sumitrathore

I travel a lot and have recently developed fear of flying. It might take just 5 minutes of any exp ATC’s/Pilot busy time to answer them but it will be really very helpful for me:
a) Brazil crash happened because transponder for one of the aircraft was accidentally turned off by pilot. I think ATC’s will be aware if a transponder was turned off in an aircraft immediately as there will be some changes in the display on your screen. What was surprising was that ATC’s in Brazil didn’t try to contact the flight for 50 minutes even after being aware of the malfunctioning.
In case transponder is turned off (or both transponder malfunction) does ATC’s immediately try to contact the aircraft. What if they are not able to contact the flight? Do they religiously try again and again to contact the flight?

b) In the Brazil’s ATC screen there were two altitudes shown. One was mode C altitude and the other one flight plan. The flight plan showed FL360 to be maintained but the flight was cleared to fly at Fl370. Once the transponder was off the mode C altitude reading was gone and the display showed FL360 as it was the flight level. For 50 minutes ATC didn’t contact the flight as it thought the aircraft was flying at FL360. Also once mode C reading was off, primary radar kicked in to replace the reading. However primary radar reading as per to report attached was unreliable and had an error of 4000 Ft. Also that reading sometime showed Fl360 instead of correct FL370. Eventually both flight collided.
· 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 they 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 they take the words of pilot for the height (after u contact him immediately once his transponder is off).
· If somehow the transponder is off and critical flight data is not coming correct for pilot the only way to land safely is primary radar assistance from ATC. Is primary radar accurate and reliable?
· How is the instrument in Indian ATC? Are they outdated or as per to western standards.

I will be really very very thankful if anyone of you can take just 5 minutes and somehow let me allay the fear of flying.

Dirty130

So figuring out how ATC responds to a transponder being turned off will allah your fear of flying?

Oops, I meant "allay" your fear of flying...

BlueMoon

When I have had a Transponder fail they told us they lost our mode C (The altitude reporting part of the transponder)...sure enough it stopped working, we switched transponders (since commercial aircraft usually have two of them)

I haven't used radar other than for weather, but my understanding is primary radar doesn't give you anything other than a target. The target could be a plane, flock of birds...whatever.

If Mode C is not working, they would ask the pilot what FL they were at...I believe they have the ability to type in information next to a primary return, so they might be able to make note of it.

If the transponder is off, they can give you vectors using your primary return (if they have one). If not you just revert to non-radar procedures. We don't need ATC vectors, they just make life easier.

Never been to India...don't know

Larry in TN

The cause of that crash was not the loss of the transponder, it was Brazilian's ATC system which failed to clear the aircraft to the appropriate altitude and it's failure to notice. The transponder and TCAS are backup systems that could have cause ATC's error and prevented the collision but they weren't the cause.

It's like a car that runs a run light and causes a collision. The cause is the car that ran the red light, not the car with the right of way (green light) which failed to avoid it.

radmanly

I think one should be afraid of flying in Brazil.

sumitrathore

Although there can be other causes of crash but this one was bothering me the most so thought of clearing my doubts about it.

astrojet

nat. geografic channel had a 2hr special on this accident: it was the chain of events=1-the new hire controler missed seeing on the strip the altitude change required for the Legacy and 2- the legacy pilot turned off the mode C by mistake;because the foot rest lies next to the mode c switch-or the mode C was intermitent as it had a history of failure on the jet. in the end the winglet of the legacy sliced the GOL737 wing in 1/2 like a knife thru butter at 1600mph closing speed. not to help they both were using GPS-IRS navigation...which we know keeps you on the center of the airway.

stinsonjr

Can you set the GPS-IRS to fly some amount, like five miles, off the center of the airway? Barry Schiif had an article about this a couple months ago in AOPA Pilot.

Swass

My thoughts exactly.

Slice

Yes, you can.