Federal Aviation Operations Specifications Administration
Term or Terms  Definition 
instrument approach (SOIA) 
Sustainable Transfer  A sustainable transfer is a transfer of operational control, without any impediment, by a contract, agreement, lease, or other written or verbal arrangement between the owner, lessor, or other entity, and any other entity, that restricts any person or entity from transferring operational control to the certificate holder.  Examples of such impediments are lease, mortgage, insurance, management agreements, and other agreements which limit the use of the aircraft to a particular party or purpose other than the certificate holder and its authorized kinds of operation. 
VFR Station-Referenced Class I Navigation  VFR station-referenced Class I navigation is any operation conducted within the operational service volumes of ICAO standard navigation aids under visual flight rules (VFR) which uses nonvisual navigation aids (stations), such as VOR, VOR/ DME, or NDB as the primary navigation reference. VFR station-referenced Class I navigation includes Class I navigation conducted on-airways and off-airway routings predicated on airways navigation facilities.  These operations also include Class I navigation using an area navigation system which is certificated for IFR flights over the routes being flown.