El Toro Takeoffs to East, North Called Doable

A long-awaited county study released Tuesday says that jets could take off from northern and eastern runways at the proposed El Toro airport without a significant risk of hitting nearby mountains, but some critics immediately challenged the findings and remain unconvinced about the airport’s safety.

The report, conducted by an aviation research firm, seeks to address concerns from the nation’s largest airline pilots union, which has questioned the safety of easterly takeoffs and suggested that its members might refuse to use it if the airport is built.

The report was undertaken in cooperation with the Air Line Pilots Assn. and concluded that planes will be able to clear the sharply rising topography around the base. The pilots association wouldn’t comment on the report Tuesday, and county officials said the organization probably will conduct its own safety review of takeoff patterns.

The county’s plan for northerly takeoffs is at odds with a 1996 Federal Aviation Administration memo, which said that the flight path might conflict with air traffic bound for John Wayne Airport and LAX.

According to the new study, jets taking off from El Toro would have to climb roughly 400 feet per nautical mile--more than is required at some airports, but less than others, including John Wayne, Burbank, San Francisco International and Lindbergh Field in San Diego.

“It compares favorably with other airports,” said Ron Ahlfedt, the county’s chief airport consultant. “What we’ve determined is that [takeoffs] . . . can occur safely and be done within FAA requirements.”

The report, based on computer simulations of jet patterns and local topography, was prepared over the last few months and comes a year before the Board of Supervisors is scheduled to take a final vote on the airport plan.

It still leaves many questions unanswered, including whether airlines would be willing to make the initial climb to get above the hills. The takeoff patterns probably would be modified if many airlines don’t approve them. Ultimately, the FAA would have to sign off on the takeoff patterns.

Airport planners now will merge the safety report with data about weather conditions and the mix of jets expected to use the airport to determine noise levels and generate a final report.

The findings offer mixed news to nearby residents concerned about noise from passing jets.

Researchers found that takeoffs to the north could follow a new, modified path that goes over scarcely populated areas around Irvine Lake. The original takeoff pattern had flights much closer to Tustin, Orange and Villa Park.

The county also examined the possibility of moving the eastern takeoff path away from Coto de Caza, Mission Viejo and Foothill Ranch, which would reduce noise for those communities.

But the report found that the modified paths were unworkable because jets would have to climb too high to avoid a mountain range--630 feet per nautical mile compared to 360 to 400 feet for the route now proposed by the county.

The airport plan endorsed by the Board of Supervisors last month calls for an international airport at the 4,700-acre base that by 2020 would handle 24 million passengers a year and about 500 daily flights.

About 70% of those departures would occur on the eastern runway, sending planes over several South County communities. The remaining jets would take off to the north.

“Nothing in that report changes the fact we are going to have hundreds of planes flying over our house day and night,” said Marcia Johnson, a Foothill Ranch resident. “This doesn’t make any difference to us.”

Leaders in Tustin, Cowan Heights and surrounding communities have urged the county to move the northern takeoff pattern away from them. On Tuesday, they expressed relief that the study found their preferred flight path to be safe.

But some airport opponents question whether the new northern route would conflict with air traffic from John Wayne, Ontario and LAX. A preliminary FAA review of air traffic in 1996 stated that a route similar to the one now proposed by the county might not be allowed because of the amount of air traffic to the north.

County officials maintained Tuesday that the jets would easily be able to climb fast enough to avoid the other traffic.

Although the land below the northern flight path is now mostly vacant, some residents point out that it may eventually contain thousands of homes.

“There are going to be 40,000 [people] living in the Irvine Lake area and directly north,” said Bob Bennyhoff, an Orange Park Acres activist. “I hope [the county] is taking them into account.”

The study released Tuesday did not assess noise levels under the flight paths, but officials expect to have such a report completed in September.

The safety of the eastern runway has emerged as a key issue in the El Toro debate--especially given the concerns of the Air Line Pilots Assn., which represents 44,000 commercial pilots. A smaller organization, the Allied Pilots Assn., also has raised questions about the runway’s safety.

The Air Line Pilots Assn. agreed earlier this year to help the county develop the criteria for the safety study released Tuesday. Airport planners hoped the report might prompt the union to reconsider its stance on the eastern runway.

Some pilots want El Toro jets to depart from a western runway. Such a flight path is free of mountains, but county officials have rejected the idea because it would send planes into heavily populated parts of Irvine, Costa Mesa, Santa Ana and Huntington Beach.

Jets using the eastern runway would encounter hills 600 to 700 feet high soon after lifting off and then contend with mountains as high as 2,100 feet.

To avoid crashing, jets would have to climb 360 to 400 feet per nautical mile on eastern departures and 410 feet per nautical mile on northern departures. County officials said they expected the planes to actually fly much higher.

Other Southern California airports, including Burbank and San Diego’s Lindbergh Field, require planes to climb slightly higher. Jets taking off from John Wayne Airport have an extremely steep climb--1,000 feet per nautical mile--because of strict noise rules.

K&M; Aviation Consultants conducted the study using computer models that simulate jet flights and determine whether they meet FAA standards and are possible given the topography along the path.

The county has not yet fully analyzed how wind, hot temperatures and other weather conditions would affect takeoffs.

Times correspondent Jean O. Pasco contributed to this report.

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

High on Departure

Jets taking off from an El Toro airport would face topographical obstacles up to 2,100 feet above sea level. The three proposed departure patterns--one to the north and two heading east--would require aircraft to gain about 400 feet per nautical mile to avoid surrounding hills.

Getting Out Safely

Initial climb gradient is a measure indicating how high a departing jet must be when it is 1 nautical mile (6,080 feet) from an airport. The climb gradient for both proposed directions out of an El Toro airport would be less than half that required at John Wayne Airport. Heights in feet per nautical mile:

1. John Wayne: 1,000 feet

2. Lindbergh Field (San Diego): 570 feet

3. San Francisco: 500-530 feet

4. El Toro North: 410 feet

5. El Toro East: 360-400 feet

Source: County of Orange