From this website: http://bigstory.ap.org/article/why-do-airplane-transponders-have-switch I find this question really interesting as it could be looked upon inexplicably the same way as "why would anyone turn off a cardiac monitor alarm?" within a hospital. Like the above, there are a myriad of legitimate reasons and situations to do so. But generally, when an automatic device is situationally not performing its intended function, then it becomes a superfluous nuisance.
There should be a redundant system of checks and balances that constantly monitors the health of the device as well as a secondary device should the first fail. We do this with data storage, it would be logical to do the same with transponders. This is the classic case of putting all your eggs in one basket. The second issue of overwhelming air traffic, this could easily be handled by making the option of shutting the transponder off only available when landing gears are down and the plane is below a specific altitude.
So many suggestions, look no further than your home to see what should be done and calculate how much effort, time and money it would all cost to have a good system of operation at home. Moreover in the family, see who is willing to do the work or not and who is going to pay and how much. How often we say to others , to justify not doing anything, spend any more money, "it happens once in a blue moon"!
What is evident in my mind about this whole fiasco is the lack of 'on station' durability of searchers. They're forced to fly hours just to get on site, and then only after a few short hours of search, are forced to turn back for fear of running out of fuel. This really dramatizes the need for extended durations aircraft, like the old airships that can literally loiter for weeks if need be. Sadly, the latest news continues to disappoint and anger surviving relatives.
Like I written above , it costs a lot of money, time and effort to get Chinese large assets covering the globe. But this is one such big asset, Liaoning, and I don't think it is on full service/deployment yet as last year it was being tested for takeover and landing for planes! Furthermore China has naval port arrangement as far west as Sri Lanka but that's a long way from South Indian Ocean. This report in German suggested that the military (implies US and Europe at least, possibly Russia/China/India, and last but not least Malaysia) already knew the aeroplane flight path and had early pictures of the crashed plane. But they have kept a tight lip as they did not want to compromise their military technological capability. The speaker was an Director General of a large commercial satellite company, he has just retired, he speculated based on his knowledge of satellite capabilities in commerce which are below the military specifications by a long way.
WTF, give me a break as I had criticized Malaysian government on handling the matter. Now, the same goes to the Chinese. Holding banners and protesting to government arent helping the matter. This search effort is a challenging task requires unprecedented cooperation between nations. Holding banners with messages like, "Hand us the murderer" and "Give us our relatives back," the family members chanted, "Tell us the truth," at a news conference held at a hotel after their arrival Sunday. Link: Angry Relatives Of Passengers On Flight 370 Demand Answers
