hevansrv7a
Well Known Member
My wife and I flew NWA to Puerto Rico today. I had a looksee at the A320 panel and a chat with the pilots. They use 3 cross-checked inertial guidance systems and the usual land based stuff, but no GPS. They told me that above 20,000 feet that GPS is not accurate. They were proud of only a half-mile position error at the end of a medium length flight. I said my hand held would beat that and that's when they said no, not at altitude. OK, so at cruising altitude I pulled out my 496 that I had in my carry on because it has the street level mapping for PR. It said the position error was 76 feet, speed 475 kts and so on.. OK, that's pretty bad compared to down low, but it's not half a mile, is it? Thanks to the new era in commercial flight, I could not share this with them during the flight and could not cross check Lat-Long at a given moment.
So, are there any real experts out there who can shed light on this question? OK, I know RV's don't fly above 20k, but the question is at least interesting.
So, are there any real experts out there who can shed light on this question? OK, I know RV's don't fly above 20k, but the question is at least interesting.