simulated Autoland 737 - RA 2 inop

[president]

In my company we have a min equip list for performing cat II/IIIA approaches One requirement is 2 radio altimeters. Today we were performing a simulated autoland on a cat I app in CAVOK. My question is: do we need to have both RAs operating for the simulated autoland since its just a requirement for a cat II/IIIA app? We had intermittent errors on RA2. Since it is not technically required by the aircraft to perform the flare and it was a normal cat I app (although with autoland) I think we could legally perform it without RA 2 as it actually is a cat I approach. In other words: do we need two RAs because we are flying an approach to CAT II/IIIA minimas (as suggested by our manuals) OR is it a technical requirement to fly any approach with automatic flare? What are your thoughts here? Our 737NGs are fail safe without automatic rollout.

[FE Hoppy]

The technical limitation applies to the aircraft not the met conditions. I would say that if your aircraft does not meet the AFM technical requirements then you are not legal to attempt an autoland regardless of the approach category.

I don't know what your AFM says but the 3 I am familiar with require 2 radio altimeters to start and 1 type allows you to continue once autoland is engaged if 1 RA fails. The other two require a manual landing or go-around.

[RAT 5]

To do an autoland you need 2 autopilots to be engaged. If a RA fails it will disengage that autopilot, and because of the selection of both autopilots, after approach logic has isolated the 2 channels, it will in fact disconnect both. The good side will be able to be re-engaged, but an autoland is no longer possible.