Re: WN 737 landing lights

Date:         27 Aug 99 03:07:42 
From:         Art & Janet <>
Organization: AT&T WorldNet Services
References:   1
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boeing707 wrote:
> I work for USAirways in FLL. Recently, I have seen Southwest 737
> (models -300/-500 and the -700) landing lights blinking on and off
> during their approach. Have only seen it on Southwest.
> The entire set of landing lights on the wings alternately blink on and
> off. Then when the airplane nears the inner marker, the blinking stops
> and the lights are on steadily.
> I have also seen this on a few Falcon 30's and Lears, but WN is the
> only airline I've seen this on.
> Can anybody give me the story on the blinking landing lights?
> And, doesnt it lower the life of the lamp?

The pulsating light concept has been available on general aviation
aircraft for many years (see Pulselight corp)

The concept is based on studies which show higher pilot awareness of the
flashing lights than a steady beam. Motorcycle and train lights also use
his concept.

As for life, the bulb actually lasts a lot longer if it is pulsed. The
filament stays cooler and stronger because the intermittent heatup
(instead of continuous current) prevents the filament from getting too
soft which would allow it to vibrate to failure.

-- Art & Janet
your mileage may vary