The pilot was killed when the chopper, packed with rescued Yazidis, crashed during takeoff after delivering aid to Mount Sinjar, two senior army officers said.
Yazidi MP Vian Dakhil, whose emotional appeal in parliament on the plight of people stranded on the mountain made her the public voice of her community, was injured in the crash.
A New York Times journalist also sustained non-life threatening injuries in the crash, the paper said.
The UN refuge agency put the number of people on the mountain at 20,000-30,000, while UN minority rights expert Rita Izsak warned they face "a mass atrocity and potential genocide within days or hours."
Insurgents led by IS jihadists launched a sweeping offensive in June that has overrun large areas of five Iraqi provinces and displaced hundreds of thousands of people.
The US military is carrying out air strikes against militants in north Iraq, including today on a mortar position it said was firing on Kurdish forces attempting to defend Yazidis north of Sinjar.