Hi Nick,
I've sometimes found that it is the people at the frontline within an organisation who are most aware of the latent conditions the organisation harbours.
For this reason, you may wish to try the following, Do up a simple questionnaire (or verbally) ask your co-workers the following scenario:
"If I were to tell you that one of our aircraft has just crashed, what do you think would be the likely causes or scenario?"
Ideally this should prompt the respondent to define the hazards they perceive in their workplace.
Good luck