The U.S. National Transportation Safety Board completed an initial review of the digital video recorder system recovered from the DUKW “Stretch Boat 7” that sank July 19 near Branson, Missouri.

The amphibious vehicle had 29 passengers and two crew members aboard for a tour when weather conditions deteriorated on Table Rock Lake. One crewmember and 16 passengers died in the accident.

Recording media including an SD card and a removable hard drive from the vehicle’s digital video recorder camera system were recovered by divers before the duck boat was salvaged. The digital video recorder media were transferred to the NTSB laboratory in Washington.

The digital video recorder recorded five channels of video: four outward facing and one inward facing. Audio was also recorded.

The NTSB’s initial review used time stamps that were recorded by the DVR and that have not yet been validated against local time. The information does not contain analysis, and NTSB says that no conclusions regarding the cause of the accident should be made.

About 18:27:08. The captain and driver boarded the previously empty vehicle. The driver sat in the driver’s seat and the captain sat in the side-facing seat to the right of the driver. (The captain operates the duck on water and the driver operates duck on the road.)

About 18:28:00. The crew was told to take the water portion of the tour first, by an individual who briefly stepped onto the rear of the vehicle.

Image shows the duck boat moments before it sank on July 19.About 18:29:13. As the passengers were loading, the captain made a verbal reference to looking at the weather radar prior to the trip.

About 18:33:10. The driver stated a passenger count of 29 and shortly after, the vehicle departed the terminal facility. The captain narrated the tour while the vehicle was in motion.

Starting about 18:50. In the vicinity of the boat ramp, the captain began a safety briefing regarding the water portion of the tour. The briefing included the location of emergency exits as well as the location of the life jackets. The captain then demonstrated the use of a life jacket and pointed out the location of the life rings. The captain moved into the driver’s seat and the driver moved into the seat directly behind.

About 18:55:20. The captain announced to the passengers that they would be entering the water. The boat entered the water. The water appeared calm at this time.

Between about 18:56:22 and 19:00:38. The captain allowed four different children to sit in the driver’s seat, while he observed and assisted.

About 19:00:25. Whitecaps rapidly appeared on the water and winds increased.

About 19:00:42. The captain returned to the driver’s seat. The driver lowered both the port and starboard clear plastic side curtains.

About 19:01:01. The captain made a comment about the storm.

Crews raise the duck boat from Table Lake in Missouri. Source: CNNAbout 19:03:15. The captain made a handheld radio call, the content of which is currently unintelligible.

About 19:04:15. An electronic tone associated with the bilge alarm activated.

About 19:05:21. The captain reached downward with his right hand and the bilge alarm ceases.

About 19:05:40. The captain made a handheld radio call, the content of which is currently unintelligible.

Final Minutes

In the final minutes of the recording, water occasionally splashed inside the vehicle’s passenger compartment. The low frame rate and relatively low resolution make it "very difficult" to be more precise in the preliminary review, NTSB says.

About 19:07:26. An electronic tone associated with the bilge alarm activated.

19:08:27. The inward-facing recording ended, while the vehicle was still on the surface of the water.

NTSB says that a group consisting of technical experts from the NTSB and parties to the investigation will convene at NTSB headquarters to begin validating the recorded data and developing a detailed transcript of the sequence of events.