SEATTLE -- The National Transportation Safety Board has released the legal docket in the accident that killed five on Seattle’s Aurora Bridge on September 24, 2015.

That accident involved a Ride the Ducks amphibious tour vehicle and a charter bus being operated on behalf of North Seattle College and loaded with new college students and staff members. One of the images released is from a video aboard the coach, just .4 seconds before impact, showing the Duck vehicle crossing the centerline.

Five students died aboard the bus in the collision.

The “docket” is not the cause of the accident, but a compilation of facts, reports, photos, and other data. The full video was not released. KING 5 News has learned the Safety Board itself will hear the case at its headquarters in Washington, D.C. At that point, the probable cause and final report will be released. The investigation by both state and federal investigators has focused on a broken axle and lost left front wheel on the Duck.

The report includes detailed, microscopic analysis by metallurgists of the broken axle. Interviews of those on board the Duck said several of them heard a “bang” prior to the collision. Eleven passengers aboard the Duck were ejected. Four people were ejected from the bus, two fully and two partially ejected.

The damage to the bus was devastating, tearing away a 19-foot-by-6-foot section; the coach actually bowed slightly in the middle. All fatalities were aboard the bus, along with 13 serious injuries. Autopsy descriptions recount one female passenger having every bone in her face broken in the impact. Passengers aboard the duck included 16 serious injuries and 20 minor injuries.

One of the first NTSB photos from inside the bus in the 2015 Aurora Bridge crash shows the 19x6-foot wide hole on the side. (Photo: NTSB)

The NTSB considered its investigation “ongoing” and has not yet set a date for a full hearing.

But the docket in the case has lots of new information, including how the Duck driver says he heard what "he described as a 'klunk-klunk' noise" as the vehicle drove over the second expansion joint while entering the bridge heading north.

According to the docket, "He then stated he thought to himself that the noise was unusual. The DUKW then made an un-commanded move to the right, coming within approximately one foot of the wall. The driver attempted to steer back to left and discovered the steering had become extremely lose. The DUKW then veered sharply to the left."

The report goes on to say that the driver could not turn it back to the left at is was "locked." The Duck, which has compression brakes, would not stop, even though he was "standing" on the brake pedal.

Both the driver of the Duck and the motor coach had good driving records, and there was no evidence of alcohol, drugs or other mind-affecting prescription drugs. Both drivers say they had plenty of sleep the night before the accident, which occurred at 11:11 a.m.

In the "Highway Factors Group Chairman's Factual Report," the traffic and fatal crash history of the bridge was studied over the last five years, from 2010 to 2015. While factoring out the Ducks crash and the five fatalities, the Aurora Bridge was the scene of 73 other accidents, 32 of which involved injuries, none of them fatal. Ten of those accidents (again factoring out the Duck crash) included 10 crashes with opposing traffic. Rear enders 33, hitting a fixed object 3 and alcohol-related 5.

The report makes no reference to the severity of the "opposite direction" collisions, whether they were simply mirrors coming together, caused by the bridge's narrow lanes or if they caused injuries. The six lanes on the bridge are as narrow as 9.2 feet wide.

The primary focus of the report examines the broken left front axle, where it joins something called the knuckle. A reinforcing "tab" was also broken at a weld. Duck number 6, which was involved in the accident and one of 10 owned by Ride the Ducks Seattle, is a so-called "stretch Duck." Stretch Ducks differ mechanically from virtually identical looking Ducks called truck Ducks. Stretch Ducks have been withdrawn from service in Seattle. Ride the Ducks currently operates with truck Ducks only.

Photo released by the NTSB in the 2015 Aurora Bridge crash shows a broken joint at the steering knuckle on the left front axle. (Photo: NTSB)

But in 2003, 2004 and again twice in 2013, stretch Ducks operated by other companies were found to have broken or cracked left axles.

Analysis of the broken surfaces on the Duck involved in the accident were taken down to the electron microscope level, along with other data analyzing cracks and stress points in the axle, which carries a total weight of 7,100 pounds, 3,500 pounds of that weight on the left end of the axle.

A colorized 3D laser scan view of what the bus in the 2015 Aurora Bridge crash looks like without the roof. (Photo: NTSB)