Now my premiums are going up again!

[GeeBee]

36 minutes ago, exM20K said:

@GeeBee what is the auto thrust trying to do during a bounce recovery?  Gusty landing?

The training is to manually advance the thrust (the servos are clutched and in any event the A/T has likely disconnected on initial ground contact) put the nose at 7.5 and then re-land. The problem is not what they are doing during the bounce, the problem is what they are doing before the bounce. The bounce is caused by high sink rate. As the auto-thrust fails to maintain the speed and a sink develops, the pilot instinctively pulls back to arrest the sink rate which only makes things worse because the airplane deteriorates further behind the curve and sinks faster. Not only that, sometimes with the rapidly deteriorating speed, the A/T comes in fast, causing a nose up pitching moment which can often cause a tail strike. 

The auto-thrust is a subset of the auto-pilot. With the A/P engaged, auto-thrust works pretty good because they are communicating together. i.e., A/P signals nose up the A/T advances in a timely manner.  With the auto-thrust on while hand flying the airplane, the A/T is more reactive than pro-active because it does not know "what's next" so it just looks at the commanded speed and tries to hold it. In gusty conditions where pitch and speed is changing rapidly, that gets ugly. I'm an "all-in" or "all-out" automation guy. If I am hand flying the airplane, I'm in command of the thrust too.

[exM20K]

4 minutes ago, GeeBee said:

The bounce is caused by high sink rate. As the auto-thrust fails to maintain the speed and a sink develops, the pilot instinctively pulls back to arrest the sink rate which only makes things worse because the airplane deteriorates further behind the curve and sinks faster.

Thanks. So if I understand correctly, the auto-thrust is trying to maintain commanded airspeed, the pilot flying thinks that he or she can pull up to arrest the sink rate while the auto-thrust maintains airspeed, which it is not presently doing? Yikes.

[GeeBee]

3 hours ago, exM20K said:

Thanks. So if I understand correctly, the auto-thrust is trying to maintain commanded airspeed, the pilot flying thinks that he or she can pull up to arrest the sink rate while the auto-thrust maintains airspeed, which it is not presently doing? Yikes.

It will start coming back on Airbus based upon radar altitude, but if the airplane is already low on energy, things don't go well. We had a lot of tail strikes with the 737NG until we made pilots turn off the A/T below 1000' on a visual landing. Tail strikes stopped.

 

[Fly Boomer]

On 3/2/2023 at 5:10 PM, M20Doc said:

It won’t be too bad considering it will be spread over the 99% who pay taxes.

Which country?

[Guest]

2 minutes ago, Fly Boomer said:

Which country?

I guess my tongue in cheek were missed.  We know that the 1% don’t ever pay taxes, so it’s left to the other 99%.

[Fly Boomer]

1 hour ago, M20Doc said:

I guess my tongue in cheek were missed.  We know that the 1% don’t ever pay taxes, so it’s left to the other 99%.

Yeah, that was my attempt to acknowledge your point and make a funny.  Sorry.

[PT20J]

On 3/4/2023 at 2:29 PM, M20Doc said:

I guess my tongue in cheek were missed.  We know that the 1% don’t ever pay taxes, so it’s left to the other 99%.

But, the 1% makes 99% of the income 

[T. Peterson]

On 3/4/2023 at 7:30 AM, GeeBee said:

Got to say, another case of an auto-thrust system screwing up a landing. Either the pilot is not aware of the mode or it fails to perform as expected and leaves you in the flare holding the bag in a low energy state.  For some reason Airbus pilots are really wedded to auto-thrust to touch down. I cannot tell you how much my landings in the Airbus improved when I started landing in manual thrust. The MD-11 had a big problem with this and I can think of 3 crashes, two of them fatal due to A/T dependence. They made a big deal after the Newark crash of training for "bounce recovery" but they never trained to turn off the auto-thrust in gusty conditions! The only time I used A/T was during low vis auto- landing (because you have to have them engaged) and usually it is not gusty during low vis and auto-thrust works reasonably well. Otherwise turn it off and then you know it is off unless you have IMC in front of your face.

 

Only time I land with auto thrust is in the Sim or doing an auto-land approach.

I think at least some hard landings are because the A/T can’t keep up in high gusty winds.