lean of peak(Peak means stoichiometric reaction ratio – exactly enough fuel for the amount of air the engine takes in. Lean of peak means more air than fuel. oshkindt)
rich of peak(Peak means stoichiometric reaction ratio – exactly enough fuel for the amount of air the engine takes in. Rich of peak usually means "best power" in practice. More fuel than air. oshkindt)
YQ(сокр. в электр. авиабилете разница между предполагаемой (когда просчитывался тариф) и реальной (на момент выписки билета) стоимостью керосина rokf.ruSerge1985)