By Deborah Hersman
Earlier this week, the NTSB met to consider the draft report on an accident at Miami International Airport (MIA). On November 28, 2008, a three-car people mover train operating along a fixed guideway failed to stop at the passenger platform and struck a wall at the end of the guideway. Six people were injured.
What happened? This accident occurred because the primary stopping mechanism failed and maintenance technicians had intentionally bypassed the secondary fail-safe system. Yet, as in so many accidents that the NTSB investigates other factors contributed to the accident. In this case, one key element was the absence of effective external oversight.
External safety oversight of public transportation systems is essential to identify and correct safety risks that may not be apparent or effectively addressed by the operator. External oversight at MIA could have detected that the maintenance company did not have formalized maintenance procedures, which allowed the trains to operate without a vital backup safety system.
Effective oversight becomes more critical as our transportation infrastructure ages. In the case of the Miami airport people mover, the train system was installed in 1980. Furthermore, the previous maintenance company expressed concerns that the trains were past their design life. We have seen the challenges of maintaining aging infrastructure in many of our investigations, including the June 2009 collision of two Washington Metro trains near the Fort Totten Station. With old and new infrastructure, we will always need proper maintenance and oversight to confirm that the system is performing to the highest safety standards.
For additional information on the NTSB investigation of the Miami crash, see the Board Meeting summary.
NTSB Safety Compass Blog 