All Older Boeings 737-300, -400, and -500 Are Under Emergency Fuselage Inspection

FAA issues airworthiness directive for Boeing Model 737-300, -400, and -500 series airplanes.

FAA emite diretriz de aeronavegabilidade para modelos de aviões Boeing séries 737-300, -400 e -500.

Vídeo mostrando a extensão da avaria  Youtube video

• Airworthiness Directive 2011-08-51 FAA Diretriz de Aeronavegbilidade

Data: 05 ABRIL 2011

Diretriz de Aeronavegabilidade

Esta emergência foi resultada de um relatório indicando que um Modelo de  Boeing série 737-300, matrícula N632SW, experimentou uma descompressão rápida quando uma junção na cobertura do teto na corda S-4L entre a estação (BS) 664 e BS 727 rachou e abriu. A investigação mostrou que a rachadura foi localizada na superfície inferior da fileira de fixadores. A aeronave tinha acumulado 39.781 ciclos totais de voo e 48.740 horas totais de voo. Esta condição, se não corrigida, poderia resultar numa descompressão descontrolada no avião. Devido à junção na cobertura e a configuração do rasgão ser o mesmo nos modelos de Boeing das séries 737-400 e -500, estas aeronaves podem estar sujeitas à condição da insegurança identificada.

The Southwest Airlines jet forced to land last week after a gash opened in its fuselage had made an average of seven flights a day over its 15 years of service - a demanding schedule for any jetliner.

O avião da Southwest Linhas Aéreas forçado a pousar na última semana após um talho aberto na sua fuselagem tinha feito uma média de sete vôos por dia durante seus 15 anos de serviço – um programa de demanda para qualquer jato de linha aérea.

Federal Aviation Administration officials disclosed Tuesday that the Boeing 737-300 had flown 48,740 hours over its lifetime and gone through 39,781 flight cycles -- takeoffs and landings that tend to place the most stress on a plane's fuselage along with changes in cabin pressures.

Agentes da FAA revelaram na Terça-feira (5) que o Boeing 737-300 tinha voado 48.740 horas durante seu tempo de serviço e atingido 39.781 ciclos de vôo – decolagens e pousos que tendem a colocar o maior estresse na fuselagem do avião acompanhado de mudanças na pressão da cabine.

Aviation experts had initially speculated that the wear and tear Southwest planes typically endure - making an average of six flights per day - contributed to the incident. Southwest is the leading low-cost carrier in an industry that is highly competitive.

Especialistas em aviação tinham inicialmente especulado que o uso e o rasgão nos aviões que Southwest tipicamente sofreram – fazendo uma média de seis vôos por dia – contribuiu para o acidente. A Southwest é a líder de empresas aéreas de baixo-custo numa indústria que é altamente competitiva.

Flight 812, bound from Phoenix to Sacramento, had 118 passengers aboard when it made a safe emergency landing in Yuma, Ariz., Friday. There were no serious injuries.

After the incident, Southwest cancelled about 630 flights and inspected its 78 Boeing 737s, finding five others with fuselage cracks. The airline resumed normal flight operations Tuesday.

O Voo 812, saiu de Phoenix para Sacramento, tinha 118 passageiros a bordo quando ele fez um pouso de emergência em Yuma, Arizona, na Sexta-Feira (1). Não houve feridos graves.

Após o acidente, a Southwest cancelou cerca de 630 voos e inspecionou seus 78 Boeings 737s, encontrando cinco outros com rachaduras na fuselagem. A empresa aérea assumiu operações normais de vôo na Terça-feira (5).

Also on Tuesday, the FAA ordered all airlines to conduct detailed inspections within five days of older model Boeing 737-300s, 400s and 500s that have logged more than 35,000 flight cycles. The directive also requires airlines to check heavily-used 737s before they reach 30,000 cycles and orders that the older planes, which are mostly owned by Southwest, be re-inspected every 500 cycles.

Também na Terça-feira (5), a FAA ordenou a todas empresas de linhas aéreas a conduzir inspeções detalhadas dentro de cinco dias nos modelos antigos de Boeing 737-300, -400 e -500 que tenham acumulado mais que 35.000 ciclos de vôos. A diretriz também exige que as empresas verifiquem os Boeings 737 com uso pesado antes que eles atinjam 30.000 ciclos e ordena que os aviões mais velhos, os quais são principalmente pertencentes à Southwest, sejam re-inspecionados a cada 500 ciclos.

Paul Richter, chief project engineer for 737s at Boeing, said during a media briefing that the fatigue cracks suspected in the Southwest rupture occurred sooner than Boeing expected in the life of the plane. The company also issued a service order instructing airlines to check their planes.

Paul Richter, engenheiro chefe de projeto dos 737s na Boeing, disse durante uma explanação à mídia que a suspeitadas rachaduras por fadiga na ruptura do avião da Southwest ocorreram mais cedo do que o esperado na vida do avião. A companhia também emitiu uma ordem de serviço instruindo empresas aéreas  verificarem seus aviões.

FAA officials estimate that about 175 planes will be affected worldwide, including 80 in the United States. Domestic airlines must comply with the directive, whereas foreign carriers often honor the orders voluntarily.

Agentes da FAA estimam que cerca de 175 aviões serão afetados mundialmente, incluindo 80 nos Estados Unidos. Empresas de Linhas Aéreas Domésticas devem sujeitar-se à diretriz, enquanto empresas estrangeiras frequentemente honram as ordens voluntariamente.

Southwest Airlines Flight 812, a Boeing 737 carrying about 118 people out of Phoenix for Sacramento, Friday, diverted to Yuma Marine Corps air station in Arizona after an in-flight fuselage rupture caused rapid decompression at 36,000 feet. Passengers who called in to local news stations said a six foot long gash opened with a loud bang in the top of the cabin. They said the sky was visible through the opening and that some passengers lost consciousness during the rapid descent to 11,000 feet. According to Southwest, a flight attendant was the only one aboard to have suffered an injury. One passenger who saw the flight attendant speculated that the crewmember may have broken his nose. The NTSB has sent a Go Team to investigate the fuselage rupture.

Southwest Airlines Voo 812, um Boeing 737 carregando cerca de 118 pessoas de Phoenix para Sacramento, na Sexta-feira (1) alternou para estação aérea Yuma Marine Corps, no Arizona após uma ruptura da fuselagem em voo causando descompressão rápida a 36.000 pés. Passageiros que foram entrevistados por telefone pelas emissoras de notícia disseram que um talho abriu com 1,80 m com um estrondo antes no topo da cabine. Eles disseram que o céu estava visível através da abertura e que alguns passageiros perderam a consciência durante a descida rápida para 11.000 pés. De acordo com a Southwest, uma comissária de voo foi a única a bordo a sofrer ferimento. Um passageiro que viu a comissária de voo, especulou que a comissária pode ter quebrado seu nariz.

Inside Aircraft's Lavatories - Pray for not Occurring Rapid Decompression from Now On

A mission for Super Flight Attendants.

FAA's Determination and Requirements of This AD

FAA Airworthiness Directive

Since the unsafe condition described is likely to exist or develop on other airplanes of the same type design, we issued AD 2011-04-09 to eliminate a hazard with chemical oxygen generators in the lavatory, which, if not corrected, could jeopardize flight safety. The AD requires either activating all chemical oxygen generators in the lavatories until the generator oxygen supply is expended, or removing the oxygen generator(s); and, for each chemical oxygen generator, after the generator is expended (or removed), removing or re-stowing the oxygen masks and closing the mask dispenser door.
We have determined that notice and opportunity for prior public comment on AD 2011-04-09 were contrary to the public interest, and good cause existed to make the AD effective immediately by individual notices issued on February 10, 2011, to the known U.S. owners and operators of certain passenger-carrying transport category airplanes operating in 14 CFR part 121 air carrier service; or U.S.-registered and operating under 14 CFR part 129, with a maximum passenger capacity of 20 or greater; and equipped with any chemical oxygen generator installed in any lavatory.

These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons.

The FAA says it will take comments until April 22 on an airworthiness directive (PDF) that was issued in secret on Feb. 10 to all U.S. airlines with airplanes that have bathrooms. The existence of the AD, which required the airlines to disable the chemical oxygen generators that create oxygen for decompression masks in the lavs, was made public last week after all those who got the February notice had confirmed their compliance with it. About 6,000 aircraft were affected. The agency said in the AD that the systems could "jeopardize flight safety" and that it was in the public interest to have the work done quietly. The FAA didn't say specifically what the hazard is but there are various reports that suggest the action was taken to prevent would-be terrorists from going behind closed doors to turn the bathroom oxygen generators, which are identical to those in the main cabin, into something capable of bringing the aircraft down.
Oxygen Generator Deactivation

(g) Within 21 days after the effective date of this AD, do the actions specified in paragraphs
(g)(1) and (g)(2) of this AD.
(1) Activate all chemical oxygen generators in the lavatories until the generator oxygen supply is expended. An operator may also remove the oxygen generator(s), in accordance with existing maintenance practice, in lieu of activating it.
(2) For each chemical oxygen generator, after the generator is expended (or removed), remove or re-stow the oxygen masks and close the mask dispenser door.

Note 1: Chemical oxygen generators are considered a hazardous material and subject to specific requirements under Title 49 CFR for shipping. Oxygen generators must be expended prior to disposal but are considered a hazardous waste; therefore, disposal must be in accordance with all Federal, State, and local regulations. Expended oxygen generators are forbidden in air transportation as cargo.
For more information, contact 1-800-HMR-4922.

ADDRESSES: You may send comments by any of the following methods:

- Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.

- Fax: 202-493-2251.

- Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.

- Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Lavatories' Oxigen Mask Removal.

After rapid decompression the crew should push the aircraft nose down and likely turning away flight route.

Take a look in this image above to understand outside aircraft view on rapid descent.

The fixed oxygen system in the cabin supplies oxygen to the occupants in case of cabin depressurization.

Chemical generators produce the oxygen. Each generator feeds a group of 2, 3, or 4 masks. Generators and masks are in containers above the passenger seats, in the lavatories, in each galley and at each cabin crew station.

OPERATION
Each container has an electrical latching mechanism that opens automatically to allow the masks to drop if the cabin pressure altitude exceeds 14000 feet (+ 0, - 500 feet). Members of the flight crew can override the automatic control.

When the masks are released, the passenger address system automatically broadcasts prerecorded instructions (if installed) for using them.

The generation of oxygen begins when the passenger pulls the mask toward the passenger seat. The chemical reaction used for oxygen generation creates heat. Therefore, smell of burning, smokes and cabin temperature increase may be associated with the normal operation of the oxygen generators. The mask receives pure oxygen under positive pressure for about 22 minutes, until the generator is exhausted.

A reset is available for the rearming of the system after the masks are restowed. A manual release tool allows crew members to open the doors manually in case of electrical failure.

OPERAÇÃO (A330)
Os compartimentos de cada unidade abrem:


- As máscaras de oxigênio caem e ficam penduradas por cordas.


- O usuário puxa uma das máscaras em direção ao rosto.


(As cordas puxam o pino de liberação do conjunto do disparador do gerador).


- O disparador atinge o pino de percussão e o fornecimento de oxigênio é gerado.


- O oxigênio flui pelas mangueiras flexíveis de fornecimento até o reservatório.


- O indicador do fluxo é a parte verde do resrvatório. Ele infla quando o oxigênio está fluindo.


- O gerador químico de oxigênio fornece um fluxo de oxigênio de baixa pressão por no mínimo 22 minutos.


CUIDADO: UMA VEZ ATIVADO, O GERADOR NÃO PODER SER DESLIGADO
NOTA: Depois da queda de emergência das máscaras, será apropiado fazer um anúncio aos passageiros, explicando a possibilidade de um cheiro de queimado na cabine, associado com a operação normal do sistema do gerador de oxigênio.

Let's calculate the descent after rapid decompression.

We are flying at Flight Level 39000 feet.

A rapid decompression will force the crew to start descent for a flight level in which human being can breathe normally. It’ll be below 14000 feet, so our aircraft should be set for a descent rate of 6000 feet per minute (Maximum Rate of Descent). The airplane will have lost 27000 feet at flight level 12000 feet. We will level off on that altitude after 4.5 minutes.

Now you think about those passengers seated on last seats near the aircraft tail, they will feel their bodies slipping forward because of plane’s angle of attack. Pitch down, like a car descending an abrupt slope.

He/She should hold the oxygen mask on his/her nose for breathing oxygen during 4.5 minutes, otherwise he/she will die before the aircraft has reached 12000 feet.

Now let’s think about a flight attendant trying to walk slope up inside the plane (or slope down) toward any lavatory to help someone inside it.

Very likely all flight attendants will hover the passenger seats.

Someone will be hurt, inside the lavatory or on passenger cabin.