The morning of the incident, Operator had completed his morning preventative maintenance check on the engine. This included checking tire pressure and checking the wheels for rust, discoloration, cracks, dents, abrasions, cuts, bulging, and lug tension via hand. Throughout the entire incident we had been driving on highways, bumpy dirt roads, sandy areas, and dozer lines. At roughly 1800, we were driving down Homestead Rd., Doyle, CA, which was a smoother dirt road, doing about 15-20 MPH, when I noticed a sound that mimicked that of a rock in the duel or a flat tire. I had my Operator stop so that we could check to see what the issue was. After inspecting the rear duels, we didn’t find anything to be an issue. We got back in the vehicle and started driving again. Once again I could hear a noise and now feel some sort of vibration. Once again we stopped immediately. This time I had my Operator drive forward while I watched the rear duels rotate from behind the vehicle. They had normal rotation and nothing stuck in-between them. I then went out in front of the truck and had him drive slowly at me while I watched. At that point the right front steer tire was noticeably wobbling side-to-side. I quickly had him stop the truck. As I inspected the wheel I noticed that there were two lug nuts missing next to each other and the four of the remaining six were half way loosened on the studs. On closer inspection, I also noticed that where the lug nuts were missing, there was a paint color different than the rest of the wheel. I ran my finger over the two different color paints and could feel a slight depth difference between the two leading me to believe that the original wheel color had been painted over. Our Division arrived and inspected it as well. He stated that he had heard of another report of a wheel coming off due to the wheel being repainted. He said the report concluded that after repainting a wheel, over time it chips or rusts away, leaving a slight gap. This could have been the root cause of the lug nuts backing off the studs.
Once we inspected the wheel, tire, and studs for any damage, we lifted the truck up via a jack, remounted the tire, and secured the remaining lug nuts. It was at this point that I went around to the lug nuts on every tire to check to see if they were loose as well. I discovered that every lug nut on the truck was a quarter to a half turn loose. I tightened them all down using the lug wrench, and we made our way back to the ICP at a slow pace.
After arriving at the Incident Command Post, I notified our home units’ duty officer and our mechanic of the issue that had occurred. We made arrangements for our on call mechanic to bring out spare lug nuts to replace the ones that were missing and to inspect the wheel and studs for possible damage the following morning. The next day he arrived, inspected the wheel and studs finding no damage, and replaced the missing lug nuts. We then returned to our Division without any issues for the remainder of the Incident.
The situation that occurred to us was brought up to not only the Safety Officer on our Division, but also the Type II Teams (So. CAL Team #2) Safety Officer in which he used as part of one of his briefings. |
