Skyhawk 172/Cutlass 172
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Commercial
Flight Crew Last 90 Days 80; Flight Crew Total 560; Flight Crew Type 100
Distraction; Situational Awareness
Aircraft Equipment Problem Less Severe; Conflict NMAC; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Took Evasive Action
Human Factors; Procedure
Left seat pilot was under hood; instructor was looking for traffic. An A-10 moving the opposite direction seemed to take evasive action to avoid our training flight. After startup and during our run-up; we neglected to put the transponder in Altitude reporting mode; which caused the controller to miss us on secondary radar. My mistake as an instructor was not remembering to verify altitude reporting mode; not being as vigilant with traffic scan; and neglecting to talk to approach control in the practice area.
A flight instructor reported an airborne conflict with a military aircraft that may have been caused by the failure to operate the transponder in altitude reporting mode.