Tow team lead reported after parking aircraft at the gate; the aircraft had moved and contacted a pickup truck causing minor damage to the #1 engine cowling.

Narrative

My shift started at XA:00 AM and I was assigned to direct the XA:00 AM tow team. I was assigned 4 crew members (one brake rider; a tow driver and 2 wing walkers. One crew member was not located so I contacted management and a replacement was found. The tow driver who usually tows; informed me that the usual tow tug was empty on fuel and this tug is the most reliable tug in ZZZ inventory and has closable doors to protect the driver from the elements. I then contacted the brake rider (3 weeks experience) and verified that he was capable and had his necessary checklist (he did). Next I tried to locate the designated pickup that tow teams utilize but after searching it was nowhere to be found. Went back to management and was given keys to the manager's pickup and could not locate that vehicle; so I told the crew that we would utilize 2 regular tugs to the designated RON remote parking. I obtained the tow inventory and order from Operations and briefed the crew as to the order of towing and tail numbers. The first tow was an A321 that was towed to gate X and was straightforward and without incident. Weather conditions were light drizzle at XB:00 AM. I contacted management regarding the location of the pickup and it was found 'in use' and it was made available to our team. We then proceeded back to overnight parking area in the pickup for the second tow which was a A319 which was to be towed to gate Y. We did the usual tow preparations and once the APU was started; the push operator signaled the wing walkers (sounding of the horn) that the tow was ready for the push-stop-disconnect-turn to tow position and reconnect procedure. The weather had turned into a steady and medium rain. The push straight back and the perpendicular to the chock point was approximately 500 ft. I followed in the pickup and once the wing walkers were walking back to the tow bar disconnect point; I positioned the truck towards the tow-bar area (in the area adjacent to the cockpit) to use the headlights to help illuminate the dark and stormy conditions. I put on the headlights in the 'high-beam' position; set the parking brake and turned off the ignition. The wing walkers disconnected the tow-bar and the tug then turned around and was being reconnected. On the push out I did notice that the wingtip 'nav' lights were not illuminated and I exited the truck and asked the tug operator to inform the brake rider to 'turn these position lights on' and the tug operator informed me that he was having difficulty with the headset communication and handed them to me and I then tried to communicate but while I could hear my transmissions he had difficulty understanding my message. I gave the headsets back to the driver and asked him again to relay this instruction before we commenced any tow as the weather was a driving horizontal downpour. I sensed the anxiety of the driver (and the crew who were moving hastily back to the truck) as he was attempting to clear the inside of the window as it was covered in pouring rain. I inspected the tow bar and pin and went back to the truck passenger seat as the wing walkers were in the driver seat and back seat. At this point the truck itself was being rocked by the gusting wind/rain and I thought that I was seeing flashes of lightning but I realized the brake rider had turned on the strobe lights and not the nav lights. I took off my glasses to wipe the rain water and put them back on and thought that we were moving but it did not feel right and I asked the driver; is the plane moving forward? I noticed the plane moving slowly forward; told (yelled) for the driver to start and move the truck and he exclaimed that the parking brake was on and did not know where the release was (dark cab). I told him the release was automatic and to tap the accelerator and also told him to immediately blare our horn to alert the tow driver that we were not clear yet. He did in one continuous blast; which caught his attention and he hit his brakes but the#1 engine cowling at about the 4 o'clock position made contact with the truck. I exited the truck; went to the tow driver and made sure that he could coherently understand my instruction to reverse the tug 12 inches (I was yelling over the wind and rain). He reversed and I went to the truck and told them to return to the terminal and bring back the manager on duty. I inspected the engine the best I could and could vaguely make out a small scratch of about 2 inches but no observable dent or puncture. I then went to the driver and told him to remain in this position until I instructed further. I then proceeded to one of the other RON planes to get under the wing and out of the storm and called the manager on duty. I then noticed that the plane was moving forward and to the active taxiway (the exit towards the terminal). I asked the manager on duty if we should remain here or move the aircraft to the gate. He responded that maintenance was alerted and would inspect the cowling at the gate. The 737 was towed to the gate and maintenance and the manager on duty were present.The event was somewhat surreal. Lightning that was strobes; rain; wind; getting out of the elements and thinking that the truck driver was moving when in fact the plane was actually moving; which to be honest; didn't really register for a moment; as in; 'this should not be happening and it makes no sense. Then trying to get the driver whom was probably experiencing the same disbelief; to move and alert the tug. We had probably 10 seconds as the plane moved forward a good 50 feet or so as we were forward. No doubt I realized it had happened in what seemed to be slow motion. I actually thought there would be no contact because of the horn alert but the tow driver once he stopped his slow tow; contacted the truck. Thank the Almighty; no one was injured. This event occurred through a combination of minor and significant contributing components. Not having a weather protected push-tow tractor in an extreme weather event obviously created a stressful situation for all involved. Having a open tractor; being covered in driving rain on the interior window and watching the driver trying to wipe clear to be able to see; I sensed the drivers anxiety and urgency to get at another 'angle' (as he stated to me); in my opinion; was an issue. Clear and understood communication between the brake rider and tow driver was a contributing issue. The brake rider as I understand gave no verbal instruction to move forward to the tow driver. Situational awareness and recognition was being interrupted with other simultaneous factors as the driver surely knew we were there with the truck with lights illuminated for the previous 5 or so minutes. As mentioned; I had made numerous calls to both manager on duty's on duty and one immediate call once the aircraft-truck contact was made (1 minute?) She coordinated with maintenance and instructed us to move the aircraft to the gate. The Manager also arrived at the gate along with about 5 mechanics. The scratch was barely visible and almost smooth if you ran your hand over it. I believe we connected the aux power but told the crew not to connect the external air because of the gusting wind. The Manager and myself inspected the pickup truck and she assumed that a hood dent was the contact point though the truck had many dents; scratches and wrinkles in that area that had been already present. Certainly; most if not all accidents or incidents are preventable. In yesterdays mishap; while serious it could have been much worse. For one; we were (the wing walkers and myself) were within seconds either way of having a moving aircraft come in serious contact with us let alone the pickup truck. If I had slipped in the storm or even bent down to tie my shoe or pick up a piece of FOD; we could have been crushed. My first impression of what the most serious issue of what went wrong was the fact that we seem to be missing some confirmation verbiage that should be acknowledged before any plane moves. Pushing a plane forward is more straightforward; the push driver has a considerable full view of his surroundings; BUT the tow driver facing forward in reality has a limited view of what's behind him. The manual suggests certain verbiage but moving forward; perhaps the brake rider to tow driver verbiage should include; 'verify area ALL clear'. If that had taken place yesterday; that extra and added surveillance should have forced the driver to turn around and respond; 'ALL clear'. Our truck was positioned as we always have done as practice; to illuminate the area with the headlights in a very dark area; especially in a storm. The trucks position was approximately 32 ft. from the center of the plane and in an example containment line this has in past practice for years been where tow crews position the truck to 'shine light on the scene' which in inclimate conditions; add an extra element of safety. In ZZZ's case; there are no containment envelope designated lines at this parking area and even some of our mainline gates and our widebody gate. On the area where we park to reverse the push tug; there are NO lines and NO spots and it is basically an uncontrolled space where other airlines in their towing; simply 'go for it'; another accident waiting to happen. While ZZZ has 2 new push tugs; they remain doorless and I am told that the doors are at the ground equipment facility and have NOT been installed for over a year (though many have continually ask). A driver should not have to fight the elements while moving a expensive chunck of metal full of fuel... This unfortunately was a distraction factor of yesterdays incident. Fueling at ZZZ has been an issue for years and if we had sufficient fuel yesterday we would have had an appropriate tug for the tow operation. In ZZZ; we block a gate for an hour or so mid-morning for fueling yet there can be a full compliment of 4 flights being turned at the same fueling envelope and as a result; many units miss being fueled. The obvious way to fuel is in the middle of the night; lining up all equipment adjacent the gates and a dueler just goes right down the line (which other companies do). Our company; nope and we are told the fuelers 'can't do it'. So get another fueler; yes? I mentioned headset quality and I had to deal with it myself with the nav light issue. Our headset; especially the tow equipment is old; dated and continually failing. Yet we are told that new equipment is not available because of 'cost'. Would you tell a Captain that we won't change out his mike because it cost to much? This is simply the price of doing business.