Print from Airliners.net discussion forum
http://www.airliners.net/aviation-forums/general_aviation/read.main/5675640/

Topic: EY A332 Lands Without Any Airspeed Indication
Username: Gonzalo
Posted 2013-01-29 13:01:16 and read 19612 times.

I 'am curious about this incident, and I have a couple of questions for our "bus drivers" and experts here in the site.
What could be the cause of this failure ? Pitot tubes clogging ala AF447 ? Computer glitch ?
And what says the SOP about this ? Always continue the approach / landing with pitch and power inputs ? Or are occasions where a missed approach / Go Around is the rule to follow ?



http://www.avherald.com/h?article=45ced9e2&opt=0

Thanks in advance !!

Rgds.
G.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Wisdom
Posted 2013-01-29 13:16:45 and read 19463 times.

My input: if you're stable, you continue and land, although you add a bit of airspeed/thrust just to play safe.
Your DME can provide you with ground speed indication and you can continue to use that with surface wind information from the tower to avoid that you lose all speed awareness.

If you go around and can't restore the airspeed indication, your next approach is more likely to be much less table and more risky.

This is a very serious incident.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: rfields5421
Posted 2013-01-29 14:24:48 and read 19065 times.

Quoting Gonzalo (Thread starter):
What could be the cause of this failure ? Pitot tubes clogging ala AF447 ? Computer glitch ?

The article is probably not completely accurate about the loss of data.

What probably occured is an airspeed disagree message - when one or more pitot tubes or static ports did not provide data. The system is designed to say "I have a disagreement between the airspeed from one of the ADR systems and the other two or all three disagree / are unreliable. You are the human - you make the decisions."

That's how all modern glass cockpit aircraft work - not an A or B issue.

As to what happened - that time of year, that location - I'm guessing localized icing. It can cause a short term ADR Disagree message - and return to reliable air speed information after a few seconds to a minute like AF447 did.

I would also expect A330 crews, and most other glass cockpit crews in other aircraft, have been a bit focused on UAS - Unrealiable Air Speed - procedures in the past couple years.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Roseflyer
Posted 2013-01-29 14:30:36 and read 19019 times.

Interesting that after the airplane had diverted to MUC, they got the airspeed problem into arrival into FRA. The crew must have been exhausted by that point.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Aesma
Posted 2013-01-29 14:43:24 and read 18934 times.

Did they forget to turn pitot heat on ?

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Md88Captain
Posted 2013-01-29 14:58:42 and read 18793 times.

Sounds serious. There are some additional sources of airspeed: ground speed readout, INS gs readout, and ATC ground speed readout.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: longhauler
Posted 2013-01-29 15:02:25 and read 18762 times.

Quoting Aesma (Reply 4):
Did they forget to turn pitot heat on ?

They are always ON. On the ground with an engine running, in the air always, or manually selected out of the AUTO position to the ON position. Barring any failures, you can not turn pitot heat off.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: longhauler
Posted 2013-01-29 15:05:38 and read 18746 times.

I wonder if it was the "indication" that was lost, or the actual airspeed information? Was the autothrust still working?

If it was just the indication lost, then with the autothrust engaged, the aircraft will fly at the Vapp selected in the FMS.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Gonzalo
Posted 2013-01-29 15:07:44 and read 18732 times.

Quoting Wisdom (Reply 1):
My input: if you're stable, you continue and land, although you add a bit of airspeed/thrust just to play safe.

I think that is the best decision too ( although not ideal in gusty winds, but certainly we don't know IF there were any wind when this happened... Somebody with the METARs for FRA at the time of this incident ?? )



Quoting rfields5421 (Reply 2):
The article is probably not completely accurate about the loss of data.

Definitely not a complete description of what the crew saw on their screens, but if they lost the three indicators ( according the article ) that seems to be a little more problematic than "just" an "AIRSPEED DISAGREE" label in the screens, which ( I understand ) can appear when only one or two indicators fail. The article says they "lost" the three indications ( left, right and Standby ). If I'm on Approach ( with a VApp of, lets say, 148 knots ) and suddenly I have two indicators with unreliable airspeed but I still have one indicator with a "logic speed" ( 148 knots or close ), I will be more happy than having the three indicators failing !!


Quoting rfields5421 (Reply 2):
As to what happened - that time of year, that location - I'm guessing localized icing. It can cause a short term ADR Disagree message - and return to reliable air speed information after a few seconds to a minute like AF447 did.

By the article I understand that they landed about two minutes after the failure and without any airspeed indication...but yes, I know, the article is only a ( very short ) description of a much more complex situation.

Quoting Roseflyer (Reply 3):
The crew must have been exhausted by that point.

Well, 162 nm is not a long time of flying to add, but certainly the diversion and all the changes involved are a load of extra work for the crew...but hey, I guess this things are part of the fun of being a long haul airline pilot !!      


Rgds.
G.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Gonzalo
Posted 2013-01-29 15:13:07 and read 18682 times.

Quoting longhauler (Reply 7):
If it was just the indication lost, then with the autothrust engaged, the aircraft will fly at the Vapp selected in the FMS

How can this "total loss of airspeed indication" affect the Autopilot / Autoland functions ? Are this enough to cause a "degradation" of the flight mode ( I remember the AF plane going to ALTERNATE LAW after loss of data ? )


Rgds.
G.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: BoeingGuy
Posted 2013-01-29 15:16:10 and read 18638 times.

Quoting longhauler (Reply 6):
Quoting Aesma (Reply 4):
Did they forget to turn pitot heat on ?

They are always ON. On the ground with an engine running, in the air always, or manually selected out of the AUTO position to the ON position. Barring any failures, you can not turn pitot heat off.

On Boeing airplanes (at least the newer models that I'm familiar with) Pitot heat is automatic as the other poster indicated. You can turn it off by pulling the circuit breakers, but of course there's no reason to do so. However, if Pitot Heat is off or fails, the Air Data system will invalidate the input and put up an EICAS message. This is designed so the Air Data Computer wouldn't just be using bad pitot inputs due to icing and calculating an erroneous airspeed.

I'm assuming all manufacturers have robust Unreliable Airspeed checklists and charts and the crews used it.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: rfields5421
Posted 2013-01-29 15:18:42 and read 18613 times.

Quoting longhauler (Reply 7):
Was the autothrust still working?

If the aircraft lost airspeed data, it would have shutoff the autopilot and autothrottle. It would have gone into an alternate law.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: s5daw
Posted 2013-01-29 15:26:52 and read 18528 times.

Quoting Gonzalo (Reply 8):
if they lost the three indicators ( according the article ) that seems to be a little more problematic than "just" an "AIRSPEED DISAGREE" label in the screens

Holy .... remember AF447 CVR?

-We’ve lost the the the speeds so...
-I have no more displays

???

[Edited 2013-01-29 15:35:25]

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: longhauler
Posted 2013-01-29 15:33:56 and read 18499 times.

Quoting rfields5421 (Reply 11):
If the aircraft lost airspeed data, it would have shutoff the autopilot and autothrottle. It would have gone into an alternate law.

That is what I am wondering. If the data is actually lost, then yes, what you suggest would occur. However, if the data is not lost, just not displayed ... I wonder what would occur.

As I really cant imagine what could cause the loss of airspeed data from three sources at exactly the same time.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: ikramerica
Posted 2013-01-29 17:18:33 and read 18146 times.

Ground the A330 until the system is "proven safe." Isn't that how things work now?

Quoting s5daw (Reply 12):
Holy .... remember AF447 CVR?

-We’ve lost the the the speeds so...
-I have no more displays

Seriously though, this is similar to what happened on AF447, but there the pilots panicked and didn't communicate properly. Sounds as if this crew did everything right or close to right.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Gonzalo
Posted 2013-01-29 17:36:17 and read 18059 times.

Quoting ikramerica (Reply 14):
Seriously though, this is similar to what happened on AF447, but there the pilots panicked and didn't communicate properly. Sounds as if this crew did everything right or close to right.

I don't want to play Devil's Advocate, but the AF crew was in a situation with basically zero external reference... Unless this EY crew was landing with a very adverse visibility condition, I think there is a big chance of a good visual reference for them, and probably that helps a little....

Rgds.,
G.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: packsonflight
Posted 2013-01-29 17:44:55 and read 18008 times.

It is not a problem to fly airliner like that with out any airspeed indication. The problem pilots face when one or more airspeed indicators, fail is what instrument to trust and what not to trust, and on top of that things can go very wrong very quickly if this is not done properly.

The proper way to continue in a situation like that is to relay only on pitch and power, That is, If a given power setting and pitch angle is maintained, the result is certain speed.
Aircrafts have a kind of emergency handbook with a reference table where the pilot can obtain this info for all faces of flight. In fact any good pilot memorises the basics of this table not to end up in a situation like the unfortunate AF447

This is not very accurate method, but enough to keep the aircraft safe.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: TWA772LR
Posted 2013-01-29 18:31:47 and read 17688 times.

If it was just the display that went out, then couldn't have they landed on autothrottles and then switched them off when the wheels touch to reverse thrust on landing?

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: 3rdGen
Posted 2013-01-29 19:14:14 and read 17112 times.

If its a newer bus then they would have had the Back-up Speed Scale (BUSS) which gives a band with no numbers just colours, representing safe and unsafe zones of the flight envelope, its based off the angle of attack data.

For them to have continued the approach is seriously dangerous and not as easy as saying that I would just play with thrust look at the GS on the ND and have a go. This isn't flight sim.

If the BUSS was available then it would be a lot safer for them to go around, trouble shoot and then have another go on the basis of an authorized procedure. Pilots cannot just be improvising on the job, which is what I hear a lot of people recommend.

Quote:

If it was just the display that went out, then couldn't have they landed on autothrottles and then switched them off when the wheels touch to reverse thrust on landing?

No it was only the speed data that disappeared. The displays were fine, the chance of 4 of the DU's and the standby instruments all disappearing at the same time is very remote, the units are powered off of different sources with the ability to switch between PFD and ND on the pilots' DUs.

This is certainly a very very strange occurrence. I cannot imagine what would cause all airspeed data to be lost, especially since there are various sources from where the air data is measured and they are all supposed to segregated right from the source to the output. The culprit would have to be something that all three share in common, but I can't figure out what that would be?

[Edited 2013-01-29 19:31:06]

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: gihanjaya380
Posted 2013-01-29 20:43:46 and read 15974 times.

This is a very serious problem. And these pilots landed the aircraft using proper procedures, whatever it maybe. Great pilots for sure.

The AF447 was in a different condition and night without any visual references.

Anyone know the MATA data at the time of the incident? According to the article the aircraft was diverted to Munich due to weather. I do not believe there was extreme liquid ice on the approach. It had to be something else.

Glad to see this aircraft landed safely.

Gihan

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: dynamo12
Posted 2013-01-29 22:52:14 and read 14507 times.

Quoting gihanjaya380 (Reply 19):
The AF447 was in a different condition and night without any visual references.

To be very clear the AF447 was at 30,000+ feet in a stable cruise configuration.

This plane was much lower to the ground and needed to go through some changes in speed / thrust / configuration to finish the landing safely. I've got to imagine groundspeed etc was known as were prevailing winds at airport to help give a sense of things. If they landed by "hand " with no airspeed indications still very impressive and a bravo.

Looking forward to hearing more details though.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: LH526
Posted 2013-01-30 00:28:58 and read 13280 times.

Not trying to sound amateurish here ... but isn't the GPS able to provide a more or less accurate GS indication? Take into account the wind and you might get a good TAS readout.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: flyingturtle
Posted 2013-01-30 02:31:57 and read 11813 times.

Quoting LH526 (Reply 21):
Not trying to sound amateurish here ... but isn't the GPS able to provide a more or less accurate GS indication? Take into account the wind and you might get a good TAS readout.

The GPS gives you the GS, yes, and an it's accurate.

When you have much time and fuel to kill and you're in cruise anyway, you can figure out wind speed by flying a straight GPS course and noting how much yaw you have to apply... but that's an academic question.  


David

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: nicoeddf
Posted 2013-01-30 03:05:45 and read 11398 times.

Ok, lets take the drama out of this, please.

A fully configured A/C on the glide slope 2 miles out loses airspeed indication - just fly it to the runway. A few knots more or less are well within the safety envelope between stall speed and Vapp...

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Gonzalo
Posted 2013-01-30 03:13:04 and read 11281 times.

Quoting nicoeddf (Reply 23):
Ok, lets take the drama out of this, please.

A fully configured A/C on the glide slope 2 miles out loses airspeed indication - just fly it to the runway. A few knots more or less are well within the safety envelope between stall speed and Vapp...

I wouldn't say that without knowing the weather conditions when this incident happened... a sudden gust of tail wind can kill a good portion of your airspeed, and that is something very dangerous when you are in a low energy state on the final approach ( at least is dangerous when you don't see that airspeed loss in your screen because the indicator failed ).

Rgds.
G.

[Edited 2013-01-30 03:15:30]

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: faro
Posted 2013-01-30 03:22:11 and read 11527 times.

Quoting Gonzalo (Reply 24):
a sudden gust of tail wind
Quoting Gonzalo (Reply 24):
is dangerous when you don't see that airspeed loss in your screen because the indicator failed

If it's sudden, pretty fair chance you'll feel it in the seat of your pants...IMHO the danger would arise if the airspeed changes more sublty.


Faro

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: s5daw
Posted 2013-01-30 03:23:02 and read 11520 times.

Quoting nicoeddf (Reply 23):
Ok, lets take the drama out of this, please.

A fully configured A/C on the glide slope 2 miles out loses airspeed indication - just fly it to the runway. A few knots more or less are well within the safety envelope between stall speed and Vapp...

Well, we should not discard it as nothing serious either.

If all the 3 indications went out (which by itself is mind-blowing AND might indicate a bigger problem, specifically because of AF447) it also means at least alternate law, correct?

So you are flying low and slow AND suddenly you loose all protections, hence you need to boot your brain into a completely different mindset in a split second. There is next to 0 margin for error - you are low and slow.

And again, most airplane crashes happen as a chain of events. So all you need here is a crew that lacks "real" flying experience without automation (which FAA warns is becoming a problem). Remember the poor PF of AF447, who was saying "but I'm pulling up, we have engines, why ware we going down!?" till the very end?

You could also have decreased visibility. What if this happened 2 weeks ago, when it was snowing in Germany? Could they fly manually with no visual reference, only with NAV aids? Again, AF447 could not...

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: faro
Posted 2013-01-30 03:33:53 and read 11540 times.

Quoting 3rdGen (Reply 18):
all supposed to segregated right from the source to the output

I may be wrong but I recall something to the effect that there was only 1 or 2 graphics display generators (feeding off the individual air data computers' input).

You would need 3 to ensure that all was perfectly segregated (left PFD, right PFD and standby airspeed indicator).


Faro

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Gonzalo
Posted 2013-01-30 03:42:58 and read 11409 times.

Quoting faro (Reply 25):
If it's sudden, pretty fair chance you'll feel it in the seat of your pants...IMHO the danger would arise if the airspeed changes more sublty.

Point taken. My problem with the "this is not a big deal" position of nicoeddf is, regardless the cause ( a subtly change of wind direction, a windshear ala EA 401 ), you certainly can have speed variations that can affect the safety of the flight since you are in a vulnerable moment ( low and slow) , and loosing all your airspeed data in that moment is certainly a big deal IMHO.

Rgds.

G.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: nicoeddf
Posted 2013-01-30 03:49:09 and read 11380 times.

Quoting Gonzalo (Reply 24):
I wouldn't say that without knowing the weather conditions when this incident happened... a sudden gust of tail wind can kill a good portion of your airspeed, and that is something very dangerous when you are in a low energy state on the final approach ( at least is dangerous when you don't see that airspeed loss in your screen because the indicator failed ).

I know the weather conditions - the A/C landed right in front of my window.

And...

Quoting faro (Reply 25):

If it's sudden, pretty fair chance you'll feel it in the seat of your pants...IMHO the danger would arise if the airspeed changes more sublty.

...while I concur with this, 2 miles out, fully configured, as I explained above, there is not too much time for the subtle change in speed to make any difference.

Quoting s5daw (Reply 26):
Well, we should not discard it as nothing serious either.

I don't do that.
This is a case were a thorough investigation should take place to remove the chances of a repeat of this happening.
However - I don't like the drama here being made out of it. The aircraft was not close to crashing and the crew is there to do exactly what they have done. I am pretty sure they were well aware, that being (I know, I repeat myself) configured on the glide slope close to the threshold, just flying the aircraft to the runway is the best option...

[Edited 2013-01-30 04:45:32]

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: CamiloA380
Posted 2013-01-30 04:05:02 and read 11133 times.

Quoting Gonzalo (Thread starter):
What could be the cause of this failure ?

Radome damage... air probe failure...obstruction.

Quoting Gonzalo (Thread starter):
And what says the SOP about this ?

Check FCOM III see 3.02.34 p18.

Quoting Gonzalo (Reply 8):
Somebody with the METARs for FRA at the time of this incident ??

They are in your link. 
Quoting Gonzalo (Reply 9):
How can this "total loss of airspeed indication" affect the Autopilot / Autoland functions ?

I don't get whether you mean the loss of the indicator or the airspeed info, the former one is not a big deal in this case, the later will cause the AP to disconnect and regarding Autoland, forget it.

Quoting Gonzalo (Reply 9):
I remember the AF plane going to ALTERNATE LAW after loss of data ?

ALT LAW/ ALT LAW 2

Quoting gihanjaya380 (Reply 19):

Well, airline pilots are trained for this.

Quoting Gonzalo (Reply 24):
I wouldn't say that without knowing the weather conditions when this incident happened... a sudden gust of tail wind can kill a good portion of your airspeed, and that is something very dangerous when you are in a low energy state on the final approach ( at least is dangerous when you don't see that airspeed loss in your screen because the indicator failed ).

Windshear warning anyone? You dont actually check the speedtape for a windshear. And its not really that dangerous, you give TOGA and follow SRS orders.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: tdscanuck
Posted 2013-01-30 06:10:28 and read 9300 times.

Quoting 3rdGen (Reply 18):
For them to have continued the approach is seriously dangerous

Less dangerous than going around...you're set up, stable, and headed for the runway. If you go-around you're going to have successfully execute the go-around then to try to set up the stable approach again, only without airspeed. Continuing the approach, given the circumstances, certainly seems like the prudent option.

Tom.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: aaexecplat
Posted 2013-01-30 06:23:59 and read 9128 times.

If I read this article correctly, the crew didn't lose all airspeed indicators...they just thought that they were invalid. The reading of the flight data suggests the speeds all made sense, so they are looking into a working theory of a mismatch between automation mode and pilot expectations....

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: PlanesNTrains
Posted 2013-01-30 09:46:13 and read 5848 times.

Quoting rfields5421 (Reply 11):
If the aircraft lost airspeed data, it would have shutoff the autopilot and autothrottle. It would have gone into an alternate law.

This is somewhat similar to what happened with the TK 738 in Amsterdam, right? Only, with a different outcome of course. In any event, they are trained for such events, correct?

-Dave

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: bueb0g
Posted 2013-01-30 10:20:38 and read 5286 times.

Quoting PlanesNTrains (Reply 33):
This is somewhat similar to what happened with the TK 738 in Amsterdam, right?

No... On the TK738, one of the radio altimeters had a fault and showed that the a/c was on the ground, so the autothrottle retarded back to idle, and the crew didn't react fast enough. The autopilot and autothrottle stayed on (until the Captain took it off, but by this time it was too late).

Quoting PlanesNTrains (Reply 33):
In any event, they are trained for such events, correct?

Correct.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: longhauler
Posted 2013-01-30 10:21:45 and read 5279 times.

I think what a lot of people forget is that these are all just airplanes. Advanced yes, but still just basically airplanes.

Two miles on final, configuration is set, gear is down, thrust is set, attitude is set. Take away your airspeed and really nothing changes. Minor deviations maybe, but basically nothing will change until the flare and thrust reduction. Yes, there could have been a windshear, but the aircraft could have been hit by a meteor as well!

In fact, I would bet if you disconnected the autopilot and auto-thrust, then touched nothing ... the airplane would have ended up within inches of where it was intended anyway.

And, they still have not announced whether the A/P and A/T disconnected anyway, as apparently they didn't lose the airspeed indication ... for reasons only they know, they just didn't think the indications were valid! I like this statement ... "A mismatch between active automation modes and pilot expectation is currently considered as a working theory." It is almost like saying, the automation was working properly, but the pilots were 'expecting" something else!

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: tdscanuck
Posted 2013-01-30 10:21:45 and read 5293 times.

Quoting PlanesNTrains (Reply 33):
This is somewhat similar to what happened with the TK 738 in Amsterdam, right?

Not really. TK1951 had a faulty radio altimeter, which caused the autothrottles to pull back to idle (the airplane mistakenly thought it should be flaring). The crew did not notice until it was too late but, unlike this case, there was nothing wrong with any airspeed (or thrust) indications.

Quoting PlanesNTrains (Reply 33):
Only, with a different outcome of course. In any event, they are trained for such events, correct?

Yes, they're trained for this.

Tom.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: flyingturtle
Posted 2013-01-30 10:32:11 and read 5115 times.

Quoting PlanesNTrains (Reply 33):
This is somewhat similar to what happened with the TK 738 in Amsterdam, right? Only, with a different outcome of course. In any event, they are trained for such events, correct?

TK378 happened because the radio altimeter read back "landed", and the autothrust permantently retarded the thrust levers. A/T and A/P were working there, as did air speed data. Ultimately it happened because the pilots didn't see the airspeed degrade until they were stalled.


David

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: 3rdGen
Posted 2013-01-30 10:48:55 and read 4861 times.

Quoting faro (Reply 25):

Quoting Gonzalo (Reply 24):
a sudden gust of tail wind
Quoting Gonzalo (Reply 24):
is dangerous when you don't see that airspeed loss in your screen because the indicator failed

If it's sudden, pretty fair chance you'll feel it in the seat of your pants...IMHO the danger would arise if the airspeed changes more sublty.

This is an Airbus A330, you won't feel things like you would in a Cessna. I'm not saying its not possible but then there's more chance that you won't feel anything. The crew of AF447 were falling out of the sky and they didn't feel it.

Quoting faro (Reply 27):

Quoting 3rdGen (Reply 18):
all supposed to segregated right from the source to the output

I may be wrong but I recall something to the effect that there was only 1 or 2 graphics display generators (feeding off the individual air data computers' input).

You would need 3 to ensure that all was perfectly segregated (left PFD, right PFD and standby airspeed indicator).

I was talking about the pitot tubes and their line to the displays, should be segregated. Don't know about the A330 but the A320 has two Display Management Computers, separating the Cpts and FOs sides. Also they are run on different electrical sources.

Quoting tdscanuck (Reply 31):
ess dangerous than going around...you're set up, stable, and headed for the runway. If you go-around you're going to have successfully execute the go-around then to try to set up the stable approach again, only without airspeed. Continuing the approach, given the circumstances, certainly seems like the prudent option.

Take a look at the METAR:

EDDF 211750Z 04004KT 3500 -SG BR FEW002 BKN005 M01/M01 Q1000 R25L/2///95 R25C/2///95 R25R/2///95 R18/2///95 TEMPO BKN003
EDDF 211720Z 04004KT 4000 -SG BR FEW002 BKN005 M01/M01 Q0999 R25L/2///95 R25C/2///95 R25R/2///95 R18/2///95 TEMPO BKN003

That is not great weather, given the circumstances the Go-Around is a much better option. All Airbus pilots are trained by memory on the pitch and power to fly in the event of Unreliable Airspeed Indications, and its much safer to follow a known procedure than to improvise so close to the ground. They may not have been visual with the runway with that low cloud.

We have the privilege of sitting at our desks and on our couches in order to come to conclusions and decide what to do. If this happened at the last minute, which I think it might have done, (the snow pellets and freezing conditions might have had something to do with it) then first of all detecting the problem, then deciding what to do and then executing the plan is not a realistic option given the time frame. The aircraft was perfectly flyable, there's no issue in doing a go-around to have more time to deduce the situation. I give the crew the thumbs-up. The real danger is that you mess things up and stall the aircraft.

We are all just speculating, we don't know what the exact condition were nor what the actual problem was, nor the state of the airplane regarding whether it was stable or unstable. If there's was a difference in airspeed between CPT and FO readings the autothrust and autopilot might have been doing the wrong thing based on incorrect readings. From basic PPL theory, a blocked pitot tube will cause the airspeed indicator to act like an altimeter. So in their descent one of the airspeed readings may have been decreasing, being fully configured and close to VLS there's no time to be looking around, asking questions and troubleshooting. The right thing to do is to hit TOGA and go around.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Pihero
Posted 2013-01-30 13:59:05 and read 2861 times.

It is obvious that few peopple have read the AvHerald article , in particular this :
" The BFU was notified about the loss of all three airspeed indications, downloaded the flight data recorder and found that the indicated airspeeds properly correlated with the actual ground speed. A mismatch between active automation modes and pilot expectation is currently considered as a working theory."

We don't have any details on the technical side but it looks like a case of a crew distrusting their instruments while they were correctly displaying good values.

I don't have a clue on what really the problem was, but imagining less stable conditions - e.g a windshear, as strong winds aloft and a rather calm wind on ground - the IAS would be flown on the mini ground speed feature, thus showing a much higher approach speed than expected.
...but it's just a theory, which makes their decision to land the more bizarre : in these conditions I would have gone around and tried some fault finding... and probably gone through the unreliable airspeed procedure.


... that, again, pending further info on the incident. As things stand, it is far too soon to go onto wild / uninformed speculations.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: longhauler
Posted 2013-01-30 14:02:56 and read 2837 times.

Quoting 3rdGen (Reply 38):
That is not great weather, given the circumstances the Go-Around is a much better option.

I would tend to disagree. I can't even imagine a go-around without airspeed.

The loss of airspeed drill says 15 degrees nose up and set TOGA thrust. Now, while climbing and accelerating like crazy you want to go from Config FULL to Flaps UP, again with no idea when as you have no airspeed, all the while hand flying it in (hopefully) alternate law, but more likely direct law, as the gear was down.

Hand wrestle the thing around the circuit, (direct law is not a comfortable ride), wondering about airspeed thinking about power, to reconfigure, again with no airspeed to get back to where you were 15 minutes before .... hopefully in a stable condition, in landing configuration with no idea of airspeed.

Nope, if I was 30 seconds from touchdown and I lost my airspeed, ground just coming into view .... I'd land!

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: rfields5421
Posted 2013-01-30 15:10:16 and read 2678 times.

Quoting PlanesNTrains (Reply 33):
they are trained for such events, correct?

Yes. Pitch and power are memory items for pilots in those aircraft. And yes, after AF447 - training is much more focused on the possibility of a UAS event. It is something pilots pay more attention to now.

Quoting 3rdGen (Reply 38):
This is an Airbus A330, you won't feel things like you would in a Cessna. I'm not saying its not possible but then there's more chance that you won't feel anything. The crew of AF447 were falling out of the sky and they didn't feel it.

The crew of AF447 was disfunctional.

The PF failed to fly the correct pitch and power. It appears likely that he was trying to fly the pitch power for a takeoff or landing loss of airspeed data - not a cruise level loss of airspeed data.

Then the PF was focused on keeping the wings level - which he actually did an amazingly good job of doing, but never really realized the pitch was so high.

Few people though a heavy transport aircraft could 'mush' down in a stall from 35,000 ft to the ground without inverting, spinning or some other violent maneuver.

The PF also apparently decided that ALL the instrumentation and data available to him was wrong. He never indicated ANY reading on the panels was correct. Only that everything was unreliable. Which was incorrect - he had valid airspeed data for most of the descent..

The PNF never ran a checklist, never indicated on the CVR he was working the problem. His attitude appears to be something like "I'll let this rookie figure it out - and not help him if it kills me" - it did.

Quoting 3rdGen (Reply 38):
All Airbus pilots are trained by memory on the pitch and power to fly in the event of Unreliable Airspeed Indications,

Yes, as are Boeing pilots.

But the PNF is supposed to use the checklist to verify the PF is using the correct pitch/ power for the stage of flight. Which this crew apparently did very well.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Wisdom
Posted 2013-01-30 15:22:27 and read 2629 times.

To tell you the truth, I've been in such a situation on a single-engine aircraft.

Regardless of being trained for pitch and thrust settings it's scary as hell when your airspeed indicator is stuck at 40kts and you're running out of runway during the take-off. You look at the throttle, your RPM and even have a look at the parking brake just in case and a push at the bottom of the pedals... but feeling that the airplane wanted to lift, I decided that the indicator failed and given uncertainty of being able to stop, I rotated and took a shallower climb than usual.

Even though I knew what RPM I needed on the engine for each flap setting on approach and descent, I played safe, took a long final, less flaps than usual, and a touch more on the RPM.
I landed longer and my pattern looked like something Picasso would draw but who cares.

I've had my deal of failures in my flying history but this was one of the scariest.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: bueb0g
Posted 2013-01-30 16:36:02 and read 2511 times.

Quoting Pihero (Reply 39):
It is obvious that few peopple have read the AvHerald article , in particular this :
" The BFU was notified about the loss of all three airspeed indications, downloaded the flight data recorder and found that the indicated airspeeds properly correlated with the actual ground speed. A mismatch between active automation modes and pilot expectation is currently considered as a working theory."

While this is what it says now, that is a recent addition. Originally it stated only that "all three airspeed indications were lost" with no elaboration, hence the direction of the upper part of this thread.

Topic: RE: EY A332 Lands Without Any Airspeed Indication
Username: Pihero
Posted 2013-01-30 16:44:25 and read 2485 times.

Quoting bueb0g (Reply 43):

While this is what it says now, that is a recent addition.

Didn't know that. Thanks


The messages in this discussion express the views of the author of the message, not necessarily the views of Airliners.net or any entity associated with Airliners.net.

Copyright © Lundgren Aerospace. All rights reserved.
http://www.airliners.net/