Air Crash Equipment of the Future
Remote controlled tanks and tires filled with fire fighting chemicals offer a new look in fire fighting
FROM PISTON-ENGINED PLANES that loped along at 300 miles an hour to swept-wing jets that streak through skies at twice the speed of sound—this is the advance of aviation art since World War II. And on the horizon looms the heralded supersonic transport!
Despite this quantum jump in aviation itself, techniques for fighting airplane fires and rescuing crewmen and passengers have changed little during the past few decades.
Phil Cummins, long-time fire fighter and currently security officer at General Dynamics/Forth Worth, has long bemoaned this sad state of affairs. So much so, in fact, that he’s done something about it.
Cummins has patented, and his company is experimenting on, a new vehicle for fighting today’s much “hotter” jet fires. The concept involves futuristic-looking air crash equipment (ACE) with these features: remotely controlled tanks that can be maneuvered right to the brink of the blaze; tanker tires that carry fire fighting chemicals, a long with trailers which perform the same function and hook onto the main fire truck like link sausages; and an extensible boom, from which an operator may both fight the blaze and carry out rescue operations.
Foam and dry powder carried
The tankers carry both foam and dry powder. This gives firemen a weapon for fighting virtually any type blaze. Cummins firmly believes chemical foam is far superior to the mechanical foam now widely used for fighting jet airplane fires.
The main unit of ACE carries the tractor-type tanks (called fire cats) on a fork-lift device in front. The cats are controlled remotely by two operators, who sit in fireproof enclosures on either side of the main unit. A third operator sits in the extensible boom cabin, from which vantage point he can maneuver the boom to the desired position for rescue.
When a fire breaks out, ACE speeds to the burning airplane. The fork is lowered and the two fire cats positioned strategically at the lip of the blaze. The rescue boom operator moves the boom immediately over the cockpit, or area from which rescue is to be made. Thermally insulated curtains are draped down over the entry, and the trapped airplane crewmen are evacuated through an opening in the bottom of the boom, then raised to safety.
“If necessary,” Cummins said, “circular saws on the bottom of the boom can be used to cut holes in jammed doors or other inaccessible places.” Such equipment is also needed to cut through some of the tougher materials used these days.
Since ACE comes equipped with the agents for making chemical foam, plus dry powder, firemen can fight different types of fires—say electrical and jet fuel—at the same time. ACE’s sophisticated conduit system makes this possible. Interconnecting hoses link all tanker tires and agent-carrying trailers directly with ACE’s 10 turrettype nozzles.
It is these high-powered nozzles— four on the fire cats, four on the main unit, and two on the boom—which give ACE its tremendous fire fighting power. Going full-tilt, the 10 nozzles on ACE enable firemen to dump 10,000 gallons of foam on the flame in a minute.
Such power is the crux of Cummins’ philosophy for fighting modern jet fires: massive retaliation. “Fighting a real hot fire with most of the methods we have today is like hunting an elephant with a .22 rifle,” he explains. “What we need—and what ACE provides—is a means of pouring a big blanket of foam over the blaze in a short period of time.”
These multiple, higher-pressure turret nozzles of ACE furnish the necessary volume of foam; the tanker tires and trailers afford the virtually limitless supply of fire fighting agent.
Though mechanical foam is used widely on fire fighting machines today, Cummins is a strong advocate of chemical foam. He used it for years in battling tough oil field blazes.
“Forming mechanical foam involves pumping water and a detergent from separate tanks together. The agents form a foam upon hitting the air through a nozzle.
“Chemical foam, on the other hand, is formed by using two chemical agents to create a carbon dioxide gas. This mixture expands at a 10-to-l ratio into foam, compared to only an 8-to-l ratio for mechanical foam.”
But the biggest advantage for chemical foam, Cummins asserts, is in its composition. Bubbles in either foam are subject to burst at the extremely high temperatures created by jet-fuel fires. Mechanical foam bubbles contain oxygen, which can cause re-ignition of the fire—or flashback. The bubbles in chemical foam contain carbon dioxide, which inerts or cuts oxygen from the atmosphere around them when they burst.”
ACE figures to have greater stability and mobility than any other comparable fire fighting device around. One reason, of course, is that the extinguishing agent is carried in trailers and in the tanker tires. Another is that the inflation pressure of tanker tires is lower than that of conventional tires, making it unnecessary to use springs and shock absorbers on the vehicles.
These factors, coupled with increased tread contact on tanker tires, enables ACE to usually take the shortest, most direct route to the fire.
The tanker tires on ACE, incidentally, are punctureproof. And to prevent the tire from deflating as liquid is withdrawn, the interior is connected to a source of gas pressure through a tube in the hollow of the axle.
Normally, ACE would require three operators, one for each of the enclosures on the main unit. At least twice this many trained fire fighters would be needed to operate existing equipment of equal capability.
The building-block concept of ACE —linking on additional trailers as needed—pennits adding ACE equipment without further training of personnel or replacement or modification of existing equipment. This also enables a progressive build-up of fire fighting capability.
ACE offers fire fighters a potent new punch to throw at dreaded jet airplane fires. Hopefully, the new concept will add a new dimension to air safety —both for the military and commercial airliners.