What is the maximum pressure differential allowed during initial landing (at touchdown)?

The correct answer is based on the guidelines for safe landing procedures in aviation, which specify that during initial landing at touchdown, a maximum pressure differential of 1.0 psi is allowed. This pressure differential is critical as it helps ensure that the aircraft is capable of maintaining structural integrity and safety during the landing phases. Pressure differentials play an essential role in the performance of the aircraft’s systems, particularly in pressurized cabins, and exceeding the recommended limits can lead to potential system failures or structural issues.

The other options provided relate to different contexts within aviation, specifically airspeed rather than pressure differential. The inclusion of speeds, like 280 KIAS and 220 KIAS, reflects operational limits related to aircraft performance in different phases of flight but do not pertain directly to pressure differentials during landing. The focus here is solely on the pressure aspect, making 1.0 psi the relevant figure for touchdown conditions.