Today's Message Index:
----------------------
1. 06:06 PM - [Aviatia.ro] Re: Hudson River Ditching - Ceva Consideratii (rblarry69)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: [Aviatia.ro] Re: Hudson River Ditching - Ceva Consideratii |
---Iata ce spun cei de la NTSB
"
NTSB provides new details about US Airways flight
Buzz Up Send
Email IM Share
Digg Facebook Newsvine del.icio.us Reddit StumbleUpon Technorati
Yahoo! Bookmarks Print By LARRY NEUMEISTER and DAVID B. CARUSO,
Associated Press Writers Larry Neumeister And David B. Caruso,
Associated Press Writers ' 41 mins ago AP ' New York City police
officers look over part of the US Airways Airbus 320 that crashed
into the Hudson =85
Slideshow: US Airways plane crashes into Hudson River Play Video
Video: New Video Shows Flight 1549's Dramatic Splashdown CBS 2 New
York Play Video Video: Miracle on the Hudson ABC News NEW YORK '
Investigators provided a dramatic new account Saturday of what
unfolded inside US Airways Flight 1549 when it slammed into a flock
of birds moments after takeoff and lost both engines. Within seconds,
the pilot knew where he would end up: "We're gonna be in the Hudson."
The account by the National Transportation Safety Board demonstrates
just how quickly the flight deteriorated from a routine takeoff to a
perilous crash-landing.
It began with a thump at about 3,000 feet and the loss of all engine
noise, followed by the pilots' quick realization that returning to
LaGuardia or finding another airport was impossible.
With both engines out, flight attendants described complete silence
in the cabin, "like being in a library," said NTSB member Kitty
Higgins. A smoky haze and the odor of burning metal or electronics
filled the plane.
The blow had come out of nowhere. The NTSB said radar data confirmed
that the aircraft intersected a group of "primary targets," almost
certainly birds, as climbed over the Bronx. Those targets had not
been on the radar screen of the air traffic controller who approved
the departure, NTSB board member Kitty Higgins said.
As the details emerged, investigators interviewed the pilots and
worked to pull the airliner from the river. The jet lay almost
entirely submerged Saturday next to a sea wall in lower Manhattan
where workers positioned a crane to haul it onto a waiting barge.
Crews need to remove the cockpit voice and flight-data recorders and
locate the left engine, which came off and floated away following the
crash-landing. Divers originally thought both engines were lost, but
realized Saturday that the right engine was still attached. The water
had been so dark and murky that they couldn't see it.
The conditions were treacherous, with the temperature dipping to 6
degrees and giant chunks of ice forming around the plane by midday.
Divers who went into the river had to be sprayed down with hot water
during breaks on shore.
Teams worked into the evening to remove the plane, with floodlights
shining down onto the scene and emergency boats surrounding the
aircraft.
The investigation played out as authorities released the first video
showing the spectacular crash landing. Security cameras on a
Manhattan pier captured the Airbus A320 as it descended in a
controlled glide, then threw up a spray as it slid across the river
on its belly.
The video also illustrated the swift current that pulled the plane
down the river as passengers walked out onto the wings and ferry
boats moved in for the rescue.
Authorities also released a frantic 911 call that captured the drama
of the flight. A man from the Bronx called 911 at 3:29 p.m. Thursday,
three minutes after the plane took off.
"Oh my God! It was a big plane. I heard a big boom just now. We
looked up, and the plane came straight over us, and it was turning.
Oh my God!" the caller said.
At almost the same moment, the pilot told air-traffic controllers
that he would probably "end up in the Hudson."
Investigators began interviewing the pilot, Chesley B. "Sully"
Sullenberger, and his co-pilot for the first time Saturday.
Sullenberger guided the crippled aircraft into the river on Thursday
afternoon, saving the lives of all 155 people on board.
Sullenberger was seen entering a conference room of a lower Manhattan
hotel, surrounded by federal investigators. The silver-haired pilot
was wearing a white shirt and slacks and seemed composed.
When a reporter approached him for comment, one of the officials
responded: "No chance."
His wife, Lorrie Sullenberger said "the enormity of the situation"
had only begun to sink in Friday night as she watched the news.
"It was actually the first time that I cried since the whole incident
started," she said on "The Early Show" on CBS.
She suggested the happy ending was good for the country.
"I think everybody needed some good news, frankly," she said.
Experts say the threat that birds have long posed to aircraft has
been exacerbated by two new factors over the past 20 years: Airline
engines have been designed to run quieter, meaning that birds can't
hear them coming, and many birds living near airports have given up
migrating because they find the area hospitable year-round.
Canada geese, one of the most dangerous birds for aircraft,
historically migrate not because of cold but a lack of food. Winter
weather kills the grass they eat and sources of fresh water freeze
over.
But in developed areas, there is often both food and grass year
round, found in parks and golf courses.
And there isn't much that be done in the engineering of jet engines
to armor them against a strike without hurting their ability to
generate thrust.
The most vulnerable part of the engine is the fan, which can be bent
or smashed by an ingested bird. Pieces of busted blade then rip
through the rest of the engine like shrapnel.
Engines have been fortified so that they can stay intact in the event
of such a strike, but they usually cannot be restarted once they are
damaged, said Archie Dickey, an associate professor of aviation
environmental science at Embry-Riddle Aeronautical University's
campus in Prescott, Ariz.
He said hits hard enough to cause a total failure are rare, only
happening two or three times a year worldwide.
"That's extremely rare," Dickey said. "The chance of it hitting both
engines, I'd guess it is less than 1 percent."
Most bird strikes happen within five miles of an airport, lower than
1,000 feet, as planes are taking off or landing. Aircraft hit
thousands of birds every year, but they usually bounce off
harmlessly.
The US Airways flight hit the birds at 3,000 feet, the NTSB says.
That caused a total engine failure, and the plane hit the river 3 1/2
minutes later.
"Brace! Brace! Head down!" the flight attendants shouted to the
passengers.
Then, they were in the water. The flight attendants likened it to a
hard landing =97 nothing more. There was one impact, no bounce, then a
gradual deceleration.
"Neither one of them realized that they were in the water," Higgins
said.
The plane came to a stop. The captain gave a one-word
command, "Evacuate."
___
Associated Press writers Adam Goldman and Colleen Long contributed to
this report."
Oricum, abia astept sa-l vad "disecat" pe National Geographic
la "Seconds from disaster"!
In aviatia@yahoogroups.com, "lancer_two_one" <lancer_two_one@...>
wrote:
>
>
> Ca o nota initiala am folosit intentionat termenul "ditching" in
linia
> de subiect pentru ca n-am gasit in lb. Ro un (una bucata) cuvint
care sa
> acoperea respectiva notiune. Si pe de alta parte, ditching este
termenul
> de referinta in toate documentele de specialitate incepind de la
> Specificatii de Certificare si pina la Manualele de Zbor. Ca
explicatie,
> ditch/ditching inseamna in context finalizarea zborului pe o
suprafata
> de apa (ocean/mare, riu, lac...).
>
>
>
> Problema ditching-ului deriva din caracterul diferit al suprafetei
pe
> care trebuie adus avionul. Plecind de aici sint doi factori care a
> caror influenta poate decide sfirsitul unui ditching: viteza
avionului
> fata de sol (Ground Speed) si conditia suparfetei apei.
>
> Legat de GS, avionul trebuie adus la o viteza cit mai mica inainte
de
> luarea contactului, dar in niciun caz nu trebuie angajat.
>
> Pentru a intelege mai bine complexitatea activitatii echipajului,
am sa
> redeau mai jos cam ceea ce se intimpla dupa luarea acestei deciziei
de
> ditching. Cind timpul o permite, ar fi vorba de doua etape.
>
> Prima, Pregatirea, cind pilotii declara starea de urgenta si
alerteaza
> echipajul de cabina. In continuare echipajul de cabina (FA) trece la
> revederea procedurii de ditching cu pasagerii (PAX). Tot ceea ce
apare
> ne asigurat prin cabina trebuie asigurat, iar pilotii imbraca
vestele de
> salvare si isi verifica si asigura centurile de siguranta. Tot aici
> semnaleaza si in cabina PAX "FASTEN SEAT BELTS" si "NO SMOKING".
>
> A doua faza, Approach-ul, ar incepe cu decuplarea GPWS (sistemului
de
> avaertizare fata de proximitatea solului). Pentru ca practic tot ce
se
> intimpla de acum incolo se realizeza intr-o configuratie de zbor
> anormala, GPWS s-ar activa si ar pune o presiune nedorita pe
activitatea
> pilotilor si in plus poate i-ar distrage sau ar masca alte
semnalizari
> care ar fi de interes.
>
> Se deconecteaza apoi BLEED-urile (aer adus de la motoare pentru
> climatizarea cabinei). Iarasi, in functie de specificul sistemului,
se
> decupleaza circuitul de semnalizare a pozitiei necorespunzatoare a
> trenului, si se verifica ca maneta de comanda a pozitie trenului
este pe
> ESCAMOTAT (unde si trebuie sa ramina).
>
> Se configureaza flap-ul; in general daca nu exista alte
considerente,
> flap-ul se bracheaza maxim pentru a realiza ulterior cerinta de GS
cit
> mai redusa (in functie de conditii, acesta bracare se poate realiza
in
> trepte). Viteza de zbor pentru vint null este de obicei VREF (o
viteza
> de referinta, determinata in principal de greutatea avionului si de
> configuratia de aterizare). Se mai pot lua si alte masuri cum ar fi
cele
> legate de lumini normale si de avarie, ELT, etc. Inainte de luarea
> contactului, se urmareste realizarea unei viteze de infundare de
> 200-300fpm si se mai da odata ordinul BRACE, pe care FA il vor
relua pe
> sistemul fonic al cabinei PAX. Se recomanda ca imediat inainte de
luarea
> contactului avionul sa fie adus intr-o attitudine cu botul peste
> orizont. In functie de tip, unghiul ar trebui sa fie 10-12 grade
> (Dash-8-300 recomandarea este 10; Falcon F7X recomandarea e 14...)
Aici
> este evident punctul critic al ditching-ului. Luarea contactului la
o
> viteza cit mai mica fara a angaja avionul este critica.
>
> In cazul ca nu sistemul de propulsie a fost cauza ditching-ului,
> motorul/motoarele ar trebui oprite de asemenea ininate de luarea
> contactului.
>
>
>
>
>
> Legat de conditia suprafetei apei, ar fi de spus ca aceasta joaca
un rol
> deosebit de important. Atit de important incit daca exista valuri,
> directia de ditching este in lungul si paralele cu creasta, directia
> vintului jucind un rol secundar. In cazul in care suprfata este
calma se
> vine bine-inteles dupa directia vintului.
>
> Ceea ce am mentionat mai sus nu este in nici un caz o solutie de
genul
> one size fits all, poate da insa o idee a ceea ce se intimpla.
>
> Dupa luarea contactului, evaolutia avionului incepe a nu mai fi sub
> autoritatea nimanui, depinzind de configuratia aerodinamica
specifica.
> Nu exista experienta comparativa, dar m-as astepta ca un avion cu
aripa
> sus si ampenaj in T sa aiba o comportare mult mai predictibila si
> controlabila decit un avion cu aripa jos si ampenaj clasic. Pozitia
> aripii sus, este nunumai favorabila unei treceri gradualae de la
starea
> de zbor la cea de flotatie, ci si pentru ca este mai toleranta fata
de
> un posibil contact al virfului de plan cu suprafata apei care ar
putea
> rezulta intr-o cedare structurala catastrofica, concomitent sau
urmata
> de pierderea totala a controlului (adica asa cum s-a intimplat cu
zborul
> Ethiopian).
>
> Mentinerea integritatii structurale are de asemenea o importanta
> deosebita in asigurarea supravietuirii. Orice constructor trebuie
sa
> demonstreze ca in orice conditie a suparfwtei apei resonanil
posibila,
> timpul de plutire va fi suficient pentru a permite tuturor
ocupantilor
> sa evacueze aeronava si sa se imbarce pe plutele de salvare. In
cazul
> cind rezervoarele de conbustibil sint goale, acest fapt contribuie
la
> cresterea timpului de plutire. In sensul asta ar fi chiar indicat ca
> dupa luarea hotoririi de ditching sa se goleasca rezervoarele, daca
> acest lucru este posibil. Totodata insa, daca structura este
> deteriorata, rezervoarele sau alta parte a fuselajului este
indundata
> rapid, reducind sansele de supravietuire.
>
> Din punctul de vedere al configuratiei structurale in relatie cu
sansele
> supravituiriila impact, in conditii egale, un avion cu aripa jos,
> ampenaj clasic si motare sispuse sub aripa ar fi situatia cea mai
> dezavantajoasa. Motoarele, mai bine zis intregul ansamblu al nacelei
> sistemului de propulsie sint in general proiectate ca la depasirea
unei
> anumuite sarcini sa se desprinda de pilonul de sustinere cu un efect
> minim asupra structurii.
>
> Revenind la ceea ce s-a intimplat cu zborul US Air, este foarte
probabil
> ca ei sa fi urmat o varinata de procedura adaptata situatiei si nu
> neaparat identica cu ceea ce am mentionat eu mai sus. Se pare ca
dupa
> declararea urgentei, ATC-ul le-a oferit Teterboro (mentionat in
mesajul
> lui Lucian), dar raspunsul a fost Unable. Fiind imediat dupa
decolare
> si intr-o zona dens populata, nu cred ca au avut timp de prea multe
> actiuni, decit sa se axeze pe directia de ditching. Cred de
asemenea ca
> au aterizat cu ceva vint lateral (din stinga), pentru ca imediat
dupa
> ditching, avionul se intorce la 90 de grade fata de directia pe
care au
> venit si ramine asa. Se pare ca i-a mai jutat putin si faptul ca au
> venit pe directia refluxului, cee ce a mai contrinuit putin la
> ameliorarea contactului.
>
> N-as vrea sa mai adug decit ca la reusita generala este datorata nu
> numai pilotului comandat, ci si a intregului echipaj; fiecare si-a
facut
> datoria la momnetul in care a fost actorul principal. N-am nici o
> indoila ca atunci cind va da primul interview, Comandantul lor va
> clarifica acest lucru de la primele vorbe.
>
> Link-ul unde puteti vedea (cit se poate vedea) ceea ce s-a intimplat
> este mai jos:
>
> http://tinyurl.com/7nl2or
>
>
> Sorin
>
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|