Fifth Marine dies in crash

All five U.S. Marines aboard a military aircraft that crashed Wednesday afternoon in Imperial County were killed, officials said.

The MV-22B Osprey crashed during a training mission near Glamis, officials with the 3rd Marine Aircraft Wing said Thursday. Glamis is about 150 miles east of San Diego near the borders with Arizona and Mexico.

The names of the deceased Marines will not be released until after relatives are notified.

“We mourn the loss of our Marines in this tragic mishap,” Maj. Gen. Bradford J. Gering said in a statement. “Our hearts go out to their families and friends.”

The aircraft was based at Marine Corps Air Station Camp Pendleton and crashed around 12:25 p.m. near Coachella Canal Road and Highway 78. Contrary to reports on social media and early radio calls from the scene, there were no nuclear materials onboard, Cpl. Sarah Marshall, a spokesperson for the 3rd Marine Aircraft Wing, said Wednesday.

An investigation is underway.

The Osprey is a tilt-rotor aircraft that can take off and land like a helicopter and fly like an airplane by pivoting its rotors. Versions of the aircraft are flown by the Marines, Navy and Air Force to transport troops and equipment. The aircraft, however, has a troubled and controversial history since its first test flights in 1989.

Rex Rivolo, a former Air Force pilot and retired analyst with the the Institute for Defense Analyses, a Pentagon think tank, followed the V-22’s development from 1992 through 2009. Early on, he concluded that the aircraft’s complex design made it susceptible to uncontrolled rolling.

“Because of its complexity, it can be very slippery,” Rivolo said Thursday.

Before it was officially introduced in 2007, the aircraft was involved in a crash that killed 19 Marines during a training exercise at Marana Northwest Regional Airport in Arizona on April 8, 2000.

Rivolo said that all aircraft have “flight envelopes,” operational limits for airspeed and other factors. Most have about a dozen f light envelopes, parameters that pilots should not exceed to maintain control.

“The problem with the V-22 is it doesn’t have five or six envelopes. It’s got thousands of envelopes, because each different pitch of the cells has its own set of envelopes,” Rivolo said. “A small mistake in a typical helicopter just causes minor problems. Maybe it scares the pilot, but in a V-22 a minor mistake can kill you.”