The Airbus transport factor deals only with the additional fuel required to carry fuel, it doesnt account for the cost of carrying that fuel in terms of extra stress on the aircraft/brakes/thrust reversers/engines, therefore its not ideal when you are trying to make a financial assessment on tankering fuel....
First : Airbus did not invent the *transport factor*. It came from one of these guys who used to ply the sky in the sixties and it's a broad simplification of the Breguet range equation.
In all fairness, you are right but in real terms, we are talking of relatively low increases on the aircraft weight.
Add the fact that tankering over more than three sectors - short haul - is not recommended on most airlines, we are really talking about peanuts.
Example :
Landing 4000 kg of extra fuel, lets say that our landing weight increased from 56 to 60 T.
The landing speeds have one up from 125 kt - 64.3 m/sē - to 130 kt -66.9 m/sē.
The kinetic energy upon landing therefore has gone from 115.8 MJ to 134.8 MJ, an increase of 16% either taken by braking energy or brake/reverse energy.
I really don't see a dramatic increase of operational constraints here, as seen by SNS3Guppy.
Tankering on a long haul sector, as I demonstarted is only worth the trouble if the fuel prices are drastically different.
One of the more challenging - and interesting - aspects of our job is that we make decicions based on reason and experience. Going to LHR at six a.m wth the computed fuel seem rather idiotic as a lengthy hold is very likely...How much extra fuel for holding then ? Depends whether you know the ATC controller or you're a pessimist. Or just experienced enough on the sector...
I personally have seen on occasions people who took off 30 min behind me having to divert while I made it after a 50 minute racetrack pettern over BIG...