The black boxes from Malaysia Air Flight 17 are unlikely to reveal what caused it to plunge from the sky six miles above Ukraine, but tiny holes in the scattered wreckage can provide telltale evidence it was struck down by a missile, experts said Tuesday.

There could be one hole or there could be dozens — none much bigger than a dime — but they are unmistakable evidence that a missile did the damage.

"It's a very distinct type of damage," said Robert Benzon, a former lead investigator for the National Transportation Safety Board. "The fastest you're going to crash an aircraft might be 800 or 900 miles an hour, and these [missile] shrapnel pieces are going thousands of miles an hour."

While it's possible that a missile actually hit the airplane, Benzon stressed that surface-to-air missiles are designed to detonate when they come close to planes and spray them with high-velocity particles, much like the spread of buckshot fired from a shotgun.

While the black boxes have been delivered to Malaysian authorities, the wreckage of the plane lies strewn across eastern Ukraine, unsecured in territory held by separatist rebels. Some of it apparently has been picked over by civilians, and there have been reports that some pieces may have been moved.

Three of America's leading airplane-crash investigators, all now retired, agreed that the flight data recorder and cockpit voice recorder carried in the tail section of the Boeing 777 would not tell investigators much about what happened on board.

"The recorders are going to be of less value and less importance than they would in a shoot-down, as opposed to an accident'" said Steven Wallace, former director of accident investigation for the Federal Aviation Administration. "Because it's a shoot-down, apparently, the recorder goes from everything's normal to nothing's being recorded."

There could be some data, Wallace said, but not enough to prove meaningful.

Two of the investigators — Benzon and Jim Wildey — played leading roles in unraveling the most complex aviation mysteries of modern times: the 1988 downing of a Pan Am airliner over Lockerbie, Scotland, that killed 259 people, and the 1996 crash of a TWA 747 off Long Island in which 230 people died.

There were reports that TWA 800 had been taken down by a missile — and conspiracy theorists still argue that case — but the most exhaustive investigation in NTSB history concluded it was a fuel-tank explosion.

"On TWA, we didn't find any holes at all, which is why we concluded it wasn't a missile," said Wildey, former chief of the NTSB Materials Laboratory, describing the distinct qualities of a missile explosion.

"If they penetrate through the [plane's] structure, they leave the signature of a high-velocity penetration," Wildey said. "If you take a baseball bat and hit the hood of your car, you leave a big dent. A high-velocity particle, it penetrates without denting it.

"Basically, if you see a pattern of these holes, and they're from the outside to the inside, there's no other way for them to be made except for a high-velocity particle," he said.

"You don't find this kind of damage in any other aircraft accident," said Benzon, who was deputy director of the TWA crash and the lead U.S. investigator in Lockerbie.

"When something explodes, the small bits of shrapnel are going very, very fast — hypersonic speeds — and when they strike metal, they make very tiny punctures in sheet metal," he said.

And the particles hit so fast that they melt the edges around the holes they create.

"If you can conclusively show that, it's pretty strong evidence that it was a missile," Wildey said. "All the evidence I've been hearing from the United States and other people says that it's a missile, but you really would like to have that backed up with the physical evidence."

Wildey said investigators would need at least two months on the ground in Ukraine to gather the evidence.

"It's not something you can do in a hour or two hours or a couple of days," he said. "It takes months to do this and to document this, and you don't want to be sacrificing more lives to try to determine this."

Benzon was adamant about that.

"You should worry about why it occurred, not how it occurred," he said. "The answer isn't going to be in the recorders, and it's not going to be in the wreckage. It's going to be interviewing people who operated the anti-aircraft missiles."