Aircraft performance monitoring

Transcription

1 Regional Seminar Aircraft performance monitoring Presented by Steve BARKER / Senior Performance Engineer

2 Contents What is aircraft performance monitoring? Performance monitoring principle Causes of deterioration Implications Performance recovery APM results Conclusion Page 2

4 1 What is aircraft performance monitoring? Definition Procedure of determination of the actual performance level of each airplane of the fleet versus the manufacturer s book level through analysis of data gathered in operations Book level established by the aircraft manufacturer as a result of theoretical analysis and test flights Flight Crew Operating Manual IFP, FLIP or APM software (part of the Performance Engineers Package) Page 4

5 1 What is aircraft performance monitoring? Definition Baseline level established at the entry into service of an individual aircraft during the acceptance flight or delivery flight can be above or below the book level Trends performance levels are measured over time so that trends are identified the baseline level is the starting point for the trend monitoring Page 5

6 1 What is aircraft performance monitoring? Aim To adjust the performance factor of the computerised flight plan the FMS predictions To monitor the aircraft condition periodically in order to analyze the trend of a given tail number or of a whole fleet To identify any degraded aircraft within the fleet and take the necessary corrective actions: Maintenance actions Operational recommendations Regulatory requirement from authorities for ETOPS and reduced reserves operations Page 6

8 2 Performance monitoring principle Three commonly used methods The fuel used method The fuel on board method The specific range method Page 8

9 2 Performance monitoring principle The fuel used method measurement of the fuel burnt by the aircraft in level flight (stabilized cruise) over a significantly Advantage: long time leg Smoothes variations in recorded parameters over comparison to the fuel the prediction recording of period the Flight Crew Operating Manual (FCOM, Volume 2, Flight Planning sections) or the High Speed Performance calculation program developed by Airbus Industrie (the IFP program). Disadvantage: Tedious manual recording of data in flight Compares the IFP model to the actual aircraft in cruise Page 9

10 2 Performance monitoring principle The fuel burn off method comparison of the aircraft performance over a complete flight with the one forecasted by the computerized Advantage: flight planning Easy to implement the actual aircraft performance is corrected depending on the differences between the actual flight profile and the predicted one. Disadvantage: Compares Accumulation the IFP model of errors to actual due to aircraft differences over a between all phases of a flight CFP and the actual flight Page 10

11 2 Performance monitoring principle The specific range method The data observed in flight represents punctual (instantaneous) airframe/engine performance capability. The data is recorded during stable cruise flight legs and is used to determine: the actual specific range, the delta specific range in percentage relative to the book level (predicted specific range), the delta EPR/N1 required to maintain the flight conditions, the delta fuel flow resulting from this delta EPR/N1, the delta fuel flow required to maintain this delta EPR/N1. Compares the IFP model to actual aircraft Page 11

12 2 Performance monitoring principle Cruise Point Aircraft Model Theoretical N1 or EPR Engine Model Theoretical Fuel Flow Airframe* GW CG EPR Bleeds Mach TAT Fuel Flow... Real Aircraft Actual N1 or EPR Engine Model Real Engine Calculated Fuel Flow Engine* Actual Fuel Flow A/C * Only if engine thrust to N1/EPR relationship same as model Page 12

13 2 Performance monitoring principle DSR: Delta Specific Range DFFA, DFFB: Delta Fuel Flow A, B Cruise Point Aircraft Model Theoretical N1 or EPR Engine Model Theoretical Fuel Flow Airframe* DFFA GW CG EPR Bleeds Mach TAT Fuel Flow... Real Aircraft Actual N1 or EPR Engine Model Real Engine Calculated Fuel Flow Engine* DFFB Actual Fuel Flow A/C DSR Page 13

15 3 Causes of deterioration Engines 80% Fan blade Leading Edge erosion Blended blades (FOD) Fan rubstrip wear Fan & Compressor dirt High time engine core deterioration System settings Nacelle air leakage Page 15

16 3 Causes of deterioration Airframe 20% Aerodynamic surface misrigging Seals missing or damaged Doors not flush or leaking Rough or deformed surfaces Chipped paint Dirty aircraft Airbus experience is that this is no more than 1 to 1.5% DSR for an aircraft in bad condition Page 16

17 Aircraft performance monitoring 3 Causes of deterioration Examples of aerodynamic degradation External Patches Peeling Paint Misrigged Slat Mismatched Doors Rough or Damaged Panels Page 17 Repaired Lightning Damage Misrigged Spoiler

19 4 Implications Flight planning If the Computerised Flight Plan is based on new aircraft performance, deteriorated aircraft will burn more trip fuel than planned. Planned reserve fuel will also be optimistic. Flight operations The Flight Management System (FMS) fuel prediction function (FOB at Destination, Alternate, Extra Time, etc) will initially show values close to CFP, but these values will decrease as the flight continues. Crew confidence If no action is taken at the dispatch level, the aircrew will lose confidence in the fuel planning and will start adding their own reserves. They will normally overcompensate. Page 19

20 4 Implications Perception Operators with no previous knowledge of aircraft monitoring are often surprised by the deterioration, and believe that there is a problem with the aircraft. Operations Extra fuel due to aircraft deterioration may impact payload, and in the worst case make some routes not viable for some tail numbers. Operating costs As fuel is a major component of costs, any increase significantly affects the overall operating costs. In addition, overcompensation of reserves also increases fuel burn and costs. Page 20

21 4 Implications Assuming a 5% fuel burn increase over one year kg more fuel kg more fuel kg more fuel Page 21

23 5 Performance recovery Major improvements are difficult without engine change However Regular engine core wash reduces deposits helps Keeping an aircraft clean helps Aircraft should be well maintained aerodynamically Engines systems, bleeds, etc. should be kept in trim and functioning properly Remember that trend monitoring of APM results can detect aerodynamic or engine system irregularities Page 23

25 6 APM results Performance trending: Allows trending over flight hours, flight cycles: For individual tail PERFORMANCE numbersin REVENUE SERVICE Performance Monitoring EVOLUTION SINCE EIS For the whole fleet. Evolution versus number of flight cycles Can be used as a trigger condition for corrective actions. Specific Specific Range Range Deviation Deviation from (%) IFP from (%) IFP Number of T/O from EIS Quarters from EIS Page 25

26 6 APM results Changing the fuel factor Technique 1 - Step Fuel Factors: Fuel factor is changed when a difference of more than a given percentage is noticed between the new figure and the last retained one Monitored fuel factor (%) Jun 12 Jul 12 Aug 12 Sep 12 Oct 12 Nov 12 Dec 12 Jan 13 Feb 13 Actual monitored fuel factor Retained monitored fuel factor Page 26

27 6 APM results Changing the fuel factor Technique 2 - Smoothed Fuel Factors: Monitored fuel factors are averaged using a rolling average technique over say three months Monitored fuel factor (%) Jun 12 Jul 12 Aug 12 Sep 12 Oct 12 Nov 12 Dec 12 Jan 13 Feb 13 Actual monitored fuel factor Retained monitored fuel factor Page 27

29 7 Conclusion Routine aircraft performance monitoring identifies trends First step towards the identification of a aircraft degradation Aid to monitor the shift of the aircraft performance level Particular attention to degraded aircraft within the fleet Determination of ABSOLUTE aircraft performance level is NOT the goal Page 29

30 Noise abatement recommendations Thank you Xie xie 谢谢 This document and all information contained herein is the sole property of AIRBUS China LTD. No intellectual property rights are granted by the delivery of this document or the disclosure of its content. This document shall not be reproduced or disclosed to a third party without the express written consent of AIRBUS China LTD. This document and its content shall not be used for any purpose other than that for which it is supplied. The statements made herein do not constitute an offer. They are based on the mentioned assumptions and are expressed in good faith. Where the supporting grounds for these statements are not shown, AIRBUS China LTD. will be pleased to explain the basis thereof. AIRBUS, its logo, A300, A310, A318, A319, A320, A321, A330, A340, A350, A380, A400M are registered trademarks. Page 30