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Explosive Decompression at Altitude

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Posted by John Radge | Posted on 28-05-2006

Category : Flying

A number of people have asked me about details of losing pressurisation in flight at altitude. Flight crews are trained to react quickly to situations were there is a loss of presurisation. The human body relies on pressure so that the lungs can work getting oxygen out of the air and into the bloodstream. No pressure, no oxygen transfer. If the aircraft cabin is punctured or the aircaft pressurisation systems fails such that the pressure inside the cabin becomes the same as that outside, this can cause major issues when cruising at altitude. For instance at 35,000 ft a typical person has 45 seconds of useful consciousness. In other words you have just 45 seconds to be able to think and react before you start suffering hypoxia. Hypoxia is another name for altitude sickness. If a person is hypoxic they most likely will feel drunk and believe that everything is fine. If the situation continues it is likely that person will lapse into unconsciousness and, in fact may possibly die. If you are cruising at 40,000 ft you have about 15 secs of useful consciousness. Not much time really. In fact when cruising above 41,000ft it is mandatory for flight crew to be always wearing oxygen masks.

Now you may be saying, well I can just hold my breath at 35,000ft. This will not work as I mentioned before you need pressure on the lungs to be able to be able to oxygenate the blood.

OK. So what happens if you are cruising along at 35,000 ft and a window blows out. This would create what is termed an explosive decompression. There would be a bang and air in the cabin would rush out the hole. It would be very noisy, lots of dust would be kicked up, even foggy. Various gases in your body would be also trying to escape (burp/fart) and it is likely you would have stomach cramps and ear aches. The 747-400 has 3 airconditioning packs that can actually handle a hole the size of a blown out window so it is not THAT big an issue. Never-the-less a lot of things may get sucked out that hole. Hopefully no people. The oxygen maskes would drop automatically. The crew, after putting on their oxygen masks, would immediately initiate a rapid descent. That is idle the engines back, point the nose downward and descent at maximum speed with airbrakes extended. Aim is to get down ASAP to 10,000 ft. Typically it would take 3-4mins to get from 35,000 ft to 10,000 ft. Once at 10,000 ft the oxygen masks can be removed and the crew would fly the aircraft to the nearest airport.

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Abandoned Cars at Sydney Airport

Posted by John Radge | Posted on 27-05-2006

Category : Flying

Recently I took my kids on a tour of Sydney airport run by a company called Airside Tarmac Tours (http://www.airsidetarmactours.com/) It was all very interesting stuff driving around in a bus inside the airport perimeter fence and seeing how Australia’s busiest airport works.

One thing that really amazed me was this car lot we drove past that had something like 100+ cars in it. As it turns out these cars are ones that have been abandoned at Sydney airport carparks by backpackers and the like. Basically these folks turn up from Europe or whatever, buy a car, drive it around Australia sightseeing then as they leave the country through Sydney airport just dump the car in the airport carpark. Every month the 100+ cars that are abandoned are sold off to car yards. 

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No taste or smell at 35,000ft

Posted by John Radge | Posted on 19-05-2006

Category : Flying

Wondered why airline food is so bland and tastes like rubber? When cruising at 35,000ft the cabin altitude is at about 8,000ft. Huh? We’ll basically the higher you go the lower the air pressure gets. In fact above 10,000ft the human body starts to have issues such as a reduced level of ability for the lungs to absorb oxygen. Therefore modern aircraft are pressurised so that the air pressure inside the cabin at cruising level is equivalent to say standing on an 8,000ft mountain. 

However the humidity inside the cabin is the same as outside and is very low at <1%. It is a very dry atmosphere so the body can quite easily dehydrate particularly if you drink alcohol and coffee on the flight. The human sense of smell requires humidity to work. No humidity, no smell. When you eat food a large portion of the pleasure of eating comes from smelling the food that you are eating. No smelling ability the food tastes bland.

A positive aspect of not being able to detect smells at 35,000ft is that if you have “wind” problems you can merrily release wind and, as long as it is done quietly, no one around is going to know any better. Ditto for smelly feet. Wait till you are at cruising level before taking off those smelly shoes reaking of foot odour.

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Powering your laptop in Economy Class on those long flights

Posted by John Radge | Posted on 11-05-2006

Category : Flying

If you are flying in economy class how are you able to get power for your laptop? Most aircraft are equipped with sockets at regular intervals amongst the seating to allow cleaning staff to power their vacuum cleaners (refer image). Laptop power supplies can fortunately handle a broad range of voltages. In fact the mentioned power sockets run off the aircraft 112VAC 400Hz system. Just plug your laptop into one of these and presto! Your powered up able to kill those hours away on long flights doing laptop work. Incidentally I carry a DVD or two to watch on those Pacific Ocean crossing flights rather than be subjected to the airline movie programming.

For the 747-400 row 45 (A or J seat), second seat from the back, works for Qantas.

Inflight Power
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Must do: LinkedIn

Posted by John Radge | Posted on 07-05-2006

Category : Software

Networking is a key element of the successful software entrepreneur. If you haven’t already done so you should subscribe to one of the major social networking apps for business on the web. Personally I use LinkedIn (http://www.linkedin.com/) and have found it easy to use and effective. LinkedIn caters to business people with both free and fee-based options and has 5 million subscribers. You can view my LinkedIn profile on the links bar as an example. 

LinkedIn is a great tool to find people to fill positions. Why would you pay a headhunter a large amount of $ to do a job that you can do for free with LinkedIn.

For me LinkedIn has helped me build business relationships that has led to other significant business. It has been said that LinkedIn is the search engine for business people.

Have a look.

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10 Software Technologies worth noting…

Posted by John Radge | Posted on 06-05-2006

Category : Software

The use of software technology is pivotal to enabling a software entrepreneur to bring their innovative product(s) to market rapidly. Below is a listing of 10 software technologies which your development team should atleast be aware of, if not integrate into your next product release.

AJAX
Asynchronous JavaScript + XML. AJAX enables the client to communicate with the server, when an event is triggered. AJAX can be used to produce widgets on a webpage. A simple widget can be a popup selectable drop-down list in a form. For example, imagine a Car model selector. When user selects the manufacturer, the webpage will automatically load up a list of models from the manufacturer. Traditionally, the loading of the list of models require the webpage to be refreshed. With AJAX, the webpage does not need to be refreshed. (More..)

Struts
Struts is an open source framework for building Java Web Applications. It is supported by Apache. (More..)

JATO (now known as Sun ONE Application Framework
The Sun ONE Application Framework is a mature, powerful, standards-based J2EE Web application framework geared toward enterprise Web application development. The Sun ONE Application Framework unites familiar concepts such as display fields, application events, component hierarchies, and a page-centric development approach, with a state-of-the-art design based on the Model-View-Controller and Service-to-Workers patterns. (More)

JavaFaces
JavaServer Faces (JSF) is an application framework for creating Web-based user interfaces. If you are familiar with Struts (a popular open source JSP-based Web application framework) and Swing (the standard Java user interface framework for desktop applications), think of JavaServer Faces as a combination of those two frameworks. Like Struts, JSF provides Web application lifecycle management through a controller servlet; and like Swing, JSF provides a rich component model complete with event handling and component rendering. (More..) (More..)

XML
Extensible Markup Language (XML) is a simple, very flexible text format which plays an increasingly important role in the exchange of a wide variety of data on the Web and elsewhere. XML introduces semantics to data. It is designed to be readable by other applications, and is typically used in B2B applications.
There are now industry defined standards XML schemes: ebXML, Finance XML
Look at XML.org for a full list. (More..)

Web Services (JNDI, SOAP, WSDL)
The World Wide Web is more and more used for application to application communication. The programmatic interfaces made available are referred to as Web services. (More..)

DataStage
IBM WebSphere DataStage, a core component of IBMR WebSphere Data Integration Suite, enables you to tightly integrate enterprise information, regardless of the sources, targets and timeframes. Whether you’re building an enterprise data warehouse to support the information needs of the entire company, building a “real-time” data warehouse, or integrating dozens of source systems to support strategic business systems like CRM, SCM, ERP, BI/analytics, and e-business, IBM WebSphere DataStage helps ensure the success of your enterprise data integration initiatives. (More..)

Apache
Apache is a community of open-source software projects. The Apache projects are characterized by a collaborative, consensus based development process, an open and pragmatic software license, and a desire to create high quality software that leads the way in its field. (More..)

Zope
Zope is an open source application server for building content management systems, intranets, portals, and custom applications. (More..)

Zend
Zend is a company that was founded by the architects of PHP, creators of the open source Zend Engine and on-going innovators of PHP, the most popular web application scripting language. The Zend Platform is a monitoring and management solution for PHP. (More..)

WordPress (blogging i.e. what you are reading at the moment)
WordPress is a state-of-the-art semantic personal publishing platform with a focus on aesthetics, web standards, and usability. WordPress is both free and priceless at the same time. (More..)

Magnolia (CMS)
Magnolia is the leading open-source content-management-system. Easily upload, share, version and search documents. Magnolia provides the easiest way to document business processes. Draw diagrams and document each activity directly in the browser. (More..)

Junit
JUnit is a regression testing framework. It is used by the developer who implements unit tests in Java. JUnit is Open Source software. (More..)

Wicket
Wicket is a Java web application framework that takes simplicity, separation of concerns and ease of development to a whole new level. Wicket pages can be mocked up, previewed and later revised using standard WYSIWYG HTML design tools. (More..)

Eclipse
Eclipse is a kind of universal tool platform – an open extensible IDE for anything and nothing in particular. What makes it useful are the *plugins*. For example, you can install a Eclipse Java Plugin, to start programming java. You can install a Business Objects Plugin to start authoring BI reports. (More..)

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