What is a common indication of cabin decompression?

A common indication of cabin decompression is indeed alert signals on the control panel. In the event of cabin decompression, modern aircraft are equipped with various monitoring systems that detect changes in cabin pressure. These systems can trigger visual and auditory alerts to notify the flight crew of the issue, allowing them to respond appropriately. The presence of these alerts ensures that the crew can take immediate action to maintain safety, such as deploying oxygen masks and initiating an emergency descent if necessary.

While unusual engine sounds, vibrations felt in the airframe, and rapid altitude gain can indicate other problems, they are not specific indicators of cabin decompression. Unusual engine sounds might relate to mechanical issues, while vibrations could be associated with structural or aerodynamic problems. Rapid altitude gain, while it might occur in the case of an emergency ascent to avoid obstacles, would not directly point to cabin decompression itself. The combination of crew training and instrument alerts is essential for managing cabin pressure situations effectively, making the control panel alerts the most relevant indication in this case.