RetiredWeasel
Posts: 749
Joined: Sat Jul 05, 2014 8:16 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 3:51 pm

As a general rule, if flying through an area of occasional or frequent thunderstorms then the higher you are, the better off you are. Most CBs don't top off at 50,000ft especially in the tropics (maybe not this particular area) with the majority maybe reaching up to 30,000 ft or so. However, trying at the last minute to try and top an individual cell or adjacent cells that are growing and shooting up into the trop would most likely be a useless (and perhaps more risky) maneuver as 'michi' has posted.

As previous posters have mentioned, climbing to get out of cirrus so you can see the buildups may have been this Captain's desire. The onboard WX radar is a great tool, but does have some limitations. However, it's way to premature to trying and figure out what his intentions were.

Every airline pilot that has at least 10 years or so flying, has at one time or another, had to pick his way through a line, continuous, or seemingly solid line of activity. It is either doing that or running out of fuel trying to find another alternate or U-turn. Convective activity is rapid and constantly changing. Predicting individual cell formations is useless. Occasionally, it's not fun being an airline pilot.
 
CyberEntomology
Posts: 86
Joined: Thu Nov 21, 2013 9:55 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:00 pm

I mentioned parallels to AF447 early in thread 1 and the idea was suggested as highly unlikely. Interesting to see it come around.

I expect we may see some new science come out of this as relates to WX in the ITCZ where storms don't have benefit of the Coriolis effect to dissipate storm energy laterally (much of the t-storm science out there is from mid-latitudes). This would lend some weight to the earlier comment about icing occurring at much higher altitudes than previously though possible.

I also expect that we may see some re-evaluation of Airbus' approach to FBW vs. Boeing's (which has been discussed at length in other threads here, so I won't rehash it here).
 
hivue
Posts: 2052
Joined: Tue Feb 26, 2013 2:26 am

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:06 pm

Quoting CyberEntomology (Reply 254):
I also expect that we may see some re-evaluation of Airbus' approach to FBW vs. Boeing

Please see my post 235 above.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
User avatar
scbriml
Posts: 18263
Joined: Wed Jul 02, 2003 10:37 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:07 pm

Quoting idlewildchild (Reply 213):
Had the weather not been severe there would have been no crash. I have no idea what you're talking about calling it minor.

The weather caused the pitot to freeze, resulting in loss of airspeed indication. This is something that happens regularly on all types of planes and is a totally benign event. Loss of airspeed indication does not cause a plane to crash.   

AF447 crashed because of a staggering lack of airmanship displayed by the pilots in the cockpit and a complete and utter failure to follow SOP for the situation they were in.

It was an event that should have been nothing more than a transient 'blip'. Weather did not cause AF447 to crash, the crew did.

Quoting idlewildchild (Reply 230):
"Bad weather was also a significant factor in QZ8501." is the quote from this article

Written by a reporter who wasn't there! Wait for the analysis of the FDR and CVR to know what actually happened.
Time flies like an arrow. Fruit flies like a banana!
There are 10 types of people in the World - those that understand binary and those that don't.
 
User avatar
Miami
Posts: 6101
Joined: Sat Sep 15, 2012 8:37 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:08 pm

AirAsia retired flight number QZ8501/QZ8502)

Tomorrow,the flight will be re-numbered as QZ678/679, while operational schedule remains unchanged.

QZ678 SUB0520 – 0830SIN 320 x246
QZ679 SIN1410 – 1520SUB 320 x246

https://lh6.googleusercontent.com/-oV_Sy2-eqV8/VKKR6zCMxyI/AAAAAAAAF5o/vzcAyEZBNws/s720/ScreenShot037.jpg

http://airlineroute.net/2014/12/30/qz-sub-dec14/
Aviation is proof that given, the will, we have the capacity to achieve the impossible. - Eddie Rickenbacker
 
User avatar
flyingturtle
Posts: 5740
Joined: Mon Oct 31, 2011 1:39 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:11 pm

I'm relieved to see that first wreckage and bodies have been found. So at least a crucial difference to the other great mystery.

At least for certification purposes the wings of an aircraft must not break at 150% of the highest load that can be foreseen for the whole life of the plane. Do these 150% make the plane +/- capable of punching through tropical thunderstorms (supposed that the pilots don't lose their situational awareness, and the engines do not quit)?


David
Reading accident reports is what calms me down
 
heyjoojoo
Posts: 114
Joined: Thu Dec 27, 2007 8:28 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:17 pm

Since it seems that most of us are leaning toward the weather being the cause of this incident, I still don't know why a captain and/or first officer would take his passengers in or near such a wild set of cells. Seems to be a huge risk given that they're leaving huge echoes on the radar. I know I'm making several assumptions but pilot experience and competence are at least assumptions that should be a given, no?
 
User avatar
Miami
Posts: 6101
Joined: Sat Sep 15, 2012 8:37 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:20 pm

Please continue the discussion here as the thread is already long and some members may experience problems

Air Asia QZ8501 SUB To SIN Missing - Part 5 (by Miami Dec 30 2014 in Civil Aviation)
Aviation is proof that given, the will, we have the capacity to achieve the impossible. - Eddie Rickenbacker
 
lancelot07
Posts: 1084
Joined: Mon Apr 21, 2014 8:22 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:28 pm

Quoting flyingturtle (Reply 258):

At least for certification purposes the wings of an aircraft must not break at 150% of the highest load that can be foreseen for the whole life of the plane. Do these 150% make the plane +/- capable of punching through tropical thunderstorms (supposed that the pilots don't lose their situational awareness, and the engines do not quit)?

100% should do it, but then engineers deal in N and m and not in abstract tropical thunderstorms. It does not totally rule out a storm with forces much stronger than anticipated, but this is highly improbable
 
Pihero
Posts: 4318
Joined: Mon Jan 31, 2005 5:11 am

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:33 pm

From Tim Vasquez:

1/- The surface chart at the time of QZ8501 crossing :

http://www.weathergraphics.com/awq8501/awq8501-sfc.jpg

2/- The weather at FL300. Temperatures are quite high - STD + 16°C - and the winds very light :

http://www.weathergraphics.com/awq8501/awq8501-300.jpg

3/- Satelite visible image, 8 minutes after QZ8501 crossing . As a matter of fact, the thunderclouds were in their majority behind the aircraft :

http://www.weathergraphics.com/awq8501/awq8501-2332vis.jpg

...and lastly comments from Tim :

"Conclusion: Based on the available data and a close correlation of thunderstorm activity at the last received location, it appears that weather was a factor, or was a compounding factor. The most likely hazard, if weather was a factor, appears to be icing."

The appearance of a *supercell* is not backed by this analysis and certainly not by the sat picture.
Cirrus clouds were way above the flight level (some 17 000 ft higher )

That said I do not believe in a repeat of AF447, mainly because that accident has generated too many discussions and training concerns.

AS the accident onset was very quick and drastic, look elsewhere for explanations.

[Edited 2014-12-30 08:36:38]
Contrail designer
 
User avatar
Starlionblue
Posts: 19628
Joined: Fri Feb 27, 2004 9:54 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:40 pm

Quoting flyingturtle (Reply 258):
At least for certification purposes the wings of an aircraft must not break at 150% of the highest load that can be foreseen for the whole life of the plane. Do these 150% make the plane +/- capable of punching through tropical thunderstorms (supposed that the pilots don't lose their situational awareness, and the engines do not quit)?

Windshear in storms can be strong enough to cause structural failure. The expected operational loads are based on normal operations, and while normal operations include turbulence that would make most passengers crap their pants, a strong tropical thunderstorm can be way stronger than what the plane can handle. The NLM Cityhopper F-28 crash in 1981 is an example.

Windshear caused by mountain waves is also a hazard, and was the cause of the BOAC 707 crash over Mt. Fuji in 1966.

These two hazards are much less of a risk nowadays compared to, say, 50 years ago because of much better prediction, reporting and detection, both from the ground and on board. However the hazards still exist.

Quoting lancelot07 (Reply 228):
Dozens of planes made it through that weather without harm, so it can't have been central or primary cause.

As explained by numerous posters above, tropical thunderstorms are often very localized and develop very quickly. A spot that is calm now can be an inferno of windshear five minutes later. A distance of five nautical miles can be the difference between clear skies and severe turbulence and icing.

[Edited 2014-12-30 08:42:41]

[Edited 2014-12-30 08:43:00]

[Edited 2014-12-30 08:43:20]
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Pihero
Posts: 4318
Joined: Mon Jan 31, 2005 5:11 am

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:46 pm

Sorry . I forgot the most important picture : that of the nearby radio-sounding.

http://www.weathergraphics.com/awq8501/awq8501-skew.jpg

Especially look at the winds on the extreme right : they rise from 15 to 25 kt between 32 000 and 36 000 ft ( Last SSR screen picture if one wants to believe it ) ; That means that in fact the indicated airspeed was around 167 kt / M = .52
That's as close to a stall one would like to be.

(But I still don't buy on a repeat of AF447 )

[Edited 2014-12-30 08:48:56]
Contrail designer
 
Trin
Posts: 167
Joined: Mon May 02, 2011 4:45 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 4:49 pm

Quoting heyjoojoo (Reply 259):

Since it seems that most of us are leaning toward the weather being the cause of this incident, I still don't know why a captain and/or first officer would take his passengers in or near such a wild set of cells. Seems to be a huge risk....

Absolutely not! There are many instances of clear-air turbulence that is far worse than that experienced in-storm. Do you remember AF447? That flight experienced nothing more than mild-moderate turbulence - absolutely nothing that was cause for alarm, and nothing that could be described as "wild". The only thing that occurred that caused problems was the icing of the pitots.....which uncovered the very unfortunate fact that the flying pilots were lacking even basic skills/experience to deal with a lack of airspeed indications and the possibility of a high-altitude stall. The precipitating factor was the icing of the pitots (in a not overly-wild storm/cloud layer); the deadly factor was the crew's response and the man-machine interface between them and the Airbus.
 
SimonDanger
Posts: 76
Joined: Mon Mar 17, 2014 5:51 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 5:50 pm

Full disclosure, I'm not a pilot. But I love flight, and things that fly, it's why I like this site. As I commented on the MH370 threads (what was the last count?), I am facinated with the flight deck management environment, or Cockpit Resource Management, and in particular the Aviate - Navigate - Communicate protocol.

Here's my concern/question: Why isn't communicating a higher priority?

Any first responder, fireman, policeman, or military commander knows that the sooner you ask for help the sooner resources are going to come your way. They may not save your own butt, but they will let others know that there is a really big problem. I'm just flumoxed that if I were at the helm of a craft that I wouldn't key the thumb switch to ATC (emergency channel or not) and announce I have a problem, ala, "Houston, we have a problem".

If anything, the communication of the onset of emergency conditions would alert nearby aircraft to give a wide berth to the stricken aircraft, enabling its freedom to make any necessary maneuvers to avert a disaster. And as one commentor mentioned above, were the PIC to declare an emergency, he/she would be able to pretty much fly where ever they needed to in order to save the aircraft and passengers. My sense is that there is some inherent stigma in declaring an emergency that prevents pilots from announcing they are losing control of their aircraft. Not trying to be controversial or a troll, just curious if some of the pilots here feel the same. Or not.  
 
idlewildchild
Posts: 236
Joined: Sun Nov 20, 2011 8:38 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 6:11 pm

Quoting RetiredWeasel (Reply 253):
As previous posters have mentioned, climbing to get out of cirrus so you can see the buildups may have been this Captain's desire. The onboard WX radar is a great tool, but does have some limitations. However, it's way to premature to trying and figure out what his intentions were.

Every airline pilot that has at least 10 years or so flying, has at one time or another, had to pick his way through a line, continuous, or seemingly solid line of activity. It is either doing that or running out of fuel trying to find another alternate or U-turn. Convective activity is rapid and constantly changing. Predicting individual cell formations is useless. Occasionally, it's not fun being an airline pilot.

Thanks for this, it makes a lot of sense. What I'm wondering is if we're seeing the weather pattern intensive (global warming) as exemplified by 50,000 CB storms which are normally unheard of. Perhaps there's a 'new weather pattern norm' emerging and what must aviators due to not have to face conditions that could lead to an AF or QZ scenario.

I'd rather not have pilots having to face those "most challenging" conditions, especially if they're going to become chronic.
 
lowbank
Posts: 511
Joined: Wed Mar 25, 2009 9:10 pm

RE: Air Asia QZ8501 SUB To SIN Missing - Part 4

Tue Dec 30, 2014 6:44 pm

Pihero,
I am trying to build a picture of events in my mind from all the things that have been written about this tragic event and also from readings lots of other events.

We have a crew that know the area and it's weather, it's not new to them.
We have a pilot who flew fighters according to earlier reports.

They requested a course change which was granted, a height change was not immediately granted and we can see why from one of the graphics shown as there were several planes around but higher.

There is also information that suggests the plane climbed and the speed dropped.

If the airspeed did indeed drop blow the flight envelope, the recovery, from what I read about AF447 is to go nose down and recover your airspeed. In the report Dubois realised he did not have enough height to recover the situation when he did put the nose down, what surprised me at the time was how high they were at that point, I cannot find the report now but I am sure it was over 10,000 feet. Please correct me if I am wrong.

Why it dropped will not be known for while, I don't wish to speculate either as there could be a hundred reasons.

So if they did climb and the plane slowed to a stall, a pilot of his experience may have put the plane nose down.

That could explain the rapid loss of height, would it take say 10,000 feet to get the speed back, after that again we need to wait to see what comes from the black boxes.

I am not going with the broke up at altitude due to the small items of debris and the fact so many people have been found in such a small time frame.
Every days a school day.

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos