Greetings my fellow captains, real and imagined!

 

I'm brushing up my autoland skills in the NGX (assuming it takes skill to perform one, but that's another matter), and in doing so have come across a seemingly strange occurrence. When performing a single A/P autoland following a bog standard ILS approach, the NGX seems to execute a perfect landing flare automatically. However, FCOMv2 4.20.19 says:

 

Approach (APP) Mode Single A/P

 

A single A/P ILS approach can be executed by engaging only one A/P in CMD

after pushing the APP mode select switch. Single A/P approach operation is the

same as dual, with the following exceptions:

 

• full automatic flare and touchdown capability is not available. FLARE is

not annunciated and stabilizer trim bias is not applied

 

Am I misreading that bullet point and does the 737 still perform a kind-of flare and autoland, instead of a full automatic one, when only a single A/P is engaged? Or, is what I'm seeing purely the result of the ground effect, and is a flare not executed at all? Or... are we dealing with a PMDG bug here? Regardless, shouldn't the A/P disengage just prior to touchdown when FLARE mode isn't armed (as would be the case during a single A/P approach)?

 

For the record, I'm using the Collins MCP, with fail-operational autoland enabled in the aircraft options.

 

Any insight into these baffling matters would be most appreciated!

 

Oh, and pictures, of course (or it didn't happen):

 

Fifty!

 

 

Thirty!

 

 

Twenty! (Retard! Retard!)

 

 

Ten!

 

 

Um... Four! (note V/S is down to -200 fpm)

 

 

And a silky smooth touchdown

 

thats peculiar, did you try it with the fail passive system?

Though it's prohibited and dangerous, but at least any certified simulator of 737 can flare on one autopilot. And doesn't matter fail-op or fail-passive.

 

However, FCOMv2 4.20.19 says:

 

That's for pilots. There must be some secret docs which are explaining autopilot system in-depths.

 

Regardless, shouldn't the A/P disengage just prior to touchdown when FLARE mode isn't armed (as would be the case during a single A/P approach)?

 

On NGX it does only while on IAN at 100'.

Yep, as Rostyslav confirms, this is correct behaviour, a fail-safe, one might say. You do lose automatic go-around capability though, and if the single autopilot fails at the worst moment, you should probably look for a chiropractor.

Aha! This NGX works in mysterious ways indeed! Thanks for the comments, guys. Much obliged!

I'm going to fly the NGX straight down an ILS later with a single A/P see what happens