Radar screens not necessary?

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Peminu
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Radar screens not necessary?

Postby Peminu » Thu Apr 24, 2008 6:13 pm

Mexico City's airport has inaugurated a new terminal building, called "Terminal 2". A lot of problems have appeared and last week have been conflictive and with a lot of delays.

But, what do you think about this declarations by the head of the Mexican Transports and Communications Secretary (SCT)?:


Respecto a la supuesta falla de radares reportada en días pasados, el titular de la SCT aclaró que “no hay riesgo en materia de control aéreo en el país, nunca se ha escatimado un peso en materia de seguridad aérea nacional”.

Puntualizó que la información que dio a conocer un controlador respecto a la falla en la terminal 2 del aeropuerto internacional “es totalmente falsa”.

Por su parte, el director general de Servicios a la Navegación en el Espacio
Aéreo Mexicano, Agustín Arellano, explicó que la realidad es que falló la presentación de los radares en las pantallas.

“No es absolutamente indispensable ver los radares en la pantalla; es más importante la radio localización” y aseguró que los sistemas de navegación aérea “son de los mejores del mundo”.

Agregó que “no es posible que de la noche a la mañana todo sea un caos” y aseguró que el trasfondo de la supuesta falla en los radares tiene un interés sindical
.


Free translation (please forgive me if I make some mistakes):

"About the supposed radar failure reported on recent days, the head of the SCT made clear that "There is no risk in the country in the matter of air traffic control, we have spared no expenses in the matter of national air safety".
He pointed out that the information made public by a controller about a failure in the Terminal 2 of the international airport "is completely false".
On other part, Agustin Arellano, general director of the Services for Navigation on the Mexican Air Space, explained that what really failed was the presentation of the radars on the screens.
"It is not absolutely indispensable to see the radars on the screen; it is more important the radio localization", and assured that the aerial navigational systems "are the best of the world".
He added that "it is not possible that from one day to the other everything becomes a chaos" and assured that behind the supposed radar failure there is a union conflict.



Complete note on:

http://www.milenio.com/index.php/2008/04/23/228816/


What do you think? Back to 1930 with only radio and no screens is the best of the world?
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Re: Radar screens not necessary?

Postby Dmmoore » Thu Apr 24, 2008 9:04 pm

Radar screens should not be "required" to provide a safe environment "IF" the aircraft in the area are not operating with spacing that requires positive radar control. "IF" they are I question the validity of his statement.

ATC controller comments, please.
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VectorForFood
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Re: Radar screens not necessary?

Postby VectorForFood » Sun Apr 27, 2008 8:45 am

I'm having a bit of trouble with the translation, but on the note of radar/non-radar.

ATC services quite obviously can be safely provided in a non-radar envrionment. In ATC terms we call this "Procedural control".

Essentially without radar the only way to separate airplanes is through the use of time standards based over a given segment of time.

Every country has slightly different standards depending on the non-radar airspace invovled, for me two airplanes at cruise at the same speed must have 10 minutes longitudinal separation, now at a groundspeed of 500 knots that is an incredible distance between the two, but it is based for us on the fact that going across the Atlantic they will have adequate separation on the other side coming back into radar coverage.

There are ICAO standards for every country, but each has their own set depending the airspace (length of time in non-radar)

There are allocations for differences in mach speed, faster aircraft in front you need less than 10 minutes since the gap will increase, EX: B744 @ M.85 flying in front of a 767 @ M.82 will need 8 minutes of longitudinal separation when they go off radar.

Now in an airport envrionment the same idea applies, operating non-radar around an airport is perfectly "Safe" however there's some things to consider:

1.) Separation is now based on pilot position reports, and controllers have to assume the pilot is issuing him the "correct" position altitude and time, and has no real way to verify it.

2.) Because procedural control is based on time, you no longer can have airplanes 3NM in trail on approach, you have to apply time standards and depending on the airport they can be quite lengthy (6 min between departures etc) thus adding considerable delays.

3.)If an airplane deviates from an altitude or routing inbetween reporting points, controllers cannot catch this, thus removing a layer of safety for everyone involved.

4.)In a radar airspace environment where normally airplanes are separate using radar standards, the removal or failure of radar service is by far more dangerous than airspace that is designed to be used as non-radar, controllers are not expecting it, airplanes are not issuing position reports, controllers have the "Picture" of the situation at hand utilizing radar, remove the visual clues and having to resort to doing it all in your head can take some time.

On that final note, as controllers we have recurrent training on radar failures, if the radar fails there is no panic, the airplanes are still safe now you have to take the time to safely transition them to procedural separation (Moving flight levels/altitudes, routings, and procuring estimates and position reports) and in fact at my centre we do a fair bit of procedural (non-radar) control both for airplanes transitioning to the North Atlantic tracks every day, and also into New York Oceanic airspace, however most of the control work we do is radar related.

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Re: Radar screens not necessary?

Postby Digger » Sun Apr 27, 2008 2:58 pm

Having asked her about this thread, I'd say that Mrs. Digger would agree with everything VFF has posted above, particularly point 4, with the exception of one thing:

if the radar fails there is no panic,


"Panic" might be too strong a word, but even with only two airplanes, losing the radar display is always an "oh shit moment". (She's also spent her entire career in the terminal environment, as opposed to enroute.)

She also questioned whether the Mexico City system still uses paper flight strips, or whether the strips are part of the display. Obviously, losing the radar, and the strips, all at once is even worse.

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Re: Radar screens not necessary?

Postby VectorForFood » Sun Apr 27, 2008 4:58 pm

Obviously there is no international legal requirement, but most systems that in a stripless envrionment, the computerized strip system are powered by a completely separate power source from the radar system itself.

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Re: Radar screens not necessary?

Postby Digger » Sun Apr 27, 2008 7:11 pm

This is the line that raised that question:

...explained that what really failed was the presentation of the radars on the screens.


Poswer source notwithstanding, if the strips are part of the "presentation", do they go away as well?

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Peminu
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On second thought...

Postby Peminu » Mon Apr 28, 2008 12:41 am

On second thought, the failure was on a radar of a new terminal. The old terminal equipment should have been working without problems and I believe that probably they handle the AIR traffic control, and the failure probably was on a ground radar.

If this was the case, then I have to agree with the declarations that the "AIR TRAFFIC" was not in jeopardy.

Probably there is no answer and depends on the design of each facility, but how does a multiple radar facility shares the job? Is there always a prmary one?
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