Truck jumping out of pumping gear

[volunteercareer]

Recently we had an incident were our 1996 class A pumper jumped out of pumping gear during a routine truck inspection, pushing the chock block, finally going over the chock block in the mean time turning the front wheels so it ripped off the front of our tanker. One firefighter was caught between the trucks and his leg was crushed, nothing serious but he is still going to rehab. The truck has a midship pump with a pneumatic pump gear actuator and automatic transmission. The operator remembers the green OK to pump light being on before this all happened. When he was throttling up the truck didnt seem to be doing anything strange until it started moving forward, we figure the turbo kicked in on the deisel engine forcing it to move the chock block (they are definitely to keep a truck from rolling, but not under power.) The operator jumped onto the sideboard thinking he could get in the cab to stop the truck. That's when he got his foot stuck between the trucks.

When we checked the truck after the accident, the actuator switch was still in the pump position.

The truck is now at a mechanical investigator to see exactly what happened.

Has anyone had this same problem?

Just trying to find out if this is a wide spread problem or a freak accident. Maybe we can keep someone else from getting hurt or killed.

Thanks!

[Rayr49]

What kind of brake system does the truck have? Were the brakes set?
Most of these incidents seem to boil down to a mechanical malfunction compounded by the chocks not big enough to hold the vehicle and the brakes either not being set or out of adjustment.

A truck with a properly working air brake system should not be able to move when the brakes are set at low to moderate rpms. We have our local dealer do an annual DOT inspection to insure everything mechanical is functioning properly.

We also train our operators to check the speedometer after shifting into pump. Most midship pump apparatus will show 5-20 MPH on the speedometer at idle if the pump is properly engaged. Also listen for the sound of the pump impellers running. If both indications of a successful pump engagement are not present, look for a problem.

[truckman38]

Can i ask the brand of the truck? This sounds like a nasty accident, keep us posted as to the cause so we can prevent somthin like this from happening again.

[volunteercareer]

The truck does have air brakes. The chock block was in place. Our firefighters are trained to look at the speedo and you can hear it shift into gear, it is pretty obvious. The air brake was still engaged when we found the truck on the other side of the road. Yes it was up to moderate RPMS (Normal for pumping 150 psi) but not screaming when it started moving. After the accident the truck would not go into pumping gear. We didn't do any other investigation since we knew the insurance company would want to check it out. They hired an independent mechanical investigator. We haven't heard from them yet. We did take pictures of the levers and their positions.

We did here of a similar incident south of here in Belen NM.

Anybody have any ideas?

[Bones42]

Happened to us around 1988ish. Was a 1982 Pierce, midmount pump. Was in pump but not pumping any water. Was parked at scene (it's own firehouse) for about 15 minutes before it jumped and drove through a garage behind the firehouse. Truck has been replaced since then.

[Rayr49]

I would wait for the investigation to be completed. Chances are that it will reveal a mechanical failure of some type on the pump shift and a problem with the brakes. I would also check the federal DOT and NTSB web sites for possible recalls or investigations. Your insurance company will propbaly have access to a data base of similiar incidents.

Were the chocks NFPA compliant for the size of the vehicle? We had to purchase some for our 65' Telesquirt and it almost takes two people to deply them. I am not convinced that they will stop a vehicle from moving on a paved surface (probably just slide along) but they are big enough to probably stop the vehicle from driving over them.

Let us know what the investigation finds. It could prevent another incident.