Technical Note: Airplane Ground Operations
How do you estimate airplane emissions?
Ground operations refer to the airplane taxing from the gate and back to the gate, or a final parking place at the airfield. During this operation, the airplane rolls at relatively low speed, stops, restarts, turns, etc.
Gas turbine engines are known to be inefficient in these conditions, and their emissions, particularly NOx and particulates are responsible to poor air quality.
Some airplanes, notably turboprops, can taxi back to the gate on a single propeller. OEI operations are not normally encouraged, certainly not on departure, when a delay or failure to start up of the inoperative engine could jam the departure schedule.
Calculation of engine emissions during taxi-out and –in, requires setting up a sequence of events, which include various combinations of acceleration, roll, braking, stopping/idle and turning, such as in this graphical example.
As far as ground loads are concerned, further calculations are performed. These are both thermal loads and structural loads.
In terms of structural loads, there is nothing that comes close to the loads experienced by an aircraft tyre (or tire). These tyres are under tremendous stress, with more weight on a single tyre than a full-size car.
Most aircraft tyre (tire) manufacturers provide a wealth of data, except the weight of their tyres (tires). It is possible that there are small changes even between individual tyres.
You generally find data such as: manufacturers, models, tyre size, ply rating, maximum speed, rated load, inflation pressure, diameter, rim, width, width between flanges, but NO WEIGHT.
Tyre wear add to the complexities in addressing tyre weight and how much has been lost in the operation.
Various configurations are calculated by FLIGHT-X, some examples are given here, and in absence of harder data, these are the working numbers for selected aircraft (single main tyre):
C208: main tyre = 23 kg
A320-2xx: main tyre = 67 kg
B767: main tyre = 71 kg
B787-800: main tyre = 91 kg
C17: main tyre = 110 kg
A330-200/300: main tyre = 117 kg
This is done with FLIGHT-X.