What should you do when your vertical speed indicator shows a descent of 100 feet per minute while taxiing?

When the vertical speed indicator (VSI) displays a descent of 100 feet per minute while taxiing, it's crucial to interpret this reading correctly. Using the reading as a zero indication is appropriate because the VSI is designed to respond to changes in altitude. When taxiing, the aircraft is on the ground, and fluctuations in vertical speed can sometimes occur due to ground effects like uneven surfaces or tire compression.

By treating this reading as a zero indication, pilots can effectively monitor minor vertical speed changes without overreacting to what may simply be normal instrument variance while on the ground. During taxi operations, altitude changes should generally be minimal, and understanding the VSI's functionality allows for a more informed response to any deviations that may actually indicate a problem should they arise.

This choice is grounded in the understanding that the VSI is ultimately a tool to help gauge altitude changes primarily in flight rather than during ground operations, where such readings may not always align with actual conditions. Therefore, recognizing that the VSI can display minor fluctuations while taxiing enables pilots to maintain situational awareness without unnecessary concern.