Just Reward by Jed Hart
Book 3 in The Jake Hunt Series
Jake Hunt joined the Navy at seventeen and in three years achieved his dream of landing on an aircraft carrier and becoming a naval aviator. The price is a transfer to helicopters and the 135th Assault Helicopter Company in Vietnam. The relentless demands of flying combat assaults dawn to dusk are hard enough, but criminal forces have infiltrated the company.
Jake struggles with the emotional demands of any young man, with the beautiful Tran at Bearcat Base and sweethearts in the USA and Australia. But they must take second place to his commitment to the unit he serves and his duty to fallen comrades.