As planes fly faster and higher, it becomes harder for controllers to track their movements. Today only controllers have an accurate picture of air traffic. They use this information to guide pilots around potential problems. The pilots themselves have no way to independently confirm where they are in relation to all other flights. They must rely on controllers to tell them.
Labor Day weekend, 1986. Approach controller Walter White guides Aeromexico flight 498 in for a landing at Los Angeles International airport. The airspace around LAX is very tightly controlled. It is called the TCA, the terminal control area. As Aeromexico flight 498 closes in on the airport, Walter White sees a plane he does not expect on his radar.
“Ok, you are right in the middle of TCA, sir.”
Walter White hustles the small plane out of the controlled airspace,
“… and we run a lot of jets right through there at 3,500.”

but White does not realize that there is another plane dangerously off course.
“We should be able to see the ocean by now… Take a look at the map and see…”
The Piper Cherokee is cutting across the approach to LAX oblivious to the danger. The Aeromexico flight is just minutes from landing.
The National Transportation Safety Board questions Walter White about what he saw on his radar display.
“At any time, did you see the Piper Cherokee on your scope? – No, no sir! The Piper Cherokee was not displayed. It is my belief that it was not on my radarscope. But when investigators finally get the air traffic control radar records, they conclude the Piper should have been visible.
“He was looking at one, trying to keep it clear. And lost track of another one on the same altitude as the approaching Aermexico jet”
The collision over Los Angeles drew attention to weaknesses in the radar systems used by air traffic controllers and led to some much-needed improvements.
“Intruder is an automated program that is now incorporated in all our major radar facilities. That if an aircraft should inadvertently intrude, the controller will now be given a visual in an oral alert, this giving him time to override a timely warning to the pilot.
After the collision over Los Angeles, radar systems at the airport were upgraded.

1) What functions do ATCs perform? What makes their work vital for flying? What makes the responsibility of ATCs continuously harder?
The main objective of ATCs is to provide separation. ATCs provide safe regulation and movement ordering for traffic. ATCs haven’t right for mistake as lives of people depend on their observation and reaction. As planes fly faster and higher, it becomes harder for controllers to track their movements.
2) Do pilots have an accurate picture of all air traffic around them? How can they establish their exact position in relation to other traffic?
No, they don’t. They can establish their exact position in relation to other traffic with help of ATC only.
3) What does TCA mean? How is the airspace around Los Angeles controlled?
TCA means terminal control area. The airspace around Los Angeles airport is tightly controlled by several ATCs who make the management of flight within the site.
4) How many aircraft was the Approach Controller dealing with simultaneously? What were they?
The Approach Controller was dealing with three aircraft simultaneously. They were Air Mexico 498, Piper Cherokee and unknown traffic.
5) What aircraft did he have to pay special attention to? Why?
Walter White had to pay special attention to out of control aircraft due to heavy traffic in TCA.
6) When questioned by the investigators, what did the controller say about each of the three aircraft? Was he able to see them all?
Controller said that he saw only Aeromexico flight 498 and out of control traffic. As he said he didn’t see Piper Cherokee because he was unable to see them all.
7) Did the recordings confirm his words? According to the expert, what was a possible reason for the mistake?
No, the recordings didn’t confirm his words. According to expert a possible reason for mistake was looking only for one aircraft trying to keep it clear.
8) What changes did the air collision over Los Angeles result in?
The collision over Los Angeles drew attention to weaknesses in the radar systems used by air traffic controllers and led to some much-needed improvements.
9) How were the radar systems improved?
The radar systems were improved with a visual and oral alerts mechanism. Improvements give to controller time to override a timely warning to the pilot if an aircraft should inadvertently intrude.
10) In your opinion, what are other reasons for misunderstanding? What can they lead to? Do you know any examples of non-routine situations caused by misunderstanding?
There are many reasons for misunderstanding such as the use of non-standard phraseology, poor knowledge of English, too much fluency or lack of fluency, bad pronunciation and strong local accent, poor reception on the radio, bad readability, frequency congestion, fatigue or stress.
Misunderstanding can lead to very serious problem such as flight delays, loos of separation, RW incursion, operational errors, aircraft damage and other incidents and accidents.
On 1 July 2002, Bashkirian Airlines Flight 2937, a Tupolev Tu-154 passenger jet with 69 people on board – mostly children – and DHL Flight 611, a Boeing 757 cargo jet with a crew of two, collided over the towns of Überlingen and Owingen, in southern Germany. All 71 people on board both aircraft were killed.
The official investigation by the German BFU identified as the main cause of the collision a number of shortcomings on the part of the Swiss air traffic control service in charge of the sector involved, and also ambiguities in the procedures regarding the use of TCAS, the on-board aircraft collision avoidance system.