In addition, the preliminary NTSB report was released one week ago. The short version:
1. There were actually two pilots on board, an apprentice and a master. The apprentice pilot had control at the time the emergency started, but was quickly relieved by the master once the emergency began.
2. The fatalities were six out of eight workers who were on the bridge at the time of the collision. One survivor was an inspector who was on foot and was able to run to the next truss section of the bridge prior to the collision. The other survivor was a worker who was able to free himself from his vehicle after it fell with the bridge and was picked up by the responding police boat.
3. The initial power failure was caused by two of the ship's four main electrical breakers unexpectedly tripping. The ship has four diesel generators that are configured as port and starboard pairs cross-linked by a high-voltage bus bar and then stepped down to a low voltage circuit by dual step-down transfomers, also cross-linked by a low-voltage bus bar. In normal operation, both the HV and LV bus bars are closed and only one generator pair and one transformer are active, leaving the other set as a redundant backup. At the time of the incident, the #3 and #4 generators were active, as was the starboard transformer.
4. The breakers which tripped were on *both* sides of the active transformer, one on the high voltage side and one on the low voltage side. This meant that the two active generators were still feeding the high voltage circuit via the HV bus bar crossover, but the low voltage circuit went offline. This cut electrical power to most of the ship's systems, including the main engine cooling pumps and all three steering pumps. This froze the rudder and forced the automatic safety systems to trigger a shutdown of the main engine.
5. Within no more than one minute, the emergency generator (which is a fifth independent generator) had automatically started, restoring power to critical ship systems, including one steering pump. This restored partial rudder authority, but the emergency generator does not produce sufficient power for a main engine restart. Per the NTSB it is not clear exactly how long it took the e-generator to fire up and connect itself, but it was at most one minute as this is when the bridge logging instruments turned back on.
6. The apprentice pilot, having been relieved of piloting duty, used his cell phone to call the pilot dispatcher. The dispatcher in turn called the port police emergency line, who activated the Coast Guard response and also called the police already in position on the bridge due to the ongoing maintenance.
7. The master pilot ordered 20 degrees port rudder as soon as rudder authority was restored, radioed for emergency tugs thirty seconds later as it became clear that the limited rudder available was not sufficient, and then ordered a manual anchor drop thirty seconds after that.
8. The crew subsequently restored full power by closing the two tripped breakers, bringing the LV circuit back online. However, a *second* blackout then occurred as the #3 and #4 generator breakers now tripped, dropping both the HV and LV circuits offline. The emergency generator remained active, and the #2 main generator was automatically switched from standby to active, restoring power on the HV circuit. Approximately thirty seconds later, the crew manually closed the breakers to the *other* transformer, bringing the LV circuit back online. However, the ship did not regain propulsion and hit the bridge.
9. Preliminary post-accident investigation results are that there had been a previous electrical issue while the ship was in port, but it was a generator issue rather than a breaker issue. Also, fuel testing shows that there was no issue with the ship's fuel.