Cpl Dyer joined the 48th Highlanders in Toronto in February 1996, then joined 3 PPCLI in October 1997.

In Afghanistan the 3 PPCLI were training at Tarnak Farms on the night of April 17th 2002. An American F-16 fighter jet mistook the training range for a Taliban ground attack and engaged with a laser guided bomb. Sgt Marc Leger, Cpl Ainsworth Dyer, Pte Richard Green and Pte Nathan Smith were killed, Canada’s first operational deaths in Afghanistan. Eight others were injured.