Heavy Turbulence From Airliner May Have Been Cause of Jet Crash : Investigation: NTSB officials say the corporate plane in which 5 died in Santa Ana may have mistakenly crossed the wake of a Boeing 757.

The fatal crash of a private jet into a field next to the Santa Ana Auto Mall may have been caused by heavy turbulence from a Boeing 757 landing just ahead of it at John Wayne Airport, federal investigators said Thursday.

The fiery crash at the height of the Wednesday evening rush hour killed two top executives of the In-N-Out Burger chain and three others aboard the private plane, but no one was hurt on the ground.

In-N-Out President Richard A. Snyder of Newport Beach and Executive Vice President Philip R. West of Irvine had apparently broken a longstanding personal rule about not flying together, and were both aboard the chartered jet.

The National Transportation Safety Board is studying the possibility that the crash may have occurred because the private plane mistakenly crossed the wake of the 757 and may have been affected by the resulting turbulence, officials said.

Supervisory air safety investigator Don Llorente of the NTSB said the smaller plane was flying about two miles behind United Flight 103. At one point, the private plane apparently was flying about 200 feet below the larger jet’s glide path, which is not customary, Llorente said.

“If you’re flying behind a heavier jet aircraft, the common technique is to fly at or above the level of the heavier aircraft,” he said.

The crash took the lives of Snyder, 41, head of the Baldwin Park-based restaurant chain and a well-known Republican activist; West, 37, Snyder’s childhood friend; Jack Sims, a consultant who was also a friend of Snyder’s; pilot Stephen R. Barkin, 46, of Canyon Country, and co-pilot John O. McDaniel, 49, of Long Beach.

Federal investigators have said the jet did not run out of fuel, but they have not eliminated other potential reasons for the crash, including the failure of sophisticated flight control systems, a loss of power to those systems, and pilot error.

Don Miller, a pilot and the Orange County representative of the Aircraft Owners and Pilots Assn., said he had never experienced problems in flying a small plane even 1 1/2 miles behind a 757, but said it is standard procedure to stay above the level of the heavier plane “because the wake sinks.”

Miller and other commercial pilots said wake turbulence is created by wind swirling off the wingtips, creating twin miniature, horizontal tornadoes as the aircraft flies through the air. Their force is directly proportional to the weight of the aircraft; a heavy plane like the 757 generates a stronger wake than smaller craft like the corporate jet.

At In-N-Out’s corporate headquarters in Baldwin Park, officials were tight-lipped Thursday about the long-term impact of the tragedy on the privately held company, which is one of the oldest and largest family-owned restaurant chains in the United States. The chain has 93 restaurants, all but four in Southern California, and 35,000 employees.

“The plane was on a business trip and en route to John Wayne (Airport),” company Vice President Carl Van Fleet said. “An investigation is under way. The company continues to be operated by staff and no business disruptions are anticipated.”

Outside the company headquarters, flags flew at half-staff. Most employees left early Thursday, said Johnny Miller, a security guard who wore an In-N-Out baseball cap.

“There aren’t many smiles today, and that’s unusual for this place,” Miller said. “No one knows what’s going to happen. It’s very sad.”

The executives’ one-day trip, which began in Long Beach on Wednesday morning and was scheduled to end at John Wayne Airport that evening, included a stop in Fresno for the opening of a new restaurant and scouting of other potential locations, according to family friends and company sources. The plane made stops in Orange County, Fresno, Bakersfield and La Verne before heading back to Orange County.

Snyder’s mother, Esther, who founded In-N-Out with her late husband Harry in 1948, also had been aboard the twin-engine jet--a Westwind 1124A--but disembarked at Brackett Field in La Verne about 20 miles east of Los Angeles, according to a family friend, former Irvine Mayor Sally Anne Sheridan.

NTSB investigators Thursday were examining the plane’s wreckage, which scattered some 30 yards from the point of impact off Edinger Avenue near the Costa Mesa Freeway. The crash site is about three miles from the airport.

Investigators combed the rubble as dozens of onlookers watched, some through binoculars. They cut through the plane’s fuselage with a rotating saw, trying to haul away pieces and reach the cockpit, which was lodged four feet underground. Fuel tanks on the tips of both wings still angled about 45 degrees out of the ground.

Investigators had removed the plane’s “black box” earlier, and shipped it to Washington for examination.

The plane, owned by Robert Gumbiner of Long Beach, was based at Air Flight at Long Beach Municipal Airport. The aircraft had no record of any incidents or service difficulties, according to a Federal Aviation Administration spokeswoman.

In-N-Out had a corporate policy forbidding its two top executives from flying together, according to Sheridan, who was friendly with West and Snyder.

“Rich and Phil never flew together when they went to Arizona, Vegas or other places” where the company has restaurants, she said.

West apparently adhered to the policy and took a commercial flight for at least one leg of the Wednesday trip, but then opted to take the chartered jet home, Sheridan said, recounting a conversation she had Thursday with West’s wife, Lori.

Lori West suspected he decided “to get back home to her and her son earlier,” Sheridan said.

Esther Snyder, who serves as In-N-Out’s secretary-treasurer and works in the company’s accounting department, got off in La Verne because she was not feeling well, Sheridan said. Another In-N-Out executive, Bob Williams, also left the plane in La Verne, according to sources.

Following the stop in La Verne, the twin-engine plane took off again, heading for the day’s final landing at John Wayne Airport. Moments before the crash, the pilot was cleared for landing by the airport tower, a Federal Aviation Administration spokesman said.

But just after 5:30 p.m., the aircraft suddenly spiraled straight down, plunging nose first into the ground in a field just past the Santa Ana Auto Mall, which was crowded with customers. No one on the ground was hurt.

NTSB and FAA officials said that both the Westwind and the 757 were landing under visual flight rules, which means that the pilots are responsible for maintaining proper distance from each other.

“In this environment, air traffic operations were normal,” the NTSB’s Llorente said, adding that in general, separation between planes for John Wayne approaches is from 1 1/2 to 2 miles.

An FAA official said the West-wind was told it was following a Boeing commercial jet, which implies a warning about possible turbulence.

The last recorded altitude for the small plane was 1,100 feet above sea level. Its airspeed was 150 knots.

“We do not know who was flying the aircraft at this time--whether it was McDaniel or the pilot,” Llorente said, but both have flight experience at the airport.

Friends, family members and business competitors mourned the victims Thursday, in particular extolling Snyder, the best known of the five, as a skilled, careful businessman, a considerate boss and a deeply religious, charitable man. Snyder is survived by his wife, Christina, his mother and a brother, Guy.

Snyder was active in conservative political causes, including the recent school-voucher initiative. He co-chaired the campaign for Proposition 174, defeated in last month’s election.

“He’s a real loss, he was a wonderful man,” said Roberta Ahmanson, who helped finance the voucher initiative. “He did an awful lot of good things. A year ago he was handing out truckloads of blankets to homeless people.”

“He was a man of deep, deep convictions and love for his country,” added Danielle Madison of Orange, who worked with Snyder on political causes.

Sheridan, the former Irvine mayor, said she met Snyder about three years ago when he started his search for a new corporate home. The company is scheduled to move in February into the top two floors of a building at 4199 Campus Drive in Irvine.

“He’s a fabulous person,” Sheridan said. “I’m just destroyed by the news.”

Carl N. Karcher, founder and chairman emeritus of the Carl’s Jr. hamburger chain, said he had known the Snyder family for about 30 years.

“My heart just fell, it sank,” Karcher said. “He’s a competitor but I’ve always admired him. I’m in a state of shock.”

Snyder’s style was evident in the way he crafted In-N-Out’s planned move to Irvine from Baldwin Park. Instead of disrupting corporate employees’ lives with lightning-fast decisions, “Rich took time to make sure that everyone at the company could get used to the idea,” Sheridan said. “He started the planning months in advance.

West, who lived in the Turtle Rock area of Irvine, is survived by his wife, Lori, and son, Michael, 3. He was described as Snyder’s best friend. West and his family had lived next door to Esther Snyder in Glendora; the families were so close that they were all considering moving to Newport Beach, where Richard and Christina Snyder lived, Sheridan said.

“Phil West was Rich’s closest friend, they were childhood friends,” said one Orange County attorney who knows both men. “For Esther, it’s got to be like losing two sons. They were both just super guys.”

Times staff writers Greg Johnson, Alicia Di Rado, Mike Flagg, Jodi Wilgoren, Mark Platte, Dave Reyes, Willson Cummer and Debora Vrana contributed to this report.

Accident Scenario

National Transportation Safety Board officials say a chartered jet may have flown into the wake of a Boeing 757 as it approached John Wayne Airport. This may have contributed to the plane’s fatal crash Wednesday, NTSB officials said.

What Happened

1. Chartered Westwind 1124A, flying two miles behind 757, dips 200 feet below glide path

2. One minute away from airport, Westwind, at 1,100 feet, loses control

3. Westwind plunges at 45-degree angle, rolls over, nose dives four feet into ground at a field at Santa Ana Auto Mall

Typical Flight Path

Small plane follows at least two to three miles behind, at or above altitude of larger aircraft, to avoid turbulence

How Turbulence is Created

Air flowing over wingtips creates miniature, horizontal tornadoes

Air continues to rotate, then drops toward ground and dissipates

Duration of turbulence varies according to weather conditions, but generally is gone by the time the plane has progressed three miles

Not to scale

Source: Don Llorente, supervisory air safety investigator, NTSB; Researched by CAROLINE LEMKE and JEFFREY A. PERLMAN / Los Angeles Times