books for reference
keith willams - general nav, instruments
oxford jeppesen - general nav, instruments, met, mass and balance, radio-aids, performance and power plant systems.
gsp's - flight planning and monitoring, radio, intruments.
ic joshi - met.
surinder singh - notes
ive given around 4 times nav-comp. slacked off the previous times during the exam time thinking "i already got a cpl dun need to study much ill pass" but that didnt work so well always got 60's..
i recommend you to study atlest 1-1 1/2 month before your exam spend 7-8 hrs each day studying the basics and getting through thoroughly..
the knowledge is the goal... dun listen to what is important and what is not... as u've seen this attempt they ask each and every kind question.. from multi-leg cp problems to theory of air density...
all the best..