Additionally, Workers do the following tasks: aircraft flight line servicing, operates service vehicles to replenish fuel and oil, perform pre-flight thru post-flight maintenance inspections, enters on the maintenance records description of the servicing performed, checks for fuel contamination by draining sumps and fuel drains; operates ground support equipment such as electrical power supply, tow tractors, and engine starting units, examines tires for specified air pressure and condition, assists in towing aircraft and cleans exterior and interior of aircraft, hangar deck periodic housekeeping and fluid spills using portable platform ladders, brushes, rags, water hose, cleaning compound applicator and mobile vacuum. The Aircraft Worker services aircraft, performing any combination of the following tasks directs incoming and outgoing aircraft near terminal or flight line parking area to assist pilot's maneuvering of the aircraft on the ground, using hand or light signals, and secures aircraft in parking position with chocks and tie downs.