El Toro Noise Report Has Few Surprises

By JEAN O. PASCO

July 20, 1999 12 AM PT

TIMES STAFF WRITER

Commercial jets flying to and from El Toro Marine base last month blasted some south Orange County areas with noise and went almost unheard in others, according to a county report released Monday.

Much of the information duplicates sound levels recorded by observers and airport foes during the demonstration of large jets that are expected to use a new international airport being planned at El Toro after 2005. Commercial aircraft arrived at and departed El Toro 50 times during the June 4 and 5 demonstration.

But the county’s noise reading was significantly lower for the loudest aircraft--a Boeing 747--descending over Laguna Woods for landings. The county report showed the plane generated 92 decibels on its loudest arrival, compared with 101 decibels calculated by monitors owned by Leisure World-Laguna Woods. A 10-decibel increase doubles the noise.

Laguna Woods Councilman Bert Hack said the city placed its noise monitor closer and more central to the runway than the county’s equipment, which was tucked near two buildings on the edge of the club golf course.

“Much of what the county has is skewed,” Hack said. “The interesting thing is that we never wanted the . . . tests anyway. It was the [pro-airport majority on the] Board of Supervisors who insisted.”

Irvine erected noise monitors next to six of the county’s 10 monitors for the flights. The city’s readings were similar to the results released Monday, Irvine city planner Peter Hersh said.

Despite the jet noise, county officials said nothing changed their prediction that no homes or schools will be within the high-noise zone for airports. The zone is based on average noise of 65 decibels, from readings taken over a 24-hour period. The difference between the noise of a single jet and average noise can differ by 30 to 40 decibels.

“There were no surprises,” said Ron Ahfeldt, senior vice president of P&D; Aviation, the county’s chief airport planning consultant.

County planners reiterated Monday that the test was held for demonstration purposes, not for its scientific value. For example, the loudest aircraft in the test, the Boeing 747, is expected to be used only 4% of the time when the airport is operating at full capacity in 2020.

“The item of interest was the operation of the aircraft itself,” El Toro program manager Courtney Wiercioch said.

Wiercioch announced Monday that she will be stepping down from the manager’s post while she awaits the birth of her second child. Her assistant, Michael L. Lapin, takes over beginning today. Wiercioch will continue to work with the airlines and Federal Aviation Administration as El Toro planning progresses.

Elsewhere in the county report, noise levels showed that planes generated the most noise above Laguna Woods and parts of Aliso Viejo, Lake Forest and Portola Hills. In those areas, monitors spiked to levels on par with a food blender, garbage disposal and power mower as jets landed from the south and took off to the north and east.

“There really was no impact in Irvine, Mission Viejo, Lake Forest, San Clemente, Laguna Beach, Dana Point and Coto de Caza,” said Tom Wall, chairman of the pro-airport Orange County Airport Alliance.

“It doesn’t matter if it’s 60 [decibels] or 70 or 90, it’s obtrusive to the folks who live there,” responded Supervisor Tom Wilson, who represents the largest chunk of South County. “Noise like that on a constant basis is going to make the area unlivable.”

Wilson said he will ask for the report to be discussed at the Board of Supervisors’ July 27 meeting.

Meg Waters, spokeswoman for a coalition of anti-airport cities, said her group suspects that planes arriving at El Toro skirted noise monitors so they would appear to be quieter.

“It still was loud,” she said.

The report documented that low cloud cover and reduced visibility resulted in the cancellation of the early-morning June 4 arrival of a Boeing 747. Easterly departures also were restricted after pilots were barred from flying unless cloud cover was at least 6,000 feet above the ground and visibility was five miles. The report showed tail winds of up to 4 knots during the flights.

All 25 arrivals landed from the south. Of the 25 departures, 16 took off to the north and nine headed east.

The report showed that a few jets leaving to the north were ordered by air-traffic controllers to turn to the left at eight miles out, instead of turning right where clouds reduced visibility. The change may have accounted for more noise in Anaheim Hills, northwest of the runway.

Of the 50 takeoffs and landings, five planes operated at their scheduled weights, 28 operated above their scheduled weights and 15 operated below them, Wiercioch said. Typically, the heavier the plane, the more noise it generates.

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

Noise Level Breakdown

Decibel readings by monitoring station and plane type from El Toro flight demonstrations June 4-5:

*--*

Sites 737 747 757 767 A300 A320 MD90 D Anaheim Hills 73.8 84.6 74.2 76.2 72.8 72.2 64.6 A Laguna Hills 85.1 92 84.3 89.3 84.6 80.1 79.4 D Irvine 82.4 87.7 81.3 83.8 84.9 83 80.5 D Lake Forest 83.9 - 82.3 86 - 80.8 80 A Aliso Viejo 81.3 87.6 83.1 84.1 83.5 81.2 79.9 A Dana Point 77.4 80.5 76.8 81.2 81.9 79 73.9 D Ranch S.Marg. 79.5 - 82.1 83.4 65.1 83.9 80.8 D Coto de Caza 75.7 - 76 73.2 - 73.8 74 D M. Viejo 77 - 80 79.7 - 84.1 76.3 D Foothill Rnch 83.5 - 82.7 85 - 83.9 80.8

*--*

A: Arrival

D: Departure

Table represents highest Single Event Noise Exposure Level (SENEL) decibel reading per plane.

Source: County of Orange

The Results Are In

County decibel readings recorded during El Toro flight demonstrations on June 4-5:

Anaheim Hills

Highl 84.6

Low: 62.8

Laguna Woods

High: 92.0