Click to edit Master text styles –Second level Third level –Fourth level »Fifth level 8/25/ A CO 2 versus noise trade-off study for the evaluation of ATM speed constraints in the departure phase of flight A case study at Gothenburg Landvetter Airport Debbie Rushton & Henrik Ekstrand ICAO EUR PBN TF/7 Paris

Outline Motivation for study Optimising local implementation of PANS-OPS guidance Overview of turn-related speed constraints Case study: Gothenburg Landvetter Airport Speed constraints on TOPLA 1M SID Speed constraint scenarios modelled Data and aircraft performance/noise modelling Results – CO 2 versus noise trade-off study Conclusions Possible solutions for removal of SID speed constraints

Motivation SESAR target 10% CO 2 via ATM improvements by 2020 Potential for substantial fuel savings Historically emphasis on reducing noise exposure around airports. Departure procedures based on interpretation of PANS-OPS Possibility for optimisation

Optimising local implementation of PANS-OPS guidance Local interpretation and implementation of PANS-OPS guidance. Procedure variation between airports (hence in environmental performance). Some PANS-OPS procedures based on performance of old aircraft types (e.g. MD-80). Modern state-of-art aircraft penalised increased CO 2. Identify solutions to optimise existing procedures based on aircraft performance whilst maintaining safety.

Example: turn-related speed constraints on departure PANS-OPS recommends use of speed constraints on SIDs with small-radius turns at low altitude. Designed to ensure containment within protection area during strong winds. Speed constraint dependent on: Track change of turn. Altitude. Assumed met conditions = worst-case tail wind. Max. allowed aircraft bank angle = 25° above ft. Appears overly-conservative for modern aircraft, e.g. A321.

Fuel burn penalty of turn-related speed constraints Example: 210 KIAS constraint at Gothenburg Landvetter Airport Slat retraction usually >210 KIAS Flap retraction >210 KIAS for heavy aircraft

Case study: Gothenburg Landvetter Airport (ESGG) RWY03 RWY21 ESGG

TOPLA 1M departure route 210 KIAS speed constraint 210

Speed constraint scenarios KIAS to 10 NM KIAS to 10 NM KIAS to 10 NM KIAS to Flight Level Free Speed (no constraints)

Data Flight Data Recorder data from Novair. Take-Off Data Calculation (TODC) data. Selected initial conditions for typical Winter flight. Meteorological data. Novair A321 departures along TOPLA 1M SID (RWY 03).

Aircraft performance modelling & validation Operational Flight Performance (OFP) tool in Airbus Performance Engineers Program (PEP). Replicate actual flight performance based on manufacturer’s data. Ensured PEP climb profile in good agreement with the FDR data. Made deviations in PEP by changing speed constraints.

Aircraft noise modelling Airbus Noise Level (NLC) tool. Assume microphone location 1.2 m above ground level (ICAO Annex 16) and directly under flight path. Noise calculations based on manufacturer’s Noise Power Distance tables. Maximum A-Weighted Audible Noise (LA max ) metric used for analysis (metric used in Sweden for procedure development). Also describes single-event noise.

Data analysis

Speed Constraint Scenarios - Results Climb profiles consistent until 5 NM and 2300 ft AGL. 205 KIAS scenario has highest altitude between 5 NM and 12 NM. 250 KIAS and Free Speed scenarios identical until 7 NM and 2800 ft AGL. Free Speed profile has lowest climb angle during initial climb phase (limited due to prolonged acceleration phase).

Speed Constraint Scenarios - Results Distances >7 NM Free Speed scenario generates highest LA max. Explained by shallow climb profile of aircraft. Similar noise profiles for remaining 4 scenarios above 10 NM ground distance. Noise profiles identical until ~4NM.

55 dB(A) = 155 km 2 70 dB(A) = 15 km 2 55 dB(A) = 184 km 2 70 dB(A) = 15 km KIAS to 10 NM (present day)Free Speed Speed Constraint Scenarios - Contours

Area most affected by increased noise due to removal of speed constraints Region affected by noise during prolonged acceleration phase

CO 2 vs. Noise Trade-Off Analysis – Results Potential for CO 2 savings of ~180 kg per flight if remove 210 KIAS and 250 KIAS speed constraints on LABAN 1M SID (~60 kg fuel). Increase in noise ranging between 2 dB(A) – 5 dB(A) during initial climb depending on position along flight path.

Speed Constraint Analysis - Conclusions Free Speed causes aircraft to stay closer to ground during initial climb – increase in noise profile by 2 – 5 dB(A) below 70 dB(A) depending on position along flight path. Offset by potential fuel savings ~60 kg for heavy A321 winter flight and ~180 kg reduction in CO 2. ~3500 departures along TOPLA 1M per year ~190 tonnes of fuel savings and ~575 tonnes of CO 2. Removal of turn-related speed constraints increases noise closer in to airport but alleviates noise further out (objective of NADP 2). ATM industry must prioritise between aircraft noise exposure and CO 2 emissions in order to meet SESAR target of 10% reduction in CO 2 emissions by 2020.

Possible solutions for removal of SID speed constraints Optimise use of PANS-OPS guidance Deviation from PANS-OPS & local safety case OR 1.Use of statistical winds rather than worst-case winds for procedure design. 2.Allow aircraft capable of banking 30° to fly turn without speed constraint. 3.Publish RNP procedure using radius to fix (RF) legs. Publish overlay SID procedure with less restrictive constraints. Publish overlay SID procedure for RF-equipped aircraft. Produces flight path that is almost identical to conventional one from ATC perspective – does not increase ATC workload or airspace complexity.

Track-keeping adherence

QUESTIONS?