Originally Posted by
Tu.114
A crossbleed on a CEO requires 25 and prefers 30psi of bleed pressure. This will cause a noticeable amount of thrust as a byproduct that is sometimes needed and sometimes unwanted during taxi. Pulling the donor engine back to idle during a crossbleed is not advisable and has to be consciously avoided during such a start. What happens to the unwanted surplus energy, then? It has to go into the brakes.
This procedure may well just shift costs from fuel over to maintenance. But I trust that the company has done its math before implementing such a SOP change.
TBF, on a PW NEO engine, the thrust lever can remain at idle during the crossbleed engine start, so there will be no “temptation” of reducing trust, as you won’t be able to, and on a CEO you can’t do SET without the APU running due to the engine fire suppression system not working correctly in case of emergency electrical configuration on the ground. And usually the company will have more information than the pilots on how much things cost, so if they’ve implemented a procedure, it is probably worthwhile.