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Aerospace Ice Crystal Testing

Aerospace Ice Crystal Testing. FAA Perspective. Ice Crystal Workshop - Winnipeg. John Fisher, EPD Standards Staff Federal Aviation Administration. November 29, 2011. Overview. History of Regulatory Requirements Compliance: Desires vs. Realities The Path Forward. Historical Perspective.

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Aerospace Ice Crystal Testing

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  1. Aerospace Ice Crystal Testing FAA Perspective Ice Crystal Workshop - Winnipeg John Fisher, EPD Standards Staff Federal Aviation Administration November 29, 2011

  2. Overview • History of Regulatory Requirements • Compliance: Desires vs. Realities • The Path Forward

  3. Historical Perspective • 1940s/1950s • NACA data, McNaughton data, FAA ADS-4 • In flight power losses of Britannia turboprop aircraft • 1970s/1980s • Warnings in OEM publications • NTSB: Sept.24, 1981 (part 25 aircraft safety rec.) • 2000s • NTSB: Spirit Air – June 4, 2002, Power-loss • ARAC: EHWG/PPIHWG 2003-2005

  4. Historical Perspective - Rulemaking • ARAC EHWG/PPIHWG • Identified over 100 power-loss events in mixed phase and ice crystal conditions. • Rulemaking proposed to FAA: Appendix D of part 33 • FAA rulemaking in process. Expect mid-2012 publication. • EASA • Proposing Appendix P of CS25 (similar to FAA Appendix D) Currently FAA/EASA/TC all have harmonized ice crystal environmental definition (App D – App P)

  5. Compliance: Desires vs Realities • Desires: • Well developed and validated analysis of engine susceptibility to power loss from ice crystals • Test demonstration of the most susceptible conditions. We desire to drive toward similar compliance practices as used for Appendix C conditions.

  6. Compliance: Desires vs Realities • Realities: • Currently we have significant limitations in: • Unsubstantiated environmental definition (i.e. App D) • Darwin flight test campaign (2012/2013) • Basic understanding of the physics of accretion. • NRC R&D testing underway. • Test facility capabilities to demonstrate compliance. • NRC developing test methods • Some facilities are awaiting FAA icing rule publication prior to investing in test equipment. Current proposed rule and guidance recognizes today’s realities but lays the ground work for future advances in knowledge and capability.

  7. But we continue to accumulate events! • Over 150 power loss events. • 14 total power loss events (i.e. all engines out). • Seven (7) CAAM-3* safety significant events (e.g. loss of >5000 feet altitude). * Continued Airworthiness Assessment Methodology (CAAM)

  8. So where do we need to go from here?

  9. Next Steps in our Path Forward • Substantiate environmental definition (i.e. App D (FAA) and P (EASA)). • Complete Darwin campaign. • Perform analysis on Darwin data • Gather and analyze all service event data. • Both engine and probe data. • Harmonize environmental definition. • FAA-EASA-TCCA

  10. Next Steps in our Path Forward • Improve our understanding of accretion physics: • NRC studies • NASA PSL tests

  11. Next Steps in our Path Forward • Further develop test capability • Full engine test capability • NRC • NASA PSL (?) • GLACIER (?) • Others (?) – Eglin/McKinley, GE Winnipeg, CEPR/Saclay • Wind Tunnel tests for probes. • NASA IRT • Goodrich • Others (?)

  12. Next Steps in our Path Forward • Need to standardize analytical approaches for assessing engine design’s susceptibility to accretion. • Utilize NRC and NASA accretion studies. • AIA/EIWG or ARAC/EHWG collaboration to agree on key elements of a standardized approach. Develop AC 20-147A material to identify a standardized approach.

  13. Next Steps in our Path Forward • Note that ARAC EHWG Task 2 Report which was submitted to the FAA stated: • “Validated analysis of engine icing in glaciated environment is required for assessment of this icing threat.” (Note: this will take time to develop a standardized approach. Validation of the environment as well as basic physics studies must be completed)

  14. Next Steps in our Path Forward • Need to identify critical ice crystal test conditions, when test facilities are available. • Note that ARAC EHWG Task 2 Report stated: “Manufacturers will have to demonstrate to FAA that they have thoroughly addressed Critical Point Analysis requirements for natural icing in … the new 14 CFR Part 33 Appendix D.” (Note EIWG has been recently requested to develop this)

  15. Next Steps in our Path Forward • Will need to revise compliance guidance material (AC 20-147A) and possibly regulatory requirements (14 CFR 33.68), to reflect all of these developments. • Target revisions for CY2015.

  16. Finally we need to: HARMONIZE

  17. Questions?

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