Towing aircraft with tractors has been part of the industry from the days since they got too big to push or pull around by hand and back muscle. I recently saw a picture of a group manhandling no less than a B737 NG on, what I hope for their sake, was a flat ramp so the old strong-arm procedures will still work in a pinch. I have also seen a charity pull of a B757 where teams from around the airport competed with each other in who could pull the aircraft the farthest in a given amount of time. Admittedly, it can be done but generally, a tractor is easier.
Towing can be an easy task, a hair-raising ordeal through an obstacle course, or it can be downright miserable in bad weather. On a bright sunny day, it’s easy to look good at the wheel of a rumbling iron monster pushing a loaded B747 back with effortless ease. It can be less fun even with vigilant wing walkers to keep watch to thread the aircraft backwards through a narrow taxi lane at a busy terminal.
Stupid things do happen. A B727 was nosed into a corner gate at a station where I was manager. My three mechanics were standing by for departure with the tug and towbar already hooked up. The driver was in the cab but the two wing walkers, clad in parkas and yellow rain gear, stood under the wings — a near-freezing rain was slicing down. The jetway came off and the tug driver blinked the headlights indicating they were ready to push back. The wing walkers, who act as the safety men, spread out and waved their lighted wands indicating it was clear to start pushing.
Well, there were no obstacles at the wingtips but there was a catering truck just finishing up at the rear galley door. The aircraft went back a few feet and crunched its inboard flap against the truck. With the driving, cold rain, the safetymen had not raised their heads to look. Try to explain that one on the companywide morning briefing.
Most tows are short pushbacks from the gate onto the tarmac so the aircraft can taxi. Others are considerably longer, involving taking an aircraft from the terminal to the maintenance hangar often miles away. Again, weather makes a difference. An open tug on a sunny day is like being in a sports car with the top down. A very expensive sports car at that. Still, there can be disappointing moments even on the clearest and best days. For instance, while towing a B707 to the hangar, I noticed the airplane nose had caught up with me and was trying to pass me. This was upsetting to say the least as he should have been behind me at the end of the towbar.
Towbars which couple the tug to the aircraft are equipped with shear pins which let go if an excessive load is put on them. This prevents you from tearing the nose gear out of the aircraft. Unfortunately the shear pins also often failed from fatigue, which is what had happened here. The aircraft was rolling on its own, and I was dragging a long and now useless tube behind me that wasn’t attached any longer to the aircraft. The intercom cable naturally had snapped and so my frantic call of “brakes” to the mechanic in the aircraft were not heard. All I could do was accelerate and try to get out in front so he could see me. Fortunately, he did notice and with the sight of a big yellow towbar tube bouncing behind my tug, he figured out what happened and applied the brakes before he ran off into the sand.
I notified ground control of our little difficulty using the tug radio (B707 had no APUs installed, hence had no radio working). Naturally, the spare shear pin that was supposed to be attached to the bar was missing, but a Phillips screwdriver made a useful substitute and I reassembled the head to the towbar, hooked up and we were off once again.
Those long tows to the hangar were pretty infrequent, as it was easier to taxi if possible. This meant that the diesel-powered tugs spent most of their lives pushing back 200 feet at the most and returned to the gate to await the next pushback. Lots of idling — lots of carbon buildup in the exhaust system. Then would come the occasional long tow to the hangar and all that nice carbon buildup would catch fire and burn, producing some pretty horrific flames and sparks from the exhaust stacks. This little problem is not limited to tugs, by the way. The big standby generator at the main base was faithfully checked every day, started, run for 10 minutes and shutdown. Some years of daily tests went by until the power blackout came, and now the unit faithfully roared to life. It manfully put out the amps needed while the carbon buildup in the exhausts and muffler heated and finally glowed cherry red and caught fire. You might want to think about that if you are responsible for the standby power plant.
Oddball tugs exist and I have written of the old Olivers and Farmall tractors that we had in the 1950s. They certainly had the torque needed but were awfully hard on the towbar shear pins. The Farmall had the nasty habit of rearing up, which was certainly interesting as you had no seat, but stood to operate it. It might be difficult to get OSHA to pass it today.
Later, there was the big Silent Hoist tug for the “jets” (vintage 1960) which resembled a super carrier complete with an island (the cab) on the right (sorry, I mean starboard) side. It featured special brake locks. You could lock the inboard wheel to pivot the tug around to make a sharp turn by applying the brake and then pulling out the appropriate knob on the panel. It trapped the fluid to the inboard wheel. Unfortunately, it sometimes didn’t release it when you pushed it back in making the tug immoveable. A bad feature when there was a loaded jet attached.
