Investigations
MCI Drive Shaft Safety Loop Failures
NHTSA Engineering Analysis EA12007 - closed, opened 2012-09-13.
NHTSA investigation EA12007 is a Engineering Analysis opened on 2012-09-13 and currently closed. The subject is tracked inside the Office of Defects Investigation queue. Latest activity on this investigation was logged on 2015-12-03 - NHTSA updates that field whenever an Information Request goes out, a supplement is filed, or a status change is recorded in the public docket.
An Engineering Analysis like EA12007 is the deeper technical phase that follows a PE. NHTSA requests design, warranty, and field-failure data from the manufacturer, conducts its own testing when needed, and determines whether the evidence supports a safety defect finding that would compel a recall.
Investigators summarized the matter as follows: "In the fall of 2011, network contacts made ODI aware of four (4) incidents of drive shaft failure on the subject buses involving a loss of vehicle control. Two of the incidents were relatively low speed non-crash events;..." Investigations are the early-warning layer of the federal auto-safety system, sitting upstream of formal recalls and defect orders. Whether this one closes without action or escalates into an Engineering Analysis, the full history stays in the ODI archive so researchers, litigators, and buyers can pull the paper trail at any time.
Investigation Summary
In the fall of 2011, network contacts made ODI aware of four (4) incidents of drive shaft failure on the subject buses involving a loss of vehicle control. Two of the incidents were relatively low speed non-crash events; and two resulted in motor coach rollovers. All four events showed signs of a common failure mode. The incidents and crashes studied during this investigation all resulted from a series of complex events that began with the the yoke journal ears on the drive shafts fracturing. Once the drive shaft failed. it was not adequately contained by a drive shaft safety loop or structure. The spinning and unrestrained drive shaft caused severe damage to components on the steerable tag axle at the rear of the vehicle and created a forced steering condition. Once the rear of the bus was being forcibly steered by the tag axle, the driver lost control of the vehicle. These conclusions are based on the forensics evidence and testing conducted by the Vehicle Research and Test Center (VRTC). The VRTC test report is attached to this closing resume that provides details on how the test center was able to conclusively identify the defective components on the buses and demonstrate the sequence of events that caused the buses to crash. Prior to the drive shaft failure events, there were no indications of improper maintenance or that maintenance was required that would have prevented the incidents. Additionally, the U-joints on the incident vehicles were found to be in good working condition at the time of the failure. Finally, records of driver interviews indicated a sudden onset of the failure with no warning. Following the VRTC testing, MCI issued recall 14V-335 involving certain model year 1993-1995 102DL3 motor coaches manufactured November 1992 to January 1995, and 2006 and 2008 D4505 motor coaches manufactured June 2005 to April 2008. The affected buses are equipped with a drive shaft with a compressed length of 30 inches or less (allowing it to escape containment i
About This Investigation Type
An Engineering Analysis (EA) is the in-depth phase following a Preliminary Evaluation. NHTSA engineers conduct testing, collect data from manufacturers, and perform detailed technical analysis to determine whether a safety defect exists. An EA may lead to a voluntary recall by the manufacturer or, in rare cases, a mandatory recall order.
Data from NHTSA Office of Defects Investigation. Cross-references: NHTSA recall campaign API and NHTSA FARS where fatality records overlap. PlainCars does not rate or recommend vehicles. about how PlainCars sources NHTSA data.
Read our methodology - how this data is sourced, computed, and verified.