AerospaceFan
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How Loud Are Eicas Master Warning Sirens?

Sun Jun 18, 2006 3:11 pm

Exactly how loud are sirens for critical warnings issued by typical EICAS systems in large passenger aircraft, like the Boeing 747, 777, etc., and the Airbus A340, A330, etc.? I assume that both Boeing and Airbus install EICAS systems in all of their production aircraft.

I know it's hard to describe how loud a siren is. Perhaps one can compare the sound level to such things as clock radio alarms (although these, too, vary in intensity). I will leave the manner of description to those who desire to respond, although if one uses decibels, I will simply have to look up their practical equivalent.

Thanks in advance.

[Edited 2006-06-18 08:14:36]
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Matt72033
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RE: How Loud Are Eicas Master Warning Sirens?

Sun Jun 18, 2006 3:55 pm

its hard to say really, though i will say the audible call outs for the GPWS system are much louder on the airbus.....well certainly the 340 over the 747 anyway!.......in my opinion its almost too loud!
 
EMBQA
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RE: How Loud Are Eicas Master Warning Sirens?

Sun Jun 18, 2006 9:41 pm

Quoting AerospaceFan (Thread starter):
Exactly how loud are sirens for critical warnings issued by typical EICAS systems in large passenger aircraft

Loud enough..!! We were out doing high power engine runs yesterday with a turboprop and had the 'Config Warning' go off. Myself and the mechanic running the plane were shouting at each other just to be heard over the engine noise....but we heard that. It was part of the test and scheduled to happen.
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AerospaceFan
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RE: How Loud Are Eicas Master Warning Sirens?

Sun Jun 18, 2006 10:03 pm

Thanks for the great answers! I really appreciate them.
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CSMUK
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RE: How Loud Are Eicas Master Warning Sirens?

Sun Jun 18, 2006 10:04 pm

I am not totally sure, but the other week when I was having my diner with the pilots in the flight deck the aircraft (744) reached a certain altitude and we got the ‘beep’ but it was so loud I spelt cola everywhere!

Surely they can adjust the volume? I know that TCAS can get louder depending on the type of alert/warning?

I know that the GPWS is very loud, the pilots always say that its one warning you will never miss…

Dana
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AerospaceFan
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RE: How Loud Are Eicas Master Warning Sirens?

Sun Jun 18, 2006 10:29 pm

I must admit that the reason I asked this question yesterday was that my curiosity was piqued by the "Vietnam Airlines pilots allegedly fell asleep" story that was discussed in the Civil Aviation Forum. Someone mentioned that there is a crew alertness monitor, also referenced on the Internet as an "electronic pilot activity and alertness monitor" (EPAM), installed on certain late-model airliners, that determines whether pilots are possibly or probably inattentive or asleep, and, if so, flashes visual inquiries onscreen accordingly, sounds an audible warning if video inquiries are not answered. I have no idea how loud this warning would be, and whether critical EICAS sirens would be as loud or louder.

Since I am a fairly sound sleeper, I was curious as to whether such a system, and EICAS systems in general, would be loud enough to waken all pilots who had fallen asleep. (If not, and if sounds aren't necessarily sufficient, then one could also contemplate the invention and use of "seat shakers", analogous to "stick shakers".)

Interesting to me, also, is the fact that collision avoidance or ground proximity warning systems I have seen covered in the news can emit urgent verbal warnings, such as "PULL UP! PULL UP! PULL UP!" The messages undoubtedly vary by need, and although such systems will never be accused of being good conversationalists, I suspect that they have the necessary vocabulary of phrases to fulfill their critical function.

[Edited 2006-06-18 15:35:58]
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PhilSquares
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RE: How Loud Are Eicas Master Warning Sirens?

Sun Jun 18, 2006 11:19 pm

Quoting AerospaceFan (Reply 5):
Since I am a fairly sound sleeper, I was curious as to whether such a system, and EICAS systems in general, would be loud enough to waken all pilots who had fallen asleep. (If not, and if sounds aren't necessarily sufficient, then one could also contemplate the invention and use of "seat shakers", analogous to "stick shakers".)

The crew activity EICAS message starts as an advisory, then caution and finally warning. Very loud.

Quoting AerospaceFan (Reply 5):
Surely they can adjust the volume?

No adjustment (from the cockpit)

[Edited 2006-06-18 16:20:55]
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AerospaceFan
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RE: How Loud Are Eicas Master Warning Sirens?

Mon Jun 19, 2006 12:13 am

Quote:
Surely they can adjust the volume?

Just a minor note to say that the above inquiry came from CSMUK.

Thanks for the response, PhilSquares; I appreciate it.

[Edited 2006-06-18 17:14:34]
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PhilSquares
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RE: How Loud Are Eicas Master Warning Sirens?

Mon Jun 19, 2006 1:08 am

Quoting PhilSquares (Reply 6):
Quoting AerospaceFan (Reply 5):
Surely they can adjust the volume?

No adjustment (from the cockpit)

Sorry, didn't even check, must have highlighted incorrectly....:-(
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HAWK21M
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RE: How Loud Are Eicas Master Warning Sirens?

Mon Jun 19, 2006 2:20 am

EICAS related Warning Bell on the B752s are Loud enough & cannot be not heard  Smile
Typical Sound.
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MEL
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litz
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RE: How Loud Are Eicas Master Warning Sirens?

Mon Jun 19, 2006 7:24 am

I can tell you this ... was seated in First on a DL MD88 and we were coming into ATL ahead of a seriously huge thunderstorm band.

Ie: Welcome to Atlanta, Mid-Summer.

We actually OVERFLEW the airport, and the GPWS sounded off as we passed over the airfield (I assume 'cause we hit the leading edge of the storm and such) ... It also went off again, AFTER we'd circled and actually landed on our 2nd attempt, wheels on the ground and all, right before we hit the edge of the squall line (and the wall of water that came with it).

Seated in First, it was clearly audible. In the cabin. Loudly. I wouldn't be surprised if the first 5 or so rows in coach clearly heard it.

20 or so people leaning out into the aisle looking up at the cockpit door with wide eyes ...

We landed safely, however, but we sat on the taxiway for 45 minutes wating for the storm to pass so the rampers could marshal us in ...

- litz
 
lincoln
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RE: How Loud Are Eicas Master Warning Sirens?

Mon Jun 19, 2006 12:40 pm

Quoting PhilSquares (Reply 6):
No adjustment (from the cockpit)

Yeah, I think having a volume adjustment would be a very bad idea. Anyone want to take bets on how often it would be turned down (or off) due to nusence alerts...and then how often no one would remember to turn it back up/on? It's purpose in life is to be annoying; providing a volume control would lessen that.

Though, I do think "WHOOP WHOOP Too Low Pull Up" would make a nice ringtone...but I'm a geek.

Quoting Litz (Reply 10):
Seated in First, it was clearly audible. In the cabin. Loudly.

I've heard a few of those... I always wonder how an already twitchy pax (i.e. the one who starts screaming "we're all going to die, we're all going to die"[1] at the first sight of turbulance) is going to react to that

Lincoln

[1] I, thankfully, have only had one of this type of pax seated next to me. And it wasn't on one of the aforementioned flights.
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Markhkg
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RE: How Loud Are Eicas Master Warning Sirens?

Mon Jun 19, 2006 6:03 pm

Quoting Litz (Reply 10):
GPWS sounded off as we passed over the airfield (I assume 'cause we hit the leading edge of the storm and such

Which GPWS warning was it?
"WINDSHEAR, WINDSHEAR, WINDSHEAR"?
Or something else equally terrifying?
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HAWK21M
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RE: How Loud Are Eicas Master Warning Sirens?

Mon Jun 19, 2006 8:20 pm

Quoting Litz (Reply 10):
We actually OVERFLEW the airport, and the GPWS sounded off as we passed over the airfield

What Audio.
regds
MEL
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Matt72033
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RE: How Loud Are Eicas Master Warning Sirens?

Tue Jun 20, 2006 1:51 am

Quoting Litz (Reply 10):
We actually OVERFLEW the airport, and the GPWS sounded off as we passed over the airfield (I assume 'cause we hit the leading edge of the storm and such) ... It also went off again, AFTER we'd circled and actually landed on our 2nd attempt, wheels on the ground and all, right before we hit the edge of the squall line (and the wall of water that came with it).



Quoting MarkHKG (Reply 12):
Which GPWS warning was it?
"WINDSHEAR, WINDSHEAR, WINDSHEAR"?

Windshear isnt part of the GPWS system
GPWS is a box with a terrain database in it......it gives you the "terrain terrain" call outs!

Windshear is a function of the weather radar!

(i'm pretty sure anyway)
 
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HAWK21M
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RE: How Loud Are Eicas Master Warning Sirens?

Tue Jun 20, 2006 2:08 am

Quoting Matt72033 (Reply 14):
Windshear is a function of the weather radar!

Isn't Mode 7 Windshear.
regds
MEL
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Matt72033
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RE: How Loud Are Eicas Master Warning Sirens?

Tue Jun 20, 2006 2:54 am

Quoting HAWK21M (Reply 15):

Isn't Mode 7 Windshear.

i'm not sure.....i know certainly on the 744 GPWS is a terrain database, we have to update the database evry now and again, any terrain shown on the ND is taken from the GPWS database.....not the radar!

Windshear cant be detected from a stored database!
 
dc10hound
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RE: How Loud Are Eicas Master Warning Sirens?

Tue Jun 20, 2006 5:28 am

Quoting HAWK21M (Reply 15):

Isn't Mode 7 Windshear.
regds
MEL

MEL, you are correct:

AAL B757 AMM 34-46-00-0

(7) Mode 7 Function

(a) Mode 7 warning signals are provided when flying into an excessive windshear condition during takeoff or approach. If an excessive downdraft or tailwind condition is detected, a two tone siren followed by an aural WINDSHEAR, WINDSHEAR, WINDSHEAR warning is heard. A red WINDSHEAR message is displayed on the captain's and first officer's PFD, and the red WINDSHEAR and master warning lights come on. When the windshear warning is active, all other GPWS modes are inhibited. These modes stay inhibited as long as there is an excessive windshear condition.

(b) Aural messages are prioritized; windshear warnings take priority over all other ground proximity warning system alerts.

Quoting Matt72033 (Reply 14):
Windshear is a function of the weather radar!

Matt, Predictive Winshear signals are sent to GPWS from the WXR system:

AAL AMM 34-46-00-0

i) Weather Radar System The EGPWS uses status word data (predictive windshear alerts, onside/offside WXR data) from the Weather Radar System (WXR), if the WXR data input bus is connected.
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KAUSpilot
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RE: How Loud Are Eicas Master Warning Sirens?

Tue Jun 20, 2006 5:36 am

Quoting Matt72033 (Reply 14):
Windshear isnt part of the GPWS system
GPWS is a box with a terrain database in it......it gives you the "terrain terrain" call outs!

Windshear is a function of the weather radar!

Windshear alerting systems use the same type of aural warnings that the GPWS system uses (as does TCAS), but they are seperate systems. Windshear alerting systems do not use the weather radar however. The Windshear alerting system exchanges data with the AHRS, ADC's, SPS, radio altimeters and symbol generators. It searches for any sign of windshear and generates signals to the flight displays and aural warning systems as appropriate.

I will qualify this by saying that is the case on the aircraft I fly....we don't have predictive wx capability, only a real time radar with no link to the GPWS/WAS.

[Edited 2006-06-19 23:04:12]
 
KAUSpilot
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RE: How Loud Are Eicas Master Warning Sirens?

Tue Jun 20, 2006 6:12 am

Also, a bit more info concerning the above post....the the winshear detection function is performed by the GPWS computer, so in that way, windshear detection is linked to the GPWS. It does function differently from GPWS in the sense that GPWS gets its info from a terrain database whereas the WAS gets its info from aircraft sensors....
 
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litz
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RE: How Loud Are Eicas Master Warning Sirens?

Tue Jun 20, 2006 6:38 am

Quoting MarkHKG (Reply 12):
Which GPWS warning was it?
"WINDSHEAR, WINDSHEAR, WINDSHEAR"?
Or something else equally terrifying?

First time, (at about 1000 feet as we overflew the airport) it was WHOOP WHOOP PULL UP!

Second time -- after we had landed and were decelerating, it was WHOOP WHOOP TOO LOW! PULL UP! (or something similar).

- litz
 
Matt72033
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RE: How Loud Are Eicas Master Warning Sirens?

Tue Jun 20, 2006 7:02 am

Quoting Dc10hound (Reply 17):



Quoting KAUSpilot (Reply 18):
Windshear alerting systems use the same type of aural warnings that the GPWS system uses (as does TCAS), but they are seperate systems. Windshear alerting systems do not use the weather radar however. The Windshear alerting system exchanges data with the AHRS, ADC's, SPS, radio altimeters and symbol generators. It searches for any sign of windshear and generates signals to the flight displays and aural warning systems as appropriate

great answers! thank you both!

Quoting Litz (Reply 20):
First time, (at about 1000 feet as we overflew the airport) it was WHOOP WHOOP PULL UP!

Second time -- after we had landed and were decelerating, it was WHOOP WHOOP TOO LOW! PULL UP! (or something similar).

thats strange
 
AirWillie6475
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RE: How Loud Are Eicas Master Warning Sirens?

Tue Jun 20, 2006 10:26 am

How else would pilots wake up?
 
Markhkg
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RE: How Loud Are Eicas Master Warning Sirens?

Tue Jun 20, 2006 2:00 pm

Quoting Litz (Reply 10):
We actually OVERFLEW the airport, and the GPWS sounded off as we passed over the airfield (I assume 'cause we hit the leading edge of the storm and such)



Quoting Litz (Reply 20):
First time, (at about 1000 feet as we overflew the airport) it was WHOOP WHOOP PULL UP!

Second time -- after we had landed and were decelerating, it was WHOOP WHOOP TOO LOW! PULL UP! (or something similar).

The alert probably doesn't have to do anything with the storm per-se...it was probably due to something else that caused the alarm.
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HAWK21M
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RE: How Loud Are Eicas Master Warning Sirens?

Tue Jun 20, 2006 5:56 pm

Quoting MarkHKG (Reply 23):

The alert probably doesn't have to do anything with the storm per-se...it was probably due to something else that caused the alarm.

Thats what I was thinking exactly.
Interesting.Considering the Circumstances.
regds
MEL
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