What happens to the hydraulic system when there is a failure of the power pack in landing gear operation?

When there is a failure of the power pack in landing gear operation, the correct implication is that the nitrogen accumulator maintains gear position for a limited time. This is critical because the nitrogen accumulator serves as a reserve of pressurized fluid, allowing the landing gear to be operated even when the primary hydraulic system fails.

The functionality of the nitrogen accumulator provides an essential safety feature. It ensures that the landing gear can extend or retract, depending on the situation, allowing pilots to maintain operations safely even in the event of a power pack disruption. However, this is not indefinite; the accumulator will only maintain the gear position for a specific duration, after which pressure will diminish, potentially affecting further operations.

In contrast, the other potential outcomes do not accurately depict the system's design or emergency response. The immediate retraction of the gear or defaulting to gravity extension would not occur without intentional pilot input or other hydraulic assistance. The option indicating that the landing gear remains locked does not align with the system's ability to use the accumulator to control gear position temporarily.