Which of the following is NOT a decompression type?

• A. Slow
• B. Rapid
• C. Explosive
• D. Partial

Answer: (D)

Decompression types describe how quickly cabin pressure falls. The standard categories are slow, rapid, and explosive. Partial isn’t a recognized decompression type because it doesn’t define the rate of pressure change across the cabin; it would imply only part of the system losing pressure or a non-uniform loss, which isn’t treated as a full decompression event. In practice, slow decompression means a gradual pressure loss over time, rapid decompression is a quick drop, and explosive decompression is an extremely rapid, violent loss that can cause structural damage. Since partial doesn’t specify the overall rate of pressure drop, it isn’t considered a decompression type.