US Air Plane down in the Hudson River in NYC

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Giles
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Re: US Air Plane down in the Hudson River in NYC

Postby Giles » Wed Feb 11, 2009 8:09 pm

FROM : AIRBUS FLIGHT SAFETY DEPARTMENT TOULOUSE

ACCIDENT INFORMATION TELEX - ACCIDENT INFORMATION TELEX

SUBJECT: US AIRWAYS Flight US1549 ACCIDENT IN NEW YORK

OUR REF: USA US1549 AIT N2 DATED 23rd JANUARY 2009
Previous ref: USA US1549 AIT N1 DATED 16 JANUARY 2009

SUBJECT: US AIRWAYS Flight US1549 ACCIDENT IN NEW YORK

This is an update to the AIT N1 issued on 16th January 2009.

The information which follow has been approved for release by the US National Transport Safety Board (NTSB) and represent the highlights from the initial analysis of the available data: mainly Digital Flight Data Recorder, aircraft components, ATC script and radar.

The A320 aircraft was operating a scheduled flight US1549 from New York, La Guardia airport to Charlotte, Virginia on 15th January 2009, when the aircraft ditched on the Hudson river shortly after take-off at 15:30 local time.

The aircraft performed a normal flex take-off in slats/flaps configuration 2 from La Guardia airport with the co-pilot as Pilot Flying.

At time T0, soon after the aircraft was in clean configuration at an airspeed of about 210kts, both engines suffered a simultaneous and sudden loss of thrust at about 3000ft pressure altitude. The engines N1 decreased abruptly to 35% and 15% on engines 1 & 2 respectively. This sudden and simultaneous loss of engine thrust is consistent with the reported bird strike on both engines and also with the initial observations from the remaining engine 2. (Recovery of engine 1 being still in progress).

The captain took immediately control of the aircraft making smooth nose-down pitch inputs to maintain the airspeed at about 200kts.

At approximately T0+20 sec, the crew changed the aircraft heading towards the Hudson river.

There was no more response from the engine N2. The engine N1 continued to deliver a minimum thrust (N1 around 35%) for about 2 minutes and 20 seconds after T0.

At approximately T0+2min20sec, the crew attempted at about 500ft/200kts a quick relight on engine 1 without success.

The crew then selected slat/flap configuration 2 which was achieved.

From then on and until the ditching, the heading remained almost constant. The speed decreased from 200kts to 130kts.

Ditching occurred 3 minutes and 30 seconds after the thrust loss in the following conditions:
- Airspeed was about 130kts (at the Gross Weight, Valpha max is 125kts and Valpha prot is 132kts)
- Pitch attitude was 10 degrees up and bank attitude was at 0 degree.
- Flaps and slats were in configuration 2. Landing gear up

It is to be noted that at all times during the event and up until the ditching, the normal electrical supply (AC and DC buses) and all three hydraulic systems were fully operational and the flight control law remained in Normal law.

In line with ICAO Annex 13 International convention, the US NTSB (National Transportation Safety Board) continues the investigation assisted by Accredited Representatives from the French BEA (Bureau d'Enquetes et d'Analyses) as State of aircraft manufacturer. Airbus continues to support the NTSB investigation with advisors on-site and in the various investigation working groups.

Airbus has no specific recommendations at this stage. Should there be the need for recommendation as a result of the investigation, operators will be notified accordingly.

VICE PRESIDENT FLIGHT SAFETY
AIRBUS

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Gabriel
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Re: US Air Plane down in the Hudson River in NYC

Postby Gabriel » Wed Feb 11, 2009 10:14 pm

Re: hig glide ratio.

The airplane traded kinetic energy (speed) from 200kts to 130kts, for a potential energy equivalent to an extra 1000ft of altitude to glide from. When the glide starts at 3000ft, thats a lot.

Look at the distance between the 400ft mark and the 300ft mark and compare with the other marks where the speed remained more or less constant (and the airplane still had another 20kts to bleed from the 300ft mark).

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aardvark2zz
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Re: US Air Plane down in the Hudson River in NYC

Postby aardvark2zz » Thu Feb 12, 2009 2:30 am

Yes, also the winds would give them an extra 0.75 sm travel.
.
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aardvark2zz
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Re: US Air Plane down in the Hudson River in NYC

Postby aardvark2zz » Thu Feb 12, 2009 2:32 am

Giles wrote:
aardvark2zz wrote:If you have better data pls do post it. Or if you have other engine EPR, RPM, etc. data pls do post it.


Dmmoore wrote:Normal idle N-2 should be in the 55 -60% range.
Normal idle N-1 should be in the 25 - 30% range.


A key word there is should, not the actual N1 and N2.
.
Roger Murdock: We have clearance, Clarence.
Capt. Clarence Oveur: Roger, Roger. What's our vector, Victor?

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Giles
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Re: US Air Plane down in the Hudson River in NYC

Postby Giles » Thu Feb 12, 2009 3:07 am

aardvark2zz wrote:
Giles wrote:
aardvark2zz wrote:If you have better data pls do post it. Or if you have other engine EPR, RPM, etc. data pls do post it.


Dmmoore wrote:Normal idle N-2 should be in the 55 -60% range.
Normal idle N-1 should be in the 25 - 30% range.


A key word there is should, not the actual N1 and N2.
.

the point is, there was no thrust.

but you didnt answer my question;

who is "us" that you claim that graph makes sense to?

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3WE
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Re: US Air Plane down in the Hudson River in NYC

Postby 3WE » Thu Feb 12, 2009 4:32 pm

Summary attempt to Aarvark2zz:

1) Nice try.
2) You never said they should have gone for an airport.
2a) Nevertheless- there is an implication in your graph that they should have gone for an airport (not an accusation, nor putting words in your mouth- just a fact- the graph suggests that they could have made an airport)
3) You offered it for discussion (and that's A-OK).

But here's the biggie:

4) The discussion has questioned a number of your items:
-Splashdown location challenged by one poster.
-Comments regarding engine power challenged by Giles.
-Glide ratio questioned by several.

Bottom line:

The discussion is fine...

BUT

Make a new graph, or let's move on.
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aardvark2zz
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Re: US Air Plane down in the Hudson River in NYC

Postby aardvark2zz » Thu Feb 12, 2009 6:05 pm

3WE wrote:Make a new graph, or let's move on.


U guys do the work ! Find better data*, etc... I've published the data. Data doesn't give opinions.

*: I'll even give you a hint, use the splash down vids to determine splash location I'll give you another hint, splash down was around 130 kts IAS. Here's another piece of data, winds 340/13 (ATIS). Here's another piece of data, upper winds at 2000ft ASL were around 340/13 knots at 7pm nearby. Hudson points north south. Anymore spoon feeding needed ? Etc....
.
Roger Murdock: We have clearance, Clarence.
Capt. Clarence Oveur: Roger, Roger. What's our vector, Victor?

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Half Bottle
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Re: US Air Plane down in the Hudson River in NYC

Postby Half Bottle » Thu Feb 12, 2009 6:40 pm

aardvark2zz wrote:
3WE wrote:Make a new graph, or let's move on.


U guys do the work ! Find better data*, etc... I've published the data. Data doesn't give opinions.

*: I'll even give you a hint, use the splash down vids to determine splash location I'll give you another hint, splash down was around 130 kts IAS. Here's another piece of data, winds 340/13 (ATIS). Here's another piece of data, upper winds at 2000ft ASL were around 340/13 knots at 7pm nearby. Hudson points north south. Anymore spoon feeding needed ? Etc....
.


Great hints, here's my best effort:


.
Presentation1.jpg
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Giles
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Re: US Air Plane down in the Hudson River in NYC

Postby Giles » Thu Feb 12, 2009 7:12 pm

aardvark2zz wrote:
3WE wrote:Make a new graph, or let's move on.


U guys do the work ! Find better data*, etc... I've published the data. Data doesn't give opinions.
.

it is meaningless. it is worthless because nobody agrees with it. unless you can back up who "us" is.

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3WE
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Re: US Air Plane down in the Hudson River in NYC

Postby 3WE » Thu Feb 12, 2009 7:19 pm

Giles wrote:
aardvark2zz wrote:
3WE wrote:Make a new graph, or let's move on.


U guys do the work ! Find better data*, etc... I've published the data. Data doesn't give opinions.
.

it is meaningless. it is worthless because nobody agrees with it. unless you can back up who "us" is.


Absolute statements are usually bad.

It has some meaning and some value and I will count myself somebody among "us" who agrees that it is an approximation of the flight path/glide profile....give or take a couple of miles.
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Re: US Air Plane down in the Hudson River in NYC

Postby AndyToop » Thu Feb 12, 2009 11:06 pm

aardvark2zz wrote:
3WE wrote:Make a new graph, or let's move on.


U guys do the work ! Find better data*, etc... I've published the data. Data doesn't give opinions.

*: I'll even give you a hint, use the splash down vids to determine splash location I'll give you another hint, splash down was around 130 kts IAS. Here's another piece of data, winds 340/13 (ATIS). Here's another piece of data, upper winds at 2000ft ASL were around 340/13 knots at 7pm nearby. Hudson points north south. Anymore spoon feeding needed ? Etc....
.


Data - Teterboro Rwy 24 is 45000 ft from the flight aware point for 2000 ft and at that point he was pretty much aligned with it
Data - If he splashed down abeam he Intrepid he made 50000 ft from that point

So to make Varky happy the data indicates he could have made Teterboro.

More Data - With the 17:1 glide ratio of an A320 you should be able to get 34000 ft from that point with zero thrust.
More Data - there was a very small amount of residual thrust coming from the engines which would have increased the distance achievable above best glide
More Data - The engines were significantly damaged and there is no way that the additional thrust could be relied upon to remain present.

So using all of the data it should have been eliminated as a possibility immediately

Good call.

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Re: US Air Plane down in the Hudson River in NYC

Postby Gabriel » Fri Feb 13, 2009 2:33 pm

AndyToop wrote:More Data - With the 17:1 glide ratio of an A320 you should be able to get 34000 ft from that point with zero thrust.

More data: With a 17:1 glide you should be able to get 51000ft from 3000ft
More data: Bleeding speed from 200kts to 130kts, as they did from that point at 2000ft to the ditching, gives you an energy equivalent of an extra 1000ft of altitude.
More data: That alone explains the differences, now you can add the much less significant little of residual thrust and a little of tailwind.

When they impacted the birds at some 3200ft they were making some 250kts. So in total they traded speed from 250kts to 130kts. That's an energy equivalent to nearly 2000ft. So at the time of impact they had 3200ft of actual altitude plus another 2000ft stored as speed to bleed.

I still think thay could have reached both La Guardia and Teterboro. I still congratulate them for not attempting that and going to what was secured.

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Re: US Air Plane down in the Hudson River in NYC

Postby flyboy2548m » Fri Feb 13, 2009 3:24 pm

Giles wrote:i dont think there is one person on here who believes the accuracy of your graphic.
so, please tell me, who is "us" that you refer to.



The "us" is dumbvark and all his alter egos. It's not like this is the first time he posts a garbage graph.
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Re: US Air Plane down in the Hudson River in NYC

Postby OldSowBreath » Fri Feb 13, 2009 3:56 pm

No one has taken into consideration the financials involved.

First, how much additional fuel would have been consumed trying to reach Teterboro?

Secondly, the airport probably would have charged them something to land there; I mean there are no freebies, right?

Thirdly, USAir had no regularly scheduled flights from there, so they would have to ferry the plane back to JFK.

Fourthly, reaching the airport would have resulted in an additional 6 frequent flyer miles per pax, or roughly, 910 aggregate ffmiles, something the bean counters would have fits about.

So by ditching - insurance pays! Good call, Captain!

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Re: US Air Plane down in the Hudson River in NYC

Postby Half Bottle » Fri Feb 13, 2009 4:07 pm

OldSowBreath wrote: ferry the plane


That happened anyway, in a manner of speaking.
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Giles
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Re: US Air Plane down in the Hudson River in NYC

Postby Giles » Fri Feb 13, 2009 4:17 pm

Gabriel wrote:
AndyToop wrote:More Data - With the 17:1 glide ratio of an A320 you should be able to get 34000 ft from that point with zero thrust.

More data: With a 17:1 glide you should be able to get 51000ft from 3000ft
More data: Bleeding speed from 200kts to 130kts, as they did from that point at 2000ft to the ditching, gives you an energy equivalent of an extra 1000ft of altitude.
More data: That alone explains the differences, now you can add the much less significant little of residual thrust and a little of tailwind.

When they impacted the birds at some 3200ft they were making some 250kts. So in total they traded speed from 250kts to 130kts. That's an energy equivalent to nearly 2000ft. So at the time of impact they had 3200ft of actual altitude plus another 2000ft stored as speed to bleed.

i believe they were also in a turn around the time of the bird strike. could you please explain the energy usage of that?

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Re: US Air Plane down in the Hudson River in NYC

Postby Half Bottle » Fri Feb 13, 2009 4:18 pm

Giles wrote:i believe they were also in a turn around the time of the bird strike. could you please explain the energy usage of that?

Refer back to my chart.
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Giles
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Re: US Air Plane down in the Hudson River in NYC

Postby Giles » Fri Feb 13, 2009 4:20 pm

Half Bottle wrote:
Giles wrote:i believe they were also in a turn around the time of the bird strike. could you please explain the energy usage of that?

Refer back to my chart.

no

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Re: US Air Plane down in the Hudson River in NYC

Postby Half Bottle » Fri Feb 13, 2009 4:21 pm

Giles wrote:no

ok
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Re: US Air Plane down in the Hudson River in NYC

Postby Robert Hilton » Fri Feb 13, 2009 7:30 pm

Giles wrote:i believe they were also in a turn around the time of the bird strike. could you please explain the energy usage of that?

Yes, lots.
I believe Sulley made the right call. Anything else could have caused even more potential loss of life than ditching in the water. He assumed that everything was going to go wrong and he acted accordingly. That he pulled off a perfect landing was just the icing on the cake. He deserves all the acclaim he gets, and then some.

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Re: US Air Plane down in the Hudson River in NYC

Postby Dmmoore » Fri Feb 13, 2009 9:28 pm

Robert Hilton wrote:
Giles wrote:i believe they were also in a turn around the time of the bird strike. could you please explain the energy usage of that?

Yes, lots.
I believe Sulley made the right call. Anything else could have caused even more potential loss of life than ditching in the water. He assumed that everything was going to go wrong and he acted accordingly. That he pulled off a perfect landing was just the icing on the cake. He deserves all the acclaim he gets, and then some.


Amen!
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Re: US Air Plane down in the Hudson River in NYC

Postby ZeroAltitude » Sat Feb 14, 2009 11:40 am

Robert Hilton wrote:
Giles wrote:i believe they were also in a turn around the time of the bird strike. could you please explain the energy usage of that?

Yes, lots.
I believe Sulley made the right call. Anything else could have caused even more potential loss of life than ditching in the water. He assumed that everything was going to go wrong and he acted accordingly. That he pulled off a perfect landing was just the icing on the cake. He deserves all the acclaim he gets, and then some.
He couldn't be sure that hydraulic pressure and electrical power wouldn't fail, could he?
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Robert Hilton
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Re: US Air Plane down in the Hudson River in NYC

Postby Robert Hilton » Sat Feb 14, 2009 4:17 pm

ZeroAltitude wrote:He couldn't be sure that hydraulic pressure and electrical power wouldn't fail, could he?

My reasoning exactly, he couldn't guarantee that his services would remain 'turning and burning' for the duration. If he failed over a built up area then it isn't just those in the a/c that get it. Landing on the water ensured less possible casualties.

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Giles
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Re: US Air Plane down in the Hudson River in NYC

Postby Giles » Sat Feb 14, 2009 5:18 pm

no argument here.
i hope aard gets it.

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Re: US Air Plane down in the Hudson River in NYC

Postby OldSowBreath » Sat Feb 14, 2009 6:46 pm

I haven't seen it noted here, but our local rag had a tiny blurb that the Smithsonian confirmed that they were Canada geese.


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