Well not quite, I think what they are asking is:
If the CDI is full scale deflection then the Flight Technical Error or ability of the aircraft to fly the RNP track or in Boeing speak the cross track error is at its maximum. That means that the aircraft is not following the track centerline due to some aircraft flight control reason, such as strong winds, AP steering error etc.
What you are discussing is if you have a CDI deflection showing "off track" and a navigation solution that is not great at the same time giving an ANP that could also be at the limit.
ANP (EPU) is a confidence of position statement not a measurement of actual error, so the assumption that a cross track error at full scale and an ANP at maximum is an error of 2 x RNP is incorrect.
Last edited by c100driver; 15th Apr 2009 at 09:10.