ANP Data Verification and Validation

Transcription

1 ANP Data Verification and Validation JRC Workshop January Brussels Laurent Cavadini The European Organisation for the Safety of Air Navigation

2 ANP Data - Contents and Formats Aircraft table Jet engine coefficients table Propeller engine coefficients table Aerodynamic coefficients table Default weights table Default departure procedural steps table Default approach procedural steps table NPD data table Spectral class data table NOISE DATA ANP datasets for individual aircraft (airframe-engine) types Default fixed-point profiles table PERFORMANCE DATA 2

3 ANP Data - Contents and Formats NPD data Noise Power Distance The heart of the Doc.29 methodology Noise levels perceived underneath a notionally infinite straight horizontal flight path Tabulated levels at 10 distances SEL, LAmax (+ EPNL & PNLTmax) For different engine power settings Distinct NPDs for approach and departures V = Constant d i+1 d i 3

4 ANP Data - Contents and Formats Spectral Class data In 1/3 octave bands Spectral shapes for groups of aircraft Average of individual spectra from different aircraft types Normalized to 70 db at 1000Hz Not real spectra Used to adjust NPDs for non-standard atmosphere (air absorption effect) 4

5 ANP Data - Contents and Formats Performance data Standard flight procedures Approach and departures ICAO-A and ICAO-B departure procedures For different aircraft weights (associated to different trip lengths) Performance coefficients Aerodynamic Engine 5

6 Source of ANP Data ANP data is processed and supplied by aircraft manufacturers Using their in-house (noise and performance) databases and models Source noise data gathered during measurement campaigns for certification purpose Gold standard data include full time-history of SPL spectra for different (and well-controlled) noise source states (speed, power settings,..) Following specific ANP guidelines ANP Data Request Form Specifying the assumptions to be made when deriving the data Normalization to reference conditions Ensure consistency of ANP data throughout aircraft from different manufacturers 6

7 Source of ANP Data The datasets submitted by the manufacturers include in particular individual spectra at the time of LAmax 1/3 octave band unweighted At a 1000 ft reference distance For each tabulated engine power setting in the NPDs Individual spectra used To assign a spectral class to the new aircraft entry In the V&V process applied to the NPDs 7

8 Verification and Validation: Why? Manufacturers are likely to use different (e.g more or less detailed and sophisticated) types of measured data and processing tools to generate ANP data Have they strictly followed the guidelines? Risk of errors during processing and reporting of the ANP data Need to cross-check any new ANP submittals, following a specific Verification and Validation (V&V) process 8

9 Step 1 NPD V&V Reprocessing of the NPD data, based on the simplified correction method from ICAO Annex 16 Environmental Protection, Volume I - Aircraft Noise Re-calculate SEL values at the 10 tabulated distances, using: The manufacturer-supplied 1/3 octave band spectra at the time of LAmax at 1000 ft The manufacturer-supplied SEL values at 1000 ft Comparison with the manufacturer-supplied NPDs Supposed to have been generated using the integrated method (e.g. based on full time-history of SPL spectra) Typical differences should not exceed 1 db at shorter distances (< 4000 ft) 9

10 Step 2 Spectral Class Assignment Submitted spectra are normalized to 70 db at 1000 Hz (and adjusted to represent free field conditions) 10

11 Step 2 Spectral Class Assignment Comparison of spectral shapes Candidate spectral classes are compared to the normalized individual (aircraft-specific) spectra The best candidate is the one scoring the smallest sum of absolute differences by frequency band Comparison of atmospheric effects Candidate spectral classes and the normalized aircraftspecific spectra are respectively used to calculate the NPD corrections to be applied at the 10 distances for 6 different Temperature and Humidity conditions (incl. extreme ones) The best candidate is the spectral class scoring the smallest sum of individual db correction differences at the 10 distances 11

12 Step 2 Spectral Class Assignment Comparison of ground effects Candidate spectral classes and the normalized aircraftspecific spectra are respectively used to calculate excess ground attenuation corrections At the 10 NPD distances and for 12 emission angles Using the theoretical model documented by Embleton, Piercy and Daigle (the EPD model) The retained candidate is the spectral class scoring the smallest sum of individual differences 12

13 Step 2 Spectral Class Assignment Comparison of barrier effects Candidate spectral classes and the normalized aircraftspecific spectra are respectively used to calculate barrier effect corrections At the 10 NPD distances and for 7 path-length differences Using the method documented by Barry and Regan (Highway Traffic Noise Prediction Model) The retained candidate is the spectral class scoring the smallest sum of individual differences 13

14 Step 2 Spectral Class Assignment Final spectral class assignment Ideally, the different tests should designate the same best spectral class If not, the majority rule applies In some cases, need to create a new spectral class 14

15 Step 3 Performance Data V&V Internal consistency check Detect possible contradictions in the data submittals Consistency check with prior submittals For similar aircraft from same manufacturer Reasonableness check Comparison with other similar aircraft types E.g. similar maximum takeoff/landing weights, engine types, static thrust 15

16 Step 3 Performance Data V&V Suitability across different atmospheric conditions Performance data (engine and aerodynamic coefficients) are checked to ensure their suitability for use across typical range of atmospheric conditions (airport elevation, temperature, pressure) Vertical profiles (height, speed and thrust Vs distance) are calculated from procedural step profiles under different atmospheric conditions and analysed to detect any unusual behaviour When available, comparison with manufacturer-supplied reference vertical (fixed-point) profiles 16

17 Step 4 Comparison with Certification Data Submitted ANP data are integrated in the database of the Doc.29 compliant model, which is then run to mimic a certification flight test Use of the submitted NPD data for EPNL and PNLTmax EPNL calculated at the three certification points (lateral, flyover and approach) Comparison with certification levels of the aircraft 17