'CW2' by Layne Heath is a good helicopter novel. Other good aviation novels/biographies are:
'Fate is the Hunter' - E.K Gann
'Song of the Sky' - Guy Murchie
'Wind, Sand and Stars' - Saint-Exupery
'Southern Mail/Night Flight - Saint-Exupery
'Sagittarius Rising' - Cecil Lewis
'Serenade to the Big Bird' - Bert Stiles
'West with the Night' - Beryl Markham
'Flying for Fun' - Jack Parham
'A Gift of Wings' - Richard Bach
Happy reading!