How can you identify damage to the airframe during a depressurization?

Identifying damage to the airframe during a depressurization is critical for the safety of the flight. The correct choice indicates that the altitude indicator shows the altitude you are currently at. In the event of a depressurization, maintaining awareness of your altitude is essential, as it enables the pilot to effectively manage the aircraft's response and take necessary actions.

The altitude indicator serves as an essential instrument in confirming that the aircraft is still at a safe flying altitude post-event; it helps in monitoring descent rates if the cabin loses pressure. Understanding precise altitude during such an event aids in situational awareness and may influence emergency procedures and routing to ensure safety.

Other options do not provide the necessary information related to monitoring altitude during a depressurization: for instance, an altitude indicator rising to a maximum would not provide useful information if the airframe is damaged; seeing negative values on a pressure gauge may indicate a serious problem but requires context; and having no change in altitude shown would be misleading or demonstrate a malfunction, potentially obscuring important information.