Author Topic: "Power lines" warning  (Read 3769 times)

Offline jrdioko

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"Power lines" warning
« on: April 09, 2011, 08:27:58 PM »
During a flight lesson today, on frequency we heard a brief warning siren, then a recorded voice saying "Power lines" several times. What was that?



Offline StuSEL

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Re: "Power lines" warning
« Reply #1 on: April 09, 2011, 08:42:02 PM »
What were you flying?
CFII

Offline jrdioko

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Re: "Power lines" warning
« Reply #2 on: April 09, 2011, 08:55:12 PM »
A Cessna, the recording was on whatever frequency we were on (tower, I believe). I looked back at the recordings and couldn't find it.

Offline MikeNYC

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Re: "Power lines" warning
« Reply #3 on: April 09, 2011, 09:41:57 PM »
Jrdioko,

Where are you located? There are automated systems in certain parts of the world to alert aircraft to wind turbine farms, aerial tramway cables, and power lines. You can find more information here:

https://www.pprune.org/archive/index.php/t-341173.html
http://ocas-as.no/solutions_2/power_lines/
Feed Provider Of:
NYC Helicopter Class B/Ops
KEWR Tower (TCA/Helicopters)
NYC Helicopter CTAF
KLGA NY Approach (HAARP/Final/Dep)
KTEB Del/Gnd/Tower
NYC MilAir/MISC

Offline jrdioko

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Re: "Power lines" warning
« Reply #4 on: April 09, 2011, 09:45:36 PM »
Interesting. Hayward, California.

Offline NoMad

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Re: "Power lines" warning
« Reply #5 on: April 10, 2011, 10:47:49 AM »

The transmission tower on the approach path (presumably) has a receiver that picks up the aircraft's transponder reply so it knows there is a nearby aircraft.  It is a ~ 1/2 watt transmitter on the appropriate comm channel that makes that audible warning.  So it only transmits when there is an A/C nearby and at very low power so only the nearby A/C hear it.