In our study material one or more instruments (the HUD being one off the top of my head) are described as non-certified instruments. What does that mean? Apart from the obvious explanation that it lacks certification...
I am flying an aircraft, it offers several tools to help me flying and navigating. If one of these tools is not certified, does it mean it is not reliable or accurate (enough)? What purpose would it serve if that's the case?
The main reason I ask is because the study material as well as my instructor(s) emphasized using the instruments, at least during IFR procedures. But I find myself in numerous situations where the HUD is so much more convenient to use from a multi-tasking perspective. For instance I would hate to see my TVV gone, having to continuously monitor the Altimeter and the VVI to remain in level flight or to land.