...do you keep your APU running to start-up the other engine or rather perform a cross-bleed start?
Keep the APU running - which is why the saving is only 5kg/min.
single engine taxi on an airliner... ...just unprofessional, bean-counter bull..
Complete and utter codswallop! A luddite's approach to aviation. Modern aircraft have sufficient reliability and redundancy to allow single engine taxying to be performed safely, subject to conditions. Do I have scientific data to support this? Absolutely! Would it change your mind? I doubt it.
PM