Another Air Asia plane missing

[Hank]

Seems the pilot had 6K with the airline, after leaving the Air Force. Total time ~20K.

Initial reports were rather confus(ed)(ing).

[bd32322]

Actually its difficult to say if I would board the flight. I will place my trust in the hands of the professionals to divert and do the right thing just because I happen to know nothing about airline ops, jet aircraft capabilities etc. For example they could board the flight and wait until a window shows up during which a bunch of aircraft decide to take off. If on the other hand the weather is somewhere in between, I would expect the pilots to do the right thing and divert as necessary.

 

The only way to not board the flight is to ask the pilots - hey are you going to fly through that purple section on the radar  - if they answer yes - I am staying away. But it is never clear cut like that ofcourse.

[Alan Fox]

Question , does the transponder transmit with enough power to be picked up that far offshore , or are they tracked on primary ......also , if there is a few minutes between sweeps (requests) it is entirely possible that the transponder didn't reply before it went down...

[Parker_Woodruff]

Have some confidence in the airline pilots. None of them "like" turbulence or storms and none of them will tell you "yes" if you ask them before a flight that they are going to willfully go into the purple stuff.

As altitude increases the margin for appropriate speed becomes very small. Research "Coffin Corner". I have no idea if such a thing applies here, but one report said they were likely too slow for turbulence.

Weather related accidents for airliners in the USA are often a result of a chain of things going wrong. They are almost nonexistent from the perspective of a pilot just deciding to go through a bad cell.

Look at what happened with the American crash in Little Rock in 1999. They knew they were in over their heads. They caved to external pressures and should have diverted.

[bd32322]

Have some confidence in the airline pilots. None of them "like" turbulence or storms and none of them will tell you "yes" if you ask them before a flight that they are going to willfully go into the purple stuff.

As altitude increases the margin for appropriate speed becomes very small. Research "Coffin Corner". I have no idea if such a thing applies here, but one report said they were likely too slow for turbulence.

Weather related accidents for airliners in the USA are often a result of a chain of things going wrong. They are almost nonexistent from the perspective of a pilot just deciding to go through a bad cell.

Look at what happened with the American crash in Little Rock in 1999. They knew they were in over their heads. They caved to external pressures and should have diverted.

 

Yeah I was expressing confidence in airline pilots in response to some earlier posts about whether it is possible for a passenger to make a call while on the ground I dont think its possible for the passenger to make that call.

 

I was saying that no one willingly goes through the purple stuff - which is why I was saying that the only way to stay away was to get a straight answer from the pilot saying he will fly through the bad stuff - which ofcourse no one plans to do and the answer to that will always be no.

[Johnnybgoode]

A big part of the decision as a passenger on whether to board or not, would depend on what type of aircraft it is. There is a reason some say " If it ain't Boeing I ain't going".

In the industry there is some laughter at this attitude. It is usually made by "senior" (to be polite) guys who don't want to learn a new set of systems. Just my experience - yours may vary, of course.

[aviatoreb]

There have been two occasions in my road-warrior career that I have taken my seat on a big airliner jet at some major airport and I deeply regretted it and wished they would let me off and they could go ahead and risk the flight without me.

 

One occasion was at O'Haire in a brutal snow storm that was much worse than I had realized sitting in the terminal but then once we were taxiing around I was astonished that anyone was flying.

The other was at Ottawa, ON in a regional jet.  You know how it is - you board the plane and it can be 30 minutes before they even push off .  By the time we were taxiing - A thunderstorm was bearing down on the airport and I could not believe that anyone would fly with a thunderstorm so close.  We got the hold short and the storm was right on top of the airport and another jet departed right then with massive swirling winds and sideways rain and thunder strokes right on top of the airport.  I couldn't believe it.  I was very thankful when the pilot came on the intercom to apologize that he was going to taxi out of position and back to the terminal and wait for 15 minutes.  That was one delay I was most thankful for.

 

I lived both times.  Knock on wood.  You gotta trust these guys know what they are doing, have better training and equipment than me.  Statistics bear this out in spades.

[Piloto]

Question , does the transponder transmit with enough power to be picked up that far offshore , or are they tracked on primary ......also , if there is a few minutes between sweeps (requests) it is entirely possible that the transponder didn't reply before it went down...

 

Typical ATC radar sweep is 5 seconds for 360 deg coverage. Transponder range at 32,000 is a about 250nm.  Longer distances can be achieved when the ground radar site is located on a mountain top. Airline transponder power is 400 watts vs 200 watts for GA. Primary radar (skin reflection) is limited by weather and aircraft reflection.

 

Unlike GA transponders that can run on battery DC power, air transport transponders run on 120/400Hz AC power that comes from the AC generator on the engines.

 

José 

[bonal]

As I have said on other posts I have tons of respect for the men and women that reach the level of pilot required to fly the bigs. I also know they are put under a lot of pressure from the company's they fly for to keep scheduled flights on schedule. I also know the aircraft they fly are much more capable than my little Mooney. But as I said Mother Nature can laugh at our efforts to wistand Her power. And I'm sure no one would have made that flight if they knew the outcome. It was a bad decision to try to cross that region especially with all the sophistication available to the pilots and controllers at the time.

Sad for the families and friends.

God speed.

[aviatoreb]

Can one of the heavy iron pilots here answer this?

 

I know the coast guard flies right through hurricanes on a regular basis to collect data.  They do it by well understanding the role of Va.  How about a 777? Suppose a 777 finds it self in the heart of the worst of purple tstorms by error? Can they survive by slowing to Va?  At Va or below the airplane is supposed to stall before it falls apart, right?  In other words I am asking if a break up like this (if that is what it was) is really two errors.  1 is getting into a tstorm, 2 is staying too fast in the tstorm?

[Hank]

The Hurricane Hunters fly 4-engine turbo props, specially reinforced to withstand the turbulence. Armor plating is put on the outside to protect against ice and hail. The flight crews are experienced in this environment. Someone (Pilot? Flying?) had an article on them in the last 3-4 years.

No thank you, I don't want to ride along.

They have no screaming passengers or shifting cargo & luggage to deal with, either.

[Piloto]

The Hurricane Hunters fly 4-engine turbo props, specially reinforced to withstand the turbulence. Armor plating is put on the outside to protect against ice and hail. The flight crews are experienced in this environment. Someone (Pilot? Flying?) had an article on them in the last 3-4 years.

No thank you, I don't want to ride along.

They have no screaming passengers or shifting cargo & luggage to deal with, either.

 

Here  at http://www.hurricanehunters.com/plane.html are some interesting facts about hurricane hunters.     

 

The 53rd WRS uses the WC-130J to penetrate tropical storms. These aircraft are not reinforced in any way in fact the only differences between a WC-130J and a C-130J is the addition of two external fuel tanks (giving them longer range), a radiometer pod on the left wing and the two addition crew pallets in the cargo bay (see below for more information on specific weather instruments). 

[aviatoreb]

I thought va was defined in terms of gust loading and stall before a prechosen gust loading. Not the full deflection concept which is ancillary to that concept. I am not an aeronautical engineer - who can speak up definitively on this?

[Piloto]

If the Air Asia plane would have gone into a stall the transponder data would have indicated a descent from 32,000ft.

 

Feliz Ano Nuevo!!!

 

José

[Bluevalley]

As a "senior" pilot (I got a chuckle out of that from a previous post, although 45 years in aviation does qualify) I "drove" the Airbus 319-320 for a couple of years when they first came out, and can say it is not my first choice for flying around thunderstorms. Not to say that any would be a good choice, it just wouldn't be my first. Parker's observation is probably a good place to start looking.

[Piloto]

Another weather hazard for the airlines is CAT Clear Air Turbulence. Most commonly found in the proximity of the jet stream above 30,000ft, Sudden winds changes can be greater than 100kts with severe turbulence. The problem with CAT is that it can not be detected by ground or airborne radar, so there is no warning to the pilot when in the proximity of it. This is one of the reason why airliners has to withstand sudden severe turbulence. On my last years at Honeywell we experimented with thermal imaging for CAT detection but the system turn out unreliable with too many false alarms. Distance to the phenomena were too erratic.

 

More on CAT at  

 

http://en.wikipedia.org/wiki/Clear-air_turbulence

 

José

[Piloto]

Josè,

I have to wonder at the wisdom of flying into that weather with external fuel tanks attached?

Maybe they use that fuel first after initial,climb segments? Maybe they are built better and attach better than those of older days?

 

Fuel in the wings is less stressing on the bending moment than fuel in the fuselage. It also allows for more cargo room.

 

Another form of handling turbulence is through wing load alleviation.

 

http://www.flightglobal.com/news/articles/airbus-exploits-a320-load-alleviation-to-offer-higher-319049/

 

We look into it by embedding the function into the B777 FBW. But there were too many variables to risk it. An out phase condition could cause a flutter event.

 

For now just tighten your seat belt.

 

José