During APEX-3, researchers continued testing two CFMI model CFM56-3B1 engines, the same type tested during APEX-2 on a Boeing 737-300 airframe. In addition, five other jet engines of various sizes were studied. These engines included the following:
The aircraft engine test pad was located on the eastern extension of the Cleveland-Hopkins International Airport and across the street from the NASA Glenn aircraft hangar. The plume sampling system was composed of three probes located at the plume centerline 15 m, 30 m, and 43 m behind the starboard engine, as well as an additional probe located 1 m behind the engine. End-of–runway sampling of advected (wind transported) aircraft plumes was also attempted during APEX-3, but later abandoned due to poor wind conditions.
The goal of these tests is to update and improve emission factors (indices) and chemical source profiles for aircraft-generated fine particulate matter.
APEX-3 took place in November 2005 at Cleveland Hopkins International Airport.