What is the first sign of fuselage opening?

What is the first sign of fuselage opening?

• A. Sudden drop in room temperature
• B. Increase in humidity
• C. Hissing sound
• D. Vision blur

Answer: (C)

When a breach opens in a pressurized fuselage, the immediate cause is high-pressure cabin air rushing out to the lower-pressure outside environment. The first sign you’ll usually notice is a hissing or whistling sound as air jets through the opening. A strong draft or rapid cooling can follow, since outside air is cooler and the escaping air changes the cabin environment. Humidity changes and vision blur aren’t reliable early cues—they aren’t as immediate or directly linked to the initial air leakage as the hissing sound.

When a breach opens in a pressurized fuselage, the immediate cause is high-pressure cabin air rushing out to the lower-pressure outside environment. The first sign you’ll usually notice is a hissing or whistling sound as air jets through the opening. A strong draft or rapid cooling can follow, since outside air is cooler and the escaping air changes the cabin environment. Humidity changes and vision blur aren’t reliable early cues—they aren’t as immediate or directly linked to the initial air leakage as the hissing sound.