Forgive my ignorance here, if any...
I've seen many backtrack 180 take off's on the 737 (and 320) and as far as I can remember, the turn itself involves both engines with N1 at about 40% to accomplish the turn. I have never seen differential thrust being used on the 737 to assist a 180. This means, both engines are already symmetrically spooled and once the a/c is lined up and the PF advances the throttle levers (TOGA switch), both levers move forward in unison to T/O thrust with A/T armed, assisted by the FADEC.
I have not seen engines set to idle N1 at intersection T/Os or before T/O after completing the 180, unless T/O clearance has not been obtained or the crew is waiting for another a/c to clear the runway, a frequent scenario at Goa.
Could it be that FADEC was malfunctioning?
Last edited by India Charlie; 28th Dec 2016 at 12:12.