What is required during a static pressure system test under 14 CFR 91.411?

During a static pressure system test as mandated by 14 CFR 91.411, it is essential to ensure that the system is free from moisture and to determine that leakage is within allowable limits. Both of these requirements are critical for maintaining the integrity and functionality of the static pressure system.

Ensuring that the system is free from moisture is important because moisture can cause inaccurate readings and damage sensitive components within the pressure system. Any water present can adversely affect the performance of the altimeter and other instruments relying on static pressure, leading to potential safety issues during flight.

Determining that leakage is within allowable limits is equally crucial. A static pressure system must maintain a precise pressure to provide accurate altitude readings to the pilot and other systems. If the system has excessive leakage, it can lead to erroneous instrument information, which can compromise the safety of the operation.

Thus, both requirements are part of a comprehensive approach to ensuring the reliability of the static pressure system and its components, making the correct response to the question the choice that includes both ensuring cleanliness from moisture and confirming leakage limits are adhered to.