Anyone knows what they mean by RNP 20 and 12.6
RNP - Required Navigation Performance.
From the FCOM's :
The aircraft navigation system, required by regulation to fly within a Required Navigation Performance (RNP) airspace, shall comply with RNAV functionality criteria and with navigation position accuracy and integrity criteria.
When referring to RNP-X, e.g RNP 20 or RNP12.6, the value of X is the navigation accuracy expressed in NM, which has to be met with a probability of 95 %. An RNP value can be associated with an airspace, a route, a SID, a STAR, a RNAV approach or an RNAV missed approach procedure.
Depending on the RNP value, and on the airspace environment (ground radio navaid), different navigation equipment may be necessary.
An operational approval from the airline’s national authorities may be necessary.
This site may also be of interest:
http://www.pprune.org/tech-log/26032...-airspace.html