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Author Topic: Plane headed to CLT from LGA down in Hudson River  (Read 58767 times)
darry2385
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« Reply #135 on: January 20, 2009, 10:20:39 PM »

What's with the "so-called"?  It iscalled a ram-air turbine, nobody is making it up. 
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laylow
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« Reply #136 on: January 20, 2009, 11:08:34 PM »

Quote
so-called fly-by-wire system
There it is again.  The news always likes to sow seeds of doubt, to make things sounds sinister and scary.
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phil-s
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« Reply #137 on: January 20, 2009, 11:56:03 PM »

Not sinister at all  - the "so-called" is in there so you'll know that the writer doesn't expect you (the reader) to understand these horribly technical terms, like, ram, air, turbine, fly, and wire. Keep an eye out, though, for any mention of "so-called geese" in an article. That I'd like to see. 

To change the subject, kudos to all of you who posted real information here (as opposed to the crap on the networks). This was certainly the place to go for those of us who actually wanted to understand what had happened.

And to change it again, the goose problem is just going to get worse before it gets better. They're so happy living (and crapping) on golf courses that many no longer even leave for the winter.
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atcman23
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« Reply #138 on: January 21, 2009, 07:36:30 AM »



fly-by-wire system used computers to prevent the jetliner from stalling, or becoming uncontrollable and falling out of the air.


I wasn't aware that a fly-by-wire system would keep a plane from stalling.  Always thought that it just moved control surfaces via electrical inputs (using a computer) instead of hydraulic inputs, which explains why the Airbus is so complicated with all of the springs on board the airplane to provide the pilots with some form of force feedback.  Now if the plane had lost all electrical power, then I believe the A320 has a redundancy that allows for control to be maintained (such as batteries) but, sorry, I just don't think that a fly-by-wire system is going to keep a plane from stalling.  You need to do one of two things to prevent a stall: add power (which they did not have) or lower the nose (which is a bad option close to the ground).  I think the pilot pitched the plane for it's published best glide speed, not relied on a computer to "prevent" the plane from stalling.  If anyone would like to correct me if I am incorrect, please feel free to; but this was my understanding.

I think the media needs reporters specialized in the aviation industry to report for them and not rely on a run-of-the-mill journalist.
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Mark Spencer
kea001
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« Reply #139 on: January 21, 2009, 08:50:49 AM »


I think the media needs reporters specialized in the aviation industry to report for them and not rely on a run-of-the-mill journalist.

Looks to me like he's qualified.

"Andy Pasztor, senior special writer at the Los Angeles bureau of The Wall Street Journal.

Since coming to Los Angeles, Mr. Pasztor has written about white-collar crime, defense-related topics, the satellite industry and aviation safety. He has provided in-depth analyses of the commercial air disasters involving Trans World Airlines, Alaska Airlines, Egypt Air and the Concorde."

UCLA Anderson School of Management | Gerald Loeb Awards | Andy Pasztor
http://www.anderson.ucla.edu/x5058.xml

You can reach him here if you have any further questions:
andy.pasztor@wsj.com


Also of interest:

Emergency directive issued over Airbus A320 engines
Thursday, 08 January 2009

"EASA's directive calls for airlines with around 1500 Airbuses to urgently check and repair high pressure compressor fans on CFM 56s on A318s, A319s, A320s and A321s.

EASA says since April last year six different engines used by three different operators had stalled. These were followed by the Air France incident.

``Stalls on both engines during flight can cause a dual IFSD (in flight shut down).''  The FAA warned such stalling problems ``could prevent continued safe flight or landing.'' "
http://www.businessday.co.nz/industries/4811789

Emergency Airworthiness Directive 2008-228
http://ad.easa.eu.int/blob/easa_ad_2008_0228E.pdf/EAD_2008-0228-E_1

Airworthiness Directive AD 2009-01-01
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/b13c349078ebee5086257530004ec0a4/$FILE/2009-01-01.pdf

Left engine of US Airways jet still missing in NYC

Two days before the emergency landing, the same plane experienced a compressor stall while in flight. Passengers aboard the flight that left LaGuardia Airport on Jan. 13 reported hearing loud bangs from the right side of the plane. A short time later the situation appeared to return to normal and the flight continued on to Charlotte, N.C.

The compressor is essentially a fan that draws air into the engine and helps create thrust for the jet. A compressor stall is a situation of abnormal airflow resulting from a stall of the blades within the compressor. Compressor stalls can vary in severity from a momentary engine power drop to a complete loss of compression requiring a reduction in the fuel flow to the engine.

The stall will no doubt be looked at as the investigation moves forward, but pilots and aviation experts doubt the malfunction made the plane more vulnerable to the bird strikes that are believed to have imperiled the Airbus A320.
Retired Delta Air Lines pilot Joe Mazzone, who has flown planes that had compressor stalls, said he doesn't believe a compressor stall could have created or added to the total engine failure vis-a-vis a bird strike.

"If you have a big Canadian goose ingested in those engines, I would bet the farm that's what caused the engines to quit," Mazzone said. "The compressor stall would be a totally different issue unrelated to those birds."


http://www.google.com/hostednews/ap/article/ALeqM5ipKRkY9XnWmqqvBNAlBju1taRJCQD95RG14G0

« Last Edit: January 21, 2009, 11:03:50 AM by kea001 » Logged
cessna157
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« Reply #140 on: January 21, 2009, 10:14:50 AM »

fly-by-wire system used computers to prevent the jetliner from stalling, or becoming uncontrollable and falling out of the air.
I wasn't aware that a fly-by-wire system would keep a plane from stalling.  Always thought that it just moved control surfaces via electrical inputs (using a computer) instead of hydraulic inputs, which explains why the Airbus is so complicated with all of the springs on board the airplane to provide the pilots with some form of force feedback.  Now if the plane had lost all electrical power, then I believe the A320 has a redundancy that allows for control to be maintained (such as batteries) but, sorry, I just don't think that a fly-by-wire system is going to keep a plane from stalling.  You need to do one of two things to prevent a stall: add power (which they did not have) or lower the nose (which is a bad option close to the ground).  I think the pilot pitched the plane for it's published best glide speed, not relied on a computer to "prevent" the plane from stalling.  If anyone would like to correct me if I am incorrect, please feel free to; but this was my understanding.
I think the media needs reporters specialized in the aviation industry to report for them and not rely on a run-of-the-mill journalist.

Unforutnately I'm afraid to say that you are incorrect in this matter.  Allow me to explain:
This here is the difference in philosophy between airbus and Boeing FBW systems.  On a Boeing FBW (B-777), if the pilot tries to do something stupid (ie stall the aircraft, roll it too far, etc), the FBW system will provide feedback urging the pilot to correct himself, but it will still allow him to do it.  In other words, FBW will tell you that you are doing something stupid, but it'll still allow you to do it.
airbus FBW is jsut the opposite.  With all of the FBW computers in operation (airbus calls this "Normal Law"), it will absolutely prevent the pilot from doing anything outside of the normal flight envelope.  If the pilot holds the side stick controller completely to the left, the aircraft will roll to the left a predetermined amount of roll, then stop.  The pilot can continue holding the stick full left, but the aircraft simply will not do it.  Same thing applies with stall protection.  At high speed, if the pilot pulls full aft on the stick, the aircraft will pitch up at a normal rate not to exceed design tolerances.  At slow speed, full aft stick will pull the nose up to just above stall and the aircraft will not stall.  It will hold an attitude to maintain airspeed just above the critical AOA (which is most likely what occurred on the river). 
In simple words, in a Boeing, the pilot has final say of what happens.  In an airbus, the computers have the final say.

If you want to see a real life example of this, watch 2 videos.  Search for ITVV, it was a British company that made flight deck videos back before 9/11.  One is a few actual Cathay Pacific B-777 proving flights, but it also includes some demonstrations in the simulator of the flight envelope protection, including the demonstration of a full stall and recovery.  Then go find the ITVV video of an SAS A-320 simulator.  Here, the pilot demonstrates "Normal Law" and "Direct Law" flight envelope protection.

Hope this all helps.
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cessna157
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« Reply #141 on: January 21, 2009, 10:27:58 AM »

After some searching on the videos I mentioned in my previous post, I found these. 

Roll protection clip:


Clip 1:  Cockpit and simulator overview


Clip 2:  Takeoff (engine fail) and RTO, Takeoff (engine fail at V1) single engine pattern and landing.


Clip 3:  Autoland in Cat-III weather
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atcman23
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« Reply #142 on: January 21, 2009, 07:42:17 PM »

Wow very interesting!  Thank you for sharing.  It's very interesting to see the differences in operations between Boeing and Airbus aircraft. 

Maybe it's a good thing aircraft of today don't run Windows...   tongue
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Mark Spencer
cessna157
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« Reply #143 on: January 21, 2009, 08:01:26 PM »

Yeah, Fly-by-wire systems are a great benefit and add an extra layer of safety and protection to the aircraft. 

But sometimes they work against you.  Think back to the Air France crash of the A-320 that did the flyby at the airshow when the A-320 was first unveiled.  The pilots did the low pass, then added power to go around.  But the aircraft didn't agree with the pilot's attempt at a go around, so it just kept flying straight ahead and crashed into the trees.  Turns out that if the pilots would have pushed full forward on the control stick (counter intuitive), the plane would have thought "Oh no, this is bad, let's go around" and would have allowed the go around.

A funny side effect of fly by wire is on my airplane too.  Not all of the controls of my aircraft are fly by wire, but there are a few.  Included in that are the engines.  The thrust levers are just big switches that send signals back to the FADECs on the engines.  Our QRH says the following about a FADEC failure (complete failure of all control channels on an engine):

The engine will:
1) Respond to thrust lever movement with no overspeed and idle protection
2) Not respond to thrust lever movement and stay at last commanded power
3) Roll back to idle
4) Shut down

We always laugh at this QRH procedure, as it basically says "We have no idea what will happen to the engine, so hold on tight."  In any event, I think it always ends with the engine being shut down.
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atcman23
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« Reply #144 on: January 22, 2009, 07:30:03 AM »

That's true, the Air France A320 crash was something that could have been prevented.  Had that been a revenue flight, it would have been much much worse.

I'm taking it you're a FO on a CRJ-700 or CRJ-900? (not like there's a lot of difference between the two)
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Mark Spencer
oreotsi
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« Reply #145 on: January 22, 2009, 01:32:39 PM »

That's true, the Air France A320 crash was something that could have been prevented.  Had that been a revenue flight, it would have been much much worse.

I'm taking it you're a FO on a CRJ-700 or CRJ-900? (not like there's a lot of difference between the two)


They both have fancy bright lights compared to the older ones
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cessna157
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« Reply #146 on: January 22, 2009, 02:32:40 PM »

They both have fancy bright lights compared to the older ones

Ha, ain't that the truth.  All I know is when a red light comes on, I'm supposed to push it and the fire will go out.

Oh, Dr. Oreotsi, I finally got my AT-SAT score back.  I'm on my way to working with you.  You staying put or moving south?
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KSYR-pjr
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« Reply #147 on: January 22, 2009, 02:50:47 PM »

Cessna157, just noticed your change in sig.  Are you done flying for a carrier?  If so, I am very sorry to see that.
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Regards, Peter
ATC Feed:  Syracuse (KSYR), NY
cessna157
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« Reply #148 on: January 22, 2009, 03:04:06 PM »

Yeah, my airline has about 300 pilots out on the street now.  I was in the last batch of them to go.

But I hear there's somebody in SYR that commutes to NYC quite often that is looking into buying a Citation.  I know where they could find an experienced Citation pilot!   grin
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glencar
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« Reply #149 on: January 22, 2009, 04:26:07 PM »

Comair sucked anyway, no? Good luck getting on with someone else.
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