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Topic: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: cubastar
Posted 2013-03-24 11:33:49 and read 23064 times.

An Etihad A340-600 enroute Abu Dhabi to Melbourne at FL350 on 03 Feb 2013 in moderate to heavy turbulence experienced oscillations in the Captains and Standby indications. Autopilot and auto thrust disconnected automatically and aircraft flight control law shifted from normal to alternate.

Various resets were accomplished but erroneous indications continued. The flight declared a Pan Pan message and they diverted into Singapore Changi after dumping 12T of fuel.

It mentions that the crew turned on the pitot heaters (rather than checking them on) after first getting the erroneous indications. One question I have; does the airbus checklist list call for turning on the pitot heat prior to takeoff?

This incident bears remarkable resemblance to the AF447 accident in that much of the same issues with it and this flight appeared to be similar.

I used the "blue check button" to check for previous posting but did not find any earlier postings.

Click on this link:

http://www.gcaa.gov.ae/en/ePublicati...%20A6-EHF%20Report%2005%202013.pdf

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: cedarjet
Posted 2013-03-24 13:24:51 and read 22567 times.

It differs from Air France 447 in one very important aspect - the aeroplane remained totally in control and flyable throughout the incident and landed safely. Loss of airspeed is a serious situation but should never ever prove to be deadly. Well done Etihad crew for being qualified to fly the aeroplane and handling the situation safely.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: zeke
Posted 2013-03-24 14:39:37 and read 22120 times.

Quoting cubastar (Thread starter):


It mentions that the crew turned on the pitot heaters (rather than checking them on) after first getting the erroneous indications. One question I have; does the airbus checklist list call for turning on the pitot heat prior to takeoff?

No, they turn on automatically.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: AA737-823
Posted 2013-03-24 15:14:40 and read 21915 times.

Quoting cedarjet (Reply 1):
It differs from Air France 447 in one very important aspect - the aeroplane remained totally in control and flyable throughout the incident and landed safely. Loss of airspeed is a serious situation but should never ever prove to be deadly. Well done Etihad crew for being qualified to fly the aeroplane and handling the situation safely.

We also, however, know that AF447 was completely controllable as well; pilot disorientation resulted in inappropriate power lever position, resulting in a flat stall and fatalities of all souls onboard. Had they had daylight, I suspect they could have more readily seen what was going on. But- all that to say that this situation COULD be similar.

Quoting zeke (Reply 2):
No, they turn on automatically.

Interesting; compare switchology for me, Zeke. On the 737NG, pitot heat switches are one of two configurations: the first, standard config is ON or OFF; the second, optional config is ON or AUTO.
Is the Airbus similar? Perhaps the switch was in AUTO, and upon encountering trouble, they switched it to ON?

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: AA87
Posted 2013-03-24 17:36:02 and read 20982 times.

Did anyone notice in the report the 25-year old FO on duty had a total of 520 hours ? as in, TOTAL, all flying, everything (and almost 10% of that in the preceding 28 days). I think I may have more hours in the sack than this kid had in the air. And yet, thanks to him and the other pilots, miraculous and heroic outcome.

I have a few questions:

1) I have a grand total of 120 hours mostly in a Cessna 172. So Etihad will put me in the right seat of an Airbus if I run out and get an instrument ticket and build a few hundred hours of multi time ???

2) Does the successful outcome mean that: a) this crew was luckier or simply handled the situation better than AF447, b) the AF447 situation was somehow more extreme (I believe it was - the AF crew appears to have lost all speed data on both sides and standby, for at least some period of time) or c) total hours mean less than judgment/personality/crew team dynamics ?

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: 9VSIO
Posted 2013-03-24 17:46:30 and read 20844 times.

Quoting AA87 (Reply 4):
1) I have a grand total of 120 hours mostly in a Cessna 172. So Etihad will put me in the right seat of an Airbus if I run out and get an instrument ticket and build a few hundred hours of multi time ???

I'm willing to bet that he's one of their cadets, meaning he's been with the airline since 0 hours. Outsiders would need at least thousand hours.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: SCQ83
Posted 2013-03-24 17:47:47 and read 20844 times.

Quoting AA87 (Reply 4):
Did anyone notice in the report the 25-year old FO on duty had a total of 520 hours ? as in, TOTAL, all flying, everything (and almost 10% of that in the preceding 28 days). I think I may have more hours in the sack than this kid had in the air. And yet, thanks to him and the other pilots, miraculous and heroic outcome.

He is more than probably local; he doesn't have FLN. Gulf airlines make an effort to train locals and locals are above anybody else in the work chain; the UAE is not a meritocracy. Probably that is why he is FO as well, while the (more likely) 32 y.o. Jordanian with x10 times his flight hours is 1st officer Relief.

Quoting AA87 (Reply 4):
1) I have a grand total of 120 hours mostly in a Cessna 172. So Etihad will put me in the right seat of an Airbus if I run out and get an instrument ticket and build a few hundred hours of multi time ???

Yes, if you have an Emirati passport.

[Edited 2013-03-24 17:51:54]

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: AA87
Posted 2013-03-24 17:58:48 and read 20680 times.

Interesting ... so in light of all that, isn't it quite impressive this "local cadet" (who arguably shouldn't have been there at all) was an effective part of the team and didn't do anything rash/wrong/unprofessional ? I'm honestly not making a comparison to the AF447 FO but this happy ending is all the more impressive given the novice in the right seat. I don't know what the lesson is, but the kid's a hero in my book .. and of course the other 3 seasoned pilots as well. Those pax owe their lives to them, and many probably still don't truly know it.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: zeke
Posted 2013-03-24 18:49:21 and read 20019 times.

Quoting AA737-823 (Reply 3):
Interesting; compare switchology for me, Zeke. On the 737NG, pitot heat switches are one of two configurations: the first, standard config is ON or OFF; the second, optional config is ON or AUTO.
Is the Airbus similar? Perhaps the switch was in AUTO, and upon encountering trouble, they switched it to ON?

Its auto all the time, it turns on
or after engine 2&3 are started,
or in flight,
or if the probe/heat button is selected to "ON".

I have put the "or" there deliberately, as it is an or gate in the logic. On the ground it is in ground mode, in flight it goes to normal.

The unreliable airspeed checklist does call for this to be selected on.

Quoting AA87 (Reply 4):

1) I have a grand total of 120 hours mostly in a Cessna 172. So Etihad will put me in the right seat of an Airbus if I run out and get an instrument ticket and build a few hundred hours of multi time ???

If you meet the selection criteria, you would need no additional hours. Cathay had similar.

Quoting AA87 (Reply 4):
2) Does the successful outcome mean that: a) this crew was luckier or simply handled the situation better than AF447, b) the AF447 situation was somehow more extreme (I believe it was - the AF crew appears to have lost all speed data on both sides and standby, for at least some period of time) or c) total hours mean less than judgment/personality/crew team dynamics ?

My personal view is that the crew of AF447 acted inappropriately, in my view they caused the situation they got themselves in. Putting aside the unreliable airspeed, with valid airspeed making the control inputs they made it would have been extremely difficult if not impossible to recover the aircraft once they got the aircraft into such a high angle of attack. In my view, the crew applied the "memory items" from the unreliable airspeed checklist which are designed for when the aircraft is close to terrain, not whist in the cruise. The memory items are prefaces with the statement "if safe conduct of the flight is impacted". S&L in cruise the aircraft is stable, at a normal AoA, clear of terrain.

What AF447 has done is increased the awareness of all crew (not just Airbus crews) of these sort of problems, they happen regularly, and most times are benign like this event. This crew did not overreact (unlike AF447), they just maintained the pitch attitude and thrust, got out of the Wx, and things basically return to "normal".

Quoting 9VSIO (Reply 5):
I'm willing to bet that he's one of their cadets, meaning he's been with the airline since 0 hours.

Normally they actually start with the airline after they have completed flight training, while being sponsored as a cadet pilot under training they may not have been an employee.

Quoting SCQ83 (Reply 6):
Yes, if you have an Emirati passport.

I believe that has not always been the case.

Quoting SCQ83 (Reply 6):
32 y.o. Jordanian with x10 times his flight hours is 1st officer Relief.

Which is a more senior pilot, it is the relief pilots normally prompted to captains.

Quoting AA87 (Reply 7):
(who arguably shouldn't have been there at all)

Why ?

Quoting AA87 (Reply 7):
I don't know what the lesson is

If you follow the correct procedure, the outcome is predictable.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: 3rdGen
Posted 2013-03-24 20:16:27 and read 19053 times.

The fact that the FO had has low hours means he was up doing stalls and hand flying a single and twin piston only a few years ago. Making him far more competent to handle an airplane than someone who has been flying an Airbus for 10+ years with little or no time in anything else.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: AA87
Posted 2013-03-24 20:35:00 and read 18889 times.

Quoting 3rdGen (Reply 9):
The fact that the FO had has low hours means he was up doing stalls and hand flying a single and twin piston only a few years ago. Making him far more competent to handle an airplane than someone who has been flying an Airbus for 10+ years with little or no time in anything else.

Isn't that amazing ?? Great point. Maybe we all need a smart, low-time rookie up front. IIRC about 10 years ago the Wall Street Journal ran a cover story on safety concerns bc jumbo pilots were flying fewer but longer flights, with fewer take offs and landings, and less and less actual "stick time" versus managing automated systems. As I said to a commercial pilot after AF447, "hand flying in alternate law, with no speed data, in heavy IMC is not in an Airbus pilot's job description". I was exaggerating slightly to make a point, but could well be that on the day I passed my FAA exam in a 172, I had greater sensitivity and awareness of stalls and AOA than a high time Airbus pilot who has become accustomed to being a manager.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Norcal773
Posted 2013-03-24 21:19:28 and read 18477 times.

Typical A.Net these days, this thread went down-hill quick. Reading it, one would think the thread is about pilot hours!

Quoting AA87 (Reply 7):
who arguably shouldn't have been there at all

Why the hell not?

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: AA87
Posted 2013-03-24 21:33:41 and read 18332 times.

It is about pilot hours bc that's what I asked about and others responded. Not everyone here is a professional pilot, and some, like me, participate out of interest and a desire to be educated. Are you suggesting pilot hours is so inane a subject, that has so little bearing on safety/competence, that its beneath A.net to be discussed ??

Maybe this is common knowledge in the industry, but I find it extraordinary that pilots w 500 hours are flying heavies across the ocean. If this had become another tragedy, the headline would have been 520.4 hours. I know pilots are fed up with being monitored, drug tested, analyzed, recorded, second-guessed, and incarcerated in the cockpit to boot, I understand all that ... but the public has a right to ask to be educated on the correlation between hours and safety. I personally think judgment, maturity and personality are key (look at Buffalo 2009) but hours are definitely relevant.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: flyenthu
Posted 2013-03-24 21:52:04 and read 18120 times.

I am a flight enthusiast, but a lay person with respect to aviation. I might be overreacting a bit, but I find it unnerving that speed data were lost again in turbulent weather on a relatively new aircraft. I understand that a successful outcome is entirely possible as in this case, and I commend the cockpit crew highly. I also understand that this is a very serious situation. So, my question as a passenger is why is this type of serious situation occurring with some regularity for the Airbus aircraft in similar weather conditions? Planes run into rough weather all the time, but losing speed data with some regularity is a very serious problem in my opinion. It definitely needs to be addressed. I really don't care if it's Airbus or Boeing, but I do care if safety is a concern.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: dynamo12
Posted 2013-03-24 22:21:24 and read 17836 times.

I believe the Air France pilot union withdrew from the investigation into the AF 447 accident in protest of certain injustices. Additionally, the union came out very strongly against a safety memo as "shocking". The memo cited a number of safety lapses such as skipped procedural steps and ignored alarms and said " There is no need to fix procedures or create new ones, the mere application of planned procedures would have helped avoid the problems." - goo.gl/lFiyW

I do wonder if maybe a low time rookie who simply follows the procedures for situations might not be a good balance to the experience of the rest of the crew, particularly if the crew pulls the plane into a climb as a result of instinct but perhaps not as a result of procedures. The outcome here from following procedures was very successful.

While serious, I don't think the traveling public should be so unnerved by the fact that once in a very long while something doesn't work perfectly. If so, let me unnerve the public with stats on driving your car on the road! In particular, while speed data makes flying the plane HUGELY easier, an airbus will fly stable without it and losing speed data really DOES NOT make the plane immediately crash into the ground.

Airbus alternate law WAS normal law for a long time, air travel predates the envelope protections that now exist.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: AA87
Posted 2013-03-24 22:35:46 and read 17695 times.

Quoting dynamo12 (Reply 14):
Airbus alternate law WAS normal law for a long time, air travel predates the envelope protections that now exist

Another good point on this thread ... problem is that I suspect most Airbus pilots have learned to take those envelope protections for granted, and I imagine its hard to make the sudden, required mental shift under pressure ... certainly not impossible, just hard ...

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Speedbird128
Posted 2013-03-24 23:21:23 and read 17225 times.

Quoting flyenthu (Reply 13):
losing speed data with some regularity is a very serious problem

I'd hazard a guess and say it's not actually a very serious problem. A problem, yes, agreed. However, the issue of malfunctioning (or erroneous data from) instruments has been around since instruments themselves. There are (sometimes very simple) procedures laid down for dealing with all of them.

Same for us in ATC. Things go wrong. This is fact. We are trained to recover from it with all the dots on the screen still moving and accounted for when the screen does come back on.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: zeke
Posted 2013-03-25 00:56:07 and read 16091 times.

Quoting AA87 (Reply 12):
Maybe this is common knowledge in the industry, but I find it extraordinary that pilots w 500 hours are flying heavies across the ocean. If this had become another tragedy, the headline would have been 520.4 hours.

Your government is happy putting younger pilots in charge of multi-million, and in some case billion dollar aircraft, and happy to let the same pilots be responsible of the carriage of WMD. Please keep age and experience out of this, it is a pilots competency that matters.

In an airline environment, pilots are part of a team, it is not a single pilot operation.

Quoting AA87 (Reply 15):
I imagine its hard to make the sudden, required mental shift under pressure ... certainly not impossible, just hard ...

What mental shift ?

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: ecbomberman
Posted 2013-03-25 01:26:01 and read 15748 times.

Quoting AA87 (Reply 15):
Quoting AA87 (Reply 15):
Another good point on this thread ... problem is that I suspect most Airbus pilots have learned to take those envelope protections for granted, and I imagine its hard to make the sudden, required mental shift under pressure ... certainly not impossible, just hard ...

Do they? I would find it hard to think that any competent pilots would rely on computers to prevent them from getting into any danger zone. Any competent pilot would have AVOIDED those situations in the first place.

Quoting AA87 (Reply 12):
Quoting AA87 (Reply 12):
Maybe this is common knowledge in the industry, but I find it extraordinary that pilots w 500 hours are flying heavies across the ocean. If this had become another tragedy, the headline would have been 520.4 hours.

It seems that the 500hr pilot in question was able to operate an aircraft with such high stress situation, so yes hrs may matter, but at the same time I do think that competency also matter and the latter proves true.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: s5daw
Posted 2013-03-25 01:38:47 and read 15580 times.

Uhm.... is A330/40 family subject to some kind of avionics bug?
Remember the "EY A332 Lands Without Any Airspeed Indication"? EY A332 Lands Without Any Airspeed Indication (by Gonzalo Jan 29 2013 in Civil Aviation)

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: AirPacific747
Posted 2013-03-25 02:13:16 and read 15218 times.

Quoting AA87 (Reply 15):
Another good point on this thread ... problem is that I suspect most Airbus pilots have learned to take those envelope protections for granted, and I imagine its hard to make the sudden, required mental shift under pressure ... certainly not impossible, just hard ...

BS. In everyday flying, pilots will never get close to the envelope protections. So there is nothing to take for granted.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Northstar80
Posted 2013-03-25 02:30:50 and read 15010 times.

Quoting AA87 (Reply 4):
Did anyone notice in the report the 25-year old FO on duty had a total of 520 hours ? as in, TOTAL, all flying, everything (and almost 10% of that in the preceding 28 days). I think I may have more hours in the sack than this kid had in the air.

Nothing wrong with that - also, very common in Turkish Airlines and Middle eastern carriers. Hundreds of them are flying widebodies. Seniority system in this part of the world is not like in the US. Mostly, for new FOs, WB or NB is not a carreer stage, but luck, they get assigned into which ever type needs new more pilots.

Most new pilots do not like flying WB's due to the fact that they get to do much less takeoffs and landings in comparison to NB FOs.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: David L
Posted 2013-03-25 02:38:33 and read 14900 times.

Quoting ecbomberman (Reply 18):
Do they? I would find it hard to think that any competent pilots would rely on computers to prevent them from getting into any danger zone. Any competent pilot would have AVOIDED those situations in the first place.
Quoting AirPacific747 (Reply 20):
In everyday flying, pilots will never get close to the envelope protections.

   If people learned a little about Airbus design and operation rather than guessing, a lot of threads would be much shorter.  

[Edited 2013-03-25 02:40:23]

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: flyenthu
Posted 2013-03-25 07:21:50 and read 11523 times.

Quoting Speedbird128 (Reply 16):
Quoting Speedbird128 (Reply 16):
I'd hazard a guess and say it's not actually a very serious problem. A problem, yes, agreed.

Then, why is the report a "Serious Incident Investigation Report" and is being treated as an "accident?"

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Speedbird128
Posted 2013-03-25 08:11:52 and read 10796 times.

Quoting flyenthu (Reply 23):
Then, why is the report a "Serious Incident Investigation Report" and is being treated as an "accident?"

Because a serious incident is an incident, not an accident as implied.

Is it worth investigating - most definitely yes. Is it an accident - no. No need to scaremonger.

An investigation occurs in thousands (every year) of these incidents with uneventful landings, the majority of which passengers may never know about. These investigations sometimes lead to Airworthiness Directives, or crew training changes.

Just because an investigation is being undertaken, doesn't automatically mean it was a catastrophic accident.

Red up the difference between an accident and an incident.

In fact I shall write it for you and the others who don't realise that there is even a difference: An aviation incident is defined as an occurrence, other than an accident, associated with the operation of an aircraft that affects or could affect the safety of operations

Notice the bit where it doesn't even have to have had a direct impact on flight, in order to be investigated. See my bit about SMS below.

We have investigations in our ATC world where scenarios have developed that *could* have been a problem. This is called a Safety Management System, and is in place to ensure the safety of everybody concerned, whether crew operating the flight, or passengers sitting in the back.

So to imply that its an "accident" is disingenious at best, as its clearly described as a serious incident and is correctly being treated as such.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: flyenthu
Posted 2013-03-25 08:38:26 and read 10608 times.

Speedbird128: I am not trying being "disingenuous" and it is not my intention to "scaremonger."

These terms are used in the report issued by the GCAA. In fact, the title rubric is "AIR ACCIDENT INVESTIGATION/ SECTOR SERIOUS INCIDENT INVESTIGATION REPORT/UNRELIABLE AIRSPEED." The details are then specified in the "AIRCRAFT ACCIDENT BRIEF" section on pp: 2.


It is their term and not mine. Not trying to split hairs here, but trying to understand the significance and implication. That's it. I appreciate your input.  

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: BrouAviation
Posted 2013-03-25 08:51:08 and read 10421 times.

Quoting David L (Reply 22):
If people learned a little about Airbus design and operation rather than guessing

True, but answering one extreme by using another doesn't help much either. Especially when one does so while the ignorant person in this case is not at all stating things as facts, but how they appear to him.

Having been in the same position as the other poster - it helps the most when one professional takes the time to explain how things work exactly, instead of just starting the rant with terms like BS. If someone is not willing to put in that time and extra effort to explain things, why is he or she on A-net in the first place?

There are some great professional and helpful minds on this forums who tirelessly go on explaining how exactly things work in their profession. They make strolling around in the A-net community worth your time. Of course it is a two-way street, but I have spent my time reading airbus-manuals for training purposes and I fully understand when others don't.

Quoting AirPacific747 (Reply 20):

BS. In everyday flying, pilots will never get close to the envelope protections. So there is nothing to take for granted.

The tailstrike-protection is one envelope protection pilots 'get close to' - to use your phrase - on a daily basis, especially those flying 77W's, A346's and A333's. After all, it is there for a reason.
Which doesn't mean they would slam the tail into the ground as soon as they would be flying without it..

As said above: You are answering one extreme with another, which doesn't help.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Speedbird128
Posted 2013-03-25 08:58:51 and read 10523 times.

Sorry, having worked there for some years, its not unusual for me to see the title of "Aircraft Accident Brief" to be written. It is their (UAE GCAA) standard terminology for the heading of the paragraph describing the involved aircraft and very basic overview of its situation etc, irrespective of whether its an accident or incident.

The only times I have noticed that "Aircraft Accident Brief" be ommitted is once the report has been published in its final version.

The classification of whether it was an incident or accident is, however, clearly written midway down the cover of the initial report.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: David L
Posted 2013-03-25 09:06:24 and read 10361 times.

Quoting BrouAviation (Reply 26):

Given the very general nature of what I thought was a fairly mild comment and not aimed at anyone in particular, I have to say I find your response a tad ironic.  

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: airproxx
Posted 2013-03-25 09:28:08 and read 10029 times.

Quoting zeke (Reply 8):

My personal view is that the crew of AF447 acted inappropriately, in my view they caused the situation they got themselves in. Putting aside the unreliable airspeed, with valid airspeed making the control inputs they made it would have been extremely difficult if not impossible to recover the aircraft once they got the aircraft into such a high angle of attack. In my view, the crew applied the "memory items" from the unreliable airspeed checklist which are designed for when the aircraft is close to terrain, not whist in the cruise. The memory items are prefaces with the statement "if safe conduct of the flight is impacted". S&L in cruise the aircraft is stable, at a normal AoA, clear of terrain.

What AF447 has done is increased the awareness of all crew (not just Airbus crews) of these sort of problems, they happen regularly, and most times are benign like this event. This crew did not overreact (unlike AF447), they just maintained the pitch attitude and thrust, got out of the Wx, and things basically return to "normal".

Zeke, I haven't been reading such a true and correct statement about the AF447 crash for a long time. Amongst all the erroneous details and sensational PR that we've seen, your point of view appears to be the most factual and correct analysis so far. I won't argue more here, as it's clearly not the subject, but anyway, I just wanted to thank you. I really appreciate it. Cheers.

Dave

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: airproxx
Posted 2013-03-25 09:39:32 and read 9830 times.

Quoting cubastar (Thread starter):
This incident bears remarkable resemblance to the AF447 accident in that much of the same issues with it and this flight appeared to be similar.

What makes me wonder, why such incidents keep happening again and again on Airbuses.... It's not the first time that flying through turbulences causes A320/330/340 family aircraft to have troubles with probes/software resulting in loss of airspeed indications.... Quiet worrying...
The B787 has been grounded for less than that, IMHO, with greater industrial pressure because the airplane is brand new and needs good publicity to keep selling well...

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: BrouAviation
Posted 2013-03-25 09:56:00 and read 9582 times.

Quoting David L (Reply 28):
Given the very general nature of what I thought was a fairly mild comment and not aimed at anyone in particular, I have to say I find your response a tad ironic.

It wasn't aimed at your post, but merely at the post you were giving thumbs up to. I hope no offense was taken, as none was intended.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: AirPacific747
Posted 2013-03-25 11:56:03 and read 8111 times.

Quoting BrouAviation (Reply 26):
The tailstrike-protection is one envelope protection pilots 'get close to' - to use your phrase - on a daily basis, especially those flying 77W's, A346's and A333's. After all, it is there for a reason.
Which doesn't mean they would slam the tail into the ground as soon as they would be flying without it..

So the pilots have this protection in the back of their minds when taking off and landing? I highly doubt it. They fly the planes as any other aircraft without this protection. Therefore my answer is still 100% valid.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: airmagnac
Posted 2013-03-25 11:59:12 and read 8093 times.

Quoting s5daw (Reply 19):
is A330/40 family subject to some kind of avionics bug?
Remember the "EY A332 Lands Without Any Airspeed Indication"?
Quoting airproxx (Reply 30):
why such incidents keep happening again and again on Airbuses

There is a difference between actual number of ocurrences and perceived number of ocurrences.

The perceived number of air data problems on the A330/A340 is higher relative to other types, but that is most probably just because there is more interest in those incidents following AF447, so they get reported in the media and in fora like a-net more often, and the information tends to better stick to our minds.
I honestly don't have any hard data about the actual number, but I'd bet that it's comparable to the number of sensor problems that happen to all types, and more generally have happened to all sensors on all aircraft for the last 100 years.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: cubastar
Posted 2013-03-25 12:49:34 and read 7923 times.

Quoting airproxx (Reply 30):
What makes me wonder, why such incidents keep happening again and again on Airbuses....

I really did not want to start up an AF447 thing again, but I too was just wondering why there was such a difference in the outcome of two incidents that both began with loss of airspeed and then the associated loss of important data computers. This Etihad crew did a great job in understanding the initial problem and the resultant disconnects, in my opinion.

Quoting zeke (Reply 8):
The unreliable airspeed checklist does call for this to be selected on.

Thank you, Zeke. Obviously I'm an old timer and most of the aircraft that I flew, it was either on or off. As I read this article it stated that the crew "turned the heaters on" during their running of the checklist so I was just a little confused.

Thanks again for clearing it up for me.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: rampbro
Posted 2013-03-25 13:37:52 and read 7785 times.

Quoting AA87 (Reply 15):
sudden, required mental shift under pressure

Maybe we need a new cockpit indicator; 'Pilot must PAY ATTENTION'

Everyone is arguing about the bloody crew, but the WX and the operation of the WX radar appears to be a central point of interest in this story?

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: kellmark
Posted 2013-03-25 14:58:14 and read 7638 times.

Quoting cubastar (Reply 34):
I really did not want to start up an AF447 thing again, but I too was just wondering why there was such a difference in the outcome of two incidents that both began with loss of airspeed and then the associated loss of important data computers. This Etihad crew did a great job in understanding the initial problem and the resultant disconnects, in my opinion.

For one thing the Etihad crew had to be well aware of the previous problems with the pitot/static system on the Airbus series, especially the A330-340 series of aircraft. No doubt they knew of the AF447 situation. The AF447 crew did not necessarily have the same benefit of hindsight.

But in any case, it seems the captain flew the aircraft initially in Etihad. If one loses a critical item like the airspeed indicator, the usual practice is to use pitch and power to maintain proper attitude, and things will generally take care of themselves. If you still have altitude and vertical speed indications, and in this case angle of attack, then the crew should be able to fly the aircraft safely. Apparently, that is what they did.

Every new instrument rated pilot is taught to monitor their instruments and cross check them with their scan. And then to make allowances for the inoperative instrument and fly partial panel. It looks like this crew did all the right things and should be highly commended for their flying skills, leadership and teamwork, as they flew the airplane first, then tried to communicate, and then decided to declare an emergency and divert to Singapore. No matter the experience of the crew, the result was very good.

I will say one thing though. It is troubling that we see yet another pitot/static system failure of airspeed on an Airbus. Did this aircraft have the new version of the pitot unit that was being installed on these aircraft? What are the details of this?

We see the 787 is grounded for a serious problem, but no injuries or fatalities. Here we have another serious problem in my view. It seems the risk is still there with the Airbus. A crew even when trained and capable of handling it, should not be put into this type of situation, which has been repeated a number of times, one of which resulted in a serious accident with a high number of fatalities.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: AA87
Posted 2013-03-25 15:42:22 and read 7468 times.

Quoting rampbro (Reply 35):
Everyone is arguing about the bloody crew, but the WX and the operation of the WX radar appears to be a central point of interest in this story?

Because we all know instruments fail, especially in ways not anticipated. The whole reason we have human pilots, and will continue to do so for the forseeable future (dog and monkey jokes aside), is because they earn their entire life's compensation in 3 or 4 exceptional emergencies over the course of their entire careers. How they handle them should be of keen interest to all of us. Not defending or criticizing Airbus or the avionics suppliers, but instruments fail. We all want pilots to be properly trained to handle the "survivable" ones like Etihad.

BTW, not sure if this came up in the AF447 threads, but years ago I read a fascinating account of the US judicial opinion on the Air India 747 that lost the captain's ADI shortly after take off, and after much debating/questioning about which ADI was failing and which to follow, the plane rolled into the Indian Ocean I think. IIRC the US judge was a pilot and gave a "split decision" that basically said the ADI shouldn't failed, but given that it did, the captain had enough info from other instruments so that continued safe flight should have been possible; and therefore the captain was ultimately at fault. Anyone else recall that, perhaps more accurately ?

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: flyenthu
Posted 2013-03-25 15:44:14 and read 7456 times.

Quoting kellmark (Reply 36):

Couldn't have said it better. It appears that the pitot tube issue is lingering. I feel that because of a catastrophic precedence like AF, and with the problem still recurring, thorough investigation needs to be conducted and a permanent solution needs to be found.

I, too, was wondering if this aircraft had the modified version of the pitot tubes which was supposed to have taken care of the icing problem.

Anyway, I will be flying in an SQ A333 on a night flight through monsoon-laden skies and over water. I can't help but feel a bit jittery. Just saying!

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Nimish
Posted 2013-03-25 16:10:49 and read 7374 times.

Not meaning to be flippant, but even lowly phones these days have great GPS receivers that show the speed/altitude etc, why don't planes use such systems as a backup to Pitot tubes?

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: airproxx
Posted 2013-03-25 17:46:51 and read 7169 times.

Quoting kellmark (Reply 36):
Every new instrument rated pilot is taught to monitor their instruments and cross check them with their scan. And then to make allowances for the inoperative instrument and fly partial panel. It looks like this crew did all the right things and should be highly commended for their flying skills, leadership and teamwork, as they flew the airplane first, then tried to communicate, and then decided to declare an emergency and divert to Singapore. No matter the experience of the crew, the result was very good.

I will say one thing though. It is troubling that we see yet another pitot/static system failure of airspeed on an Airbus. Did this aircraft have the new version of the pitot unit that was being installed on these aircraft? What are the details of this?

We see the 787 is grounded for a serious problem, but no injuries or fatalities. Here we have another serious problem in my view. It seems the risk is still there with the Airbus. A crew even when trained and capable of handling it, should not be put into this type of situation, which has been repeated a number of times, one of which resulted in a serious accident with a high number of fatalities.

Couldn't have said it better. The 787 problem, and its treatment by FAA and NTSB, compared to what happened with AF447 and considering the (too) often occurencies of such troubles implying air data sources on Airbuses makes me feel a little bit uncomfortable to fly those types, to say the least.
Maybe a little overconfidence on Airbus types is starting to show little by little, by its own manufacturer....
I remember my type rating course on A320 and some Ground Instructors teaching us that "an Airbus cannot stall".
Fortunately the AF447 crew did not disappear for no reason; I'm sure this Etihad crew did a wonderful job because of gained knowledge.

This is how aviation builds itself actually, but yet some lessons need to be taught soon.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Mir
Posted 2013-03-25 18:04:03 and read 7108 times.

Quoting AA87 (Reply 7):
Interesting ... so in light of all that, isn't it quite impressive this "local cadet" (who arguably shouldn't have been there at all) was an effective part of the team and didn't do anything rash/wrong/unprofessional ?

Umm, no. Not at all. Why would anyone do anything rash/wrong/unprofessional just because they don't have a whole lot of experience? Especially something unprofessional - that's something that has no tie to flight experience at all, it's a personality trait.

-Mir

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: aloges
Posted 2013-03-26 06:56:00 and read 6668 times.

Quoting Nimish (Reply 39):
Not meaning to be flippant, but even lowly phones these days have great GPS receivers that show the speed/altitude etc, why don't planes use such systems as a backup to Pitot tubes?

because ground speed is useless in a storm where it may very well bear little to no similarity to airspeed

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Nimish
Posted 2013-03-26 12:20:20 and read 6396 times.

Quoting aloges (Reply 42):
because ground speed is useless in a storm where it may very well bear little to no similarity to airspeed

Interesting - never thought about that, and now it seems obvious   

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: o0OOO0oChris
Posted 2013-03-26 13:40:34 and read 6250 times.

Groundspeed really doesn't help.
The Groundspeed Record for a A330 is 721knots:
http://www.groundspeedrecords.com/re...rds/record%20A330-200%20721kts.htm
Compare that to the max cruise speed of 493kn  

[Edited 2013-03-26 13:42:06]

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: airtechy
Posted 2013-03-26 15:27:34 and read 6066 times.

Using the data derived from the INS... or the pitots themselves... when the airspeed is valid, the ground speed calculation of the GPS can be corrected on a real time basis to derive true airspeed. If the pitots should fail, this data could be used accurately on a short term basis to sub for the pitots. If the case of AF447, I believe the pitot airspeed returned in a matter of seconds. I doubt if the derived airspeed would be inaccurate enough in that short time to make any difference....maybe if the plane was in the middle of a thunderstorm.....where it should not be.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: bobby88
Posted 2013-03-27 06:09:58 and read 5632 times.

Just for your info:

The cadet was not local, and he was Cruise-Relief First Officer. Some cadets in EY were transferred to the wide bodies (A340 and B777) as relief pilots because the training department on the A320 fleet (where the cadets were being trained as full FOs) was overloaded.

The CRP was on duty when the incident happened and the other much more experience FO was having his rest. In fact he was in the seat when the plance landed.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Pihero
Posted 2013-03-27 09:08:35 and read 5481 times.

Where to start ?

The first thing is that **unreliable airspeed** has been with aviation since the days of instrument flying . That's the reason why the check-list is in every QRH, be they A, B or L or D.
I have trained for that event on every new type rating I have done.
That the 'Bus gets more publicity is due to the perceived reporter's - and the public - interest after AF447. Nothing more.
Pilots working for an airline receive in their mail boxes the airline safety mag. They should know better about this problem.

Quoting rampbro (Reply 35):
the WX and the operation of the WX radar appears to be a central point of interest in this story?

Before appointing blames, you should have a look on reflectivity of ice crystals on a radar - Zero - and then read the report - entry into moderate to severe icing and the new radar picture - red -.

Quoting kellmark (Reply 36):
We see the 787 is grounded for a serious problem, but no injuries or fatalities

Are you so sure that would still be the case had the Japanese captain not elected to divert and land ASAP, in spite of basically no information to do so ? Apparently people in charge of air safety disagree with you.

Quoting AA87 (Reply 37):
the Air India 747 that lost the captain's ADI shortly after take off

It's a bit more complicated : The ADI failed without any warning and certainly no flag. The gradient of authority in that cockpit was exceptionally steep and the captain refused all infos / comments from the FO and the FE... and didn't even bother to xcheck the flight instruments.

Quoting flyenthu (Reply 38):
I, too, was wondering if this aircraft had the modified version of the pitot tubes which was supposed to have taken care of the icing problem.

Yes, the Thales probes have been removed from all Airbus aicraft. Read the report on AF447 and find that in fact the Goodrich probes had quite a few failures, too.

Quoting Nimish (Reply 39):
even lowly phones these days have great GPS receivers that show the speed/altitude etc, why don't planes use such systems as a backup to Pitot tubes?

Because what we are interested in is Corrected Airspeed and Mach number ( CAS / M )
In the instance of an airplane flying at FL 350 and M=.80, the indicated airspeed is 275 kt, equivalent to 460 kt at OAT -55°C... and there is no direct relation with ground speed, which the GPS is providing.

Quoting airtechy (Reply 45):
Using the data derived from the INS... or the pitots themselves... when the airspeed is valid, the ground speed calculation of the GPS can be corrected on a real time basis to derive true airspeed. If the pitots should fail, this data could be used accurately on a short term basis to sub for the pitots.

I really don't see how you could say that. Pls elaborate.

The preliminary report isn't accurate enough to make any conclusions but there are quite a few differences with AF447 :
1:- The event happened in broad daylight
2/- Only the Captain's PFD and the ISIS were concerned : the FO side wasn't
3/- The loss of airspeed lasted 14 seconds.
There isn't anything about crew procedures, control transfer to the FO, application of an abnormal check-list ... there is very little to comment on the crew proficiency and CRM.
There is though the 832 ft climb in an RVSM area that has me a lot more concerned than the usual Airbus bashing from the usual suspects.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: airtechy
Posted 2013-03-27 16:04:05 and read 5206 times.

Quoting Pihero (Reply 47):

Quoting airtechy (Reply 45):
Using the data derived from the INS... or the pitots themselves... when the airspeed is valid, the ground speed calculation of the GPS can be corrected on a real time basis to derive true airspeed. If the pitots should fail, this data could be used accurately on a short term basis to sub for the pitots.

I really don't see how you could say that. Pls elaborate.

The INS (not sure what it is called by Airbus) continuously calculates a bunch of stuff....including wind direction and speed...when nothing has failed. This data can be used to correct the GPS data...ground speed and heading...so that it yields ... airspeed and heading. This "corrected" data would normally not be used.....but if all the pitots die, it....at least for a few seconds...would be accurate enough to use for whatever the pitot airspeed is normally used for such as airspeed display on the flight instruments. Hopefully it would be accurate enough to eliminate having to disengage the autopilot.....at least for 14 seconds.

GPS data is the most accurate "ground speed" data available on the airplane. Correcting it "real time" to get accurate airspeed data should be trivial.

I'm sure that if only one pitot died, it would be removed from the flight calculations and a flag would be displayed. All I'm suggesting is a way to do this if they all fail....with flags of course.

I suggested this once before, but it was thought unworkable just for your info.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Pihero
Posted 2013-03-27 17:09:40 and read 5148 times.

Quoting airtechy (Reply 48):
The INS (not sure what it is called by Airbus) continuously calculates a bunch of stuff....including wind direction and speed...when nothing has failed.

An INS is basically a set of three accelerometers on a gyro ( mechanical, ring laser...etc... ) stabilised platform.
Given an origin, it calculates in a double integration first a velocity along a direction, then a position... sooo the infos one can get from an INS are heading / Ground speed / drift angle / geographical position.
NOthing else can be obtained .
The GPS provides with more accuracy : Ground speed / Position., as you see : the same basic data for air navigation
So both systems are quite unable to provide an airspeed information, not even the True Airspeed.
That's where the ADR - air data reference - comes in handy : it provides from the total pressure measurement - from the pitot system b- and the static pressure - from the **static** ports - first an equivalent and then a **corrected** airspeed, the one which we use for piloting, and which is, broadly speaking the velocity of the air molecules on the wing... a further computation, this time using the temperature probes of the airplanes provides the **True ** airspeed and the Mach number.

Now, if one puts in the same system an ADR and an INS, the result is called an ADIRU - for air data and inertial reference unit. the first computation will be to reproduce the famous speed triangle TAS-Wind-GS which is the basis of air navigation.
As you can see, without a TAS reference - which can only come from the ADR, both the INS and the GPS are left with the end product of GS and drift angle, and that info is totally unexploitable for piloting use.
And I say again : what we need in order to fly the airplane is the corrected airspeed . It is , for sheer laziness, called IAS.
That's the reason why your suggestion is unworkable.

Regards

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: airtechy
Posted 2013-03-27 18:18:17 and read 5087 times.

Quoting Pihero (Reply 49):

Now, if one puts in the same system an ADR and an INS, the result is called an ADIRU - for air data and inertial reference unit. the first computation will be to reproduce the famous speed triangle TAS-Wind-GS which is the basis of air navigation.
As you can see, without a TAS reference - which can only come from the ADR, both the INS and the GPS are left with the end product of GS and drift angle, and that info is totally unexploitable for piloting use.
And I say again : what we need in order to fly the airplane is the corrected airspeed . It is , for sheer laziness, called IAS.
That's the reason why your suggestion is unworkable.

Being a pilot, I am familiar with all the "speed" calculations.....well maybe not the Mach number stuff. I did miss that the INS cannot calculate airspeed. I would still contend that up until the moment of failure wind speed and wind direction vectors are known as they are continuously calculated... as you say... by the ADIRU. That data could be used in a running calculation with the GPS to yield correct airspeed and heading.....which could be used when the pitots fail......for 14 seconds at least. No?

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Pihero
Posted 2013-03-28 03:27:34 and read 4879 times.

Quoting airtechy (Reply 50):
That data could be used in a running calculation with the GPS to yield correct airspeed and heading.....which could be used when the pitots fail......for 14 seconds at least. No?

I see...
You're assuming that after the failure, all the parameters remain constant : heading, airspeed, thrust, altitude... Change any single one of these data and your idea goes down the drain.
There is a much simpler piloting technique : fly pitch and thrust and you can deal with this situation whatever the Wind or the heading or the altitude.
That's what the *Unreliable IAS* check-list is all about.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: BrouAviation
Posted 2013-03-28 05:11:10 and read 4749 times.

Quoting o0OOO0oChris (Reply 44):
Compare that to the max cruise speed of 493kn

Then why is the TAS 501kts? 

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Focker
Posted 2013-03-28 05:47:11 and read 4676 times.

Quoting Pihero (Reply 47):
Because what we are interested in is Corrected Airspeed and Mach number ( CAS / M )
In the instance of an airplane flying at FL 350 and M=.80, the indicated airspeed is 275 kt, equivalent to 460 kt at OAT -55°C... and there is no direct relation with ground speed, which the GPS is providing.

Pihero,

Can you clarify this to this uneducated soul?

There is TAS, which I assume stands for True Air Speed. But what is Corrected Air Speed in this respect? And why the huge difference between the 275 kt figure and 460 kt (and what speed is the latter)?

Thanks,

Focker

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Pihero
Posted 2013-03-28 07:50:27 and read 4543 times.

Quoting Focker (Reply 53):
Can you clarify this ?

I'll try and you could call this post "A very basic History of air speeds "
- In the early days of aviation, those "magnificent men and their flying machines " were only concerned with generating enough forward speed for the wing to start generating lift. They had some poetic lore as saying that " lift is a timid flower borne from speed" ans as the only thing they were interested in was to get - and stay - airborne, everybody ignored the works of such geniuses as Bernouilli, Eiffel, d'Alembert, Rayleigh... and al.
- Then it was apparent that lift was also a function of height, or rather air density, and suddenly all the theoretical work started to make sense.
- The discovery that lift is a function of the dynamic pressure launched a whole set of experiments on airfoils, incident angles ( the now-called AoA )... etc... but what is apparent is that a tube measuring dynamic pressure can also measure the velocity of the air mass over the airfoil... That's our *pitot tube*, an evolution of the *venturi* sensor on early airplanes.
As a ballpark approximation, the IAS gauge on early aircraft, and to the end of WW2, gives a pretty good idea of the lift generated.
- Then the effect of air compressibility appear, doing havoc with the simpler approximation as the onset of a shockwave would disturb the airflow over the wing, hence the introduction of the Mach number.

-Let's now leave the history for some simple - I'd say *simplistic* - relationship between what we read on the ASI gauge and what is happening on the wing. For that we have to introduce the notion of EAS or *equivalent airspeed*.

- EAS is the basis of all certification speeds and is taken at level zero of the International Atmosphere Model... If we go higher, EAS is the airspeed value for which the dynamic pressure at altitude will be equal to the initial dynamic pressure at sea level, or simply q0 = 1/2 d0 x V^2 where d0 is the density at sea level and V the EAS..

As it happens, the *IAS* gauge gives values that are close to EAS, with 1/ an instrument error correction - ki - and 2/ a compressibility effect correction - kc - (that's the Mach number influence)

- the Relationship between IAS : Indicated Airspeed ; CAS corrected Airspeed and EAS are then :

IAS --> + ki --> CAS --> x kc --> EAS

One can easily see that for lower speeds, kc is negligible and IAS ~ EAS bar the instrument correction
With the Mach effect, that's the speed that determines all sorts of aerodynamic phenomena : stalling speeds, overspeeds, aerodynamic loads... etc...

Now, if we want to know how fast we are going over the earth, we need an info of true airspeed, hence the TAS computation. Compared to the EAS, TAS is just a function of air density away or rather a function of **density relative to level zero**, and
EAS --> x 1 / sqrt ( density ) --> TAS

So : the higher one flies, the wider the difference between EAS and TAS. On modern aircraft EAS = IAS..

There is a rather nice twist to that notion : When I flew DC-4s, the ASI was in *mph*, which wasn't easy for air navigation ( need to convert from mph to knots ). As it happened, the conversion wasn't necessary as at around our cruising altitude of 10,000 ft, the instrument would give us a very good precision of a TAS in knots ; in other words, at FL 100, IAS 180 mph = TAS 180 kt. as the relative density was equivalent to 1 mph / 1 kt. = .87

On modern aircraft, airspeed computations are done by the ADRU and as we fly in the compressibility region , the Mach effect is a lot more important than just the density effect. The computer uses a five term Mach effect from the ** St Venant Law **.
Look it up if you want, as I'm just dealing with basics.
Suffice it to say that an airplane flying at FL 350, at an OAT of - 55°C and a Mach number of .85 would read IAS ~ 294 kt and TAS = 490 kt.

I hope it helped.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: RickNRoll
Posted 2013-03-28 08:04:57 and read 4523 times.

Quoting airproxx (Reply 40):
Couldn't have said it better. The 787 problem, and its treatment by FAA and NTSB, compared to what happened with AF447 and considering the (too) often occurencies of such troubles implying air data sources on Airbuses makes me feel a little bit uncomfortable to fly those types, to say the least.
Maybe a little overconfidence on Airbus types is starting to show little by little, by its own manufacturer....

In the case of the AF447 incident, a competent pilot team will retain control of the plane using principles they have been trained on since they started training. That is, pitch and power.
In the case of 787 battery, there is nothing the pilot can do to remedy the problem while in the air, except to land ASAP. They have no access to the battery and cannot put out any fires or that may develop.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Focker
Posted 2013-03-28 08:24:33 and read 4479 times.

Thanks for the clear explanations Pihero!

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: airbuster
Posted 2013-03-28 08:44:21 and read 4483 times.

When I was 21 and had about 250 hours I was a long haul cruise relief FO on the MD11. Sometimes I would be sitting there at night with the Captain in the bunk and the FO nodding of to sleep next to me, over the Atlantic or the Himalayas.

I had little to no "management" experience but was well trained and able to at least perform the initial recovery and or memory items for a lot of failures. Subsequent failure management and situation analysis grows with time.

When I look back I see that I have better skills, knowledge, awareness and am more self critical now than I was back then.

It's very hard to say how wel a low timer vs a high timer will handle a specific situation. Though I believe that experience does pay off. Most of the time there is more knowledge and experience in high time pilots, skill is debatable.

But as long as you have a experienced captain with a capable and well trained FO to whom tasks can be delegated I believe safety won't be impaired.

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: airtechy
Posted 2013-03-28 21:45:23 and read 4120 times.

Quoting Pihero (Reply 51):

I see...
You're assuming that after the failure, all the parameters remain constant : heading, airspeed, thrust, altitude... Change any single one of these data and your idea goes down the drain.
There is a much simpler piloting technique : fly pitch and thrust and you can deal with this situation whatever the Wind or the heading or the altitude.

You missed my point. I would agree with you that all the things you mention would be true if you disconnected the autopilot....at least they could. My point is to use the corrected data so that you don't have to disconnect the autopilot. The loss of pitots should not affect pitch or roll control as they should sense off the attitude indicator. Autothrust would use the calculated airspeed. Should be good for 14 seconds.

Actually, I think the worse problem would be to determine when to switch from the "dead" pitots to alternate calculated airspeed.

If you think about it, the need for pilot intervention could have been avoided if the throttles had been frozen at the existing thrust level for 14 seconds and nothing else done. Assuming the 14 seconds is correct, the airplane would have fixed itself quickly. How much of an airspeed change would result from a locked throttle over a short period of time even considering moderate turbulence?

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: airmagnac
Posted 2013-03-29 02:44:05 and read 3980 times.

The first rule of automation is : you do not run automatic devices on unreliable data
The second rule of automation is : you do not run automatic devices on unreliable data

The movements of the air mass is extremely dynamic and subject to a great many things. And the aircraft itself is plowing through it at 500kts (this is a TAS   ), so covers great distance in a few seconds.
This means that you'd be trying to estimate a wind speed at a given point in space and time based on what it was several seconds and hundreds of meters before. It might work sometimes, but there is just no way you can be sure that will work all the time.
So no way you can guarantee that the estimate is any more reliable than the direct airspeed measurement. So there is no way you can run an auto-pilot off that estimate.

And the main problem is not to fly the plane. Airplanes are stable, they'll take care of themselves in the short term.
As you say yourself

Quoting airtechy (Reply 58):
the worse problem would be to determine when to switch from the "dead" pitots to alternate calculated airspeed.

That is The Problem. If we could detect with 100% certainty and quasi-instantaneously that the air data sensors have switched from "working fine" to "failed", then it would be possible to display an alarm saying "air speed lost", and from there things should be rather clear and straightforward.

But we can't.

Ever notice that there is no explicit "Air speed lost" warning, but a mere "ADR Disagree" or at the most something like "Air Speed is weird - please check" ? And why's that ?
Just think about it : the probes are sticking out in a highly dynamic environment, with air swooshing around at 900km/h, shock waves dancing around, vortices swirling here and there, changing temperatures, changing pressures, changing densities, dry air or liquid moisture or very dense liquid water or small ice particules or big pieces of ice or water in exotic forms with interesting behaviours. And on and on...
I already find it amazing that we can back out a speed indication from all this. But trying to figure out whether a variation in the measurements is actually a problem, or merely some local noise, is terribly difficult. Especially as a failure can appear in many ways ; we're not talking about a sudden switch from value xxx to 0, or from ON to OFF.

That's why the ADIRS have to open comparison windows for several seconds when they think something is wrong, just to try to confirm the problem.
That's why a probe blockage can have such a wide variety of effects on aircraft systems.
Why sometimes you'll get no alarm, but in other cases you'll get more text on ECAM/EICAS than there is in the full works of Victor Hugo.
And why unreliable airspeed events are so confusing. And this confusion in turn is what triggers such a wide variety of reactions from aircrew (see the list of events reported by the BEA), some of which can be potentially dangerous.

So the point is not to design super-duper automatic functions. It is to reliably detect and identify loss of air speed data in all cases. The engineering term for this is "integrity" of the air data system, if you want to look it up. And it's no trivial matter.
And again, it's not an Airbus problem - it's a physics problem

[Edited 2013-03-29 02:53:34]

[Edited 2013-03-29 03:00:18]

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: Pihero
Posted 2013-03-29 07:08:33 and read 3739 times.

Superb post, Airmagnac !

You should - if you don't know it already - take a look at Pr Peter B. Ladkin's work at the Bielefeld University. a summary of his team's work is :

" interests nowadays lie in system safety and the failure analysis of complex heterogeneous systems. I am the originator of the Why-Because Analysis (WBA) method of causal analysis of incidents, which has been adopted as company standard by Siemens Transportation Systems Rail Automation and Mass Transit Divisions; as well as Ontological Hazard Analysis (OHA) for relatively-complete hazard analysis and maintenance of safety requirements during refinement in safety-related system development."

His site, as an entry gate to the University work is here

Topic: RE: Etihad A340-600 Loss Of Instruments On 03 Feb-13
Username: airtechy
Posted 2013-03-29 11:33:22 and read 3553 times.

Interesting discussion.....thanks Pihero and Airmagnac.

Jim


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