What is generally used in the construction of aircraft engine firewalls?

• A. Aluminum alloy
• B. Carbon fiber
• C. Titanium nickel alloy
• D. Stainless steel

Answer: (C)

Firewalls must act as a durable barrier against extreme engine-fire conditions, keeping heat and flames from reaching the cabin long enough for safe shutdown. That means the material needs to stay strong, resist oxidation, and not warp or fail when exposed to high temperatures. Among the options, a titanium-nickel alloy offers a favorable combination of high-temperature strength, oxidation resistance, and lighter weight than stainless steel or other nickel-based alloys. Aluminum would soften or melt under the same conditions, and carbon fiber can burn and lose its protective properties. So, using a titanium-nickel alloy provides the toughness and heat resistance needed for a firewall while helping keep overall weight down, which is why it’s the preferred choice in this context.