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 TCA, sir.”
Walter White (hustles) the small plane out of the controlled airspace, but White does not realize that there is another plane dangerously off course.
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. the same altitude is approaching Airmexico 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?
They control air traffic on the ground and in the air.
What makes their work vital for flying?
Because there are a lot of flights needing to use the same airspace, the same airports, and the same runways at almost the same time. Today only controllers have an accurate picture of air traffic.
What makes the responsibility of ATCs continuously harder?
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?
No they don’t. Only controllers have an accurate picture of air traffic.
How can they establish their exact position in relation to other traffic?
They must rely on controllers to tell them.
3) What does TCA mean?
TCA stands for terminal control area. It is airspace around one or more major aerodromes.
How is the airspace around Los Angeles controlled?
The airspace around Los Angeles is very tightly controlled.
4) How many aircraft was the Approach Controller dealing with simultaneously?
There were two aircraft.
What were they?
The first was DC-9 performing flight 498. The second was a small plane that had entered into TCA inadvertently.
5) What aircraft did he have to pay special attention to? Why?
There were another aircraft – Piper Cherokee flying through the TCA. It was about to cross the flight’s 498 approach path.
6) When questioned by the investigators, what did the controller say about each of the three aircraft? Was he able to see them all?
The controller said that he had been able to see only two aircraft on his radar scope.
7) Did the recordings confirm his words?
No, they concluded that the Piper should have been visible.
According to the expert, what was a possible reason for the mistake?
Experts supposed that while the controller had been looking at one aircraft and trying to keep it clear he lost another one at the same altitude as the approaching Aeromexico jet.
8) What changes did the air collision over Los Angeles result in?
The collision drew attention to weaknesses in the radar systems used by air traffic controllers and led to some improvements.
9) How were the radar systems improved?
Mode C Intruder – an automated program was incorporated in all major radar facilities allowing them to alert controllers about any aircraft inadvertently intruding into controlled airspace.
10) In your opinion, what are other reasons for misunderstanding?
English language proficiency has always been a paramount factor in providing flight safety. Pilots and ATCs have to know standard phraseology to avoid miscommunication and communication breakdowns during radio exchanges. But Plain English is essential, too, especially in non-routine situations.
What can they lead to?
Runway incursion – or unauthorized entry onto an active runway.
Do you know any examples of non-routine situations caused by misunderstanding?
The most horrible accident in the history was caused by misunderstanding. In 1977 on the Spanish island of Tenerife two Boeings 747 collided on the runway. There were some other contributing factors, but misunderstanding certainly played its role.