However, the Associated Press reported that most of the planes are expected to be back in the air Wednesday after a fleet-wide inspection was expected to be completed Tuesday night.
AETC flies 446 of the turboprop aircraft as an entry-level pilot training for joint primary pilot training. The aircraft are largely flown at Columbus Air Force Base, Mississippi; Vance Air Force Base, Oklahoma; and Laughlin Air Force Base and Sheppard Air Force Base in Texas.
AETC first stood down the aircraft on April 10 following indications of an engine oil line malfunction, according to AETC. The command is undergoing a fleet-wide inspection, called a Time Compliance Technical Order, to determine the next step.
"All AETC wings flying the T-6 are meeting the inspection requirements as safely and quickly as possible to minimize impacts to flying training operations," AETC said in a statement. "The personal safety of AETC aircrew members is, as always, the Air Force's primary concern."
The Navy and Marine Corps use the same aircraft to train entry-level pilots. The Navy is aware of the Air Force's decision to ground the T-6s, and is monitoring the situation, but has made no decision to ground the plane, according to Lt. Tim Hawkins, a Navy spokesman.
The aircraft is among the newest in the Air Force's fleet, first deployed in May 2000 at a unit cost of nearly $4.3 $4.272 million, according to the Air Force. It is produced by Raytheon Aircraft Co.