Final answer:
A lapsed ATPL with a Group 1 IFR rating usually reverts the pilot to the privileges of a Private Pilot License (PPL) if they maintain PPL recency requirements. To regain the IFR privileges, the pilot must complete the necessary renewal process.
Step-by-step explanation:
When the Holder of an ATPL with a Group 1 IFR rating sees their rating lapse, typically the license privileges revert to those of a Private Pilot License (PPL), as long as the pilot maintains the recency requirements for the PPL. This is because the Instrument Flight Rules (IFR) rating is an additional endorsement on top of a pilot's existing license, and without it being current, the pilot is not authorized to fly under IFR conditions and can only exercise the privileges of a VFR (Visual Flight Rules) pilot. It's important to note that specifics can vary by country and the governing aviation authority. The individual would need to complete the required renewal procedures to regain their lapsed IFR rating.