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AF A320 Near To A Stall On Approach?  
User currently offlineGonzalo From Chile, joined Aug 2005, 1985 posts, RR: 2
Posted (11 months 1 day 10 hours ago) and read 11027 times:

I found this ( serious ) incident very intriguing.
From the article linked below :

" On approach to Bordeaux's runway 29 at 3000 feet the aircraft encountered hail causing the first officer's windshield to crack. The aircraft continued the approach, while descending through 2800 feet ( on autopilot ) the aircraft pitched up to 25 degrees nose up and alpha floor protection and TOGA LOCK activated "
http://avherald.com/h?article=466b79cf&opt=0

Questions :

Wasn't a bad idea trying to land there and not divert ?
Why the pitch up attitude ?? Obstructed pitot ?

Thoughts ?

Rgds.
G.

[Edited 2013-08-14 06:48:30]


80 Knots...V1...Rotate...Gear Up...DC-3 / EMB-110 / Fairchild-227 / Ab318-19-20 / B732 / B763
43 replies: All unread, showing first 25:
 
User currently offlineKC135Hydraulics From United States of America, joined Nov 2012, 289 posts, RR: 0
Reply 1, posted (11 months 1 day 10 hours ago) and read 10995 times:

Maybe the pitot tubes got clogged with ice and there was a subsequent malfunction is some air data computer?

User currently offlineKarelXWB From Netherlands, joined Jul 2012, 10328 posts, RR: 30
Reply 2, posted (11 months 1 day 10 hours ago) and read 10948 times:

Quoting Gonzalo (Thread starter):
Why the pitch up attitude ??

If the speed drops, the nose must go up to increase the lift.



Only two things are infinite, the universe and human stupidity. And I'm not sure about the universe.
User currently offlineGonzalo From Chile, joined Aug 2005, 1985 posts, RR: 2
Reply 3, posted (11 months 1 day 10 hours ago) and read 10580 times:

Quoting KarelXWB (Reply 2):
If the speed drops, the nose must go up to increase the lift.

Well, yes, I know, but I don't see any reference to a "meaningful" or sudden loss of speed in the article... A change from a descent attitude to a 25 degrees nose up attitude needs two things, a really important loss of speed, and a crew not paying attention to that loss of speed in a timely manner ( in other words, before the Alpha Floor protection do something ).

Rgds.
G.



80 Knots...V1...Rotate...Gear Up...DC-3 / EMB-110 / Fairchild-227 / Ab318-19-20 / B732 / B763
User currently offlineKarelXWB From Netherlands, joined Jul 2012, 10328 posts, RR: 30
Reply 4, posted (11 months 1 day 10 hours ago) and read 10552 times:

Quoting Gonzalo (Thread starter):
http://avherald.com/h?article=466b79cf&opt=0

That's another A320, here is the correct link: http://avherald.com/h?article=466d11a4&opt=0



Only two things are infinite, the universe and human stupidity. And I'm not sure about the universe.
User currently offlineDTWPurserBoy From United States of America, joined Feb 2010, 1492 posts, RR: 7
Reply 5, posted (11 months 1 day 3 hours ago) and read 9516 times:

Quoting KarelXWB (Reply 2):
If the speed drops, the nose must go up to increase the lift.

If the speed drops, the nose goes DOWN to increase speed and increase airflow over the wings providing lift. If it goes up it will stall.



Qualified on Concorde/B707/B720/B727/B737/B747/B757/B767/B777/DC-8/DC-9/DC-10/A319/A320/A330/MD-88-90
User currently offlineKarelXWB From Netherlands, joined Jul 2012, 10328 posts, RR: 30
Reply 6, posted (11 months 1 day 2 hours ago) and read 9472 times:

Quoting DTWPurserBoy (Reply 5):
If the speed drops, the nose goes DOWN to increase speed and increase airflow over the wings providing lift. If it goes up it will stall.

Only if you can increase the speed again or when you have enough altitude. On flight 1549 (the A320 in the Hudson river), the FBW was gradually increasing the pitch to maintain lift.

[Edited 2013-08-14 14:20:55]


Only two things are infinite, the universe and human stupidity. And I'm not sure about the universe.
User currently offlineearlynff From Germany, joined Sep 2007, 232 posts, RR: 0
Reply 7, posted (11 months 1 day 2 hours ago) and read 9246 times:

Quoting Gonzalo (Thread starter):
encountered hail causing

  

Quoting Gonzalo (Thread starter):
The aircraft continued the approach, while descending through 2800 feet ( on autopilot )

so, the pilots disregarded a big red/magenta spot on their radar

Quoting KC135Hydraulics (Reply 1):
Maybe the pitot tubes got clogged with ice and there was a subsequent malfunction is some air data computer?

rather unlikely

Quoting KarelXWB (Reply 2):
If the speed drops, the nose must go up to increase the lift.

  

Quoting Gonzalo (Reply 3):
but I don't see any reference to a "meaningful" or sudden loss of speed in the article...

once you fly through a cell of heavy precipitation (obviously), you´ll have a nice headwind component turning into a tailwind condition within seconds, augmented by additional downdraft in the centre of that cell. In that case you see the speed drop like a stone...

google for "microburst" and related accidents!

[Edited 2013-08-14 15:19:32]

User currently offlinezeke From Hong Kong, joined Dec 2006, 8840 posts, RR: 75
Reply 8, posted (11 months 23 hours ago) and read 8664 times:

Quoting Gonzalo (Thread starter):
Why the pitch up attitude ?? Obstructed pitot ?

Could have been other damage such as a radome which prevented the AoA vanes from getting clean airflow.

Quoting earlynff (Reply 7):
so, the pilots disregarded a big red/magenta spot on their radar

Frozen material is not a good reflector of Wx radar.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlineairproxx From France, joined Jun 2008, 623 posts, RR: 0
Reply 9, posted (11 months 23 hours ago) and read 8240 times:

Quoting earlynff (Reply 7):
so, the pilots disregarded a big red/magenta spot on their radar

You have radars that see hail?? Wow this is something!  



If you can meet with triumph and disaster, and treat those two impostors just the same
User currently offlinebarney captain From United States of America, joined Nov 2001, 919 posts, RR: 13
Reply 10, posted (11 months 22 hours ago) and read 7467 times:

Quoting airproxx (Reply 9):
You have radars that see hail?? Wow this is something!  

While hail is a poor reflector of radar, the associated TRW was directly over the field at the time. The TRW would have certainly been visible on radar.

LFBD 021830Z AUTO 29012KT 2400 +TSRA BR BKN046/// BKN066/// BKN096/// //////CB 23/18 Q1014=

"....TOGA LOCK activated at 20:45L (18:45Z)"

Note the times.



...from the Banana Republic....
User currently offlineroseflyer From United States of America, joined Feb 2004, 9460 posts, RR: 52
Reply 11, posted (11 months 22 hours ago) and read 7334 times:

It sounds like a possible micro burst. Glad they had enough altitude to recover safely. Enough haul to crack a windshield is going to be associated with some nasty weather. The 25 degree pitch up could be associated with the rapid drop in airspeed associated with exiting a microburst.


If you have never designed an airplane part before, let the real designers do the work!
User currently offlineflymia From United States of America, joined Jun 2001, 7083 posts, RR: 9
Reply 12, posted (11 months 21 hours ago) and read 7199 times:

I am a bit confused. What's with the speed drops nose up theory? If you are closing in on stall speed isn't nose down?? Haven't we had three crashes in recent years with pilots pulling up instead of down in stalls? OZ 214, AF 447 and Colgan 3407.

Someone mind if they can clear this up for me.



"It was just four of us on the flight deck, trying to do our job" (Captain Al Haynes)
User currently offlinezeke From Hong Kong, joined Dec 2006, 8840 posts, RR: 75
Reply 13, posted (11 months 15 hours ago) and read 7071 times:

Quoting barney captain (Reply 10):

Metars are for conditions within 5nm of the reference point, I often fly into airports with metars like that and never get wet. It means nothing in isolation.

Quoting roseflyer (Reply 11):

Could be many reasons, including following the correct windshear recovery technique which can result in even higher pitch attitudes and TOGA lock.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently onlineStarlionblue From Greenland, joined Feb 2004, 16975 posts, RR: 67
Reply 14, posted (11 months 15 hours ago) and read 7061 times:

Quoting flymia (Reply 12):
What's with the speed drops nose up theory?

If the speed drops, the angle of attack must increase to maintain altitude. Of course you don't want to go too far to a stall but since the aircraft didn't stall...

Quoting flymia (Reply 12):
If you are closing in on stall speed isn't nose down??

Sure, but this assumes that the aircraft was heading for a stall. We don't know if the aircraft was approaching a stall or not. All we seems to know is that it was heading for hail and pitched up.

If you are trying to get out of windshear you want maximum lift, which is achieved at an angle of attack just short of the stalling AoA.

On windshear warning, the recovery procedure is something like this.
- TOGA power.
- Do NOT change configuration.
- Pitch up to Clmax or thereabouts for maximum lift. Max lift is right before stall. In the case of Boeing, this means pitch to stick shaker and in the case of Airbus FBW hold the stick back and let the system worry about Clmax.

The point is to climb as much as possible since if you go through a microburst you'll go from lots of headwind to downdraft to lots of tailwind in a hurry.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offline3rdGen From Bahrain, joined Jul 2011, 235 posts, RR: 0
Reply 15, posted (11 months 7 hours ago) and read 6847 times:

Its a bit early to start debating what happened. Firstly we don't know why the aircraft pitched up 25 degrees, i.e. was it weather related or due to malfunction. The other thing you must remember that Alpha floor is a function of angle of attack not of speed so if there was a large pitch up moment and a significant increase in load factor and AofA then with the speed already very low there's a good chance of A Floor Activation, aircraft may not actually have been in a sustained stall.

User currently offlineflymia From United States of America, joined Jun 2001, 7083 posts, RR: 9
Reply 16, posted (11 months 6 hours ago) and read 6802 times:

Quoting Starlionblue (Reply 14):

If the speed drops, the angle of attack must increase to maintain altitude. Of course you don't want to go too far to a stall but since the aircraft didn't stall...

Got, not getting to stall speed, yea that makes sense.

Quoting Starlionblue (Reply 14):
The point is to climb as much as possible since if you go through a microburst you'll go from lots of headwind to downdraft to lots of tailwind in a hurry.

Thanks for the info!



"It was just four of us on the flight deck, trying to do our job" (Captain Al Haynes)
User currently offlineXFSUgimpLB41X From United States of America, joined Aug 2000, 4189 posts, RR: 37
Reply 17, posted (10 months 4 weeks 1 day 21 hours ago) and read 6590 times:

Quoting zeke (Reply 13):
Metars are for conditions within 5nm of the reference point, I often fly into airports with metars like that and never get wet. It means nothing in isolation.

Considering the aircraft got hail damage, they obviously got a bit wet. Pretty safe to say the metar and what they experienced are related....



Chicks dig winglets.
User currently offlinezeke From Hong Kong, joined Dec 2006, 8840 posts, RR: 75
Reply 18, posted (10 months 4 weeks 1 day 20 hours ago) and read 6554 times:

Quoting XFSUgimpLB41X (Reply 17):

Not obvious at all, I have been in hail before and not in rain.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlineXFSUgimpLB41X From United States of America, joined Aug 2000, 4189 posts, RR: 37
Reply 19, posted (10 months 4 weeks 1 day 19 hours ago) and read 6527 times:

Quoting zeke (Reply 18):
Not obvious at all, I have been in hail before and not in rain.

You're being obtuse at best. Perhaps some more practice flying 180 to 5 miles is in order?  



Chicks dig winglets.
User currently offlinezeke From Hong Kong, joined Dec 2006, 8840 posts, RR: 75
Reply 20, posted (10 months 4 weeks 1 day 17 hours ago) and read 6477 times:

Quoting XFSUgimpLB41X (Reply 19):
You're being obtuse at best.

Not at all, the contents of a metar do not reflect what an aircraft will see on the final approach path (around 0.2 sq nm in area). The metar relates to conditions within 5 nm of the reference point (around 80 square nm), and it is possible not to go into rain or hail while the metar has a TS on it. I have done it twice in the past week, even flew through a typhoon this week without getting wet on final.

Quoting XFSUgimpLB41X (Reply 19):
Perhaps some more practice flying 180 to 5 miles is in order?

We dont fly 180/5, we leave that up to those heros in the US who "never" have accidents or incidents with the worlds best ATC, and best RT standards.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently onlineStarlionblue From Greenland, joined Feb 2004, 16975 posts, RR: 67
Reply 21, posted (10 months 4 weeks 1 day 16 hours ago) and read 6469 times:

Quoting zeke (Reply 20):
Quoting XFSUgimpLB41X (Reply 19):
Perhaps some more practice flying 180 to 5 miles is in order?

We dont fly 180/5, we leave that up to those heros in the US who "never" have accidents or incidents with the worlds best ATC, and best RT standards.

Could someone please explain the 180 to 5 miles expression?



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinezeke From Hong Kong, joined Dec 2006, 8840 posts, RR: 75
Reply 22, posted (10 months 4 weeks 1 day 16 hours ago) and read 6461 times:

Quoting Starlionblue (Reply 21):
Could someone please explain the 180 to 5 miles expression?

Maintain 180 kts indicated to 5 nm from landing, 160 to 4 is more common and a lot safer.

Kinetic energy is 0.5*m*v^2, an extra 20 kts is only an extra 12% in speed (above 160), however around an extra 27% in kinetic energy. 180 kts is above or at the maximum flap speed for most jet aircraft.

[Edited 2013-08-16 01:05:17]


We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently onlineStarlionblue From Greenland, joined Feb 2004, 16975 posts, RR: 67
Reply 23, posted (10 months 4 weeks 1 day 13 hours ago) and read 6408 times:

Quoting zeke (Reply 22):
Quoting Starlionblue (Reply 21):
Could someone please explain the 180 to 5 miles expression?

Maintain 180 kts indicated to 5 nm from landing, 160 to 4 is more common and a lot safer.

Kinetic energy is 0.5*m*v^2, an extra 20 kts is only an extra 12% in speed (above 160), however around an extra 27% in kinetic energy. 180 kts is above or at the maximum flap speed for most jet aircraft.

Thanks!



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently onlineMir From United States of America, joined Jan 2004, 21423 posts, RR: 56
Reply 24, posted (10 months 4 weeks 1 day 7 hours ago) and read 6256 times:

Quoting Starlionblue (Reply 21):
Could someone please explain the 180 to 5 miles expression?

In the US, ATC will often ask pilots to maintain 180kts until a 5 mile final. This requires a technique where you don't extend the flaps for landing until past the 5 mile point (due to flap extension speeds). And that runs up against certain foreign carriers' SOPs which require the aircraft to be fully configured for landing earlier than that.

-Mir



7 billion, one nation, imagination...it's a beautiful day
25 Post contains images XFSUgimpLB41X : Still being obtuse. It's quite obvious the two are related in this situation. Just giving you crap from all the yelling you did on the Asiana thread.
26 glen : Setting TOGA-Thrust and maintaining the configuration is correct. But then - at least on the Airbus - you follow the Flight Director Pitch Commands w
27 Starlionblue : Thanks for clarifying!
28 zeke : Not at all, how many winshear go-arounds do you do a year ? I would do at lest one, and every time it is due to mechanical turbulence of wind interac
29 XFSUgimpLB41X : Correct! Our prescribed response is TOGA power, 15 degrees nose up, and then follow the guidance. I experienced the real deal for the first time (and
30 XFSUgimpLB41X : Considering hail damage and subsequent windshear, are you really that hard headed to not notice the linking? Your airline's stabilization is 1500...
31 Starlionblue : Zeke's home airport is HKG. It is the 12th busiest in the world for pax and the busiest in the world for cargo. Not really low volume...
32 Post contains links zeke : As I said earlier, it goes to show your inexperience if you say they HAVE rather than COULD be linked. I have operated into over half of the top 30 b
33 XFSUgimpLB41X : If ~9000 hours is inexperienced, so be it. Most if my time at my current carrier was in the 767 fleet, which of course included flying the 757. I bid
34 TheRedBaron : Great that I read this thread. I flew on US airways 3 weeks ago from MEX to PHX a morning flight. The approach was a little bit bumpy with scatered cl
35 Pihero : - On an approach, when you select *FLAPS 1*, only the slats will extend --> the configuration was therefore *FLAPS 2* - A further extension then w
36 flylku : Now that is hilarious! I've also heard it called a lawn dart because of the nose down pitch during approach.
37 TheRedBaron : Thanks ! I guess we were at that height, I was really alarmed, because I am very acustomed to approaches where you can see the changes in configurati
38 zeke : Just goes to show hours in a logbook does not equate to experience. 295klb is a light aircraft for me, I am flying that plus the weight of a full A32
39 XFSUgimpLB41X : If you saw the flaps come out, then that was flaps going to Flaps 2. The gear is typically deployed and Flaps 3 is selected, which is the second move
40 XFSUgimpLB41X : It's still a widebody, very clean and proved your point wrong. Only airports like JFK that do very wide patterns was I ever able to get away without
41 zeke : 767-200 "very clean", I guess that is why they are still selling so well .... Tactical and cost index in the same sentence......OMG. Where has the ma
42 XFSUgimpLB41X : Never flew the 767-200. Only the 300 and 300ER. The 200s were parked before my time. Go on? We do variable cost index during the flight depending on
43 mandala499 : Airbus FBW 101 training.... from the very beginning pilots moving to the Bus FBW get told that the aircraft on pitch maintains longitudinal trajector
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