Table: wide_body_aircraft
Columns: model
eis_final_prod_year
eng
maximum_metric_mtow
outside_diameter_main_passenger_deck

Question: What is # Eng., when Outside Diameter, Main Passenger Deck is "inches (m)", and when Maximum Metric MTOW is "231.3 tons"?
SQL: SELECT "eng" FROM wide_body_aircraft WHERE "outside_diameter_main_passenger_deck" = 'inches (m)' AND "maximum_metric_mtow" = '231.3 tons'