Where the rubber leaves the road

Courtesy Photo | Rubber buildup on a runway creates a flight safety hazard. A specialized piece of equipment strips the runway of the hazard without stopping airfield operations. The equipment was used to clean the runways at Ali Base this month. (U.S. Air Force photo by 1st Lt. Robert E. Grimmett) (Released)  

ALI BASE, IRAQ

10.22.2005

Courtesy Story

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By Senior Master Sgt. Darron J. Williams
407th Expeditionary Operations Support Squadron airfield manager
10/17/2005

ALI BASE, Iraq -- Combat airlift and training of the Iraqi air force are two of the most visible missions here; both are critical to the war effort, both require an airfield with safe runways.

Every plane that lands leaves a small amount of rubber from its tires on the runway. This rubber accumulates to the point where it becomes a hazard to flight safety: planes need a greater distance to stop because of the rubber build up, and the surface is more slippery in wet or icy conditions.

The distance an aircraft needs to stop actually increases proportionally to the thickness of rubber on a runway increases. High rubber deposits can reduce the braking action of an aircraft by 50 percent or more when the runway is wet. The situation is worse in icing conditions.

The potential for problems may be lower here because of the absence of sub-zero temperatures and low rainfall, but the potential is far from zero. Rubber removal is used at Ali Base to come as close as possible to removing any risk of an aircraft not being able to stop in time, or being the reason it slides off a runway, on the occasional days it does rain.

Because the accumulation of rubber depends on the number of landings, the frequency of the cleaning varies too. Some airfields have to be cleaned up to four times a year. Here at Ali Base it's an annual task, which has just been completed.

The specialized cleaning truck that cleans the runways here travels the area of responsibility cleaning all coalition bases. It uses a unique system that's both efficient and environmentally friendly: super-high-pressure water.

The truck has the capacity to carry about 4,000 gallons of water, which is pressurized by a 500-horsepower engine and sent sizzling out of three spinning nozzles below a deck cradled in front of the driver's cab. The pressure is high enough to strip the rubber from the runway without damaging the runway surface.

The same deck housing the cleaning nozzles also houses a vacuum assembly that sucks up the debris from the cleaning process: water, rubber and a little paint. This mixture is routed to another tank on the same truck. The strip of runway behind the cleaning truck is almost spotless and virtually dry.

A second truck provides the cleaner with water and removes the waste while cleaning continues, allowing for a non-stop operation. This system also works well for airfield operations because both vehicles can exit and reenter a runway quickly for arriving and departing flights. This non-impact to airfield operations is critical in the AOR.

Both ends of a runway can be cleaned in about two nights and the equipment only uses about the same amount of water needed to fill a couple of backyard pools (about 17,000 gallons).

Sure, those videos of smoke puffs when the wheels of an aircraft touch the runway are neat, but the machine that cleans up the mess is just as cool.

• Date Taken: 10.22.2005
• Date Posted: 10.22.2005 17:47
• Story ID: 3453
• Location: ALI BASE, IQ