\version "2.19.16"

fluteI =  \new Voice \relative c'' {
%fluteI =  \relative c'' {
  c4 b8 a b4 c8 g | a1
}

fluteII =  \new Voice \relative e' {
%fluteII =  \relative e' {
  e4 d c8 b a e' |
  fis1
}

flute = \new Voice {
  << \fluteI \fluteII >>
}

\score {
  \new Staff {
    \partcombine
      \fluteI
      \fluteII
  }
}