What is acceptable visual cue at Decision Height when performing CAT II approach?
Short answer: for CAT II, seeing the approach lights (minimum 3 segments) is sufficient given a lateral element is also acquired.



Visual acquisition definition may vary between FAA, EASA, ICAO, etc. What follows is for EASA (as tagged).

For CAT II, you may descend below the DH if you can see:


3 consecutive approach lights,
or touchdown zone (TDZ) lights,
or runway centerline lights,
or runway edge lights,
or a combination of the above,
and must include a lateral element, i.e., crossbar, threshold, or TDZ pattern lights.


(Source: Airbus) A crossbar plus 3 segments.



For CAT IIIa and CAT IIIb (fail-passive; no roll-out mode):


The same as above, minus the lateral element.


For CAT IIIb (fail operational; roll-out mode):


At least one centerline light is attained and can be maintained.




Do not use for flight.