The airspace over the N-Atlantic is RVSM, so it is both MNPS and RVSM. As most planes crossing the Atlantic fly the precribed tracks (A,B,C,D and so forth) and the tracks are seperated by 60 NM laterally and 1000' seperation vertically on a same track it is recomended to turn of the track during emergency descent and the fly offset by 30 NM. This should keep the troubled aircraft away from other traffic as there is no radar coverage over most of the N-Atlantic (except from the Faroe Islands, Iceland and Greenland).