DEPARTMENT OF LABOR
MINE SAFETY AND HEALTH ADMINISTRATION
COAL MINE SAFETY AND HEALTH
REPORT OF INVESTIGATION
Surface Mine
Fatal Powered Haulage Accident
August 30, 2002
Hawkeye Construction, LLC (A654)
Robinson Creek, Kentucky
at
Elswick Fork Mine #1
AEP Kentucky Coal, LLC
Lick Creek, Pike County, Kentucky
ID No. 15-18041
Accident Investigators
Robert M. Bates
Electrical Engineer
Paul Bailey
Mining Engineer
Dennis Ferlich
Mechanical Engineer
Jerry Hall
Coal Mine Safety & Health Inspector
Originating Office
Mine Safety and Health Administration
District 6
100 Fae Ramsey Lane
Pikeville, Kentucky 41501
Franklin M. Strunk, District Manager
Release Date: November 21, 2002
OVERVIEW
On August 30, 2002, a 34 year old truck driver was fatally injured when the articulated truck he was operating left the haul road, traveled approximately 800 feet down a steep embankment, and came to rest on a lower portion of the haul road. Shortly before the accident, the driver brought the truck to a stop in the haul road near the top of the hollow fill and backed up to allow the truck to be loaded with soil by an excavator. The truck backed up a short distance and then rolled forward, through the berm, and over the embankment.
The mechanical condition of the truck and operator error were investigated as possible causes, but the available evidence did not support nor rule out either of these as contributory factors. The berm in the area where the truck left the roadway was not sufficient to either restrain the vehicle or provide warning of the driver's proximity to the edge.
AEP Kentucky Coal, LLC, Elswick Fork Mine #1, is located on the Elswick Fork of Lick Creek approximately 2 miles from the intersection of Kentucky Route 1373 and U.S. Route 460 in Pike County, Kentucky. The company is a wholly owned subsidiary of American Electric Power Company of Columbus, Ohio. The principal officials are Randall Risner, general mine supervisor, and Roger Cantrell, safety and health supervisor.
Hawkeye Construction, LLC, is an independent contractor (I.D. A654) specializing in pond dipping, site preparation, reclamation, and other industrial construction related activities. The main office is located at One Potter Drive, Robinson Creek, Kentucky, and the registered agent is John M. Potter. The principal officials for the Elswick Fork project are Jeff Sands, project manager, and Phillip Rife, foreman.
The mine began production on April 20, 1998, using mountain top removal and contour methods of mining. The spoil from the mountain top removal process was deposited in a hollow fill area located near the head of Elswick Fork of Lick Creek. The mine ceased production on October 17, 2000, and the work of reclamation was started.
At the time of the accident, the mine was in non-producing status and reclamation activities were being performed in the hollow fill area. The company had contracted the services of Hawkeye Construction to dip silt from the pond and to assist in the construction of rock check dams. Heavy equipment used in the process included bulldozers, excavators, and articulated haul trucks. There were approximately five company employees and ten contractor employees involved in the project. Operations were normally conducted between 7:00 a.m. and 5:30 p.m., five or six days per week.
On August 20, 2002, the company received a cessation order from the Office of Surface Mining for allowing silt from the reclamation site to enter the local watershed. Therefore, at the time of the accident, the activities of both the company and the contractor were focused on rapidly correcting the conditions leading to the citation.
The last complete safety and health inspection of the mine by the Mine Safety and Health Administration was completed on May 3, 2002. No citations were issued during this inspection. With the exception of the subject fatal haulage accident, there had been no lost time accidents since the mine was placed in non-producing status on October 13, 2001.
On the day of the accident, the Hawkeye Construction employees reported to the job site at approximately 7:00 a.m. to begin their shift. The employees met at the pond at the bottom of the hollow fill to receive their individual assignments from Phillip Rife, foreman. Keith Little, victim, was initially assigned the task of operating a John Deere 650 dozer to maintain the dump areas and berms near the bottom of the hollow fill. Rife instructed Don Owens, equipment operator, to drive the Volvo A30C articulated truck that was later involved in the accident.
During the shift mud was dipped out of the pond at the bottom of the hollow fill using a long-boom excavator and loaded into articulated trucks. The trucks hauled the mud up an inclined haul road (12% average grade) to a dumping point at the top of the hollow fill. On the return trip, the trucks stopped at a loading point approximately 400 feet down from the top and were loaded with soil and rock by a Komatsu PC300LC excavator. The excavator, which was positioned on a small bench adjacent to the haul road, was being operated by Alex Armitage, an AEP employee. The bench was slightly higher than the haul road, so trucks were required to pull out toward the elevated edge of the roadway and then back up a short incline to be loaded by the excavator. After loading, trucks pulled out toward the edge and turned sharply to make the transition back onto the haul road. The soil and rock was then hauled down to the bottom of the hollow fill.
The material was used to fill in an area adjacent to an old gas well and to help construct rock check dams above the pond. A total of five articulated trucks were involved in the process: three were owned by Hawkeye Construction, one was owned by AEP, and one was owned by Brock Construction Company.
At approximately 9:00 a.m., Rife instructed Little to begin driving the Volvo articulated truck. Little made four or five complete trips up and down the haul road prior to the occurrence of the accident. Several employees interviewed after the accident indicated that the overall pace of the day was "rushed" and that they felt pressured by the AEP supervisor, Randall Risner, to increase the rate of work.
The Hawkeye Construction employees took their lunch break at approximately 12:30 p.m. Little stopped to eat lunch at the top of the hollow fill area with another truck driver. During lunch Jeff Sands, project manager for Hawkeye Construction, talked with Little concerning the performance of the Volvo truck. In this conversation, Little indicated that there were no problems with the truck and that the brakes were operating fine. Phillip Rife also stopped by and talked to Little during lunch and, according to Rife, Little seemed "just fine".
After lunch Little resumed hauling with the Volvo articulated truck. At approximately 1:30 p.m., after dumping a load of mud at the top of the hollow fill, Little descended the haul road and stopped at the loading point. According to eyewitnesses, the truck pulled out toward the edge of the berm, backed up approximately 20 feet in the direction of the excavator, and then immediately rolled forward and over the embankment. The truck traveled approximately 800 feet down the embankment, which had an average slope of 24.5 degrees, and landed on a lower portion of the haul road.
When the truck first started over the embankment, Alex Armitage used his radio to alert other equipment operators in the area of the truck's descent. Phillip Rife, who was located near the pond at the bottom of the hollow fill, saw the truck "flip" down the hill and crash onto the haul road. Rife was the first one to arrive at the scene of the crash. He was unable to get a response from Little, who was pinned in the crushed cab of the vehicle. Randall Risner, who had heard of the incident on his radio, called 911 and requested help.
Ferrils Creek Volunteer Fire Department personnel responded to the 911 dispatch and extricated the victim from the badly damaged vehicle. Charles Morris, Pike County Coroner, arrived on the scene and pronounced the victim dead at 2:20 p.m.
Jeff Sands, project manager for Hawkeye Construction, reported the accident to MSHA at 1:40 p.m. on August 30, 2002. Clifford Newsome, coal mine safety and health inspector, received the call for MSHA and forwarded the preliminary information to Allen Dupree, assistant district manager for enforcement. Robert Bates, electrical engineer; Paul Bailey, mining engineer; and Jerry Hall, coal mine safety and health inspector, were assigned the task of investigating the accident and determining the root cause(s).
The investigation team proceeded immediately to the accident site and began the initial phase of the investigation. A 103(k) Order was issued to protect the safety of all persons until an investigation could be made to determine the extent of the hazards contributing to the accident. The investigation team examined the scene, took measurements and photographs, and informally interviewed employees who were at the site at the time of the accident.
Formal interviews were conducted on August 30, 2002, at the MSHA district office in Pikeville, Kentucky. Twelve miners and three supervisors were interviewed during this session. The interviews were tape recorded and later transcribed.
On August 30, 2002, Dennis Ferlich, a mechanical engineer from MSHA's Technical Support Division, was added to the investigation team to oversee the examination and testing of the truck involved in the accident. Due to the extensive damage sustained by the truck, the assistance of RUDD Equipment Company was necessary in order to test the undamaged components of the truck's braking system. The onsite portion of the accident investigation was completed on September 6, 2002, and the 103(k) Order was terminated.
The training records of both Hawkeye Construction and AEP were reviewed. While several deficiencies were cited, none could be conclusively linked to the occurrence of the accident.
- An autopsy was performed by the Kentucky State Medical Examiner's Office. The Pike County Coroner's report listed the official cause of death as "blunt force injuries".
- There were two eyewitnesses to the accident: Alex Armitage, excavator operator, and Paul Crider, the foreman of an adjacent surface mine.
- On the day of the accident, the sky was clear and the temperature was 83 degrees F.
- The road surface was dry and compacted at the point where the truck left the haul road and traveled over the hill.
- According to Alex Armitage (the eyewitness closest to the truck when it started the descent over the embankment) the visibility in the immediate area was not impeded by roadway dust.
- Line of sight tests were conducted on a different Volvo A30C truck following the accident. These tests indicate that a driver cannot see the ground immediately in front of the truck for a distance of 20 to 30 feet, depending on the inclination of the vehicle.
- The maximum width of the haul road at the loading area near the top of the hollow fill was approximately 36 feet. In order to be loaded by the excavator at that location, trucks were required to pull out toward the berm, stop, and then back up a short incline. Due to the size of the vehicle, the edge of the roadway would not have been visible to the victim during much of this maneuvering.
- The berm in the area where the truck initially left the elevated roadway was not sufficient in size to either restrain the vehicle or provide warning of the proximity of the edge. The berm was only 8 to 12 inches in height where the tire tracks indicated the truck left the road.
- The seat belt provided in the truck involved in the accident was intact. It latched and unlatched when tested following the accident. Reportedly, the rescue team did not have to remove the seat belt to remove the victim from the machine.
- The mechanical systems of the truck involved in the accident were examined and tested following the accident. The testing was limited in scope due to the severe damage sustained in the accident. The results of the tests did not support machine failure as a contributing factor in the accident. For a detailed description of the machine and the tests performed, see the Appendix.
The investigation focused on three possible causal factors: equipment failure, operator error, and physical environment.
An examination and test of the truck's braking system revealed no conclusive evidence that brake failure contributed to the accident. The other mechanical systems (steering, transmission, and engine) were too badly damaged in the accident to permit functional testing.
Extensive interviews with eyewitnesses revealed no evidence of operator error on the part of the victim that could have directly contributed to the accident. The victim made several trips up and down the haul road prior to the accident and was able to maneuver the vehicle without any apparent problems.
The physical environment, specifically the condition of the berm at the point where the truck left the roadway and traveled over the embankment, was deemed to have directly contributed to the occurrence of the accident. Due to the low speed and short rolling distance, an adequate berm in this area could have prevented the truck from leaving the roadway.
Although the primary cause of the accident appears to have been loss of control of the vehicle, neither operator error nor mechanical failure could be supported or ruled out by the investigation. The exact actions performed by the victim inside the cab immediately prior to the accident could not be determined, and mechanical failure of the truck could not be determined due to the damage the truck incurred when it went over the berm and down the embankment. The major contributing factor in the accident was an inadequate berm where the truck left the roadway. The berm was not sufficient to either stop or turn the vehicle away from going down the embankment.
- 103(k) Order No. 7389549 was issued on August 30, 2002, to protect the safety of all persons until an investigation could be made to determine the extent of the hazards contributing to the accident.
- 104(a) Citation No. 7389551 was issued on September 20, 2002 to Hawkeye Construction. The condition/practice cited was as follows:
"The berm on the outer edge of the elevated haul road near the top of the hollow fill was not sufficient to restrain haulage vehicles operating in the area. The affected portion of the roadway was approximately 50 feet in length. The berm in this area ranged from 0 to 20 inches in height and was very narrow in width. The axle height of the largest vehicle using the roadway was approximately 34 inches.
The affected location was adjacent to an area in which an excavator was routinely loading articulated trucks with soil and rock. During the loading process, trucks were stopping with the front wheels near the outer edge of the roadway and then backing up an incline to the excavator. This procedure resulted in the trucks being close to the elevated edge of the roadway, both while backing up to be loaded and while pulling forward after being loaded.
On 8/30/2002, Keith Little was positioning his Volvo A30C articulated truck to be loaded by the excavator when the truck traveled over the edge of the roadway and down a steep embankment, coming to rest approximately 800 feet down the slope. Mr. Little was fatally injured in the crash." - 104(a) Citation No. 7389550 was issued on September 23, 2002 to AEP Kentucky Coal, LLC. The condition/practice cited was the same as Citation No. 7389551 served to Hawkeye Construction.
Related Fatal Alert Bulletin:
FAB02C22
APPENDIX A
Randall Risner .............. Supervisor, Elswick Fork Mine
Roger Cantrell .............. Safety & Health Supervisor
William L. May .............. Human Resources Supervisor
Paul Crider Foreman, .............. Road Creek Surface Mine
Phillip Rife .............. Foreman
Jeff Sands .............. Project Manager
Mark Rowe .............. Project Manager
Robert M. Bates .............. Electrical Engineer
Paul Bailey .............. Mining Engineer
Dennis Ferlich .............. Mechanical Engineer
Jerry Hall .............. Coal Mine Safety and Health Inspector
Phillip Rife .............. Foreman
Jeff Sands .............. Project Manager
James Bartley .............. Equipment Operator
Homer Hopkins .............. Equipment Operator
Darien Johnson .............. Equipment Operator
Roy Standifar .............. Equipment Operator
Shannon Thompson .............. Equipment Operator
Jeff Hall .............. Equipment Operator
Brett Osborne .............. Equipment Operator
Randall Risner .............. Supervisor
Paul Crider .............. Supervisor
Oscar Marshall .............. Equipment Operator
Gary Ward .............. Equipment Operator
Alex Armitage .............. Equipment Operator
Ronnie Moore .............. Equipment Operator
Gary Hurt .............. Truck Driver
- MACHINE INFORMATION: The machine was a 1997 Volvo Model A30C (30 Ton) Articulated Hauler, Product Identification No. A30CV2302 (s/n 2302), consisting of the engine unit and the load unit. The overall length of the machine was approximately 33 1/2 feet, the overall track width was approximately 7 � feet, and the axle height of the machine was approximately 33 inches. The outer turning radius was approximately 26 1/2 feet. The empty hauler weight stamped on the machine identification plate was 21,500 KG (47,400 LB). The engine was a Volvo Model TD102KBE, six cylinder, turbocharged diesel engine rated at 213 KW (285 HP). The engine was not equipped with an engine retarder. The transmission was a Volvo PT1663 automatic power shift transmission with six speeds forward and two speeds reverse. The transmission had a built-in hydraulic retarder. The steering was hydro-mechanical frame articulated actuated by hydraulic cylinders with a ground dependent hydraulic pump that provided secondary steering . The hauler had permanent four-wheel drive, and a six wheel drive that could be engaged and disengaged through a longitudinal differential lock.
- BRAKE SYSTEM DESIGN: The hauler was equipped with self-adjusting service brakes and a self-adjusting parking brake. The service brakes were air/hydraulic split into a front circuit for the engine unit drive axle and a rear circuit for the two axles on the load unit. Fifty percent of the braking was provided by the front engine unit axle brakes, and fifty percent of the braking was provided by the load unit axle brakes. The engine unit drive axle was provided with disc brakes, one at each wheel, with two calipers on each disc. The load unit axles were provided with disc brakes, one at each wheel, with one caliper on each disc. The machine had four air/hydraulic units. Two air/hydraulic units supplied the engine unit drive axle. Each of these air/hydraulic units split to a caliper at each front wheel to provide braking at each wheel in the event of a failure of one of the units. Two air/hydraulic units supplied the load unit axles, one for the two forward axle brakes and one for the two rearward axle brakes. The service brakes were actuated by a foot pedal. The parking brake consisted of an air/mechanically controlled (spring-applied, air-released) disc brake that acted on the propeller shaft of the load unit. The parking brake could be applied manually with the lever in the cab or automatically with loss of air pressure. When applied, the longitudinal differential lock was engaged causing all four brakes on the forward and rearward load unit axles to be applied. The service brakes and the parking brake were activated by 30 square inch air chambers.
- DAMAGE: The hauler sustained extensive damage to the engine unit. The roof structure was completely collapsed. The engine radiator and fan, the engine unit air tank, and many other engine unit components were dislodged from the machine and scattered on the embankment and haul road. The engine inter-cooler core housing was cracked. Hydraulic lines, electrical lines, and air lines leading to the load unit were wrapped around the swivel frame joint and severed. The operator's compartment instrument panel was severely damaged, the steering wheel and steering column were bent, and the operator's seat-back was bent rearward. The load unit sustained damage, but was mainly intact. The right steering cylinder was broken from the load unit frame, and the cylinder rod was dislodged from the cylinder. The two left tires on the load unit were deflated.
- OPERATIONAL TESTS: Due to the extensive damage to the engine unit, operational tests of the hauler could not be performed.
- REPAIRS TO THE MACHINE: The engine unit air tank was dislodged from the machine and several air lines were severed in the accident. Air lines were repaired or plugged, as required, in order to test the air system and braking system. Specific air lines were repaired such that the brake treadle valve, parking brake controls, air system check valve, and all air/hydraulic braking units could be tested for air leakage and function.
- AIR SYSTEM LEAKAGE TESTS: Air pressure was supplied to the accident machine from a service truck air compressor for the air system leakage tests. Air pressure at approximately 116 psi, as recommended in the Volvo Service Manual for Volvo Model A30C, s/n 2302, was supplied for the tests. No audible air leaks were found in any of the service brake air chambers, brake treadle valve, relay valves, or parking brake system components. An audible air leak was found in the air compressor main supply line at a fitting connecting the metal supply line to a plastic supply line. This leak was tested separately by pressuring the line to 120 psi, turning off the service truck air compressor, and monitoring the line pressure with a pressure gauge. The service truck air reservoir easily maintained the 120 psi line pressure. The leakage rate was not considered a contributing factor to the accident since records showed that the air compressor on the accident machine was replaced four days prior to the accident, and there were no complaints from the operators of the accident machine regarding loss of air system pressure. The check valve located in the load unit air reservoir was tested by pressurizing the air reservoir to approximately 116 psi, then removing the air supply line from the input line to the reservoir. When the air supply line was removed, the air reservoir maintained pressure showing the check valve was functioning.
- SERVICE BRAKE MASTER CYLINDER STROKE PINS: The service brake master cylinder stroke pins provide a visual indicator regarding the operating condition of the braking system. Over-extension of the stroke pins indicate air in the hydraulic brake system, low hydraulic brake fluid level, leaking hydraulic brake components, and/or a faulty master cylinder. The service brake master cylinder stroke pin extensions were measured for each of the four air/hydraulic units, both with and without the brakes applied, in accordance with the Volvo Service Manual for Volvo Model A30C, s/n 2302. The service manual specifies a maximum stroke of 1.61 inches. With an air pressure of approximately 116 psi supplied to each air/hydraulic unit, the following results were obtained.
NOTE: The stroke pin extensions were measured several times during the investigation while testing the hydraulic brake pressure at each brake caliper. The minimum strokes measured for each air/hydraulic unit are shown below.
a) Load Unit-Rear Axle Air/Hydraulic Unit: The minimum stroke measurement was 2 7/8 inches, exceeding the maximum specified limit by approximately 1.26 inches.
b) Load Unit-Forward Axle Air/Hydraulic Unit: The minimum stroke measurement was 2 1/8 inches, exceeding the maximum specified limit by approximately 0.515 inches.
c) Engine Unit-Right Air/Hydraulic Unit: The minimum stroke measurement was 2 1/8 inches, exceeding the maximum specified limit by approximately 0.515 inches.
d) Engine Unit-Left Air/Hydraulic Unit: The minimum stroke measurement was 2 1/8 inches, exceeding the maximum specified limit by approximately 0.515 inches.
NOTE: The stroke pin extension measurements in excess of 1.61 inches, indicate that all of the air was not bled out of the system when measuring the hydraulic brake pressure at each brake caliper. No defects were found with the operation of the hydraulic master cylinders, and no leaks were visually observed in any of the hydraulic brake components. - SERVICE BRAKE HYDRAULIC PRESSURE: The hydraulic pressure at each service brake wheel cylinder was measured to determine if the hydraulic master cylinders were functioning. For these tests, a pressure gauge was installed in the alternate brake line port on each brake caliper. The brake caliper was bled, the air system was pressurized to approximately 116 psi, as specified in the Volvo Service Manual for Volvo Model A30C, s/n 2302, the service brake pedal was fully applied, and the hydraulic brake pressure was measured. The following results were obtained.
a) Load Unit-Right Rear Axle Caliper: Hydraulic pressure = 2200 psi
b) Load Unit-Left Rear Axle Caliper: Hydraulic Pressure = 2600 psi
c) Load Unit-Right Forward Axle Caliper: Hydraulic Pressure = 2900 psi
d) Load Unit-Left Forward Axle Caliper: Hydraulic Pressure = 2850 psi
e) Engine Unit Axle-Right Forward Caliper: Hydraulic Pressure = 2300 psi
f) Engine Unit Axle-Right Rearward Caliper: Hydraulic Pressure = 2300 psi
g) Engine Unit Axle-Left Forward Caliper: Hydraulic Pressure = 2700 psi
h) Engine Unit Axle-Left Rearward Caliper: Hydraulic Pressure = 2700 psi - The Load Unit forward axle hydraulic master cylinder was disassembled, and the outside diameter of the piston was measured to determine the hydraulic/air pressure ratio. The outside diameter of the master cylinder piston was 1.250 inches, resulting in a piston area of 1.227 square inches. The nominal brake air chamber area is 30 square inches, but the actual effective area due to the rolling action of the diaphragm is approximately 27 to 28.5 square inches. Using the master cylinder area of 1.227 square inches and the effective area of the air chamber of 27 to 28.5 square inches, the hydraulic/air pressure ratio was calculated to range from 22/1 to 23/1. At 116 psi air pressure, the expected master cylinder hydraulic pressure was calculated to be approximately 2550 psi to 2660 psi. NOTE: The brake system hydraulic pressures that were below 2550 psi, were likely caused by entrained air that was not completely bled from the brake system, since no other defects were found in the hydraulic braking system components.
- BRAKE COMPONENT EXAMINATION: The service brakes and parking brake were disassembled, visually inspected, and measured. The manufacturer's minimum specified brake pad thickness is 0.12 inches at the thinnest area for both the service brakes and parking brake. The manufacturer's minimum specified brake disc thickness is 0.51 inches for the service brakes and 0.79 inches for the parking brake. Reference: Volvo Service Manual for Volvo Model A30C, s/n 2302. The following results were obtained:
a) Load Unit-Right Rear Axle Brake: The inward brake pad lining was 1/4 inches thick, and the outer brake pad lining was 0.094 inches thick at the thinnest area. The inward brake pad lining was 0.026 inches below the manufacturer's minimum specified thickness. The brake pad lining wear surfaces were clean with no cracks or missing pieces. The brake disc had a wear ridge on the outer edge, and the wear surface was clean and shiny with signs of overheating (i.e. blueing). There was no visible leakage of brake fluid on any of the components. The brake disc diameter was 18 1/2 inches, and the minimum thickness was 0.440 inches, which was 0.070 inches below the manufacturer's specified minimum limit.
b) Load Unit-Left Rear Axle Brake: The inward and outward brake pad linings were 1/4 inches thick at the thinnest area. The brake pad lining wear surfaces were clean with no cracks or missing pieces. The brake disc had a wear ridge on the outer edge, and the wear surface was clean and shiny with signs of overheating (i.e. blueing). There was no visible leakage of brake fluid on any of the components. The brake disc diameter was 18 1/2 inches, and the minimum thickness was 0.426 inches, which was 0.084 inches below the manufacturer's specified minimum limit.
c) Load Unit-Right Forward Axle Brake: The inward and outward brake pad linings were 5/16 inches thick at the thinnest area. The brake pad lining wear surfaces were clean with no cracks or missing pieces. The brake disc had a wear ridge on the outer edge, and the wear surface was clean and shiny with signs of overheating (i.e. blueing). There was no visible leakage of brake fluid on any of the components. The brake disc diameter was 18 1/2 inches, and the minimum thickness was 0.457 inches, which was 0.053 inches below the manufacturer's specified minimum limit.
d) Load Unit-Left Forward Axle Brake: The inward and outward brake pad linings were 7/16 inches thick at the thinnest area. The brake pad lining wear surfaces were clean with no cracks or missing pieces. The brake disc had a wear ridge on the outer edge, and the wear surface was clean and shiny with signs of overheating (i.e. blueing). There was no visible leakage of brake fluid on any of the components. The brake disc diameter was 18 1/2 inches, and the minimum thickness was 0.469 inches, which was 0.041 inches below the manufacturer's specified minimum limit.
e) Engine Unit-Left Front Axle Brake: The inward and outward brake pad linings were 7/16 inches thick at the thinnest area. The brake pad lining wear surfaces were clean with no cracks or missing pieces. The brake disc had a wear ridge on the outer edge, and the wear surface was clean and shiny with signs of overheating (i.e. blueing). There was no visible leakage of brake fluid on any of the components. The brake disc diameter was 18 1/2 inches, and the minimum thickness was 0.397 inches, which was 0.113 inches below the manufacturer's specified minimum limit.
f) Engine Unit-Right Front Axle Brake: The inward and outward brake pad linings were 1/2 inches thick at the thinnest area. The brake pad lining wear surfaces were clean with no cracks or missing pieces. The brake disc had a wear ridge on the outer edge, and the wear surface was clean and shiny with signs of overheating (i.e. blueing). There was no visible leakage of brake fluid on any of the components. The brake disc diameter was 18 1/2 inches, and the minimum thickness was 0.398 inches, which was 0.112 inches below the manufacturer's specified minimum limit.
g) Parking Brake: The inward and outward brake pad linings were 1/2 inches thick at the thinnest area. The brake pad lining wear surfaces were clean with no cracks or missing pieces. The brake disc wear surface was clean and shiny, with no evidence of overheating. There was no visible leakage of brake fluid on any of the components. The brake disc minimum thickness was 0.980 inches, which was within the manufacturer's minimum specified limits. - CONTROL POSITIONS: The cab control positions were noted. The transmission selector was in drive. NOTE: The transmission selector positions were not labeled. The parking brake was released. The transmission inhibitor switch was in the ON position.
- THROTTLE PEDAL: The throttle pedal was tested. When depressed, the pedal stuck. The throttle cable was removed and examination showed it was crushed during the accident. With the throttle cable removed, both the fuel pump lever and the pedal moved freely.
- ELECTRICAL STROKE INDICATOR CONNECTIONS: When the air/hydraulic units were visually examined, all four of the electrical stroke indicator wires were found disconnected from the air/hydraulic units. These electrical connections provide a signal to a light in the operator's cab. When the air/hydraulic units are over-stroked, a light is turned on in the cab alerting the operator of the faulty condition.
- OTHER OBSERVATIONS: The mileage was 37,577 KM. The fuel tank cap was knocked off in the accident, and all of the fuel drained from the tank while the cab was overturned. The brake fluid reservoirs contained fluid, but the brakes had to be bled and the reservoirs refilled since the machine overturned several times in the accident.