Cardiff RNAV ACP

52 Pages·2016·2.37 MB·English

by  Ian Godsell

Cardiff Airport RNAV Replications

Airspace Change Proposal

Issue 2
April 2015

Prepared by:

Manager Operations and Training
NATS Cardiff
On Behalf of Cardiff International Airport Limited
Issue Log
Issue number Date Description
1.0 30/04/2015 Initial issue to CAA SARG
Table of contents
Table of contents ..................................................................................................................................................... 3
1. Introduction .................................................................................................................................................... 6
2. Justification .................................................................................................................................................... 7
3. Current Airspace Description ......................................................................................................................... 8
4. Proposed Airspace Description .................................................................................................................... 17
5. Impacts Summary ......................................................................................................................................... 21
6. Consultation ................................................................................................................................................. 25
7. Analysis of Options ...................................................................................................................................... 27
8. Airspace Description Requirement ............................................................................................................... 28
9. Operational Impact ....................................................................................................................................... 30
10. Supporting Infrastructure & Resources .................................................................................................... 31
11. Airspace & Infrastructure Requirements ................................................................................................. 32
12. Environmental Requirements ................................................................................................................... 35
Appendices .......................................................................................................................................................... 44
Appendix A: Cardiff Standard Terminal ARrival Charts ............................................................................ 44
Appendix B: Cardiff CTR & CTA Chart ....................................................................................................... 48
Appendix C: Elements of the Y-Bar and T-Bar .......................................................................................... 49
Appendix D: Proposed Amendments to the AIP ........................................................................................ 50
Appendix E: Flight Validation Plan ............................................................................................................... 51
Appendix F: Consultation Feedback report ................................................................................................ 52
Intentionally Blank
Section Summary

Sections 1 and 2 offer an Introduction to the project and Justification for the use of RNAV, detailing the
benefits of its use.

Section 3 gives the Current Airspace Description including maps of the current aircraft tracks with indicative
inbound descent heights. Numbers and types of aircraft using the airport are also given along with predicted
traffic growth.

Section 4 details the Proposed Airspace Description, detailing the RNAV design elements and the proposed
inbound tracks and heights for both runways.

Section 5 details the Impacts on safety, the environment and other airspace users.

Section 6 outlines the Consultation, the list of invited consultees, the methods of engagement and the responses
received. It points to the Post Consultation Feedback Report for a more detailed discussion on the consultation.

Section 7, Analysis of Options, details other proposals which were considered and discounted as part of the
design process.

Sections 8 to 12 detail the CAP725 requirements in the respective areas of, Airspace Description Requirement,
Operational Impact, Supporting Infrastructure & Resources, Airspace & Infrastructure Requirements and
Environmental Requirements.

The Appendices contain the current and proposed approach procedures and CTR/CTA Charts, noise contours,
the elements which make up the T bar of an RNAV approach and the Proposed Amendments to the AIP
following the change. The Flight Validation Plan and the Post Consultation Feedback Report are also included.
1. Introduction
This document has been produced by NATS on behalf of Cardiff International Airport Limited (CIAL). CIAL is
the sponsor of this change and any queries regarding this Airspace Change Proposal (ACP) should be directed to
CIAL in the first instance. This document details CIAL’s compliance with CAP725 requirements regarding this
ACP.

The purpose of the proposed airspace change is to replicate the current conventional tracks of aircraft arriving at
Cardiff Airport for Runways 12 and 30. The replicated tracks will be more accurately defined utilising the
improved navigational capabilities of modern aircraft (Area Navigation: RNAV) and will initially be used in
parallel with existing conventional Instrument Approach Procedures. This will enable continued accessibility for
those aircraft not RNAV equipped.

The improved track-keeping ability of RNAV should, over time, result in less lateral dispersal of flights either
side of the inbound routes. Thus overall, fewer people will experience overflying aircraft. However those who
are directly beneath the flight path are likely to experience a greater number of aircraft over-flights.
CIAL is planning to implement the changes detailed in this proposal on 10th December 2015 (AIRAC 13/2015).

The consultation for this proposal, managed by CIAL, ran from 16th December 2014 until 24th March 2015, the
results of which are summarised in a post-consultation feedback report (see Appendix F).
2. Justification

This proposal aims to replicate, as closely as possible, current aircraft approach tracks through the use of new
RNAV routes. It is not the intention to introduce new aircraft tracks but rather to enable aircraft to fly their
existing tracks more accurately, keeping to broadly similar speeds and heights over the ground. RNAV routes
will enable more consistent use of efficient descent profiles (continuous descent approaches – CDAs) and should
subsequently deliver noise and emissions benefits.

Area Navigation (RNAV) enables aircraft to control their position with far greater accuracy than conventional
forms of navigation. Hence the aircraft’s position is known with greater certainty, and when operating under
“own navigation” Air Traffic Control (ATC) have much greater certainty that aircraft are conforming to the
defined RNAV routes, within close tolerances.

Since aircraft will follow RNAV approaches with greater accuracy, they will be allowed to self-navigate to a
greater extent than is the case for those following conventional approaches. Hence the number of tactical
interventions (radio calls) from the air traffic controllers will be reduced. In congested airspace, this aids
efficiency, expedition and safety.

The capabilities and benefits of the RNAV navigation specification are well documented. The background for
this change includes the stated CAA policy for adoption of RNAV in UK airspace which has already been
subject to a separate consultation by the UK CAA (SARG) and is a cornerstone of the UK Government’s Future
Airspace Strategy (FAS)1, which recommends the transition to performance based navigation (PBN)
technologies, of which RNAV is a part.

The change is supported by the airlines for the following reasons:

- Procedures designed to PBN specifications allow airlines to use their FMS equipment to its full
capability to assure predictable flights paths

- More predictable flight planning

- Improved standardisation of flight profiles in accordance with standard operational procedures. This
improves predictability, which enables the crew to plan the descent with more certainty and achieve a
more efficient descent profile

- The move away from reliance on ground based navigation aids

1 CAA Future Airspace Strategy Deployment Plan, Iteration Three, Version 1.2, December 2012. Chapter C1
PBN Implementation
3. Current Airspace Description

3.1 Arrival Routes
The Cardiff Airport runway is aligned south-east / north-west. The north westerly runway is designated as
runway 30 as aircraft landing on or taking off from the runway will be facing a magnetic compass heading of
300° whilst the south easterly runway is designated runway 12 (aircraft on that runway facing 120°).

Aircraft arrive at Cardiff airport via 5 published STARs (Standard Terminal Arrival Routes – See Appendix A:
Cardiff Standard Terminal ARrival Charts) which take the aircraft to overhead Cardiff airport. From here
aircraft will then fly one of the Cardiff Airport IAPs (Instrument Approach Procedures) to land. In practice
nearly every flight is directed by radar on tactical headings to fly away from these routes to final approach. This
is illustrated in the trajectory density plots of Figure 1 for Runway 12 and Figure 4 for Runway 30 (traffic
samples illustrated are taken from the month of July 2013).

Density plots are colour coded with the highest density of aircraft represented in red and lower numbers of
aircraft represented in yellow, green and grey for just one or two tracks. The main routes which aircraft
currently take to each runway can be seen in the density plots of Figure 1 and Figure 4, with the yellow and grey
‘paths’ (for instance in the Llantwit Major area) indicating the dispersal of aircraft along the red centre track.
This demonstrates how tactical intervention by Air Traffic Control creates a spread of tracks flown.

The proposed RNAV routes are designed to replicate the existing track concentrations (red tracks in Figure 1 &
Figure 4). The introduction of the proposed RNAV routings will not introduce new aircraft tracks in areas that
are not currently being overflown. It is anticipated that initially there will be very little change in the spread of
tracks as flown today. However as aircraft fleets are updated with RNAV navigation systems and as the airlines
and their crews adopt RNAV operating procedures, the dispersed pattern of traffic is likely to reduce and become
concentrated in the centre of the tracks.

The heights of aircraft utilising RNAV approaches should increase slightly when considered along the entire
approach path, with improved descent planning delivering increased and improved CDAs (over those achieved
by tactically vectored aircraft today).

3.2 Runway 12
3.2.1 Current Aircraft Tracks
Common routes can be seen in Figure 1 which take aircraft from the north and south and position them for final
approach to runway 12. However at times it can also be seen that many flights take more direct routings, thus
broadening the approach path from each direction.

These tactical direct routings are expected to remain for some time after the introduction of the RNAV routes,
especially at times of low traffic density and before the volume of suitably equipped aircraft increases. .

3.2.2 Current Aircraft Heights
Current aircraft height bands are indicated in Figure 2 which shows the descent profiles along the highest track
concentration. The extremes of the bands indicate the lowest and highest inbound aircraft within that band and
each banding is bounded 500ft higher and lower than the figure covered e.g. 4000 feet means 3500 feet to 4499
Feet.

Aircraft following an RNAV track and executing a CDA will maintain similar inbound levels to one another and
these are anticipated to be, on average, slightly higher than those of today, however the proposed change is not
predicated on an increase in average aircraft height or subsequently reduced aircraft noise.
3.2.3 Missed Approaches
The current missed approach procedures at Cardiff are designed for aircraft to climb straight ahead to altitude
3000 feet before turning back overhead the airport. As a result of differing aircraft performance and a very low
number of missed approaches flown per year (in 2013 there were a total of 33 missed approaches by IFR aircraft
which equates to 0.2% of the total IFR movements) data is not available to provide a detailed description of
known tracks over the ground for missed approaches being flown.

Therefore, based upon the current missed approach procedures as detailed to pilots of commercial aircraft, an
indicative Missed Approach track for runway 12 has been created and is illustrated in Figure 3. This represents a
‘best guess’ at the standard missed approach path.

Figure 1: Current Arrival Routes, Runway 12
Figure 2: Indicative Aircraft Heights for Runway 12