Crash Probe Focuses on LAX Radar

Investigators conducting a weeklong hearing on the cause of a collision last summer between an Aeromexico jetliner and a private plane that killed 82 people focused Wednesday on defects in the airport’s radar.

In their second day, National Transportation Safety Board investigators questioned Richard Cox, the air traffic manager at Los Angeles Terminal Radar Control, about the ASR-4 radar system a controller was using to track the Aeromexico DC-9 as it approached the airport.

“There are deficiencies in the system’s radar, and there are instances when an aircraft’s existence is not displayed on radar,” Cox testified. “The ASR-4 is an old piece of equipment. It’s had more than its share of failures over the years.”

Cox acknowledged that in the week before the Aug. 31 disaster, eight problems were reported with the radar system.

Despite the problems, Cox repeatedly denied charges that the radar system was unsatisfactory.

“I view the system as entirely safe,” he said, but conceded that radar “blind spots” can be created by atmospheric conditions, the speed of an aircraft and the failure of an aircraft’s transponder.

Cox testified that since January, 1986, there had been “a significant increase” in loss of data and erroneous reports in the radar’s “beacon mode C,” which receives data from an aircraft’s transponder, an electronic device indicating altitude and position.

The airport employs two radar systems for tracking planes--the ASR-4, a 28-year-old system that looks south, and the ASR-7, a 17-year-old system that looks north, said Dick Russell, Airline Pilots Assn. spokesman.

“We’ve got to have new radar. There is no two ways about it,” Russell said.

Never Saw Piper

The hearings at the Crowne Plaza Holiday Inn near the airport are being watched closely by the aviation community because they are focusing on one of the world’s busiest airports, where the air traffic control system has been criticized as unable to handle the crowded skies.

The controller who was guiding the Aeromexico jet as it approached the airport testified Tuesday that his radar scope never showed the single-engine Piper that collided with the DC-9. The Piper, flown by William K. Kramer, was in controlled airspace without authorization when the accident occurred. Officials have said that it did not have equipment that would have alerted a controller to its altitude.

En route from a suburban airport to a mountain resort north of Los Angeles, Kramer flew his single-engine plane into the DC-9’s tail, throwing the jetliner out of control and sending it plummeting to the ground. The 64 passengers and crew on the jet were killed, as were the three people aboard the Piper and 15 people on the ground. Ten homes were destroyed in the resulting inferno.