US Air Force (USAF) STAFF Sergeant (SSGT) Knapp, 19th Air Refueling Group (ARG), the Black Knights, Robins Air Force Base (AFB), Georgia (GA), waits with anticipation for his units turn to refuel a KC-135 Stratotanker aircraft during the ground refueling competition portion of the USAF Air Mobility Command (AMC) sponsored Rodeo 98 airlift competition at McChord AFB, Washington (WA)