In the past i'm reading a lot of problems with the dual autoland (Cat 3) selection/engaging.

The pre-condition for a successful autoland;

1. Both correct nav freq selected

2. Both course selectors on the same runway heading.

3. above about 1500 ft

and the most forgotten selections are

Both EFIS display rotary switch/selectors on APP

 

Regard J Broens

Imac 27" i7 (on bootcamp)

I've done lots of autolands with neither of the EFIS selections set to APP. Actually I almost never set the EFIS to APP mode.

I usually set The Captain's EFIS to APP, and the FO's to VSD if necessary.

sometimes i have to force the airplane to capture the localizer with Heading Select, because it can fly over the course without capturing it, paralleling the localizer. Most times it happens with VNAV.

I've never done both course knobs, either.

Miguel, are you sure the angle under which you intercept the localised isn't too steep? You will probably overshoot the localised if that's the case.

LNAV gets the airplane within RNP, which are low on airplane with GPS. Rarely it can paralles the airplane to localizer. It's not depends on VNAV.

As autoland doesn't depend on ND mode. It depends on aircraft systems and capabilities, approach must be stabilized before 1000ft (flare can be armed only before 500ft), second autopilot engaged prior to 800ft RA.

 

If you using heading select, 30* to intercept will be perfect and give no overshoot.

Sometimes, also the altimeter setting will change after you set it for landing if you have an active weather monitor (AS2012). This will cause you to parallel the glide slope below or above without capture. I use V/S to fly up or down to capture the glide slope. Then Autoland will engage and allow normal landing. This bugged the heck out of me for a long while until I figured it out.

What is in the PFD after dual mode is armed?

Before I see 'Single', but after some flashing at about 1500AGL the PFD shows 'CMD' again only.

(CMD A and B illuminated. )

What is in the PFD after dual mode is armed?

Before I see 'Single', but after some flashing at about 1500AGL the PFD shows 'CMD' again only.

(CMD A and B illuminated. )

 

In your case you've got fail-passive autoland installed. Flare should be armed.

On fail operational you will have LAND3 or LAND2, depending on systems capabilities and flare & rollout armed.

You are right: fail-passive was set. But what does it mean exactly? The explanation in the intro document is quite short.

Fail passive means, if the aircraft is beyond some (which?) constraints, AUTOLAND will not become active?

Fail operational means, even if the aircraft is beyond some constraints, AUTOLAND become active?

 

Thanx in advance.

You can find сomparative table in FCTM 5.26 - 5.29.

In normal operations the main difference is capability of fail-op to track runway centerline after touchdown (ROLLOUT).

Well, the table reads that the crosswind is limited to 20 or 25kts respectively.

A pity, exactly, when you need it maybe most, you cannot engage AUTOLAND.

On the other side, to do the landing on your own provides most of the fun...