Recommendation Letter Template

Honorable Annette M. Sandberg
Administrator
Federal Motor Carrier Safety Administration
400 Seventh Street, S.W.
Suite 8202
Washington, D.C. 20590

About 3:36 p.m., eastern daylight time, on April 11, 2003, in the Borough of Glen Rock,
Pennsylvania, a 1995 Ford dump truck owned and operated by Blossom Valley Farms, Inc., was
traveling southbound on Church Street, a two-lane, two-way residential street with a steep
downgrade, when the driver found that he was unable to stop the truck. The truck struck four
passenger cars, which were stopped at the intersection of Church and Main Streets, and pushed
them into the intersection. One of the vehicles struck three pedestrians (a 9-year-old boy, a 7-
year-old boy, and a 7-year-old girl), who were on the sidewalk on the west side of Church Street.
The truck continued across the intersection, through a gas station parking lot, and over a set of
railroad tracks before coming to rest about 300 feet south of the intersection. As a result of the
collision, the driver and an 11-year-old occupant of one of the passenger cars received fatal
injuries, and the three pedestrians who were struck received minor-to-serious injuries. The six
remaining passenger car occupants and the truck driver were not injured. 1

The National Transportation Safety Board determines that the probable cause of this
accident was the lack of oversight by Blossom Valley Farms, Inc., which resulted in an untrained
driver improperly operating an overloaded, air brake-equipped vehicle with inadequately
maintained brakes. Contributing to the accident was the misdiagnosis of the truck’s underlying
brake problems by mechanics involved with the truck’s maintenance; also contributing was a
lack of readily available and accurate information about automatic slack adjusters and inadequate
warnings about the safety problems caused by manually adjusting them.

Among the safety issues identified during the investigation were the maintenance of air
brakes equipped with automatic slack adjusters (ASAs) and the knowledge and skills needed to
drive air brake-equipped vehicles. The Safety Board is issuing recommendations concerning both
these issues to the Federal Motor Carrier Safety Administration (FMCSA).

With respect to maintaining air brakes equipped with ASAs, the Safety Board noted that
the majority of heavy trucks on the road are equipped with ASAs. All air-braked vehicles
manufactured after 1994 are required to have them and, in 1992, the Safety Board found that
about 65 percent of the vehicles inspected during the Heavy Vehicle Airbrake Performance
safety study 2 were already equipped with ASAs. These safety devices were introduced without a
concentrated education effort being employed.

The postaccident inspection of the Glen Rock accident truck revealed that the two rear
axle brakes were out of adjustment and produced little or no braking force. The front axle air
chambers, which were slightly more than half the size of the rear chambers, were in proper
adjustment. Yet, because the larger T-30 rear brakes produced little or no braking force,
excessive strain was placed on the significantly smaller T-16 front brakes, which caused them to
quickly overheat, resulting in severely diminished truck braking capability.

The truck was equipped with Gunite ASAs on all four brakes. After the accident, when
the two rear adjusters were tested at the Gunite facility with the worn “quick-connect” clevises
and clevis pins from the accident truck, the pushrod stroke would not go below 2 1/2 inches,
which is outside the adjustment limits, rendering the system incapable of producing braking
force. However, when the ASAs were tested with new clevises and clevis pins, they functioned
properly and the adjustment stayed well under 2 inches, which is within the adjustment limits
and would provide adequate braking forces. Therefore, the Safety Board concludes that at the
time of the accident, the ASAs for all four of the accident truck’s brakes were capable of
working properly; however, the quick-connect clevises and clevis pins for both rear brakes were
worn to the extent that they prevented the ASAs from properly adjusting the brakes, thereby
reducing the capability of the rear brakes.

The Safety Board reviewed the maintenance and inspection history of the accident truck,
which had undergone four vehicle inspections between 2001 and the April 2003 accident—three
Pennsylvania State annual inspections (August 2001, March 2002, and January 2003) and one
roadside inspection (April 2002). During two of these inspections—the 2002 roadside inspection
and the 2003 State annual inspection—the rear brakes were found to be out of adjustment. After
the 2002 roadside inspection, when the accident truck was placed out of service for out-of-
adjustment brakes, the driver of the vehicle, who was also a truck mechanic, manually adjusted
the ASAs. The Safety Board could find no record of further examination of the brakes by the
company or the mechanic to discover why the brakes had been out of adjustment. During the
2003 State annual inspection, a Ford dealership mechanic found the rear brakes to be out of
adjustment, and he manually adjusted the ASAs. In an interview with Safety Board investigators,
he said he had adjusted the brakes and thought he had fixed the problem. Had he performed a
more in-depth examination of the brake system, he probably would have found and replaced the
worn clevises and clevis pins, which would have enabled the ASAs to adjust the brakes properly
and might have prevented the accident.

realized that the adjuster itself was working properly. In addition, the Gunite service manual
indicates that mechanics should “check the foundation brake for proper function; worn cam
bushings, pins and rollers, broken springs, worn quick-connect clevis, worn clevis bushings and
clevis pins. Repair as necessary and repeat the function test.” 3

One reason that ASAs should not be manually adjusted is that every time the adjusting
nut is turned in a counterclockwise direction, the internal components experience additional wear
because the action abrades the internal adjusting mechanism. In the El Cerrito, California, brake
loss accident (also addressed in the Glen Rock accident report), the driver stated that he manually
adjusted the slack adjusters twice a week and had done so on the morning of the accident.
Postaccident testing of the El Cerrito accident truck at the Gunite factory showed that three of the
adjusting clutches were worn to the point that they could not hold an adjustment, probably due to
their age and the deterioration caused by frequent manual adjustment. For the majority of ASAs,
regular manual adjustment will cause premature wearing of the internal clutch, which is a
necessary component for the automatic adjustment feature to work properly.

Various brake component problems can cause a pushrod stroke to go beyond the limits
for producing adequate braking capability, causing the brakes to be out of service. These
problems include, but are not limited to, worn cam bushings, worn or broken pins and rollers,
broken springs, worn clevises (both quick-connect and standard), and worn clevis bushings and
pins. When a driver or mechanic finds a pushrod stroke to be long and manually adjusts an ASA
to correct the long stroke, he or she is masking the true problem with the brake, not fixing it. In
all likelihood, the adjustment will be temporary. ASA manufacturers Gunite, Haldex, and Bendix
indicated to Safety Board investigators that they do not know how long (how many brake
applications) a manually adjusted ASA will hold an adjustment.

The drivers and mechanics who manually adjusted the ASAs on the trucks involved in
the Glen Rock and El Cerrito accidents apparently did not understand that they were not fixing
the underlying problem with the braking systems. They did not appreciate that when an ASA
does not hold an adjustment, something is wrong with the adjuster itself or with some other
foundation brake component. Therefore, the Safety Board concludes that the drivers and
mechanics who manually adjusted the ASAs on the trucks involved in the Glen Rock and El
Cerrito accidents did not look for underlying problems with the adjusters or related foundation
brake components; consequently, they misdiagnosed the brake problems, probably because they
were not properly educated on the function and care of ASAs and how they relate to foundation
brake systems.

Manually adjusting ASAs to fix an out-of-adjustment brake is a dangerous practice that