Set the Power Limits challenge to "Only AT Powers" before starting a level 50 Flashback from the Pillar of Ice and Flame. Then, complete the Flashback. Level 50+ (Incarnate / Evil Incarnate) Flashbacks don't count.

Usable powers

Primary, secondary, and incarnate powers

Mark and Recall

Certain fast travel powers

Long Range Teleporter, Ouroboros Portal

Certain temporary and day job powers

Jet packs, Alignment Powers

Prestige travel powers (except fast travel)

Jump Pack / Steam Jump

Athletic / Beast / Ninja Run

Prestige Sprints

Prestige utility powers

Inner Inspiration / Mystic Fortune / Secondary Mutation

Portable Workbench, Reveal

Accolade powers

DFB, DIB, and Flames of Prometheus buffs

Inherent and Inherent Fitness powers

Brawl, Sprint, Rest

Swift, Hurdle, Health, Stamina

Disabled powers

Pool, epic, and patron powers

All other fast travel powers

Base Transporter, Supergroup Portal, Mission Transporter, Team Transporter, Assemble the Team

Most other temporary and day job powers

Prestige attacks