Wow, talk about old school! 
I haven't used an 8051 for decades! I use various Microchip PIC processors nowadays in uP based stuff I do.
Being a long time pilot, and having traveled a great deal in my working life, I can't imagine not flying. 
I also didn't have any issue trusting the avionics I developed, the development process is quite rigorous and triple-checked. I was the project engineer on the very first microprocessor based digital air data computer in 1977 based on the TI 9900 processor. We developed the uP based ADC for the Boeing 727 for United Airlines to replace the older Honeywell analog air data computers.
I hasten to add, an analog circuit can develop flaws and errors just like anything else. AAMOF, in some ways it may be less protected as it's possible with digital designs to incorporate self-checking to see if things are going awry in the processing. Just because it's an analog circuit, that doesn't make it bulletproof.
