From CGB's nice link. (
good stuff)
VMC stable by 500ft VMC (The aircraft should aim to be stable by 1,000 ft even in VMC conditions. If the crew fail to achieve this then the gate can be reset to 500 ft, but only if the crew anticipate that the aircraft will be stable by 500 ft, if not a missed approach has to be carried out).
Note: The altitude at which the gates are set and by which the approach is
judged to be stable, varies depending on airline SOPs and can range from
1500ft-500ft
Note: you have to be ahead of the aircraft to make that judgment call. Asiana's SOP's will hopefully be included in the NSTB report.
EC Law now states:
• Without Visual Ground Reference:
It is recommended that stabilisation be achieved at the latest when
passing 1,000ft above runway threshold elevation. If ATC procedures require higher speeds and is allowed in the OM, the above gate may not be met, in this case stabilisation should be achieved by 500ft.
• With Visual Ground Reference: Stabilisation should be achieved by 500ft
(however it is still recommended that pilots use the 1000ft gate as
above). If the above gates are not met pilots should consider initiating a
go-around maneuver.
Additionally, note the use of the words “recommended” and “should”.