What specific pre-flight checks are required on a pushback tug before initiating aircraft movement?

Before initiating aircraft movement, specific pre-flight checks are required on a pushback tug to ensure safe and reliable operation. First, inspect the tug's tires for proper inflation, wear, and damage. Tire pressure should be checked against the manufacturer's specifications. Inspect all fluid levels, including engine oil, coolant, hydraulic fluid, and brake fluid. Ensure that the levels are within the acceptable range and that there are no signs of leaks. Check the tug's brakes, including the service brakes and the parking brake. Verify that the brakes are functioning properly and that the parking brake can securely hold the tug on a sloped surface. Inspect the steering system for proper operation and responsiveness. Check for any excessive play or looseness in the steering linkage. Verify that all lights are functioning correctly, including headlights, taillights, brake lights, turn signals, and warning lights. Check the operation of the tug's horn and other audible warning devices. Inspect the tow bar and its connections to the tug and the aircraft. Ensure that the tow bar is in good condition and that the connections are secure. Verify that the radio communication system is functioning properly. This is essential for communicating with the flight crew and ground control. Inspect the tug's safety equipment, including the fire extinguisher and first aid kit. Ensure that the fire extinguisher is properly charged and that the first aid kit is fully stocked. Start the tug's engine and allow it to warm up to the proper operating temperature. Listen for any unusual noises or vibrations that may indicate a mechanical problem. If any discrepancies are found during the pre-flight checks, they should be reported to maintenance personnel and corrected before the tug is used to push back an aircraft. All pre-flight checks should be documented on a checklist to ensure that no steps are missed.