Mississippi Administrative Code
Title 15 - Mississippi Department of Health
Part 12 - Bureau of Emergency Medical Services
Subpart 31 - Emergency Medical Services
Chapter 3 - AERO MEDICAL SERVICES
Subchapter 4 - Aircraft Permits Required
Rule 15-12-31-3.4.2
If a substitute aircraft is in service for longer than 90 days, this aircraft shall be required to be permitted. An un-permitted aircraft cannot be placed into service, nor can an aircraft be used unless it is replacing aircraft that has been temporarily taken out of service. When such a substitution is made, the following information shall be maintained by the licensee and shall be accessible to BEMS: Registration number of permitted aircraft taken out of service; Registration number of substitute aircraft; The date on which the substitute aircraft was placed into service and the date on which it was removed from service and the date on which the permitted aircraft was returned to service.
Miss. Code Ann. § 41-59-5