M4.2 Fire Sources

docx

School

Embry-Riddle Aeronautical University *

*We aren’t endorsed by this school

Course

330

Subject

Mechanical Engineering

Date

Jan 9, 2024

Type

docx

Pages

Uploaded by samroth787

Answer the following questions. 1. Identify the combustion matrix needed for fire, and then compare and contrast the difference between an inflight fire and post-crash fire in accidents, e.g., the Zonk Air accident . 2. Apply cause and effect relationship to evaluate initial on-scene actions and any possible follow-up techniques. 3. Distinguish and list some evidential procedures needed to determine if a fire was a component in the accident error chain. Hi all, Fire burns by the combined presence of four components: combustible material, an oxidizer, an ignition source, and heat to sustain the fire (Wood & Sweggins, 2006). Combustible materials are quite simply materials that can burn, but not necessarily solid or liquids. Wood is a combustible material, but more importantly for aviation, gases and mist are also combustible despite not always being visible. Oxygen is the second requirement for a fire; in situations where oxygen is not readily available, oxidizers may step in and provide the required oxygen, such as with rockets utilizing liquid oxygen. Conversely, in areas where oxygen is readily available, it can be removed to extinguish the fire, in the way aviation commonly utilizes Halon 1211 for fire suppression. The ignition source is the component providing ignition for the fire, depending on the ambient temperature as well as the temperature of the combustible material. Finally, heat provides the ability for the fire to sustain itself continuously, and this can vary depending on the make-up of the combustible material. Let’s assume an in-flight fire has a continuous ignition source, which is also hot enough to sustain the fire. Considering that the primary oxidation source (20% oxygen in the air) is severely reduced at most altitudes, fuel vapors would not necessarily be able to burn, however combustible. In contrast, in the same conditions on the ground, especially considering the availability of additional combustible materials, the danger of a post-crash fire is much higher. On the KC-135, crew chiefs take extra precautions to ensure ignition sources are not within 50 ft of the fuel vents of the aircraft for this very reason. When the aircraft is backlit and receiving high refuel loads the vapor is clearly visible exiting the vents. The cause of an inflight fire can be a host of variables, from electrical shorts to explosion-prone batteries, whereas the fires resulting from a crash may be a result of the crash. The obvious issue with determining an in-flight fire is the evidence destroyed by the fire. Although not as good as direct evidence of a fire, indirect evidence, such as witness statements, is a good place to start in case the fire has destroyed a significant portion of the evidence. In terms of direct evidence, the materials melted are a good place to start, considering in-flight fires burn hotter and therefore melt materials that would normally not melt in a ground fire. An inflight fire will also show the effects of the wind in the burning patterns while a ground fire would be more localized, as is evident in the Zonk Air accident.

As mentioned above, the pattern of the fire’s path is a good indication of whether this was an inflight fire or not. The burnt materials, paint damage, and wiring can also provide indications of whether they caused or assisted the fire’s progression. Another thing evident from the Zonk Air accident is the lack of burn indications on the components not attached to the aircraft, suggesting the fire started on the ground, and was perhaps not a cause of the accident. References Wood, R. H., & Sweggins, R. W. (2006). Aircraft accident investigation (2 nd ed.). Endeavor Books.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version