While aircraft ground handling services often refer to refueling aircraft, marshaling and parking, luggage handling and towing aircraft with airplane tugs, we're only going to focus on the latter today. Keep reading for seven helpful tips aircraft ground handling crews can use to maintain good airplane tug traction for towing and pushback operations in winter conditions.
Note: This list is not exhaustive. For more specific instructions, consult your manual or reach out to the manufacturer.
1. Keep Airplane Tugs Outside
While it may seem counterintuitive at a glance, it's best to keep airplane tugs outside hangars at all times (except when performing maintenance). While the conditions outside may be icy, airplane hangars are outfitted with top-of-the-line heating systems to keep things warm, which isn't always ideal.
When an airplane tug is kept in a heated hangar for hours, it adapts to the warm ambient temperature. As soon as aircraft ground handling crews need to perform towing procedures and transport the aircraft tractor outside onto icy concrete, the residually heated tires will melt the coat of ice on the ground. This can cause the tug to lose grip, begin to slip and cause serious damage during the towing process. The key to avoiding this situation? Keep your pushback tug outside or in an unheated (non-icy) airplane hangar to allow it to adapt to the outside temperature.
2. Closely Inspect Aircraft Tractors Before Operation
Prior to any pushback or towing procedures, aircraft ground handling crews must inspect their aircraft tractors and the aircraft thoroughly. It's already a vital part of the job to check airplane tugs before any operations can start to avoid accidents. Still, the dangers of missing something are amplified by unsafe weather conditions. A thorough inspection of a pushback tug includes:
- Checking for any loose hardware
- Ensuring all fluid levels are adequate
- Inspecting the tug body and towbar for bends, dents and scratches
- Testing the engine
- Determining whether the tires are inflated to the right PSI
Aircraft ground handling crews should have a general safety checklist in place to be used before all operations.
3. Decrease Tire PSI
Most aircraft ground handling crews know more PSI in airplane tug tires isn't always a good thing. Tire pressure will naturally be slightly lower in cold weather conditions, but when temperatures reach critical points, it may be beneficial to keep them even lower. In extreme winter conditions, temporarily reducing the air pressure in aircraft tractor tires from the standard 60 PSI to 25 PSI can increase the surface area that comes into contact with the ground, giving operators more traction on runways and flightlines to perform the tug. Once the weather emergency has ended and things are less icy, airplane hangars are a great spot to restore air pressure safely.
4. Keep the Towbar Level
To avoid slippage during towing operations and a potentially expensive and dangerous accident, it's best for aircraft ground handling crews to keep towbars as level as possible. When using a 2-wheel drive (2WD), all-wheel drive (AWD) or rear-drive pushback tug, crews should ensure an aircraft towbar is level or slightly downhill toward the aircraft being towed. Doing so prevents contact with the ground, reduces the risk of cracking or damage, and ensures the airplane tug suspension remains in good working condition.
5. Maintain a Smooth Pushback
A wheel may lose traction when using an AWD aircraft tractor in winter conditions. If a member of an aircraft ground handling crew experiences this, they must not panic. To stop the wheel of the pushback tug from spinning, simply applying the brakes gradually allows the wheel to spin and come to a stop. When pushing an aircraft backward in icy conditions, coordinate the left foot brake pressure and the right foot accelerator to retain a smooth pushback.
6. Don't Jerk Forward
When aircraft ground handling crews perform towing and pushback operations in inclement weather, it becomes more challenging to maintain a gradual, consistent speed. Without awareness of one's surroundings, airplane tugs can often jerk forward and cause accidental damage to a towbar, the tug itself or the aircraft nose landing gear. Even when operating in ice or snow, crew members must press the accelerator gradually. In wintery conditions, cautiousness is key.
7. Sipe an Airplane Tug's Tires
When ice or snow is present, snow tires can only do so much to improve traction. In fact, when performing winter pushback or towing operations on dry or icy pavement, snow tires tend to cause an airplane tug to lose traction far easier. To avoid the pitfalls of snow tires, aircraft ground handling crews can sipe a pushback tug's tires. Siping is the process of making tiny cuts across the tires' tread to increase the gripping edges and maintain their footprints. This method offers excellent traction on slippery surfaces and increases your tires' overall lifespan.
Coincidentally, siping an airplane tug's tires in extreme heat conditions can also help aircraft ground handling crews avoid overly heated tires when runways and flightlines are hot.