Photo Clicked on 18th May thro my Mobile Camera while Transiting Thro Changi Terminal 3
Photo Clicked on 18th May thro my Mobile Camera while Transiting Thro Changi Terminal 3
Because the economics of having large oxygen tanks aboard airliners simply doesn’t work out (not to mention that the air quality inside the plane would rapidly become unpleasant if fresh air wasn’t constantly supplied, regardless of the oxygen levels), commercial airplanes have a very clever system installed to solve the problem of ultra-low pressure atmosphere at cruising altitudes.
In most modern airliners (the Boeing 787 Dreamliner not withstanding), outside air is “bled off” from the compressor stage of the turbine engines and eventually piped into the passenger areas. However, a bit of processing is needed first as the compressed air is extremely hot (on the order of nearly 400 degrees Fahrenheit or 200 degrees Celsius) at this stage. Thus, before it enters the passenger compartment, it is first allowed to expand and is run through a heat exchanger and air cycle system to cool it off sufficiently. This system also can work as a heater, with some of the hot air mixed in with the cooled air to regulate cabin temperature.
Once cooled and filtered, the pressurized air, which now has sufficient oxygen density to keep people happily conscious, is piped into the cabin area, usually at levels around 12 psi (about equivalent to atmospheric pressure at 7,000 feet). Why 12 psi instead of something like sea-level pressures of about 14.7 psi? 12 psi is sufficient for the majority of passengers while simultaneously reducing the structural strain on the aircraft itself over something like sea level atmospheric pressures.
As for the air already in the cabin, this is vented out through an outflow valve (or multiple valves in larger aircraft), usually located near the rear of the plane. (FunNote: Before smoking was banned on commercial aircraft, the area around this outflow valve was generally stained dark brown from tobacco smoke.)
This outflow valve opens and closes automatically to maintain a steady pressure inside the cabin, while the entire system is ensuring that fresh air is continually being piped into and eventually blown out of the aircraft. In fact, while many complain of airplanes seeming “stuffy,” this system ensures that all the air in the aircraft is being completely replaced on average every 2-3 minutes. Yes, that means that your car, house or office is likely significantly more “stuffy” than a commercial airplane flying at 35,000 feet.
(Note: the Boeing 787 Dreamliner handles cabin pressurization a little differently, using a modernized version of the old, somewhat inefficient, electric compressor system seen on many older aircraft.)
Unfortunately, sometimes planes lose cabin pressure. Whatever the cause, the loss of pressure (usually set at atmospheric pressures past 14,000 ft) will result in oxygen masks deploying. From here, useful consciousness may only last as little as 5-15 seconds, depending on remaining cabin pressure, which is why it’s critical to immediately put your mask on, rather than helping someone else first. You can help them much better when you’re not unconscious or dead.
So how do these airline oxygen masks actually work? It turns out, the economics of having a centralized oxygen tank to provide even emergency oxygen for passengers likewise simply doesn’t add up. Similarly, having tiny individual pressurized oxygen tanks also isn’t feasible. In fact, these masks aren’t hooked up to any tank or air line at all. So how are you able to breathe oxygen through them?
While designs can vary slightly, in general, when you pull on the device to place it over your face, the tug on the mask’s lanyard releases a spring-loaded mechanism that sets off a small explosive charge. (Yep.) The resulting spark triggers a mixture of lead styphnate and tetracene to generate heat, which will eventually cause a chemical reaction that produces oxygen for your mask. (This is why they tell you to tug on the mask to get the oxygen flowing- you’ve got to set off the explosive charge to get the whole thing going.)
That’s right. What you breathe through the mask didn’t begin as pure oxygen. Rather, the plane is equipped with numerous small chemical oxygen generators (also known as “oxygen candles,” about the size of a small package of tennis balls) which contain a mixture of mostly sodium chlorate (NaClO3), less than 5% barium peroxide (BaO2) and less than 1% potassium perchlorate (KClO4). When these chemicals are heated by the lead styphnate and tetracene, each undergoes a reaction that ultimately results in a fair bit of filtered, life sustaining oxygen running through the tube to you.
Of course, you might also smell a faint burning odor, but this is nothing to be alarmed about; it just assures you that the system is working. In fact, if the plane is actually on fire, the masks usually won’t deploy, so as not to make the fire worse with the extra oxygen.
This brings us to the question of why the plastic bag on the breathing apparatus won’t necessarily inflate as you’re using the device. More than just cosmetic, the bags serve as something of a reservoir for oxygen. If you aren’t taking a breath at all (and have a good seal with the mask tight against your face) the bag keeps the precious, continuously flowing oxygen from escaping into the thin air around you, enabling more of the collected oxygen to be taken in when you do take a breath. When this is happening, or you are breathing out with the valves on the mask releasing much of the used air, the bag may begin to inflate as oxygen collects. When you breathe in, it will deflate.
So why won’t it always inflate at least a little to show its working? To begin with, you may not have a great seal with the mask on your face, particularly if you have facial hair. This will allow any produced oxygen (and air you exhale) to more readily escape. (As long as the mask is reasonably secure on your face, this should still provide you with sufficient oxygen to get by on as long as the plane isn’t flying above 40,000 feet and the pilot does his or her job and gets the plane down below 10,000 feet as rapidly as safely possible.)
Even if you have a good seal, however, the rate at which the oxygen is generated is often not enough to fully inflate the masks’ bag before you take deep, potentially panicky breaths, deflating it. This is simply because the oxygen generation isn’t on-demand (for the passengers anyway), but simply a continuous-flow production of oxygen.
Despite the potentially slow production, the chemical oxygen generators do provide oxygen at a sufficient rate to sustain passengers, generally designed such that peak oxygen production occurs right away (when the plane may be at very high altitude) with the oxygen production rates tailing off over the course of approximately 12-20 minutes before the system burns itself out.
This should be long enough for the pilots to get the plane low enough so that the air pressure is high enough for (relatively) normal atmospheric breathing. And if you’ve ever been lucky enough to be in this sort of situation, you know that those pilots can get the plane from altitudes like 35,000+ feet to safer atmospheric levels alarmingly quickly in an emergency; while it may not be literally true, it at least can seem like roller coasters have nothing on them, which is a good thing in this case.
Source…..www.today i found out.com
If you’re flying to Sikkim, the nearest airport is at Bagdogra, in West Bengal, nearly 124 kms from the state capital, Gangtok.
The Pakyong airport now puts Sikkim on India’s aviation map. It is one of the five highest airports in the country and was built over several years, costing an estimated Rs 350 crore.
“The Pakyong (Gangtok) Airport at Sikkim got a license today for scheduled operations. It’s an engineering marvel at a height of more than 4,500 ft in a tough terrain. Will pave way for direct air connectivity to our lovely state of Sikkim, giving a boost to tourism & economic growth,” tweeted Civil Aviation Minister Suresh Prabhu.
Tourists, migrant workers and locals will soon fly on the low-cost airline SpiceJet, after it was granted permission to fly to Pakyong from Kolkata under the Centre’s regional connectivity scheme.
The picturesque runway of the Pakyong Airport in Sikkim. Image Credit: Soumen Mukherjee
1. The Pakyong airport in Sikkim is spread over 990 acres and is the first greenfield airport to be constructed in the north-east region of the country.
2. Over the years, several landslides near the runway resulted in work being suspended twice, but it was finally constructed and earlier this year, a fixed-wing 19-seater Dornier 228 IAF aircraft landed on the runway.
3. The airport is considered an engineering marvel because of its terrain. It is stationed at more than 4,500 feet and lies snugly between the Himalayas.
4. It is around 30 km from Sikkim’s state capital, Gangtok, and is located around 60 km away from the Indo-China border, giving it strategic importance. It is believed that the Indian Air Force (IAF) will be able to land various types of aircraft on the airport’s runway.
5. Until now, Sikkim was the only state in the country which did not have an airport. The Pakyong airport is the 100th functional airport in India.
According to MoneyControl, as per a previous proposal by the Ministry of Home Affairs, due to its “strategically important” location, the security of the Pakyong airport should be handled by the Central Industrial Security Force (CISF). The CISF is a professional aviation security force that handles 59 airports across the country.
The new airport will be an excellent opportunity for those of you who haven’t yet experienced this beautiful mountainous abode.
Source………Rayomand Engineer in http://www.the betterindia.com
At the turn of the last century, when aviation was still in its infancy, a German named Julius Neubronner submitted a patent for a new invention—a miniature camera that could be strapped to the breast of a pigeon so that the bird could take flight and snap pictures from the air.
Julius Neubronner was an apothecary who employed pigeons to deliver medications to a sanatorium located near his hometown Kronberg, near Frankfurt. An apothecary is one who makes medicines. A pharmacist is a more modern word, but in many German speaking countries, such as Germany, Austria and Switzerland, pharmacies are still called apothecaries.
Apothecary was Julius Neubronner’s family profession. His father was an apothecary, and so was his grandfather. In those days, homing pigeons were used extensively to carry messages and small supplies. It was Julius’s father’s idea to use pigeons to receive prescriptions from the sanatorium and send out medicinal supplies in a hurry—a practice that continued for more than half a century until the sanatorium closed.
One day, Neubronner let out a pigeon on an urgent errand but it didn’t return. When several days passed and there was still no sign of the bird, Neubronner assumed the pigeon was lost, or it got caught and killed by predators. A month later, the lost messenger showed up unexpectedly at Neubronner’s place. The bird appeared well fed, which got Neubronner into thinking. Where had he gone? Who had fed him?
Neubronner decided that he would start tracking his pigeons’ future travels.
Julius Neubronner with one of his pigeons.
Being a passionate do-it-yourself amateur photographer, it didn’t take long for Neubronner to fashion a miniature wooden camera which he fitted to the pigeon’s breast by means of a harness and an aluminum cuirass. A pneumatic system in the camera opened the shutter at predetermined intervals and the roll of film, which moved along with the shutter, took as many as thirty exposures in a single flight. The entire rig weighed no more than 75 grams—the maximum load the pigeons were trained to carry.
The pictures turned out so good that Neubronner started making different models. One system, for instance, was fitted with two lenses pointing in opposite directions. Another one took stereoscopic images. Eventually, Neubronner applied for a patent, but the patent office threw out his application citing that such a device was impossible as they believed a pigeon could not carry the weight of a camera. But when Neubronner presented photographs taken by his pigeons, the patent was granted in 1908.
Aerial photograph of Frankfurt.
Neubronner exhibited his photographs in several international photographic exhibition gaining him accolades. In one such exhibition in Dresden, spectators watched as the camera-equipped carrier pigeons arrived at the venue, and the photos were immediately developed and turned into postcards which they could purchase.
The technology was soon adapted for use during the First World War, despite the availability of surveillance aircraft then. Pigeons drew less attention, could photograph enemy locations from a lower height, and were visibly indifferent to explosions on a battlefield.
Neubronner’s avian technology saw use in the Second World War too. The German army developed a pigeon camera capable of taking 200 exposures per flight. The French too claimed they had cameras for pigeons and a method to deploy them behind enemy lines by trained dogs. Around this time, Swiss clockmaker Christian Adrian Michel perfected a panoramic camera and an improved mechanism to control the shutter. Pigeon photography was in use as late as the 1970s, when the CIA developed a battery-powered pigeon camera, though the details of the camera’s use are still classified.
Today, aerial photography has been replaced by aircrafts, satellites, and more recently, by affordable drones. But the legacy of Julius Neubronner’s pigeon photography lives on in these images which are among the very early photos taken of Earth from above.
Bonus fact: So what happened to Neubronner’s pigeon who stayed away from the owner for a month and returned fattened up? It had flown away to Wiesbaden, some twenty kilometers away, and was taken care of by a restaurant chef.
Source…..Kaushik in http://www.amusingplanet .com