SEATTLE -- Some of the biggest, most luxurious RVs on our roads may also be some the deadliest.

KIRO Team 7 Investigators spent months analyzing hundreds of fatal motor home accidents -- with startling results.

Investigative Reporter Chris Halsne starts by showing you how overheated brakes, flying debris and inadequate interior design can be a killing combination.

On a clear day, the views from the top of Hurricane Ridge are spectacular, so it's well worth the drive up the 17-mile steep winding road. However, for a family vacationing here from Missouri in their RV, it was the trip back down that was a terrifying and deadly freefall.

Based on witness accounts and 911 calls, KIRO Team 7 Investigators pieced together the last moments of the crash.

Survivor Austin Owens told us, "It wasn't slowing down. It wasn't stopping. We didn't have any brakes."

Dozens of other witnesses called 911 after seeing the 1990 Monarch Coach lose control, speed through a stop sign and slam into traffic as it approached the town of Port Angeles.

"911 Emergency. It's horrible. It's unbelievable. Oh my God! There's been a terrible accident!"

Austin said he saw his father actually standing up, pushing the brakes with his foot.

"We rear-ended that first car. We hit two more vehicles and went off a ravine. My dad, whenever he made the decision to try to stop it, he hit his own corner -- so (pause)."

Austin Owens is pausing there because it's awfully hard to describe what comes next. His father, Lonnie, didn't survive a crash in the families Class A motor home last summer during a vacation to the Olympic National Park.

Austin, who gashed his forehead open during the crash, sat down with KIRO 7 Investigative Reporter Chris Halsne to discuss his dad's life and death.

"He loved camping, loved being outdoors -- just a very big outdoorsman. So we did a lot of hiking, camping and a lot of around the open fire of the night. We enjoyed that a lot," Austin Owens said.

On top of one death, 14 people were injured in an accident near Port Angeles last June. Six of those hurt were inside the Owens' 9-ton Monarch Coach.

Certified truck brake mechanic Jerry Benoff helped police determine the downhill-rolling RV couldn't stop due to "brake fade."

"The drums heat up and they expand. It gets a surface on it that's almost glazy, like glass and it just, the friction isn't there to stop the brakes. You're really hurting when brake fade comes," Benoff said.

Austin and his girlfriend Kelly, along with his mom Vicky, younger sister Autumn, and two of his brothers, Ashton and Aaron, hung on for dear life, while dad tried to stop the out-of-control motor home.

Austin said, "People don’t realize how fast stuff like that happens."

Hot brakes may have caused this crash, but that's not what killed Lonnie Owens. The primary cause of death was skull fractures.

A lengthy KIRO Team 7 Investigation uncovered evidence that raises troubling questions about whether Owens hit his head or something poorly secured inside the RV hit him.

JD Gallant has been studying RV crashes for decades and is one of this nation's most recognized consumer experts in motor home safety.

"You can see the disintegration and why it came apart," Gallant told KIRO Team 7 Investigators.

Gallant analyzed Owens' crashed RV and found what appeared to be interior design and structural deficiencies.

Halsne: "Why did it come apart, in your opinion?"
Gallant: "Strictly, it wasn't fastened well enough. It's a matter of screw and glue. That's it. You had things come off the wall -- cabinets. One cabinet would stay on the wall and the next would just fall off the wall.”

Under the Open Record Act, KIRO Team 7 Investigators obtained dozens of crash pictures, witness statements, and reports never before released. One police photo shows small, stripped screw holes in the wall above the passenger seat and what appears to be a missing cabinet. One photo, taken by Gallant, is even more telling: it shows a 100-pound-plus wooden overhead cabinet frame is sitting across Lonnie Owens' driver's seat.

Austin Owens doesn't need a picture to remind him.

"The cabinet doors and the cabinet part up front, those came loose with the impact and pretty much the entire front of the motor home was completely smashed in," he said.

Gallant said the RV industry overall knows that poorly secured amenities and overheating brakes are big problems. This National Highway Traffic Safety database backs him up. We found nearly a thousand consumer complaints, filed by RVers, regarding braking or structural deficiency issues. Many of those resulted in driver and passenger deaths.

Gallant wishes manufacturers would do a better job of keeping sinks and tables and cabinets in place.

"If the RV industry didn't do anything more than to fasten the interior adequately, again, they'd reduce by 75 percent the amount of deaths."

KIRO-TV did offer the company that manufactures the Owens' RV, Monaco Coach, a chance to respond to the findings inside our investigation. So far, that company has declined.

Friday at 6 p.m. on KIRO 7 Eyewitness News, our investigative team reveals some secrets about motor home accidents nationwide.

What we discovered prompted a sharp rebuke from the RV industry, but praise from consumer groups.