Mid Air Collison/Brazil Crash?

Question

I have recently developed some doubts about flight safety after learning about brazil mid air collision. Hope any of you exp pilot/ATC can help me on this

In case transponder is turned off (or both transponder malfunction) does ATC’s immediately try to contact the aircraft. What if you are not able to contact the flight? Do you religiously try again and again to contact the flight?

•Does primary radar give correct data in India and western countries. I hear most of the time the radar is malfunctioning

•Once the mode C altitude is not shown, how do ATC reckon the correct altitude? Is it flight plan level (because it can be changed), or cleared flight level (it can be mistakenly wrongly entered or the aircraft might not be following it), or do ATC take the words of pilot for the height (after u contact him immediately once his transponder is off)

•If the transponder is off and flight data is not coming correct for pilot the only way to land safely is primary radar. Are they reliable

Answer 1

I'm an Air Traffic Controller so I can answer all of your questions, but it sounds to me like you really need to calm down.  Aviation is a very safe way to travel.

If a pilot forgets to turn his transponder on, a controller will let them know as soon as they are off of the ground.  As soon as the plane is in the air, ATC is looking for their transponder.  If they can't see it, they inform them and pilot will look at their transponder to see what the problem is.  Usually, the pilot will come back and say that they forgot to turn it on and ATC will immediately pick them up on RADAR when it is turned on.  

If a controller can no contact the flight, it is usually because the pilot changed to the wrong frequency.  In that case, there are what we call 'guard' frequencies that pilots and controllers are required to monitor at all times.  ATC will come over those frequencies and tell the pilot the correct frequency to change to OR the pilot can go over the guard freq and ask for a freq.  There are many many many more ways that controllers can get in touch with an aircraft.  In the rare case that there is no way to get in touch with an aircraft, a controller will watch the plane on RADAR and keep everyone out of their way.  Controlling is based on anticipated pilot actions.  

If there is no Mode C readout for an airplane, which isn't common but does happen, the pilot treats the plane just like any other plane but must ask the pilot what their altitude is much more often in order to separate them from other aircraft.  Everytime the pillot reports and altitude, the controller writes it down on a strip.  For instance, lets say a plane is at 10,000ft and the controller needs them to descend to 9,000ft.  The controller will tell them to descend and maintain 9,000, and report level at 9,000.  The controller will write 9,000 down of the flight stip below the previously assigned altiude of 10,000.  When the pilot reports leaving 10,000, the controller will put a line through that altitude.  

If the plane doesn't have an operating transponder, the primary radar works very well as a means of getting the plane from point to point.  A working transponder is the best, but not required.  Primary radar is very reliable.  I work at a RAPCON (military version of a TRACON) and we check our primary and secondary RADAR several times each day.  

As far as RADAR in other countries, I don't know.  I've only worked ATC in the states and in Iraq.  

Aviation is a very safe way to travel, especially with the big airline companies.  Don't worry!  When you are in they sky, you are always being watched by people who know what they are doing.  Even if it is a controller in training, they are being monitored by someone with years of experience.

Answer 2

yes they are reliable and human error also plays a important role in such accidents.

Answer 3

accident is accident that can happen any where,there is no need to have fear