The ground support industry's source for news, articles, events, product and services information.
Issue link: https://groundsupportworldwide.epubxp.com/i/814698
20 GROUND SUPPORT WORLDWIDE APRIL 2017 COVER STORY big tractors and there were small tractors, and the 757 was kind of like 'what do we do with it?' "In order to handle it, the airlines had to buy a wide-bodied tractor specifically for the 757 – which was then too big for the smaller airlines," he adds. "But they had no choice." Now, the AP8950SDB-AL-250 allows customers to handle all of their nar- row-bodied and regional aircraft. Finding a Solution When the industry recognized the B757 wasn't going away, Paulson and his team at LEKTRO found themselves asking the same question. "Is there any way that we can make our 8950-200 have the '57 capability?" explains Paulson. "The goal was, how do we use the chassis we have and make it grow another 30 per- cent capacity?" he continues. "Now that we have the customers using the 8950 already, rather than trying to look at another com- pletely different tractor, can we take the 8950-200 and super-size it?" The conversion required a number of custom parts and modifications to existing components of the 200 model to achieve the specs required of the 250 – most notably increasing the tug's 210,000-pound capacity to 280,000 pounds. "The motor had to be changed. The bat- tery had to be changed from an 80-volt to 120-volt system. The winch had to be upgraded. The drive tires, the wheels, had to be upgraded. The wheel drives had to be upgraded," Paulson notes. "Almost every major component in the tug had to be upgraded." Although the components required an upgrade, the basic chassis still worked, which was essential in order to handle the smaller, low-profile regional aircraft. Key Functions The AP8950SDB-AL-250's ability to han- dle a range of regional and narrow-bodied aircraft up to the B757 is made possible by the unit's Programmable Logic Control- ler (PLC) System. This onboard computer senses the aircraft's weight and makes adjustments to properly handle each plane, transforming itself from a 280,000-pound capacity tug down to a 50,000-pound capacity tractor. "Changing parameters so that the AP8950-250 doesn't exceed the limitations of all the aircraft sizes set for by the manu- facturer is critical," Paulson says. For smaller aircraft, the PLC changes motor power so there isn't as much power on the throttle; reduces braking forces; reduces the forces the winch can pull; etc. Addition- ally, if a pilot forgets to release the hydraulic steering or there's a bypass pin on the nose to avoid damaging the steering, the PLC will sense the torque and alert the operator once the tug is approaching OEM designated torque limits. If the operator continues and reaches the torque limits, the warning light becomes red and the alarm will not stop until a supervisor inspects the nose gear and tug and disables the alarm. LEKTRO team members Henry Balensifer, Danny Harms Jr., Scott Mart, Eric Paulson, Paul Davis, Jeremiah Scott and Jesse Long stand beside the company's electric towbarless pushback.