Author Topic: What is this alarm sound  (Read 10207 times)

Offline dtmf

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What is this alarm sound
« on: January 27, 2009, 08:38:19 PM »
Heard this a week ago, since I never heard an alarm that sounds for any good reason , I started to record this conversation between CYUL tower and YKL thinking I was going to hear something out of the ordinary but,  aside of the alarm sound, there was nothing special I heard??? . Today again I hear it on a other flight so I'm guessing this is not an emergency. Anyone knows what's this sound.



Offline jordan1900d

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Re: What is this alarm sound
« Reply #1 on: January 27, 2009, 09:06:32 PM »
Depending on the type of a/c, I would guess a landing gear horn (gear still up, throttle @ idle in a landing config)

djmodifyd

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Re: What is this alarm sound
« Reply #2 on: January 27, 2009, 09:56:10 PM »
you know...i hear that noise ALL the time coming from a cherokee

the pilot says its his anti collision lights causing the noise.......idk....maybe its true, but it seems kinda weird

Offline cessna157

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Re: What is this alarm sound
« Reply #3 on: January 27, 2009, 10:12:56 PM »
After I first heard it, it did sound like some odd gear horn.  But awefully loud.

But, since you mention the strobes, that is indeed what it is, but that's the worst I've ever heard.  It, if I recall correctly, is a bad ground connection from the strobe power supply, and it is causing feedback into the aircraft's electrical system.  But wow, this one is bad.
CRJ7/CRJ9 F/O, Travel Agent

Offline fholbert

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Re: What is this alarm sound
« Reply #4 on: January 27, 2009, 10:45:39 PM »
Heard this a week ago, since I never heard an alarm that sounds for any good reason , I started to record this conversation between CYUL tower and YKL thinking I was going to hear something out of the ordinary but,  aside of the alarm sound, there was nothing special I heard??? . Today again I hear it on a other flight so I'm guessing this is not an emergency. Anyone knows what's this sound.

Strobe lights. Even the big boys have that sometimes.

Frank Holbert
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Frank Holbert
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Offline CFD208

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Re: What is this alarm sound
« Reply #5 on: January 28, 2009, 04:33:05 AM »
Defiantly not strobes.  A strobe noise through a ground connection is much higher in pitch.  Almost exactly what an external flash on a camera sounds like firing and recharging.

djmodifyd

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Re: What is this alarm sound
« Reply #6 on: January 28, 2009, 10:19:24 AM »
Defiantly not strobes.  A strobe noise through a ground connection is much higher in pitch.  Almost exactly what an external flash on a camera sounds like firing and recharging.

not the ones that i've heard....they are not anywhere close to that high of a frequency

Offline beechsundowner

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Re: What is this alarm sound
« Reply #7 on: January 28, 2009, 05:33:23 PM »
I get that intermittent noise through my intercom system sometimes, never that loud and never on transmitting, but along the same type of sound.  I think Frank may be right with it being the strobes OR another thought maybe a faltering or fluctuating alternator where it will cause some fluctuating noise within the avionic stack.

Avionics a strange beast.  I get an irritating squeal noise in the headset when I transmit, yet outside the plane, crystal clear.  Not the radio since the radios are different models so it has to be the wiring between the PTT and radios.  PTT button brand new.
« Last Edit: January 28, 2009, 05:42:18 PM by beechsundowner »

Offline hkyplr18

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Re: What is this alarm sound
« Reply #8 on: January 28, 2009, 05:40:35 PM »
OVERSPEED 

KJET100

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Re: What is this alarm sound
« Reply #9 on: January 31, 2009, 01:56:47 PM »
wow, everyone is a genius. but definitely not an engineer.

Offline Switch Monkey

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Re: What is this alarm sound
« Reply #10 on: February 26, 2009, 11:26:55 PM »
Igniters mabey. King Airs and B190 make a similar sound.

Offline Unbeliever

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Re: What is this alarm sound
« Reply #11 on: February 27, 2009, 03:45:43 PM »
Interference from the power supply for the strobes into the intercom and/or radios.  I fly a 172 that makes that exact same noise (just not THAT loud) when the strobes are on.  Fortunately, it is only to the pilot, and not TXed out.

--Carlos V.


« Last Edit: February 27, 2009, 07:07:12 PM by Unbeliever »