Commercial Vehicle Safety Alliance
Letter Mail Controlled 12/19/2007 4:09:53 PM MC# 2070765: We appreciate the active participation of the National Transportation Safety Board (NTSB) in the activities of the Commercial Vehicle Safety Alliance (CVSA) and helping to support our mission of Promoting Commercial Motor Vehicle Safety and Security. As a result of our collective efforts, the purpose of this letter is to provide the NTSB with a status update and closure on NTSB Safety Recommendation H-97-32.
CVSA is an international not-for-profit organization comprised of local, state, provincial, territorial and federal motor carrier safety officials and industry representatives from the United States, Canada, and Mexico. Our mission is to promote commercial motor vehicle safety and security by providing leadership to enforcement, industry and policy makers. In addition, CVSA has several hundred associate members who are committed to helping the Alliance achieve its goals; uniformity, compatibility and reciprocity of commercial motor vehicle inspections, and enforcement activities throughout North America by individuals dedicated to highway safety and security.
The Alliance works to closely monitor, evaluate and identify potentially unsafe transportation processes and procedures as well as to help facilitate and implement best practices for enhancing safety on our highways. Commercial motor vehicle safety continues to be a challenge and we need the involvement of all affected parties to help us better understand these issues and put into place practical solutions.
The NTSB investigation revealed three deficiencies with the trucks air brake system, of which two of the defects would have been discovered during a random roadside inspection. First, the broken drain valve on the secondary air tank would have been detected during the under carriage inspection at Step 29 - Inspect Axle(s) 2 and/or 3, & Step 30 - Inspect Axle(s) 4 and/or 5, of the North American Standard Level I Inspection Procedure (attachment 1). If a leak was detected at the broken drain valve on the secondary air reservoir during the inspection, an air loss rate test would have been required at Step 34 - Test Air Loss Rate.
Steps 28, 29 & 30 of the North American Standard Level I Inspection Procedure are illustrated below:
STEP 28 INSPECT STEERING AXLE(S) BRAKES (BOTH SIDES) Check for missing, non-functioning, loose, contaminated or cracked parts on the brake system; such as, brake drums, shoes, rotors, pads, lining, return springs, cam rollers, spiders, cam shaft support brackets, brake chambers, air chamber mounting bolts, push rods, slack adjusters and air reservoir integrity and mounting. Check for “S” cam flip-over. Be alert for audible air leaks around brake components and lines. With the brakes released, mark the brake chamber push rods at a point where the push rods exit the brake chambers or use an alternative method. All push rods will be measured later. Check that the slack adjusters are the same length (from center of “S” cam to center of clevis pin), and that the air chambers on each axle are the same size.
STEP 29 INSPECT AXLE(S) 2 AND/OR 3 BRAKES (BOTH SIDES) Inspect as described in Step 28. Inspect for non-manufactured holes (i.e. rust holes, holes created by rubbing or friction, etc.) which have compromised the integrity of the spring brake housing section of the parking brake. Inspect for broken springs in the spring brake housing section of the parking brake. CAUTION: NEVER PLACE YOURSELF IN FRONT OF THE SPRING BRAKE HOUSING SECTION OF THE PARKING BRAKE. IN ADDITION, DO NOT STICK ANYTHING INTO THE SPRING BRAKE CAGING PORT. If you need to exit, always do so in full view of the driver.
STEP 30 INSPECT AXLE(S) 4 AND/OR 5 BRAKES (BOTH SIDES) Inspect as described in Steps 28 & 29.
The brake system violation would be documented under 49 Code of Federal Regulations (CFR) §393.48 (a) and would not independently be considered to be an “Imminent Hazard”; therefore, the vehicle would not constitute an out-of-service (00S) condition. However, a driver operating a commercial motor vehicle (CMV) should have conducted a self diagnostic check of the air brake system during a proper pre/post trip inspection. The draining and inspection of air reservoirs by a driver is not a new initiative and should be conducted regularly to ensure that the air brake system is not compromised, contains an adequate supply of air and that the system does not become a hazard to the operation of the CMV by becoming contaminated with water, oil and/or sludge.
The second violation documented in the report was an inoperative low-air pressure warning device, found in 49 CFR §393.51. This 00S condition would have been observed at Step 33 - Inspect Required Brake System Warning Device, of the North American Standard Level I Inspection Procedure.
Steps 33 & 34 of the North American Standard Level I Inspection Procedure are illustrated below:
STEP 33 INSPECT REQUIRED BRAKE SYSTEM WARNING DEVICES LOW AIR PRESSURE WARNING DEVICE Instruct the driver to deplete the air supply until the low air pressure warning device activates. Observe the gauges on the dash. The low air pressure warning must activate at a minimum of half the compressor cutout pressure, i.e., normally 55 psi or above.
STEP 34 TEST AIR LOSS RATE If you detected an air leak at any point in the inspection, you should now check the vehicle’s air loss rate. Have the driver run the engine at idle, ensure brakes have been released. Observe the air reservoir pressure gauge on the dash. Have the driver put the pressure at 80 psi (at about 80 psi, most compressors should be operating). With the engine idling and the air pressure between 80 - 90 psi, instruct the driver to make a full brake application. Check the air pressure gauge after initial application air loss. Air pressure should be maintained or increased. A drop in pressure indicates a serious air leak in the brake system.
This inspection procedure ensures that the warning device is functioning properly (i.e. whether the bulb is not burned out, etc.) by providing the driver with advance notice, enabling him/her to safely stop the CMV when a rapid air loss occurs. It is important to note, that our North American Standard Level I Inspection Procedure only checks that at least one low air pressure switch in the service reservoir system is working and that the light and/or buzzer are functioning properly. The violation detected would be cross referenced to Part II of the North American Standard Out-of-Service Criteria (OOSC) (attachment 2). As a result, the vehicle would not be allowed to proceed and subsequently placed 00S.
The North American Standard Out-of-Service Criteria for this violation is illustrated below:
1. BRAKE SYSTEM h. Low Pressure Warning - Device Low pressure warning device missing, inoperative, or does not operate at 55 psi (379 kPa) and below, or 1/2 of the governor cut-out pressure, whichever is less. NOTE: If either an audible or visual warning device is working as required, vehicle should not be placed Out-of-Service. (393.51)
i. Air Loss Rate If an air leak is discovered and the reservoir pressure is not maintained when: (1) Governor is cut-in; (2) Reservoir pressure is between 80 & 90 psi (551-620 kPa); (3) Engine is at idle; and (4) Service brakes are fully applied. (396.3(a)(1))
During our next scheduled CVSA meeting in March 2008 in Denver, CO, the Vehicle Committee will review the current language in the OOSC and consider adding additional language to clarify that the “Low Air Pressure Warning Device” and the “Air Loss Rate” test apply to both the primary and secondary systems. This change, if approved by the Alliance membership would assist in clearly identifying the 00S condition.
The third violation noted in the report was the reverse-connected air brake lines at the truck’s treadle valve. This violation of 49 CFR §393.48 (a) is extremely time consuming, is not feasible and nearly impossible to diagnose during a random roadside inspection. Checking for crossed lines requires that each tank (i.e. primary and secondary, and not the wet tank) be bleed to zero psi individually and operation of the remaining foundation brakes on the appropriate axle(s) needs to be observed/confirmed (such as, slack adjuster movement with cam brakes). Just figuring out which tank is which (i.e. wet, primary or secondary) is not a simple task on many vehicles due to the complexity of and layout of the brake system. Individual service reservoir bleeddown is the only procedure that will test for crossed air lines at the treadle valve and the functionality of individual low air pressure switches; and as such, we do not feel that this can be done effectively at roadside.
Once again, if a proper driver pre/post trip inspection was regularly preformed, the broken drain valve on the secondary air brake reserve tank would have been detected and hopefully corrected. Once the broken drain valve on the secondary air tank had been repaired, the draining of both air tanks following the manufactures air brake trouble shooting guide that outlines the test procedure for reversed air lines, would have allowed for checking of the cross air lines at the truck’s treadle valve. In addition, a proper diagnosis of the air brake system should have been conducted during a detailed and regulated annual/periodic inspection of the equipment.
The fourth observation in the report references state safety inspections and the testing procedure used by state and federal inspectors. It is our strong belief that the roadside inspection program and the annual periodic inspection program need to be decoupled from each other. The roadside inspection program and the OOSC are not equivalent to a “government mandated maintenance standard” for annual or periodic inspections. The North American Standard Inspection Program (attachment 3) and the OOSC have been in place for more than two decades and were never intended to serve this purpose (attachment 4).
In order to fully appreciate the roadside inspection program and the intent of the OOSC, one must recognize and fully understand the three separate and distinct types of commercial motor vehicle inspections.
1. The annual periodic and preventative maintenance requirements for all commercial motor vehicles.
2. The driver trip inspection requirements; and,
3. The roadside inspection program conducted by law enforcement officials.
All three types of vehicle inspection are intended to compliment each other, and one inspection is not any more important than another. The roadside inspection is the “last line of defense” for highway safety. When a driver or vehicle is placed 00S during a roadside inspection it is indicative that the motor carrier likely has a failing or defective preventative maintenance and/or driver trip inspection program. For this reason, CVSA has petitioned the Federal Motor Carrier Safety Administration (FMCSA) to remedy the confusion surrounding annual/periodic inspections by recognizing and developing all three types of vehicle inspections (attachment 5).
In closing, we concur that this is an important component in helping to ensure highway safety and CVSA appreciates the dedication and commitment of our partner organizations such as the NTSB in helping us address these challenges. We appreciate your attention to this issue and are hopeful that these actions are acceptable to the NTSB. For more on CVSA visit www.cvsa.org