PROFICIENCY & EFFICIENCY 88 TECHNIQUE 90 WX WATCH 93 MAINTENANCE 96 ADS-B 98 NEVER AGAIN >> Lean on me The Greek letter lambda is used to designate the air/fuel equivalence ratio, the relationship of the actual air/fuel ratio to the stoichiometric ratio-where exactly enough air is present to completely burn all the fuel. Speed or efficiency? B Y DAV E H I R S C H M A N OLIVER BURSTON 86 | AOPA PILOT February 2018