Structural and Dielectric testing of Bucket Trucks and Digger Derricks, according to ANSI criteria.

Properly maintained and tested aerial devices are essential to the safe and economical operation of a fleet. Operators and their co-workers rely on the aerial devices to perform structurally, mechanically, functionally and dielectrically as intended.



Aerial devices have been designed and built with adequate safety factors; however in-service accidents, overloads, and fatigue can cause problems to develop. Also, OSHA and ANSI require regular annual inspections. A thorough, regularly scheduled inspection and test program can identify developing problems before they cause injuries or downtime. Early identification of defects is less expensive to repair than if they are left to develop into major failures. Many equipment managers have experienced substantial monetary savings by using written test reports to obtain competitive quotations for repairing, rebuilding, and remounting.

American Test Center provides annual test and inspection at your site by a well-equipped two-man crew of nondestructive technicians who are experienced in structural and dielectric testing. A staff of degreed engineers, Level III technicians and equipment specialists supports them.

American Test Center performs the following tests and inspections:


A. Visual Inspection: A complete inspection of accessible areas including:

  1. Outriggers; Pads, structure, welds, bolts, hoses, cylinders, valves, pins and retainers.
  2. Chassis; Truck frame, aerial sub-frame, suspension, PTO, pintle hook, and components of the brake, steering, electrical, air, hydraulic, exhaust, and cooling systems.
  3. Pedestal; Mounting bolts and welds, pedestal structure, diagonal brace, attachment welds or pins, hydraulic swivel joint, hydraulic components, swing drive gearbox mounting bolts, backlash between swing pinion or bullgear, electric collector ring and brushes and lower control operation.
  4. Rotation Bearing; Upper and lower bearing attachment weld and bolts, vertical movement of bearing, and proper torque on accessible bearing bolts.
  5. Turntable; Turntable structure, bucket leveling cables, leveling cylinders, compensating chains or sprockets, and hydraulic system components.
  6. Lower Boom; Boom structure, welds, lift cylinders and attachment, hydraulic system, leveling cables or rods, upper or extend cylinder and attachment, pushlinks, boom rest supports, tie-down straps, lower insulator and mounting, extension roller assembly and wear pads.
  7. Elbow; Elbow structure, hydraulic hoses and leveling cables.
  8. Upper Boom (Extension); Structure, welds, leveling cables or rods, wear pads, upper insulator and mounting, hydraulic lines and components, jib structure and mounting, tool circuit hoses and fittings, pole claw arms and mounting brackets.
  9. Platform (Bucket); Mounting bracket bolts, leveling system, exterior condition, control operation and hydraulic lines and components.
  10. Digger and Auger; Digger mounting arm and housing, gearbox, auger, digger wind-up bracket or rope, auger stop bracket, lock mechanism and control operation.
  11. Winch; Mounting brackets, bolts, pins; gearbox, hydraulic components, load line, and controls.
  12. General; Load rating chart, electrical hazard placards, MADDDC placards and upper or lower control operation placards.

The visual inspection includes removal of inspection cover plates as necessary to do a thorough job.

B. Structural Test - Acoustic Emission (AE) Test: AE is the accepted industry method for testing fiberglass and steel structures. The AE test includes attaching sensitive sensors to the structural fiberglass and metal components from the bucket down to the outrigger or chassis subframe. A test load of 1-1/2 or 2 times the rated load (specified by customer) is applied to the boom. A computer system monitors sounds emitted by defects that are growing during the test load. The computer selects the critical noise emissions and prints a summary report.

C. Magnetic Particle Inspection: Magnetic particle is a nondestructive test method used to identify surface cracks on ferrous material. It is performed on all critical welds, plates and castings of items listed in Part A during the visual inspection.

D. Dye Penetrant Inspection: Dye Penetrant is a nondestructive test method used to identify surface cracks and works on any structural surface including all critical welds, plates, castings made of non-ferrous material and any area requiring verification in Part C or Part E.

E. Ultrasonic Inspection: Ultrasonic is a nondestructive test method used to detect flaws in accessible critical pins. Use of ultrasonic reduces the number of pins that have to be removed for inspection. Pins with flat end surfaces and do not have drilled holes are best suited for ultrasonic.

F. Torque Testing: Torque testing all critical fasteners in accessible areas including upper and lower rotation bearing, swing gearbox, boom connections, and platform mounting.


A functional and operational test is performed to check the operation of controls, bearings, pins, bushings, cylinders, holding valves, bucket leveling mechanisms, outriggers, etc. This test will also find worn swing bearings or gearboxes, worn pins or bushings, and loose fasteners critical to the operation of the aerial.


A dielectric test up to 100kV as specified by ANSI standards. The dielectric test verifies the electrical insulating strength in the FRP upper and lower booms, bucket, liners, FRP extensions on digger derricks, tool circuits, and upper control system.  AC testing not available in all areas, so extra fees may apply.

*A variety of dielectric tool testing is also available, inquire for details.


Dielectric Tests: Bucket liners; hydraulic oil to ASTM D1816 standards; Hotsticks.

Oil Spectroanalysis: Chemical analysis of oil in engines, transmissions, and hydraulic systems. Determines type and amount of contamination.

Stability Tests: Performed to meet the requirements of OSHA/ANSI specifications.

Thickness Testing: Ultrasonic thickness testing is a nondestructive test method used to determine thickness of materials where thickness is critical and difficult to measure with mechanical test equipment.


Defects found during the inspection and tests are classified for degree of severity and printed on a computerized report. American Test Center technicians will review the report with the customer designated representative. A signed and dated copy of the test report listing the defects discussed is left with the representative.

The test is reviewed by American Test Center’s staff engineers and the final report is mailed to the designated customer representative. American Test Center retains a copy of the test report on file. Units that need rework require verification of repair or retest in the customer file.


American Test Center schedules tests with each customer to best meet their individual requirements. American Test Center has mobile crews located throughout the United States to perform the test at your site. American Test Center encourages your representative to have all the appropriate people available after the test to review the test results and to ask questions. American Test Center requests that operators manuals, manufacturer bulletins, maintenance files are available for our crew and that the aerial device be adequately cleaned prior to testing to assure a thorough test.