ADA ? If you work for avionic you MUST use ADA, may be you can use also C for the low level stuff (kernel are written in C), but we are talking about an extremely safe C, which means Misra Checked and Validated.
ADA is cool, the problem is that is very difficult to qualify a compiler as "ADA", i mean that a compiler to be called "ADA compliant" MUST pass a lot of tests.
GNAT is ADA, and is very cool, try it out, it's OpenSource! There is just a little eggs problem: to compile the GNAT compiler you need a GNAT compiler, so if you look at gentoo repository you find that this is only possible (means binary compiler boot-strappers only available) for
- X86/linux
- PowerPC/linux
- Arm/Linux (maybe, there is something old around)
- MIPS/Linux and other arch are not supported!
p.s.
i checked this time ago, it may be changed, check yourself for any updated detail