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How is an airplane fire different from a regular fire? When firefighters crash jets to practice on, how do they keep people from getting hurt?

Insights

A passenger jet has crashed. Flames shoot into the air. Dozens of people are trapped inside. How can firefighters rescue anyone in a raging inferno like that?

It takes skilled professionals with special training. That's why men and women from around the country come to the new Aircraft Rescue and Fire Fighting (ARFF) Facility in Duluth, Minnesota.

There, they practice rescue techniques in a state-of-the-art airplane crash simulator designed to replicate a Boeing 757 jet. Nearly a hundred computer-controlled nozzles in and around the simulator shoot propane gas flames. When that happens, the firefighters pump foam onto the fire. But since this is a simulator, the foam doesn't actually put the fire out-the computer turns off some of the nozzles instead.

When the fire outside is under control, firefighters cut their way through replaceable panels and into the jet's "cabin." Smoke is everywhere, so they may wear goggles equipped with IRIS (infrared imaging system). In the simulation, however, the smoke isn't real. It's hydraulic fluid that has been heated to 427oC and blown out nozzles.

If trainees don't put out the fire in two and a half minutes or less, they fail the test. That may sound like a tough challenge but if a real jet crashes and the interior begins to burn, firefighters would only have about two minutes to rescue the passengers. (Fortunately, passengers can survive most jet crashes if they follow evacuation directions given on board.)

Every effort is made to see that nothing gets hurt during training-not the firefighters, not the environment. For example, in a real crash, firefighters would use aqueous film forming foam (AFFF). The chemicals in AFFF mix with water and are "fluffed up" into a foam, but they won't mix with the fuel in a jet crash fire. This means the water can float on top of the fuel and smother the fire. AFFF creates a seal around the firefighters' boots as they try to rescue the passengers. If the foam didn't do this, the fire could flash back and endanger the rescuers as well as those being rescued.

The foam used during the simulation, however, is biodegradable dish washing soap. Once it is sprayed, it slides into a pit under the simulator where it is treated and released into the regular water treatment facility.

Connections

1. What other situations could be simulated to give people the practice they need to face an emergency?
2. What would you include in a simulation to prepare firefighters for a fire in a skyscraper during the middle of a working day?

Key Words

biodegradable substance that can be broken down by natural processes
FAA Federal Aviation Administration; government agency that operates the national air traffic control system
foam mass of gas bubbles in a liquid film matrix
fuselage central body of an airplane that holds passengers, crew, and luggage
infrared electromagnetic radiation invisible to the human eye but detectable as heat
IRIS infrared imaging system; allows firefighters to see heat images even through smoke
mockup scale model used for demonstration, study, or testing
propane a natural gas, C3H8, usually used to make heat
radiative heat heat transferred from a distance. The sun and car radiators emit this kind of heat.
simulator apparatus that gener-ates test conditions close to real

Resources

1. Andriuolo, R. (1993) Firefighter: Written tests, physical exams (10th ed). Englewood Cliffs, NJ: Prentice Hall.
2. Field, F. (1992) Get out alive: Save your family's life with fire survival techniques. New York: Random House.
3. Maas, R. (1989) Firefighters. Jefferson City, MO: Scholastic.
4. Smith, D. (1988) Firefighters: Their lives in their own words. New York: Doubleday.
5. Smith, D. (1978) The history of fire fighting in America: 300 years of courage. New York: Dial Press.
6. Watson, T.W. (1992) Unhappy landings: Why airplanes crash. Melbourne, FL: Harbor City Press.

Additional resources

1. NEWTON'S APPLE Shows 1102 (emergency rescue), 1105 (jumbo jets), and 1109 (firefighting). GPN: (800) 228-4630. Or call your local PBS station to find out when it will be rerun.

Additional sources of information

1. ARFF Training Center
   11501 Highway 23
   Duluth, MN 55808
2. National Fire Protection Association-NFPA
   (800) 344-3555
   Source for two books: SFPE handbook of fire protection engineering and Fire protection handbook (17th ed.).

Main Activity

Time is critical in an airplane crash rescue. From the moment they arrive, firefighters have less than two and a half minutes to put out a fire and make a rescue. How many people could you rescue in a similar situation? This simulation will help you find out.

Materials

• masking tape, red chalk, or red construction paper
  
• a large, open area such as a playground
  
• duffel bags, backpacks, or pillow cases filled with heavy books or weights
  
• blindfolds or sunglasses with all but a narrow strip blocked out with tape to simulate smoke
  
• a stopwatch or a watch with a
  second hand
  
• squeeze bottles, enough for each rescuer. Empty, rinsed-out bottles of dish washing soap work well.

1. In your open area, mark out a rectangle 40 meters (130 feet) long and 4 meters (13 feet) wide. This will be your fuselage. If you don't have access to a space this large, reduce the lengths accordingly.
   
2. Mark emergency exits, three on each side, so they are evenly spaced apart.
   
3. Place chairs and other items in the area to serve as obstacles. The duffel bags, backpacks, or pillow cases will represent the people you must save. Make sure to vary the weights in these bags-you could even include one that is the weight of an adult.
   
4. With the masking tape or red chalk, mark Xs to indicate your fire. Or make represen-tations with the red construction paper.
   
5. Your fire and rescue team will stand
   6 meters (20 feet) from the outline of the fuselage. Start the timer and race to get into the "plane." Before you can enter the fuselage, you must put out all the fires. A fire will be considered "put out" when you have drawn a wet circle around it with a squeeze bottle.
   
6. Then rescue as many "people" as possible from inside the burning fuselage.
   
7. . Record the initial time it takes to rescue the victims.
   
8. Now repeat the entire exercise, this time wearing the blindfolds or sunglasses to represent smoke. Is there any variation in your times?
   
9. Repeat the rescue process a number of times, keeping track of each team's time. Chart each team's progress.

Questions
1. Do you get quicker with each simulation? What are some ways you could improve your rescue time?
2. How do the "sighted" rescues compare with the "blinded" rescues?
3. In what ways did you use teamwork rather than simply acting as a group of individuals?

Wrap your hand in a "glove" you've made from aluminum foil and then slip a big mitten over that. Slip a thermometer in next to your hand. Record the temperature at five-minute intervals. What do you begin to feel after the first ten minutes? Switch so that the mitten is next to your skin and the foil is wrapped on the outside. Any differences?

Interview several firefighters and find out why they chose this job. Ask about their "scariest" fire and find out why it was so scary. If you can, try and find one who has had special training for fighting jet crash fires. Ask why she or he went into this special field.

Newton's Apple is a production of KTCA Twin Cities Public Television.
Made possible by a grant from 3M.
Educational materials developed with the National Science Teachers Association.