pineteam
FCTM gives some of this information and effect of wrong fuel or ZFW entrees. But coming back to the issue at hand this does not help because you didn't get Check GW message.

Perfectly Normal people, As has been indicated by many above: Alpha Prot is a function of loading and to that end, it is indicated regardless of green dot.

This is an issue almost every time we enter a holding pattern and commence a turn at the same time, my personal minimum is to never fly in to a holding pattern at anything less than green dot plus ten knots.

It amazes me how many people are surprised by it. The FBW technology is good but far from perfect.

Hello Vilas,

Yes you are right, but I was just happy to discover something new. :)

To come back to the issue, yesterday I flew another A 321 quite heavy (over 80t) and at some point we were cruising at FL 320 at Mach 0.72 due to traffic ahead. Anyway and I could see the green dot sitting exactly on top of VLS ( VLS was there this time) and during turn at waypoint, the VLS was moving slightly up but the green dot was moving up also and never went below VLS at anytime.
That's why I'm a bit surprised.

I'm not saying you are wrong, I just never saw green dot going below VLS or worst Alpha prot before. Maybe it happens like Wille Nelson says in hold with steeper turn but I never noticed it. I'm still junior on type.:}

Next time I'm holding I will check that carefully. :)

Happens all the time, particularly at high weights and altitude. It's a great plane but the FBW does not "prevent" the aircraft from being placed in aerodynamically undesirable situations it simply mitigates the likelihood.

As a bit of a segue on a related issue: the following incident indicated what occurs when an A319 is incredulously placed in to config full with gear down for the interception of a glideslope from 2100 feet at full flap in typhoon conditions.

The flight control protections on the Airbus are awesome but they're not able to defy the laws of physics:

Highlights: 3900 fpm in the wrong direction, stalled (74 knots) Commenced climb out after reaching 884 AGL at night in IMC and well below the glideslope.

http://www.google.com.au/url?sa=t&rc...82001339,d.dGY

Willie,
Not much is said about the performance of engine thust from what i read on the report, if thrust reaction is fast enough this event shouldn't occur, there is mention of the crews failure to advance thrust under low energy warning. The only explanation is that climb thrust was not enought to cope with the situation.

Loss of speed at 7kts/second according to the report. Even if it only takes 4 seconds to reach TOGA power that's still a loss of 28 knots starting at Vapp.


Certification is, I believe, in the order of 9 seconds from flight idle from when I did some high power ground runs a few years ago. That's potentially a loss of 63kts.

MD83FO:

Fair point, notwithstanding, the crew should have been aware that thrust would sometimes be delayed and go straight to Airbus golden rule number 4 if necessary.

The thrust is sometimes slow as you say and perhaps this played a part, as fast as it might be though, no aircraft FBW or otherwise can defy the laws of physics.

OEB 48, condition 3, alpha prot jumping up 30kts in a manoeuvre.