Cause Sought in Pierce ALL STEER Pumper Rolleover

Massachusetts authorities are trying to determine why Framingham Fire Department’s Engine 7, a 2001 Pierce Quantum pumper equipped with the company’s ALL STEER system, skidded out of control and rolled over while returning to its station on April 10, injuring four firefighters.

Within days, Framingham Fire Chief Gary Daugherty said he was assured by investigators that the accident was not caused by speed or operator error.

As a precaution while state and local police investigated, the department disabled ALL STEER systems on two other Pierce apparatus it owns – Engine 1, a 2000 Quantum pumper, and Ladder 3, a 1998 Quantum 105-foot aerial.

Framingham Assistant Fire Chief John Magri said ALL STEER can be easily turned on and off using a key on the dashboard of fire trucks equipped with the system. He said it was activated on Engine 7 at the time of the accident.

Pierce ALL STEER is an electronic all-wheel steering system designed to enhance maneuverability and improve the turning radius by as much as 30 percent, allowing heavy-duty fire trucks to navigate tight city streets. It was the subject of recall notices in 2001 and 2004 when the company notified government officials of defects discovered after malfunctions were reported.

The first recall involved insulation covering a wire between the steering sensor and the electronic control unit that may have been nicked during assembly. The company said moisture could penetrate the nicked insulation over time and reach the wire, causing the rear wheels to turn unintentionally.

The second recall was spurred in part by an accident in Natick, Mass., which is not far from Framingham.

In an Aug. 30, 2004 letter to the National Highway Traffic Safety Administration, Pierce said it had found a defect where oil leaching from grease could penetrate a seal and contaminate the ALL STEER optical encoder disc. “Oil on the disc can cause the encoder to send incorrect wheel position information,” the letter said. “Incorrect wheel position information can cause the rear wheels to steer without warning.”

Pierce estimated 64 trucks were potentially affected, all from the 2002 to 2004 model years.

Framingham Assistant Chief John Magri said he was not familiar with the specifics of the recalls, but knew that Pierce had sent company representatives to the fire department to perform what he called “updates” on some apparatus over the past decade.

Following the April 10 accident, he said Pierce sent two engineers to inspect and test Engine 7 while state police forensic experts were conducting their investigation, which included downloading electronic information from the apparatus.

“We’ve had some pretty robust investigations, some pretty in-depth detail being scrutinized on that truck,” Magri said.

As of April 28, he said the department had not received reports from state police or local investigators and the four injured firefighters had not been able to return to work.

Pierce officials declined to comment on the Engine 7 accident, saying it was under investigation. But the company did offer a written description of its ALL STEER system (See accompanying statement below).

ALL STEER Developed For Maneuverability

The ALL STEER option was developed by Oshkosh Corporation as a means of improving the maneuverability performance of heavy trucks. Pierce obtained the exclusive rights to offer the product on fire apparatus in December 1994 with the first ALL STEER apparatus shipped in 1996 to improve maneuverability in tight turning radius situations.

The offering began in a single rear axle configuration and was later released for tandem applications. The initial design remained with only minor modifications until the introduction of ALL STEER II in May of 2002. The second-generation system replaced the potentiometer-based steer angle sensors with optical encoders. This shift from an analog to a digital signal, along with increased computing power, provides the system with increased precision and more prognostic and diagnostic functionality. The driver interface is also enhanced with an LCD display.

The Oshkosh ALL STEER all-wheel steering system has several different steering modes for improved maneuverability. The driver selects the desired mode based on driving conditions at hand.

There is a front steer mode for normal highway driving. In this mode, the rear axle is mechanically locked in the straight-ahead position and the vehicle drives like typical front steer vehicles.

For added maneuverability at speeds up to 35 mph, the coordinated mode can be activated. In coordinated mode both the front wheels and the rear wheels steer. The amount of rear wheel steering in this mode is proportional to vehicle speed.

For maximum maneuverability in slow speed operation (up to 10 mph), there is a fire-ground coordinated mode and a fire-ground crab mode. The fire ground-coordinated mode provides the sharpest turning possible, and the fire-ground crab mode allows the vehicle to move sideways in a diagonal manner.

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