1 / 23

Airborne spacing in the terminal area: A study of non-nominal situations

This study conducted by EUROCONTROL Experimental Centre aims to improve the sequencing of arrival flows in the terminal area through a new allocation of spacing tasks between air and ground. The study focuses on non-nominal situations such as mixed ASAS equipage, holding patterns, unexpected events, and radio failure.

annathompson
Download Presentation

Airborne spacing in the terminal area: A study of non-nominal situations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Airborne spacing in the terminal area:A study of non-nominal situations EUROCONTROL Experimental Centre European Organisation for the Safety of Air Navigation

  2. Starting point • Motivation • Improve the sequencing of arrival flows through a new allocation of spacing tasks between air and ground • Neither “transfer problems” nor “give more freedom” to pilots… shall be beneficial to all parties • Assumptions • Air-air surveillance capabilities (ADS-B) • Cockpit automation (ASAS) • Constraints • Human: consider current roles and working methods • System: keep things as simple as possible Paris Orly, 2002, source: ADP

  3. Context (1/3) To maintain predicted spacing To maintain current spacing To achieve then maintain spacing Merge Remain Vector then merge Adjust speed Adjust speed Initiate direct then adjust speed • Development and refinement of spacing instructions and working methods • Flight crew tasked by the controller to achieve then maintain a given spacing to a designated aircraft • No modification of responsibility for separation provision • New “spacing” instructions – not separation, not clearance

  4. Context (2/3) • Identification of required functional evolutions (air and ground) and route structure Aircraft under spacing Aircraft with target selected

  5. Context (3/3) Distribution of inter aircraft spacing at final approach fix Number of aircraft passing final approach fix(period 45min) Baseline With spacing 27 26 25 Number of aircraft With spacing 24 23 Baseline 22 90 60 120 150 180 • Assessment of feasibility, benefits and limits • Representative environment with very high traffic • From cruise to final approach • Controller, pilot and system perspectives Flown trajectories Baseline Flown trajectories With spacing

  6. From past to present • However, everything was in nominal conditions… • A series of prototyping sessions was conducted to investigate the use of airborne spacing under non-nominal conditions • Feasibility and definition rather than data collection • Focus on terminal area • Situations investigated • Mixed ASAS equipage • Holding patterns • Unexpected events (go-around, emergency, radio failure, spacing instructions not correctly executed)

  7. Experiment setup • Generic TMA with two or three entry points feeding a single landing runway • Traffic close to maximum landing capacity: 36 - 40 arrivals per hour with 20% heavys • Departures not simulated but strategically separated • Two controller positions • Approach (“initial”, “pick up”) • Final director (“intermediate”, “feeder”)

  8. Application to terminal area • With spacing instructions (as defined), integration achieved on a point and aircraft shall be on lateral navigation • How to integrate flows of aircraft with airborne spacing? • How to delay or expedite aircraft under airborne spacing? Today (Paris Orly, 2002, source: ADP)

  9. Specific route structure • To expedite or delay aircraft while remaining on lateral navigation FAF Merge point Envelope of possible paths IAF IAF Sequencing legs at iso distance for path shortening or stretching (vertically separated)

  10. Typical airspace EPERN EPERN BOKET BOKET FAO26 FAO26 LOMAN LOMAN MORET MORET NASIG NASIG GOVIN GOVIN ZABOU ZABOU REDKO REDKO ODRAN ODRAN KAYEN KAYEN RADON RADON MOTEK MOTEK LAURI LAURI PONTY PONTY CODYN CODYN OKRIX OKRIX PONTY/MOTEK FL100 ODRAN/KAYEN FL080 EPERN/GOVIN FL060 ILS 4000

  11. Mixed equipage

  12. Mixed equipage

  13. Holding patterns

  14. Holding patterns • A holding stack defined for each IAF • Stacks located upstream from each leg • Two flight levels for each sequencing legs • Receiving aircraft from holding and airborne spacing for final integration found feasible and comfortable • Traffic from holding very homogeneous • Lack of accurate knowledge of aircraft actual exit of holding patterns forces delay in sequence order identification • ASAS and its associated route structure found very effective to remove holding induced variability

  15. Go-around

  16. Go around • Go-around occurred while in contact with tower • Handling found not more difficult than with current practices • Easy identification of where to re-integrate the aircraft • Standard procedure defined • Re-joining of one IAF • May require cancelling spacing instructions and setting new ones • Possible re-integration before the IAF (track parallel to the sequencing legs)

  17. Emergency

  18. Emergency • Emergencies declared before the IAF • Situation found not more difficult than today • Speed difference vs. position in sequence • Key steps • Integration position decision • Gap creation • Vectoring • Sequencing legs • The emergency shall not be used as a target • A “merge at least” may be issued for the emergency in case catching up the preceding aircraft • Early speed reductions in upstream sectors to aircraft after the emergency

  19. Radio failure

  20. Radio failure • Standard radio failure procedure defined • Radio failure occurred before IAF • Situation found not more difficult than today • Early descent while on leg could create problems • Overall same techniques as for emergency but with more margins due to un predictability of aircraft

  21. Incorrect spacing instructions • Aircraft (under spacing) catching-up with its target • Situations were not rated as serious cases by controllers • Typical recovery procedure • “cancel spacing” along with a speed reduction • if appropriate re-select target (when not retained) and • re-issue spacing instruction (generally “merge”) • Worse case to be handled like a go-around • “Continue heading then merge” correctly read-back but executed as “merge” • Mistake detected quickly and found easy to handle by controllers • Typical recovery procedure • “cancel spacing, retain target” with speed (generally 220kt) to “non compliant” aircraft • vector the aircraft on a track parallel to the sequencing legs • new spacing instruction (generally “continue heading then merge”)

  22. Summary • Mixed equipage • Feasible • Reduced workload and communications scalable • Non equipped aircraft required more monitoring • Holding patterns • Airborne spacing for final integration found feasible and comfortable • Unexpected events • Less difficult than initially anticipated • Similar to today’s operations • Go-around, emergency and radio failure • Identification of re-integration location is key point • Spacing instructions not correctly executed • Not rated as serious: quickly detected and easy to handle • General principle • to “isolate” the aircraft experiencing the problem (i.e. take it out of the sequence) • not to act on the whole sequence

  23. Beyond (or before)… A new RNAV route structure? • A preliminary step to prepare implementation of airborne spacing • A transition towards extensive use of P-RNAV • A sound foundation to support further developments such as CDA (continuous descent) and 4D (target time of arrival) 120 100 New route structure 80 Altitude (feet x100) 60 Baseline 40 20 0 0 10 20 30 40 50 60 Distance to final approach fix (NM) Baseline New route structure 100 80 60 Frequency occupancy (%) 40 20 0 Final Approach

More Related