Safety: Mid Air Collision

[sumitrathore]

Hi,

My name is Sumit and i am a frequent flyer both international (to Europe/US) and to Bangalore/pune from delhi for business purposes. Till some time back i was not afraid of flying as i was sure with today’s training and superior jet an accident is a very rare phenomenon. However my belief was shaken after i heard of GOL linhas flight crash (Boeing 737-800) in brazil. I was amazed that with modern machine and all technology like TCAS still mid air collision can happen. Apparently like all important transponder failed in the embraer business jet and with a small static white text display warning pilots were able to identify the loss. I would be highly greatful if anyone of you experienced pilot in india/abroad can pacify my restlessness about Indian ATC.

a)Usually in Indian airspace/international airspace if transponder fails does ATC notice (is there a warning signal etc). What happens in such a case?. Is it possible that a transponder failure is not detected by ATC as well as pilots.
b)How are Indian ATC. I hear quite some near miss.
c)What are the normal times that transponder stop working. Are they troublesome piece of instrument or quite reliable.

I would really appreciate if any one of you can answer my question and allay my newly found fear of flying.

Thanks in advance.

Regards,
Singh

[eastern wiseguy]

Hi Singh


A transponder emits information from the aircraft which will appear on a radar display. This information may be displayed as a series of numbers or more likely as (after automatic decoding)the aircraft callsign ,it's level("height") and its destinaton and speed. In certain airspace there is "MODE S"(but thats for another time.)which supplies even more information. In the event it fails (on the radar I use)I would see a "primary" blip ie a raw unprocessed blob. This is likely to be fairly similar throughout the world where the two systems are in use. In the event that the airspace radar is secondary(ie relying on transponder derived information only) ...then the blip will dissappear completely. One of my area colleagues will be along in a moment to explain what happens in that case.


I can't comment on Indian ATC

In my experience transponder failure does happen but in many cases the aircraft is equipped with more than one.

Regards

[jumpuFOKKERjump]

The labels look like this on our screens. There are no honking alarms, because the whole world (outside the US) is not covered by radar! We look at the symbol, and provide the service appropriate. We know our radar coverage and take action when a circle unexpectedly turns into a box.
http://i49.photobucket.com/albums/f287/spodman/LABEL2.jpg
The ABC123 on the left is being received by SSR & Primary radar, if the pilot turns off his transponder or it fails the label stays on the screen changes to the display on the right. We would notice and take action.

The GHI789 on the left is in SSR coverage only, if the pilot turns off his transponder my console displays the label on the right at the position it thinks it should be based on the flight plan and any position reports entered. The level displayed is the last reported by the pilot or transponder. The transition between the two is a bit more complicated than that, and we can activate a thing which puts a green starfish at the position we last had radar contact, but don't because all the starfish get annoying after a while...

This is for Australia, your ANSP my do something different. Those who designed the system that got the GOL should be f&^ked and burnt because they chose some funny things to display.

[TrafficTraffic]

Oh My God

where is the GHI789 he is talking about.....not another day like yesterday :uhoh:

TT

[CaptTomBunn]

Hi Singh,

First, understand that TCAS is a backup system. Air traffic control is responsible for maintaining separation between planes. Generally there is no need for TCAS, because ATC does an excellent job. It is only when both ATC and TCAS break down at the same time that collision is possible. Even then, it is an extremely remote possibility.

Extremely remote possibilities do not bother most people. Most passengers and pilots can deal -- emotionally -- with the fact that there is one accident every three to five million flights. Accidents are rare enough that anxiety does not develop. But passengers who tend to be anxious seek ABSOLUTE control as the antidote. The problem is, absolute control does not exist. Even so, but many depend on the illusion that they are absolutely safe. When a passenger who depends upon an illusion of absolute control finds a flaw in the system, anxiety erupts.

Though it might seem that reassurance about this one issue is all that is needed, this is not the last issue that will come to mind. This process will continue. And, though aviation is remarkably safe, each fact that shows flying is not absolutely safe will cause anxiety.

Each such issue causes anxiety. As the number of these issues adds up, in time, anxiety builds up to the point that the anxious person becomes unable to fly.

Meanwhile, many people who recognize flying is not absolutely safe fly with little or no anxiety. This is due to their having good emotional strength, a built-in ability to regulate emotional response to life's challenges and uncertainties. A person whose emotions are well-regulate within does not need to have absolute safety to feel reasonably secure in the world, and is able to take reasonable risks. This said, I would suggest you take advantage of the means which have been developed to increase emotional strength, so that concerns about extremely remote combinations of events does not cause distress.

I have worked with anxious and fearful passengers since 1980, first with the course that was started in 1975 at Pan Am by Capt Truman "Slim" Cummings. Though those original courses -- and most currently operating courses -- are helpful only for mild flight anxiety, methods have since been developed for increasing emotional strength so that people with high to extreme flight anxiety and phobia can now fly.

If interested, I've posted a video on this at http://http://www.youtube.com/watch?v=Zcx6ZsvKHSA (http://http//www.youtube.com/watch?v=Zcx6ZsvKHSA)

[Tarq57]

Nicely worded advice, Capt Tom. (You need to repair the link, though, I think it has one too many http's in it.)

[sumitrathore]

Thanks a lot for your reply :). It seems like a aircraft will be notified as soon as transponder goes off. Is it the same with indian ATC?