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Sound Testing Requirements For Zero Flight Time (Level D) Simulators. By Mark Dransfield and David Haselum. Contents. Industry initiatives Current FFS sound requirements & regulations Draft Proposals Results of Assessment of Proposals The next steps , Summary & Conclusions.
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Sound Testing Requirements For Zero Flight Time (Level D) Simulators By Mark Dransfield and David Haselum
Contents • Industry initiatives • Current FFS sound requirements & regulations • Draft Proposals • Results of Assessment of Proposals • The next steps , Summary & Conclusions
Industry Initiatives • Greater breadth of data available should enhance • Fidelity of simulation • Effective (objective) testing • Simulator Technical Issues Group (STIG) • Industry participation • A/c manufacturers • Simulator manufacturers & operators • Regulatory authorities • Output was a draft proposal for enhanced Level D testing
Current FFS Sound Requirements • AC120-40B /C • Level C and below • Subjective assessment only (Pilot tuned) • Level D (zero flight time) • Subjective assessment • Static Tests only • No explicit tolerances • IQTG / JAR-STD1A / ICAO regulations • Level C & D requirements as above
Draft Proposals • Static tests • Four different phases • Ambient - A/C systems powered only • Gear Extended - Landing phase , gear & flaps extended • Cruise - (VMO/MMO) • On ground static - Take-Off thrust against brakes • Test type required • Third Octave band analysis • Tolerances • Algorithm developed (+/- 5dB to 10 dB)
Draft Proposals • Dynamic / Transient tests • 6 engine or configuration change tests • Engine start • Engine acceleration • Engine deceleration • Gear retraction • Gear extension • Thrust reverser operation (if applicable) • Airplane Specific Special Cases • Condition Lever Sweep (Turboprops) • Speedbrakes or other specifics
Draft Proposals • Dynamic / Transient tests (Contd. ...) • Test type required • dBA Time history (typically 30 to 60 seconds) • Octave band spectral analysis on 3 to 5 of the transients • Representative cases & bands to be specified by a/c manufacturer • Tolerances • Time history plots +/- 3db • Octave band analysis +/- 2db or 20% (on significant octave band)
Implementation • October 96 until present .... • Boeing flight test data provided for B777 (including dynamic tests) • Data analysed and incorporated • Checks developed on UAL B777 FFS • Initial results obtained • Pilot subjective assessment performed • FAA Level D achieved (static plots only)
Findings • Static tests • Tolerances seem realistic & achievable • Add Climb condition? • Dynamic Tests • Time history tolerance (+/- 3dB) • Tight but achievable • Octave band analysis tolerance (+/- 2dB) • Very tight , difficult to achieve (+/- 6dB achieved) • Equipment expensive to hire and skilled operator required • Time consuming, little effect on pilot satisfaction • Some wording in proposal needs clarification • Allowance for Pilot subjective assessment required
Next Steps • Feedback , discussion of results , comments , opinions from • A/c manufacturers • Simulator manufacturers • Pilot community • Refinement of Draft proposals • Further testing? • Adoption into regulations
Summary & Conclusions • Draft proposal developed for enhanced testing of sound simulation for Level D FFS • Assessment completed on B777 device, with some concerns on ... • Tight tolerances for Octave band dynamic tests • Some wording open to interpretation • Costs in equipment and training • Initial versus recurrent approval requirements • Allowance for subjective tuning • Refine draft proposal with industry involvement • Adoption into regulations