I thought about a new variable to be added to the allocation system, which would be assigned to the aircraft model used on a route: Passenger appeal. It's a factor I conceived under the assumption that passenger allocation is based on the number of seats each airline offers on a route. This concept can have the potential to substitute effectively the techstop and the too small penalty.
It would be a factor whose base value would vary from 0,75 to 1 and would be assigned to the aircraft model, so we could have as example:
* Very large, widebody aircraft having the highest value (1): 747/767/777/787, A330/340/350, MD11, etc;
* Large aircraft and very large early jets having a value of 0,95: 707, DC8, VC10, 737, A320, BCS (A220), Comac C919 etc;
* Regional jets having 0,90: Ejets and other RJs;
* Large and medium props having 0,85: Argosies, Connies, Britannias, Viscounts etc;
* All small aircraft having 0,75;
How it would work
This factor would affect only passenger routes and it would affect the allocation only on competing routes. The system would check all the models used on that route, pick the model with the highest appeal factor and use its value as reference. Then, the appeal factor of each model would be divided by this reference value, resulting in a penalty factor to be applied to the number of seats the model is offering on the route.
Example 1: one route being flown by a 737 and an ATR 42, both offering 100 seats each.
The highest appeal is of the 737 (0,95), so it will be used as reference. The system will then consider 100*(0,95/0,95) = 100 seats for the 737 flights and 100*(0,85/0,95) = 89 seats for the ATR flights
Example 2: one airline flying a route with Embraer 120s, offering 150 seats in 5 flights.
In this case, the E120s appeal (0,75) is already the highest appeal, so the system will consider 150*(0,75/0,75) = 150 seats, so no penalty is applied.
Put another airline offering a single 757 flight with 150 seats in the same route and the following will happen: highest reference will be 757's (0,95), so the system will consider 150*(0,95/0,95) = 150 seats for the single 757 flight and 150*(0,75/0,95) = 118 seats for the 5 E120 flights.
Reduction of model's passenger appeal over time
All aircraft model's passenger appeal would lower at a rate of 0,01/year, starting from the year of the first delivery. Intention is to give a slight advantage for newer aircraft models on competing routes.
Reduction of passenger appeal due to techstops
The passenger appeal can be further reduced in function of techstops, at a rate of, let's say, 0,10 per techstop.
Example: two competing airlines on a longhaul, one offering 400 seats on 1 direct 747 flight and the other offering also 400 seats, but on 2 757 flights with 1 techstop.
The 747's direct flight has the highest appeal (1), so the system will take 1 as reference. The system will then consider 400*(1/1 -0,10*0 = 1) = 400 seats for it and 400*(0,95/1-0,1*1) = 400*0,85 = 340 seats for the 2 techstopped 757 flights.
Reduction of passenger appeal due to route distance
Additionaly, we can use route distance to further distinct the quality of service among the airlines. The idea here is to use route distance to power the appeal factor like this: f = f ^ (distance/2000)
Let's use the same 747 x 757 example above, now considering that the route is 7000 NM long and is also considering the techstop reduction factor.
The 747's direct flight has the highest appeal (1), so the system will take 1 as reference. The system will then consider 400*(1/1-0,1*0)^(7000/2000) = 400 seats for it and 400*(0,95/1-0,1*1)^(7000/2000) = 400*0,56 = 226 seats for the 2 techstopped 757 flights.
On the other hand, when distances are lower than 2000 NM, this factor will reduce the disadvantage between larger and smaller aircraft.
Example: Two airlines flying a 900 NM, direct route, one with an ERJ and the other with an ATR. Both are offering 45 seats.
The ERJ has the highest appeal (0,90), so it will be taken as reference. So the system will consider 45*(0,90/0,90)^(900/2000) = 45 seats for the ERJ and 45*(0,85/0,90)^(900/2000) = 43 seats for the ATR.
Benefits of adopting passenger appeal factor over current penalties
- Will effectively consider the quality of service offered by an airline, favoring newer, larger models and will inviabilize frequency spam, especially in longhauls;
- As a substitute for techstop penalties, it will make techstopped routes viable again if only one, or all airlines are flying that route with a techstop.