Mostrando postagens com marcador decompression. Mostrar todas as postagens
Mostrando postagens com marcador decompression. Mostrar todas as postagens

segunda-feira, 12 de janeiro de 2015

Training for Explosive Decompression at High Altitude


There is a difference between Explosive Decompression and Rapid decompression.

ENGLISH                                                                       PORTUGUÊS

Decompression is defined as the inability of the airplane's pressurization  system to maintain its designed pressure differential. This can be caused  by a malfunction in the pressurization system or structural damage to the  airplane. Physiologically, decompression's fall into two categories; they
are:
 
Descompressão é definida como a incapacidade do sistema de pressurização do avião em manter sua pressão diferencial projetada. Isto pode ser causado por uma avaria no sistema de pressurização ou dano estrutural no avião. Fisiologicamente, descompressão caem em duas categorias; Elas são:
Explosive Decompression
Descompressão Explosiva
 
 
Explosive decompression is defined as a  change in cabin pressure faster than the lungs can decompress;  therefore, it is possible that lung damage may occur. Normally, the  time required to release air from the lungs without restrictions,  such as masks, is 0.2 seconds. Most authorities consider any  decompression that occurs in less than 0.5 seconds as explosive and  potentially dangerous.
 
Descompressão explosiva é definida como uma mudança na pressão da cabine mais rápido do que os pulmões possa descomprimir. Portanto, é possível que possa ocorrer danos aos pulmões. Normalmente, o tempo necessário para liberar o ar dos pulmões sem restrições, tais como máscaras, é de 0,2 de segundos. A maioria das autoridades consideram qualquer descompressão que ocorra em menos de 0,5 de segundos como explosiva e potencialmente perigosa.
 
 
 
Rapid Decompression
Descompressão Rápida
 
 
Rapid decompression is defined as a change in cabin pressure where the lungs can decompress faster than the cabin; therefore, there is no likelihood of lung damage. During an explosive decompression, there may be noise, and for a split second, one may feel dazed. The cabin air will fill with fog, dust, or flying debris. Fog occurs due to the rapid drop in temperature and the change of relative humidity. Normally, the ears clear automatically. Air will rush from the mouth and nose due to the escape of air from the lungs, and may be noticed by some individuals.
Descompressão rápida é definida como uma mudança na pressão da cabine onde os pulmões podem descomprimir mais rápido do que a cabine. Portanto, não há nenhuma probabilidade de danos nos pulmões. Durante uma descompressão explosiva, pode haver barulho, e por uma fração de segundo, alguém pode sentir-se tonto. O ar da cabine se encherá de névoa, poeira ou detritos voando. A neblina ocorre devido à rápida queda da temperatura e a mudança de umidade relativa. Normalmente, os ouvidos se desobristruem automaticamente. O ar apressará o fluxo da boca e nariz devido a fuga de ar dos pulmões e pode ser notado por alguns indivíduos.
 
The primary danger of decompression is hypoxia. Unless proper utilization  of oxygen equipment is accomplished quickly, unconsciousness may occur in a  very short time. The period of useful consciousness is considerably  shortened when a person is subjected to a rapid decompression. This is due  to the rapid reduction of pressure on the body, oxygen in the lungs is  exhaled rapidly. This in effect reduces the partial pressure of oxygen in  the blood and therefore reduces the pilot's effective performance time by  one-third to one-fourth its normal time. For this reason, the oxygen mask should be worn when flying at very high altitudes (35,000 feet or higher).
 
O principal perigo de descompressão é hipóxia. A menos que a utilização adequada do equipamento de oxigênio seja realizada rapidamente, inconsciência pode ocorrer em um tempo muito curto. O período de consciência útil é consideravelmente reduzido quando uma pessoa está sujeita a uma rápida descompressão. Isto é devido a rápida redução da pressão sobre o corpo, o oxigênio dos pulmões é exalado rapidamente. Isto na realidade, reduz a pressão parcial de oxigênio no sangue e, portanto, reduz o tempo de desempenho efetivo do piloto em um terço a um quarto de seu tempo normal. Por esta razão, a máscara de oxigênio deve ser usada quando voando em altitudes muito elevadas (35.000 pés ou superior).
 
It is recommended that the crew members select the 100 percent oxygen  setting on the oxygen regulator at high altitude if the airplane is  equipped with a demand or pressure demand oxygen system.
 
É recomendável que os membros da tripulação selecione a configuração de 100% de oxigênio no regulador de oxigênio em altitude elevada, se o avião estiver equipado com um sistema de demanda ou sistema de oxigênio de demanda por pressão.
Another hazard is being tossed or blown out of the airplane if near an  opening. For this reason, individuals near openings should wear safety  harnesses or seat belts at all times when the airplane is pressurized and  they are seated.
Outro perigo é ser lançado ou jogado fora do avião se perto de uma abertura. Por esse motivo, indivíduos perto de aberturas [janelas de emergência, por exemplo] devem usar cintos de segurança de ombros ou cintos de segurança em todos os tempos que o avião estiver pressurizado e que eles estejam sentados.
Another potential hazard during high altitude decompression is the  possibility of evolved gas decompression sicknesses. Exposure to wind  blasts and extremely cold temperatures are other hazards one might have to  face.
Outro risco potencial durante a descompressão em altitude elevada é a possibilidade de doenças de descompressão de gás evoluidas. Exposição a explosão de rajada de vento e a temperaturas extremamente frias são outros perigos que alguém pode ter que enfrentar.
Rapid descent from altitude is necessary if these problems are to be  minimized. Automatic visual and aural warning systems are included in the  equipment of all pressurized airplanes.
A descida rápida de altitude é necessária se estes problemas estiverem que ser minimizados. Sistemas automáticos de aviso visual e auditivo são incluídos no equipamento de todos os aviões pressurizados.
 

 

sábado, 5 de março de 2011

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.
 

quinta-feira, 22 de julho de 2010

Test Your Aero Medical Knowledge - by Dr. David Bryman

Test Your Aero medical Knowledge
















Dr David Bryman

Senior Aviation Medical Examiner

FAA/Transport Canada/JAA


Please answer the following questions to test your knowledge in Aviation medicine.

1. What is the main cause of decompression sickness?

a) Reduction in ambient pressure resulting in the formation of bubbles from gases dissolved in body tissues

b) And increase in ambient pressure resulting in the formation of bubbles from gases dissolved in body tissues

c) Hypoxia during high altitude flight

d) Oxygen toxicity resulting from the treatment of hypoxia

2. The symptoms of hyperventilation are similar to those of:

a.Trapped gas

b.Evolved gas

c.Hypoxia

d.Hypemia

3. Which of the following is the health risk associated with cigarette smoking that is of particular importance in the aviation environment?

a. Carbon monoxide in the blood

b. Carbon dioxide in the blood

c. Nitrogen in the blood

d. Nicotine in the blood

4. The Cabin Pressurization system protects you from:

a. Hyperglycemia

b. Hypoglycemia

c. Hypoxia and decompression sickness

d. Hyperventilation and hyperthermia

5.  True or False: The body can adapt to heat better than cold?

a. True

b. False

6. ___________, ____________, & ___________are medical conditions that automatically disqualify an airman from being certificated or certificate renewal.

a. Near sightedness, myocardial infarction, & unexplained seizure

b. Diabetes mellitus, acid reflux disease, & heart replacement

c. Myocardial infarction, unexplained unconsciousness, & bipolar disorder

d. Farsightedness, halitosis, substance abuse

7. Who has the absolute final authority to review a medical disqualification after an airman has been denied a certificate or renewal?

a. The Administrator of the FAA

b. An administrative law judge appointed by the NTSB

c. The Federal Flight Surgeon

d. The President of the United States

8. In order to be considered for a special issuance medical certificate after a cardiovascular event, the applicant must first wait a period of __________.

a. 90 days

b. 6 months

c. 1 year

d. 3 years

9. What is the most significant aeromedical concern with a spontaneous pneumothorax?

a. Fits of coughing

b. Increased chance of future pneumothorax

c. Permanent lung damage

d. Fluid in the lungs

10. Which of the following personality disorders is most common among pilots?

a. Paranoid

b. Histrionic

c. Borderline

d. Avoidant

11. Which conditions often result in flight disqualification?

a. Vertigo

b. GERD

c. Meniere Syndrome

d. a and c

12. What are some conditions that would temporarily disqualify a pilot from flying?

a. Headache, Upper respiratory tract infection

b. Sinusitis, Acute gastroenteritis, Myalgia, Flu, Toothache

c. Use of medications to treat a minor illness (due to the effects of the medication)

d. All of the above

13. Which transplant recipients are always disqualified from flying?

a. Heart

b. Kidney

c. Liver

e. a and c

14. The following is NOT a symptom of circadian rhythm disruption.

a. Sleep disturbance

b. Euphoria

c. Changes in appetite

d. Anxiety

15. The most common in-flight medical emergency is?

A. Neurogenic syncope and cardiac episodes

B. Ebola

C. Hepatitis

D. Parasites

Answers 1A 2C 3A 4C 5A 6C 7B 8B 9B 10A 11D 12D 13A 14B 15A