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Flying Through Bad Weather? And Why?  
User currently offlineWardialer From United States of America, joined Sep 2001, 1183 posts, RR: 0
Posted (10 years 3 months 1 week 4 days ago) and read 5438 times:

Interesting note here that I want to apply here.

I viewed the turbulence forecast map (The link below) and there seems to be very bad stuff around the Needles, Boulder, Peach Springs area.

Now, my question is, when viewing Lufthansa's flight plan, the flight plan route which is filed for this flight, is going or flying into that area of bad weather.

Now why do they have to go through this bad weather??? Can't they take an alternate route instead?

Its a B747-400 and are they equiped with Turbulence Detecting Devices or something?

The flight plan as follows:

LAXX5.TRM.EED.PGS. and so on.........

Why are they going to fly through this bad weather which I assume will call for a SIGMET for severe turbulence.

http://www.fboweb.com/20/weather/airsig.asp

24 replies: All unread, jump to last
 
User currently offlineHirnie From Germany, joined May 2004, 596 posts, RR: 0
Reply 1, posted (10 years 3 months 1 week 3 days 23 hours ago) and read 5356 times:

I don´t know what flight plan you got. Is this flight plan the actual one of this specific flight or a plan published anywhere as a plan this flight normally takes?
`Cause normally the crew takes weather into their consideration when going through weather charts...


User currently offlineFSPilot747 From United States of America, joined Oct 1999, 3599 posts, RR: 12
Reply 2, posted (10 years 3 months 1 week 3 days 23 hours ago) and read 5350 times:

Flight plans are subject to change. They're not carved in stone. Your LH 747 is not going to fly into the middle of a storm. I can't see what flightplan you're talking about, but it's irrelevant. They can always be vectored around the intense areas.

And no you can't really "see turbulence" onscreen in a 744 or any other aircraft for that matter AFAIK. But 747-400's do have weather information onscreen. Basically, I wouldn't worry about it.


FSP


User currently offlineAAR90 From United States of America, joined Jan 2000, 3494 posts, RR: 46
Reply 3, posted (10 years 3 months 1 week 3 days 22 hours ago) and read 5324 times:

The words you used in your original message answer your questions for you.

Now, my question is, when viewing Lufthansa's flight plan, the flight plan route which is filed for this flight, is going or flying into that area of bad weather.

You answer yourself with:

turbulence forecast map
A FORECAST is a prediction of likely future weather, not what is actually there. And just because an area is FORECAST to have "bad weather" doesn't mean the entire area will have "bad weather" the entire time.

The flight plan...
A flight PLAN is exactly that... a PLAN. Included in that PLAN will be additional fuel for alternative routings, alternative altitudes, alternate airports, etc. It is a PLAN that tries to include as many variables as possible giving pilots, ATC and airline the same starting point that all can work from.

Now why do they have to go through this bad weather???
They don't have to, and if (when they get there) the weather is too severe to enter, the pilots will do something else.

Can't they take an alternate route instead?
You can, but why would you PLAN to do so HOURS before the plane gets anywhere close to the area? Why add time (minutes) and cost (fuel) when you don't have to?

Why are they going to fly through this bad weather which I assume will call for a SIGMET for severe turbulence.

I flew through this exact area you mention Friday. Even though a SIGMET was issued, I encountered no severe weather, no turbulence and only a few clouds. In passing some of those clouds I noted to my FO that they (the clouds) looked like they would grow into pretty troublesome thunderstorms in a couple of hours. Driving home 90 minutes later Flash Flood Warnings were being issued for those areas due to those (now fully developed) thunderstorms. OTOH, SoCal airline flights were not appreciably delayed as they simply flew a couple of miles around the individual thunderstorm cells.



*NO CARRIER* -- A Naval Aviator's worst nightmare!
User currently offlineWardialer From United States of America, joined Sep 2001, 1183 posts, RR: 0
Reply 4, posted (10 years 3 months 1 week 3 days 20 hours ago) and read 5206 times:

I am flying in a week so I could admit that Im worried about turbulence.

My other question, are 747-400s safe from the most severe turbulence?

Like I said, I am a bit uncomfortable about flying through turbulence. Even if on medication.


User currently offlineAirplay From , joined Dec 1969, posts, RR:
Reply 5, posted (10 years 3 months 1 week 3 days 18 hours ago) and read 5129 times:

And no you can't really "see turbulence" onscreen in a 744 or any other aircraft for that matter AFAIK.

Not neccessarily true. Many modern weather radars have the capability of detecting and displaying turbulance and windshear.

The RDR-4B is one of the most popular airline weather radars out there. It was enhanced a few years ago with turbulence detection like many others have been years before. Check out its capabilities here:

http://www.flwsradar.com/Product_Info/rdr_main.html

NEXRAD also offers the ability to bring ground based doppler and weather radar information into the cockpit. I haven't seen such a system outside of GA airplanes as yet. (That doesn't mean it doesn't exist...just that I haven't seen it)

http://www.garmin.com/products/gdl49/

One other point I'd like to touch on; Just because an airplane is routed through the horizontal path of severe weather doesn't mean that it will pass through it. The airplane may be flying well above the weather which is often the case except for the largest of weather systems.



User currently offlineFSPilot747 From United States of America, joined Oct 1999, 3599 posts, RR: 12
Reply 6, posted (10 years 3 months 1 week 3 days 16 hours ago) and read 5098 times:

In which case I stand corrected.

User currently offlineKAUST From United States of America, joined Jun 2009, 110 posts, RR: 25
Reply 7, posted (10 years 3 months 1 week 3 days 15 hours ago) and read 5097 times:

There are always exceptions, such as American Airlines 1420 in Little Rock. Plane flew through and landed in a severe thunderstorm with 75 miles per hour crosswinds and used a visual approach.

I am no pilot yet, but that is not a very smart way to land an aircraft full of 100+ people.

Or for take offs for that matter, such as Pan Am 759 in New Orleans that took off in a severe storm and stalled on climb-out as a result of windshear.

So for that very reason, yes for the most part flights are routed to avoid the brunt of the storm, in order for occurances such these to be avoided. I had been on numerous occassion in an airliner flying in bad weather, but nowhere close enough to the storm center to feel anything more than a mild bump here and there.

KAUST



"Houston, this is Apollo 8. We are now in Lunar orbit."
User currently offlineBuckfifty From Canada, joined Oct 2001, 1316 posts, RR: 19
Reply 8, posted (10 years 3 months 1 week 3 days 10 hours ago) and read 5055 times:

Not neccessarily true. Many modern weather radars have the capability of detecting and displaying turbulance and windshear.

Not necessarily true either. Turbulence can only be detected if there is significant moisture in the air (water droplets), which usually means clouds (or big ones therein).

Windshear detection is a little different, it computes the aircraft's flight profile vs. the angle of attack and thrust setting. However, this function is only appreciably used during the critical phases of flight. In cruise, windshear effects are nominal, and is not really considered.

We've done a lot of flying through typhoons lately, and even though met forcasts indicate turbulence and severe weather in the area, we usually won't know exactly what it is until we get there. More often than not, SIGWX and other sorts of severe weather advisories do not indicate the true conditions in the area, and often we find ourselves in smooth air where the chart says "typhoon". It is up to the crew to decide how to divert around the storms or areas of turbulence when it comes to the nitty gritty. ATC will not, unless in certain unique circumstances, vector you around bad weather.

The weather radar is an important tool, though it is not exactly the most accurate device there is to indicate weather. It requires a skilled operator (usually meaning years of experience) to use it to it's full potential (i.e. what azimuth to scan to get the most accurate picture). The naked eye is usually your best bet, though it really can't help you a whole lot in the dark. That's why you will find that flights tend to be bumpier at night than they are during the daytime.


User currently offlinePhilsquares From , joined Dec 1969, posts, RR:
Reply 9, posted (10 years 3 months 1 week 3 days 8 hours ago) and read 5027 times:

1) The WX radar on the 744 will not detect turbulence in a clear sky. In the WX/TURB mode it will detect turbulence associated with precipitation. However, it is not all that good, sometimes you have to take the gain out of auto and really play with it to get a decent return.

2) Remember that in filing a flight plan it doesn't really mean that's what you're going to fly. However, in the original posting, the departure is most likely the only one that will work. But, that doesn't mean it will be actually flown. If there is weather, LA centre will certainly provide either a direct routing or vectors around the weather.

3) As far as the crew taking weather into account in flight planning, it is true to a degree. In today's airlines, dispatch generally does all the flight planning and they take a look at the weather, both enroute and destination. No crew shows up in ops and starts from scratch on an international long haul flight. There just isn't enough of time to do that.

4) Finally, please remember, the weather forecast is just that, a forecast. In some situations the forecast I am using will be 18 hours old when I arrive at my destination. Quite a lot can change during that time.


User currently offlinePilotpip From United States of America, joined Sep 2003, 3152 posts, RR: 10
Reply 10, posted (10 years 3 months 1 week 3 days 2 hours ago) and read 4973 times:

Wardialer,

Don't let it get to you. It's all apart of moving through the ocean up there that is the sky. Keep your seatbelt on and don't worry about that wing ripping off. It can take more than you  Big thumbs up

As for bad weather, pilots know what to look for. They don't need all the high tech detection all the time. The best detectors they have are the aircraft that went through the same area before them. Unless it's unavoidable, ATC in the US goes out of it's way to keep aircraft in favorable conditions. If it's getting bumpy, you'll often hear them asking other aircraft in the same area but at different altitudes how the ride is. If the ride is better and spacing allows, the controller will more than likely ask the pilots if they want that altitude.

Also, any airline will take a delay in the intrest of safety. Last summer, MEM was getting some severe thunderstorms in the area. We had an MD-11 divert to STL. I was talking to the F/O while I was fueling and he told me that their windshear detection started going off 1 mile from the outer marker at MEM (about 6nm from the airport). The captain put the power in, went missed. Knowing that the weather was getting worse, he diverted to STL with minimum fuel. The guys up front usually won't take chances if it risks safety. Every one of the accidents mentioned in posts above have been brought up in my CRM classes and other training as exactly what NOT to do.



DMI
User currently offlineWardialer From United States of America, joined Sep 2001, 1183 posts, RR: 0
Reply 11, posted (10 years 3 months 1 week 3 days 2 hours ago) and read 4959 times:

Correct me if Im wrong, but most pilots, esp. overseas pilots will actually preferr more turbulence and going through a nice 150KT tailwind at the same time than no turbulence at all.

For instance, lets say theres a nice tailwind (jetstream) about 150KT WITH moderate turbulence, most pilots will take the turbulent flght through that particular jetstream than flying with no jetream at all.

Meaning , that a pilot WILL NOT care if the flight is bumpy as long as the flight cuts its time off by like an hour or so. Or, to save more fuel.

I hope this is understanding.

And BTW, pilots are so used to flighing in bumpy weather that they dont usually care as long as they get there ahead of schedule.


User currently offlineAirplay From , joined Dec 1969, posts, RR:
Reply 12, posted (10 years 3 months 1 week 2 days 23 hours ago) and read 4921 times:

Windshear detection is a little different, it computes the aircraft's flight profile vs. the angle of attack and thrust setting.

Thats not the type of windshear detection we're talking about. There are two types: "Reactive" and "Predictive" windshear detection. The type that detects rapid changes in performance (not just AOA) is reactive and the airplane must be immersed in the windshear for it to provide alerts and warnings.

The windshear detection system associated with weather radar is the "predictive" type. It actually determines the presense of intense turbulence by measuring doppler shift in radar returns.

However, this function is only appreciably used during the critical phases of flight. In cruise, windshear effects are nominal, and is not really considered.

Predictive windshear is often used on line-up to detect windshear in the flight path prior to takeoff.

The WX radar on the 744 will not detect turbulence in a clear sky.

That is correct. There is no system that is as yet available that detects clear air turbulence. However, this type of turbulence is typically not as severe as turbulence associated with visible moisture. Of course there have been exceptions...

However, it is not all that good, sometimes you have to take the gain out of auto and really play with it to get a decent return.

True. The turbulence detection function isn't exactly a perfect system. But neither is the weather radar. There is still a great deal of interpretation skill needed.


User currently offlineVS346 From United States of America, joined Mar 2004, 339 posts, RR: 1
Reply 13, posted (10 years 3 months 1 week 2 days 23 hours ago) and read 4917 times:

Meaning , that a pilot WILL NOT care if the flight is bumpy as long as the flight cuts its time off by like an hour or so. Or, to save more fuel.

That may be true, or not, I dont know, but the thing to remember is the pilot will never do something that would be considered unsafe on purpose. If it would be too unsafe to use that 150KT tailwind, he wouldn't use it, EVEN if it saved him time or fuel. His life and the lives of the people on board are still a priority.

Hope all is well on your flight, don't panic!

VS346



Virgin-Atlantic: More experience than our name suggests
User currently offlinePhilsquares From , joined Dec 1969, posts, RR:
Reply 14, posted (10 years 3 months 1 week 2 days 23 hours ago) and read 4909 times:

A note to Wardialer. I don't know where you got your information but it is wrong. Pilots do care about the ride and moderate turbulence.

Although, we try to accomplish the flight in the flight time/fuel or less, getting to a destination an hour early isn't always a good idea. You run into problems like gate availability. So, sitting on the ramp for 45 minutes waiting for a gate isn't desirable.

On a 14-16 hour flight the winds are normally fairly accurate, but generally you can plan to arrive +/- 10 minutes of flight plan.

On a personal note, flying in moderate turbulence is a real pain. It is very difficult if not impossible to have any type of cabin service, people tend to get sick. All in all, it's not a good experience!!


User currently offlineWardialer From United States of America, joined Sep 2001, 1183 posts, RR: 0
Reply 15, posted (10 years 3 months 1 week 2 days 22 hours ago) and read 4899 times:

Ok, now your making me nervous about saying that a bumpy flight is dangerous.

Or do you guys mean its dangerous for the passengers who are not buckled up and not the aircraft itself???


User currently offlineXFSUgimpLB41X From United States of America, joined Aug 2000, 4229 posts, RR: 37
Reply 16, posted (10 years 3 months 1 week 2 days 22 hours ago) and read 4894 times:

Where did he say it is dangerous? It's just a pain in the butt since you cant have in flight service and the peoples cant get up and run around and use the bathroom. They get sick..and its kinda annoying bouncing around like that for hours on end.

The aircraft can handle alot more than you can imagine.



Chicks dig winglets.
User currently onlineStarlionblue From Greenland, joined Feb 2004, 17172 posts, RR: 66
Reply 17, posted (10 years 3 months 1 week 2 days 21 hours ago) and read 4880 times:

Philsquares said moderate turbulence. This is a relative term and
my understanding is that most pax would call this "severe"  Big grin



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinePhilsquares From , joined Dec 1969, posts, RR:
Reply 18, posted (10 years 3 months 1 week 2 days 21 hours ago) and read 4881 times:

My comments were in reference to what Wardialer wrote. He specifically talked about "moderate" turbulence. There is always the plain old type of chop that is more annoying than anything else. But to cut through the Jet, I can assure you, you will get moderate turbulence. Generally, flying within +/- 2000 feet of the trop and you will get continuous light-moderate chop. Not a fun time on a 14 hour flight.

Is it dangerous for pax who are not buckled up? In moderate turbulence, yes!!! It might sound trite, but when I make a PA at the beginning of the flight, I always recommend passengers keep their seat belts fastened throughout the whole flight, just like we do in the cockpit.



User currently offlineBuckfifty From Canada, joined Oct 2001, 1316 posts, RR: 19
Reply 19, posted (10 years 3 months 1 week 2 days 20 hours ago) and read 4868 times:

The windshear detection system associated with weather radar is the "predictive" type. It actually determines the presense of intense turbulence by measuring doppler shift in radar returns.

This system in general is part of the turbulence detection present in the WX radar, and I regard the function as limited in the same way. Once again, it relies heavily on precipitation in order to get any sort of returns. However, in many cases, predictive windshear cannot detect windshear at places such as HKG, where it almost happens daily due to the winds coming off the hills over Lantau. Detection of this kind depends on pilot reports, and also on the windshear detection system employed at the airport.

Predictive windshear is often used on line-up to detect windshear in the flight path prior to takeoff.

That is true. However, not all modern aircraft actually have this system built in, due to the limitations that I described above. The aircraft I fly on, for example, don't.


User currently offlineLiamksa From Australia, joined Oct 2001, 308 posts, RR: 0
Reply 20, posted (10 years 3 months 1 week 2 days 20 hours ago) and read 4857 times:

For interest's sake a couple of definitions form the Aussie docs:

Moderate Turbulence. There may be moderate changes in aircraft attitude and/or altitude, but the aircraft remains under positive control at all times - usually, small variations in air speed - changes in accelerometer readings of 0.5g to 1.0g at the aircraft's centre of gravity - difficulty in walking - occupants feel a strain against seat belts - loose objects move about.

Severe Turbulence. Abrupt changes in aircraft attitude and/or altitude - aircraft may be out of control for short periods - usually, large variations in air speed - changes in accelerometer readomgs greater than 1.0g at the aircraft's centre of gravity - occupants are forced violently against seat belts - loose objects are tossed about.


User currently onlineStarlionblue From Greenland, joined Feb 2004, 17172 posts, RR: 66
Reply 21, posted (10 years 3 months 1 week 2 days 19 hours ago) and read 4855 times:

Thank you Liamksa. So it's pretty clear that "Moderate Turbulence" would be defined by many pax as "pretty bad"

"difficulty in walking - occupants feel a strain against seat belts - loose objects move about."



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineFlymia From United States of America, joined Jun 2001, 7276 posts, RR: 6
Reply 22, posted (10 years 3 months 1 week 1 day 20 hours ago) and read 4757 times:

Wardialer: I am no pilot but have flown plenty. I have not heard of turbulance creating a dangerous situation for the aircraft. The plane is made to fly thourgh the worst turbulance you can imagine and do fine. Dont worry about the turbulance just sit back and have a nice flight. Turblance wont hurt much.


"It was just four of us on the flight deck, trying to do our job" (Captain Al Haynes)
User currently offlineAAR90 From United States of America, joined Jan 2000, 3494 posts, RR: 46
Reply 23, posted (10 years 3 months 1 week 1 day 19 hours ago) and read 4742 times:

Correct me if Im wrong, but most pilots, esp. overseas pilots will actually preferr more turbulence and going through a nice 150KT tailwind at the same time than no turbulence at all...

Meaning , that a pilot WILL NOT care if the flight is bumpy as long as the flight cuts its time off by like an hour or so. Or, to save more fuel...

And BTW, pilots are so used to flighing in bumpy weather that they dont usually care as long as they get there ahead of schedule...


I can't speak for "most pilots" but certainly EVERY pilot I've flown with prefers smooth flight rather than a bumpy flight, and an early arrival rather than a late arrival... IN THAT ORDER. That means they'll take the smooth ride over the early arrival.



*NO CARRIER* -- A Naval Aviator's worst nightmare!
User currently offlineCx346 From Greenland, joined Apr 2003, 49 posts, RR: 0
Reply 24, posted (10 years 3 months 1 week 1 day 16 hours ago) and read 4721 times:

Wardialer, I sense that you are anxious about turbulence. Some years and 290'000 miles ago, I HATED turbulence. I was terrified before every single flight. So I did some research into the matter:

a. Many people I have met over the years are actually afraid of aircraft breaking up because of turbulence. The chances of a well-maintained modern airliner breaking up because of turbulence are practically nil.
b. I once sat in a simulator and asked them to simulate turbulence. The WORST amount of shaking I had ever experienced on a flight was nowhere close to the level that would be dangerous to the aircraft's frame. On a scale of 1 to 10, where 10 would cause breakup and 1 is light turbulence, the simulator made me queezy at level 2 and terrified at level 3. Never in over 290'000 miles have I ever experience anything strong than a 3 on that simulator. As I understand it, most airlines have a policy that bars pilots from flying into any wheather that could cause more than level 4. Still 6 levels away from dangerous.

Keep in mind: millions more die each year on the roads to the airport than in the air. Ever since my simulator trip, I worry more in a Bangkok taxi than on a Boeing 747.


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