How Much Time Would You Let Pass After Loss of Communications Before Selecting Transp

[rsiano]

How Much Time Would You Let Pass After Loss of Communications Before Selecting Transponder Code 7600?

The subject of Loss of Communications Procedures is not an unusual one for discussion in the cockpit. In most discussions in which I took part, it was almost always related to and limited to total failure of the radio transceivers. In addition, it was assumed Instrument Meteorological Conditions were being experienced at the time of the failure.

In my more than 50 years of flying, I never gave any thought to the question of how long to wait until I select code 7600. This question was brought to mind by a story told by a fellow pilot. He was approaching Teterboro to land during a busy afternoon. ATC directed him to change frequencies to contact Teterboro Approach Control. Teterboro Approach was really busy and the he was unable to establish contact.

He said he just selected code 7600 on his transponder and was shortly thereafter in contact with a controller. I really liked this thoughtful approach and the initiative he used to solve the problem.

Loss of communications was an important factor in the mid-air collision in Brazil 4 years ago between an Embraer Legacy 600 and a GOL Airlines Boeing 737-800. (Both airplanes were brand new and had all the latest collision avoidance equipment installed. Both were in radar contact in Brazil's modern, up-to-date air traffic control system.) Yet, the collision occurred with the loss of 154 lives.

The loss of communications resulted from the pilots not receiving a correct change of frequency instruction. This is not an uncommon event for pilots. The Embraer pilots made numerous calls to re-establish radio contact over the next 57 minutes with no success . During this period of time the pilots did not change their transponder code to 7600. What period of time would you consider as a maximum before selecting code 7600?

Another significant factor in the Brazillian mid-air collision was the fact the Embraer pilots had turned off their transponder about and hour and fifteen minutes into their flight. As a result, the Traffic Alert and Collision Avoidance System (TCAS II) installed in both aircraft was not able to do its job. (TCAS II relies on an operating transponder to be installed and operating to function.) Had the Embraer pilots considered use of Loss of Communication Procedures earlier with the selection of code 7600, they probably would have recognized the transponder was turned off and turned it back on. This would than have permitted the TCAS II systems to provide Resolution Advisories to each pilot and prevent the accident from happening.

The main point of my post is to suggest to each of you to do some thinking about this aspect of Loss of Communications procedures. When are you going to select code 7600? After 3 minutes, 10 minutes or after 20 minutes have gone by?

Your comments are appreciated.
Thanks!
Dick Siano

For additional information:
http://apcae.files.wordpress.com/2009/06/120.pdf

[aerobat77]

i think it depends on the situation. when the radios are obviously gone due to a failure you can do it immediately- otherwise you may first try to sort out what the problem is and try to reestablish communication , trying different frequencies, including 121.5 .

when all radios go simultany you probably nevertheless have a big problem with the whole electrical system of the avionics - so the question is : does the transponder work?

[B737NG]

It depends where you are and how sensible the Area is where you fly.

To enter Iranian Airspace you need to call 10 Minutes before reaching the boundary, not possible in some areas, so you continue and call about 200 nm before the station and normaly they answer, there are two frequencies, try both of them. The radar is better then the radio.

To enter Canadian Airspace in VHF you have usualy good connection over a far distance due to the relay system they have installed. The radar coverage is less then the radio coverage, so keep calling. More effective.

In European / US Airspace you have both most of the time and if you are not able to talk with someone within 5 min. for example then there is something totaly wrong, fortunatly the previous frequency is within range and you can call them again and ask for relay.

Remember the accident at Ueberlingen / Southern Germany, Suiss controlled Airsapce, Skyguide. The controller himself was busy to establish contact on the telefone and several radio calls where also unheared.

The Thread is food for thought, I am glad it came up. There is no right or wrong. Common sense and expirience should help to solve a problem.

It was a bright idea to bring the Teterboro´s controller attention to the star on his screen when he has seen 7600..... Smart move.

Fly safe and land happy

NG

[Checkboard]

Teterboro Approach was really busy and the he was unable to establish contact.

He said he just selected code 7600 on his transponder and was shortly thereafter in contact with a controller. I really liked this thoughtful approach and the initiative he used to solve the problem.

You're kidding, right! :rolleyes:

If you switch to a busy frequency, where the controller is talking ten to the dozen - just sit back and relax. Don't get frustrated, don't continually mash the mike button and block the frequency. YOU ARE NOT OUT OF CONTACT as you can hear the controller, and their handover procedure means you are on their screens.

Generally they will call you when they have the time, and you need to be dealt with (and only they have the information needed to prioritise their radio calls!)

To use an emergency procedure, change your assigned transponder code, sound alarms at the ATC centre and initiate a HUGE distraction to a very busy controller forcing them to begin their emergency procedures is ridiculous - and incredibly unprofessional! :*

It's the equivalent of getting the Captain's attention by triggering an engine fire alarm. :rolleyes:

[A37575]

[QUOTEIt's the equivalent of getting the Captains attention by triggering an engine fire alarmQUOTE]

As you would, of course:ok: