingGhidorah,

The DOM is usually aircraft specific. One of Air Canada Express' Q400 uses a DOM of 39111lbs. For Horizon, it is 40171 lbs.

  Regards, Craig.

[jalexb88 7]

From a real world perspective, most of the Q400's at my airline have an empty weight above 40000. The last one I flew was at 40124.

 

Alex

[jordanal 70]

I've recently wondered about this exact topic when playing with the load-manager recently and have been using the tutorial value (40639) for now, anyway.  But reading this discussion brings a simple question to mind - for a relatively small airliner/airframe and how DOM/DOW seems to play a significant role, where does the 'flight crew' weight come in.  DOW from above includes fluids, TV dinners, a few drinks, a couple of spare bulbs, LOL... What about the flight crew?  Their weight and gear is not included in the DOW or the passengers/baggage weight, is it?

[MauB 74]

As far as I know DOW includes flight crew weight.

[AlphaIndiaRomeo 1]

It does indeed as far as I'm concern. In Canada anyways. 

 

@jalexb88 would this be Porter or AC Express? I'm trying to find the figure for Porter.

[jalexb88 7]

It does indeed as far as I'm concern. In Canada anyways. 

 

@jalexb88 would this be Porter or AC Express? I'm trying to find the figure for Porter.

 

AC Express

 

Alex

[norman s 15]

Hi,

 

Fly Be use 18000kg and a DOI of 80 for flight planning purposes

 

Norman