1. FAA Technical Center 07/31/02 1 Does Use Of H-field Antenna Increase Availability Of Loran When In Presence of P-static As Compared To An E-field Antenna? - Status Report R. Erikson

2. FAA Technical Center 07/31/02 2 Test Overview Ground Test –Instrumentation Check-out / Calibration –Measure effects of P-static under controlled environment Flight Test –Natural Charging –Artificial Charging

3. FAA Technical Center 07/31/02 3 Contract Support ISTI under contract –Bob Truax (subcontract)

4. FAA Technical Center 07/31/02 4 Documentation Reference –Advisory Circular –SAE –MIL Spec Safety Plan (draft) Test Plan (draft)

5. FAA Technical Center 07/31/02 5 Equipment (on hand) Instrumented Static Dischargers Sat Mate Loran Receivers (2) Apollo 618 Loran Receiver Tail Cone Field Mill

6. FAA Technical Center 07/31/02 6 Equipment (not received) Skin Map H-field Antenna (Locus) High Voltage Power Supply and Controls Acrylic Data Collector Misc.. Supplies (cable, tape, etc.)

7. FAA Technical Center 07/31/02 7 HV Power Supply

8. FAA Technical Center 07/31/02 8 Control Panel

9. FAA Technical Center 07/31/02 9 Aircraft Aero Commander (reserved August & September 2002)

10. FAA Technical Center 07/31/02 10 LORIPP Recommendations Calibrate Loran Receivers Use Wide Band Recording Of Noise Caused by P-Static Investigate effects of –Streaming –Corona –Arcs

11. FAA Technical Center 07/31/02 11 What is p-static? P-static noise is the electrical by-product of the arrival and departure of ions from an airframe in flight. Ions are produced during collision of airframe with neutral rain or ice particles, or flight in charged airspace (near thunderstorms). Once charged, the ions can create noise in three ways: –Corona - Departure of ions from trailing edges in the slipstream »Corona threshold is “tuned” by the geometry of the airframe »“Dischargers” use small curvature radii to reduce threshold –Streamers - Ion paths across dielectric surfaces (radomes, windscreens, composites) »Reduced by conductive coatings, other techniques –Arcs - Discharge between unbonded airframe parts charged to different potentials »Can be energetic, but less continuous than corona or streamers. The process involves high voltages, low currents –40 - 50 kV on GA aircraft –Tens to hundreds of uA discharge current