"Strategic Lateral Offset Procedures (SLOP) are approved procedures that allow aircraft to fly on a parallel track to the right of the centre line relative to the direction of flight to mitigate the lateral overlap probability due to increased navigation accuracy and wake turbulence encounters."
ICAO 4444 Pans ATM 16th Edition section 16.5 Note 1.
SLOP of one or two nautical miles has been recommended for use in oceanic and remote continental airspace for a long time. For example, the North Atlantic Track (NAT) system has permitted SLOP since 2004 and has been a mandatory requirement to fly SLOP over the North Atlantic since 2017.
In the 16th Edition of ICAO 4444, published in 2015, ICAO extended the use of SLOP to en-route airspace in tenths of a nautical mile up to a maximum of 0.5NM, i.e. Micro-SLOP.
This change was originally proposed in Circular ICAO 331 to counter the effect of the paradoxo de navegação after the mid air collision over Brazil in 2006, see Gol Transportes Aéreos Flight 1907.
Currently, Micro-SLOP may only be applied on routes promulgated in AIPs by aircraft equipped with the appropriate automatic offset tracking capability.
Most ANSPs do not permit Micro-SLOP in their AIPs. However, the NAT recommendations have recently changed to recommend that pilots fly Micro-SLOP over the North Atlantic, see Two is not enough.
My pilot friends tell me that small commercial aircraft fitted with the Universal Avionics SCN 1000 and 1100 FMS's can fly 0.1NM offsets but that Airbus A320's can only fly offsets in 1NM increments.
The question is: which commercial aircraft currently have the capability to fly Micro-SLOP procedures with route offsets of only 0.1NM?