Figure 9. (a) Intermittent short condition at voltage enhancement location TP-6

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discharges in the laboratory installation at a

assist in this analysis, the JSC provided

frequency of 6.8 MHz. For this frequency, the most

supplementary data showing all dominant

likely RF source would have been the on-board HF

transmitters contributing to the TWA-800

radio. However, it is known that the TWA-800 HF

environment below 30 MHz. By evaluating the

radio was not transmitting during its flight. The

entire B-747-100 airframe as an efficient and

threat analysis, therefore, needed to consider

perfectly tuned dipole antenna, it was calculated

sources external to the aircraft. (Commercially

that TWA-800 could not have coupled more than

available PEDs were determined to be insignificant

0.015 W of power from any of these sources. See

in terms of radiated power below 25 MHz.) To

[5] for analysis details.

(a)

Detected Sparking

(b)

Figure 9. (a) Intermittent short condition at voltage enhancement location TP-6. (b) Night vision system

display showing a discharge event at TP-6. (Note that this image was taken through a mirror, and is

therefore reversed.)

100,000.00

LO Z (red) to Chassis Excitation

HI Z to Chassis Induced Fault

10,000.00

1,000.00

LO Z COMP (blue) to Chassis Excitation

LO Z COMP (blue) to Chassis Induced Fault

100.00

10.00

1.00

Typ. Portable PEDs

FCC_Specs-Partial

ANSI C63.18-1997

0.10

Lab. Min Arc Power 1

Lab. Min Arc Power 2

0.01

100

1,000

10,000

Freq (MHz)

Figure 10. FQIS minimum observed arc/spark levels with different excitation and induced faults. Also

shown are PED threats, adjusted for passenger cabin-to-CWT FQIS connector path loss.