Summary of the First Meeting Special Committee 227 ... - RTCA

Section 1.1 para 3 is significant.
DaveN: We need to consider how we add discussion about the new context of updates we will make.
System overview, section 1.2, has four key sections that divide the main content going forward in the
document (same as in chapter 3 – functional requirements)
1. Position estimation
2. Path definition: lateral and vertical
3. Path steering: lateral and vertical, and time of arrival
4. User interface
DaveN: We originally wanted many aspects as requirements that had to be downgraded to optional
because it would not be feasible for everyone to implement it. We need to consider going forward how
we want to deal with this, considering that optional requirements have significantly reduced value
operationally.
Vertical containment is not treated the same as lateral – based on 99.7% reliability like prior standards.
Sections 1.3.3 – 1.3.5 may need to be updated to reflect current environment such as NextGen, SESAR,
ICAO block upgrades, etc.
FrankH: Consider changing to TBO and revising RNP RNAV to RNP
Aside: We are lacking an procedure design standard that defines how to use the RNP capabilities
appropriately in procedures and airspace design.
Section 1.4 defines RNP. Consistent use of terminology is key here. We need to be careful how we use
RNP and RNP RNAV terms to be clear what the containment, continuity, and integrity characteristics are
associated with those terms.
RNP type does not reflect just required navigation accuracy now, we also use it to reflect integrity and
continuity requirements, so we will sometimes used required navigation accuracy to be precise instead of
RNP-type.
Erwin: section 1.4 will need to updated to be consistent with the new PBN manual
JohnH: discussion of how use of RNP-10, RNP-2, RNP-1 relate to this discussion
RNP RNAV applicability range table is causing issues. Discussion about whether or not this can be
removed.
Note that section 1.4.6 allows for TOAC with lateral and vertical path adjustments, though no system yet
uses lateral adjustments to achieve a time it is technically allowed.
Frank: RNP Tables – pull out
Frank: With VNAV what is the truth line that you measure against
Section 1.5 assumptions
MarkS: 2x accuracy up against rock and airspace gets into AR issues.
Dave N: we are providing a navigation system with 2xRNP capability. How it is used will affect process
of approval.
Steve: how do we take credit for the fact that the actual performance is better than the requirement We
should recommend that RNP is 2x. If someone uses 2x plus buffer, then they can’t call it RNP. Another
point is that if we truly contain with 2x, why are people adding buffers to this
Dave N: We need to focus on the fact that we are doing a MASPS, not dealing with application of RNP
capability outside this document. We can’t solve those problems here. Detailed work on application of
this standard is not our purview. We can put pointers in to indicate where issues may be, but we cannot
15