What is required for clearance when dealing with VFR-on-top operations?

When conducting VFR-on-top operations, the requirement to ensure proper spacing with IFR operations is crucial. VFR-on-top allows pilots operating under Visual Flight Rules (VFR) to fly at an altitude above a cloud layer, while still remaining in visual conditions. However, they are still required to comply with IFR traffic rules when interacting with air traffic control and IFR traffic.

Proper spacing is essential because VFR-on-top pilots are not subject to the same restrictions as IFR flights but must still maintain separation from them. This ensures safety in shared airspace, preventing conflicts or mid-air collisions. VFR-on-top pilots still need to yield to IFR traffic in terms of obstacle avoidance and need to operate safely within the flow of controlled air traffic, which includes maintaining appropriate vertical and lateral spacing.

Other aspects, such as requesting assistance, the timing of clearance, or specific weather conditions are important considerations in flight operations, but they do not directly enforce the requirement for spacing with IFR operations, which is pivotal for the safety of all aircraft involved.