Pressure to succeed may have caused the V-22 Osprey's deadliest accident ever, according to the U.S. Marine Corps' commandant.

Though the accident happened more than 13 years ago, lessons cited in a December letter obtained by Bloomberg News via a Freedom of Information Act request may apply to similar pressures the military is under today to prove the value of new weapons such as the F-35 fighter and the Navy's Littoral Combat Ship in a time of defense budget cuts.

The 2000 V-22 Osprey accident that killed 19 Marines stemmed partly from "undeniably intense" pressure to show progress for the new tilt-rotor aircraft, Gen. James Amos wrote in a look back at the crash.

"I believe they were eager to vindicate a revolutionary technology," Amos said.

The Osprey can take off and land like a helicopter, while its propellers tilt forward so it can fly like an airplane.

Though the Marine Corps has never directly blamed the pilots for the crash, it has cited “human factors," according to Bloomberg. The crash occurred during a night exercise in Arizona.

The Marine Corps’ explanation in 2000 “failed to adequately account for the many intangibles contributing to the outcome,” Amos said, prompting his latest letter.

Congress has since appropriated $41.5 billion toward a $55 billion program to build 460 of V-22 Ospreys.

Read the full article here.