Originally Posted by AIMS by IBM
My understanding is that an aircraft that is at Alert Height with a reduced redundancy and well positioned on the ILS can continue with its approach and landing simply because it has been flight tested that it can do so under the most adverse conditions.
It is obvious that if you start to do this from 1000 ft that the failure may cause a deviation that grows as time progresses.
The Alert Height is where, if above it you can do fault rectification, switching etc but below which you don't. If you have the capability to rectify a problem before the Alert Height you may do so and continue the approach, bearing in mind your Autoland/ LVO capability. If you have passed the Alert Height then you should NOT trouble-shoot and fault rectify. You ascertain any required increase in minima due to the fault and continue to that or you go around.
I see you are in TEXAS, so I guess you would follow the relevant FARs.....
PP