I often wonder what the view of the CAA certification folk would be in response to an avionics company who knocked on their door to announce:
"We've got 2 systems for you to think about today. One uses medium wave signals and is liable to co-channel interference (particularly at night), passing Cbs, coastal refraction and other errors. It doesn't give any information to the pilot except its identification using slow more code. To use it, the aeroplane will need an expensive radio receiver, a cumbersome antenna system and a cockpit display. Unless the aircraft also has a decent gyrocompass, the pilot then has to interpret the reading and compare it against a suction driven direction indicator.
The other system uses a constellation of transmitters with considerable redundancy and a ground agency constantly monitors the system's health. It requires a relatively simple aircraft installation and antenna; software can provide the pilot with precise position/height/groundspeed and location on a moving map, the pilot can construct way points of choice and fly safe, accurate routes anywhere in the world. It can even be an entirely hand held device which the pilot can also use when driving to and from the aerodrome or when out and about on foot."
Would the CAA then say "Yes, but we think that the medium wave, interference-ridden system with its expensive airborne installation is OK for descending to the aerodrome on an instrument approach, but the modern, constantly-monitored software-enhanced system is, we feel, far too risky to use for such a purpose".
There probably are some "It's not acceptable without an astrolabe, quadrant staff and lodestone" crusties of the RIN or wherever who still chunter about the 'Tool of Satan' which has made navigation so much easier nowadays..
They should certainly be ignored!!
And yes, My Beautiful Garmin is
indeed a wonderful box of tricks. The best thing since offset TACAN, in fact. What goes in in its chips and circuits is utter magic involving the mysteries of doppler shift and high speed simultaneous equations with allowance for ephemeris and ionospheric corrections - or somesuch
. Not that anyone should ever really need to know 'how' it works, just accept that it 'does' work. And very well indeed! I bought 4 panel mounted systems for my old club's aircraft and the only failure we ever had was when one antenna (which hadn't been installed properly) allowed water ingress into the cable. Whereas we had constant problems with the King ADFs....
Checking my Garmin on the way home yesterday, I saw that it was receiving EGNOS signals from Inmarsat (ID 33) and Artemis (ID 37) at times - but the system accuracy didn't seem to be any better than when it wasn't receiving EGNOS. But 5 metre accuracy in a car doing 70 mph is still pretty amazing to me
!!