Severe Turbulence

[FlyChicaga]

You have began your descent to your destination airport, and are approximately 25 minutes from landing. You pick up an updated ATIS report, and it says: "XXX Airport information Alpha, time 1351Z, winds 290 at 15 gusting to 29, visibility 10, sky clear. Temperature 12, dewpoint 1, altimeter 30.05. ILS runway 23L approach in use. Landing runway 23L. Departing runway 23R and 27. LLWAS advisories are in effect. Occasional severe turbulence reported below 8000 feet west of airport. Advise on initial contact you have Alpha.

Now, knowing you cannot dispatch into known severe turbulence, what would you do in this situation? You have reports of gusts of approximately 15 knots, windshear alerts, and reported severe turbulence (unknown type reporting).

You have enough fuel to arrive at the destination, fly to your alternate, and for exactly 45 minutes after. Nothing extra.

[pscraig]

I'd approach the airport from the east, stay as high as possible as long as possible and request the visual runway 23L, minimizing our exposure to the turbulent sector. I'd brief the cabin crew and passengers that we may have a rough ride ahead, and discuss windshear procedure with the FO.

[Mr_Creepy]

Depends on who reported it. If it was a C172 then LOL I'm continuing.

(Most people in C172s and the like have no idea what the definition of severe turbulence entails.)

[Doug Taylor]

I think in our FOM you'll get your pee-pee whacked if you operate in an area of known severe turbulence -- especially if you review the actual definition of severe turbulence.

"...large, abrupt changes in altitude and/or attitude. It usually causes large variations in indicated airspeed. Aircraft may be momentarily out of control...."

I'd probably start talking to ATC about how other air carriers are getting thru the area, figure out who reported the severe turbulence and when and certainly talk to flight control.

If you have an injury while in a known area of severe turbulence, you're hosed.

[coldsolderjoint]

ooohh... X rated airport.. Sounds like fun!

[FL270]

Agree with Doug that you need to comply with company SOP. Definitely talk with dispatch and ATC and get details. If the turbc is west of the airport and you're coming in from the east, you might be OK. If not, diversion to the alternate (or another suitable airport upon discussion with dx) is probably in order. A lot of "gray area" on that one, depending on some of the intangibles. Also like John said, if it was a 172 reporting it, they probably don't actually understand the definition of "severe" ... food for thought.

And for the up-and-comers out there ... stuff like this is why we deserve to earn a decent living. The job isn't just pitching for 250 until 10k then turning George on. It is judgment calls about stuff like this that we make every day. Don't let anybody try to convince you otherwise ...

[Mr_Creepy]

Again, I would query the report of severe turbulence.

I have heard student pilots report severe turbulence before, and it ends up in the next ATIS.

[Doug Taylor]

Specifically what does your companies FOM say? That's the big question. Plus, which airport?

If you get a severe tubulence report from a class B airport, it's of a much higher significance than recieving one in Fresno.

[mtsu_av8er]

[ QUOTE ]
Again, I would query the report of severe turbulence.

I have heard student pilots report severe turbulence before, and it ends up in the next ATIS.

[/ QUOTE ]

May have been severe, in their eyes....

[FL270]

[ QUOTE ]
May have been severe, in their eyes....

[/ QUOTE ]I don't think anybody is arguing that, Lloyd. However, the definition of severe turbulence is not really subjective, nor based on aircraft size or pilot experience. It is objectively defined to apply to all aircraft regardless of size ... see the relevant quote from Doug above.

Again, as has been said, who reported it and where? If it was a light aircraft, you may have the subjectivity issue to deal with. Even if it is in the airspace of a major air carrier airport (ATL, etc.), the surrounding airspace is full of bug-smashers at a variety of altitudes. If it is a hub, you should have reports from multiple aircraft to rely on in making a judgment call. Ultimately, of course, one's best judgment (ensuring compliance with company policy) is the trump card here.

[mtsu_av8er]

[ QUOTE ]
[ QUOTE ]
May have been severe, in their eyes....

[/ QUOTE ]I don't think anybody is arguing that, Lloyd. However, the definition of severe turbulence is not really subjective, nor based on aircraft size or pilot experience. It is objectively defined to apply to all aircraft regardless of size ... see the relevant quote from Doug above.

[/ QUOTE ]

Agree...to a certain extent.

However, what may very well be severe turbulence may not affect a 737 the same way that it does a Cessna 172. Simply because it's light turbulence to a 737 doesn't mean that it isn't severe for a Cessna 172.

Not arguing...lol.

[Mr_Creepy]

I don't know if that's true Lloyd.

The actions that define severe turbulence are the same for any aircraft (see below.)

Private pilots, student pilots, and other low-time pilots who fly only on sunny days may not know how turbulence is defined. It doesn't matter if they are in a C-172 or not, I just used that as an indicator for the possible low experience level of the pilot.

If I recall (and my recollection powers are fading!) there is a specific definition for severe turbulence: (edit: in fact I didn't even recall that Doug had already posted this. Senility! I'm heading for the Home!)

[ QUOTE ]
Airplane behavior: Turbulence that causes large, abrupt changes in altitude and/or attitude. It usually causes large variations in indicated airspeed. Aircraft may be momentarily out of control. Report as Severe Turbulence.

Inside the airplane: Occupants are forced violently against seat belts or shoulder straps. Unsecured objects are tossed about. Food Service and walking are impossible.

[/ QUOTE ]

I've been in C-172s with students and they start calling some moderate chop severe turbulence. Or more often, they'll report moderate turbulence.

Moderate turbulence is BAD folks:
[ QUOTE ]
Turbulence that is similar to Light Turbulence but of greater intensity. Changes in altitude and/or attitude occur but the aircraft remains in positive control at all times. It usually causes variations in indicated airspeed.

[/ QUOTE ]

All definitions from: http://www.faa.gov/atpubs/AIM/Chap7/aim0701.html#7-1-23

[jonnyb]

I think what several of us are trying to say is, I'm going to take a severe turbulence pirep from a 737 crew or two a lot more seriously than from a Cessna 172 pilot. This is assuming I'm flying a transport category airplane. If I'm in a 172 as well, then the pucker factor might increase a bit.

[mtsu_av8er]

[ QUOTE ]
I don't know if that's true Lloyd.

The actions that define severe turbulence are the same for any aircraft (see below.)
[/agreed]

[ QUOTE ]


If I recall (and my recollection powers are fading!) there is a specific definition for severe turbulence: (edit: in fact I didn't even recall that Doug had already posted this. Senility! I'm heading for the Home!)


[/ QUOTE ]

You forgot your sarcasm tag...

[ QUOTE ]
Airplane behavior: Turbulence that causes large, abrupt changes in altitude and/or attitude. It usually causes large variations in indicated airspeed. Aircraft may be momentarily out of control. Report as Severe Turbulence.

[/ QUOTE ]

So, is it possible that I may encounter those conditions, but since the 737 behind me weighs 100,000 lbs, t's not as bad? I'd say that physics indicate yes. Now, if the 172 reported severe turbulence, it's severe turbulence, although it may not affect the 737 near as much. It's still severe turbulence.

Works the other way around to me....what's light chop in a 737 may indeed be moderate or greater to me.

Now, if the 737 drivers don't like the fact that the "little 172" is reporting severe turbulence, then he can buy his own private airspace. As a taxpayer, I want to know when there's severe turbulence, even though it's not severe to the 737. Irritate him? Oh, well....

I've been in C-172s with students and they start calling some moderate chop severe turbulence. Or more often, they'll report moderate turbulence.

[ QUOTE ]

Moderate turbulence is BAD folks:

[/ QUOTE ]No, it's moderate....

[jonnyb]

Isn't that kinda what I said Lloyd?
[ QUOTE ]

I think what several of us are trying to say is, I'm going to take a severe turbulence pirep from a 737 crew or two a lot more seriously than from a Cessna 172 pilot. This is assuming I'm flying a transport category airplane. If I'm in a 172 as well, then the pucker factor might increase a bit.

[/ QUOTE ]
Basically, the rule of thumb is to take the report in CONTEXT .

[mtsu_av8er]

[ QUOTE ]
Isn't that kinda what I said Lloyd?

[/ QUOTE ]

Hey, watch it buddy...I was talking to JT...

I got ya!

[jonnyb]

Cool.

[Mr_Creepy]

The C-172 should not report Severe Turbulence unless it matches the definition!

End of story.

[mtsu_av8er]

[ QUOTE ]
The C-172 should not report Severe Turbulence unless it matches the definition!

End of story.

[/ QUOTE ]

Dangit, JT...relax and read what I said! If the C-172 is experiencing severe turbulence, then (s)he should report it as such! Now, if those conditions don't rock the 737 as much, oh well! The pilot is lucky his airplane isn't affected as much. It's still severe in the 172!!

End of story. (Not really...just letting you know how silly that sounded...).

Are we having a breakdown in our communication here? Are you reading what I'm saying, or just demanding that I'm wrong?

I'm confused....

[jonnyb]

I gotcha Lloyd. I thought we already solved this.... Oh, that's right.......A----B conversation. I'll Ceee my way out. I'm sure JT will get it the second time he reads it.

[mtsu_av8er]

[ QUOTE ]
I gotcha Lloyd. I thought we already solved this.... Oh, that's right.......A----B conversation. I'll Ceee my way out. I'm sure JT will get it the second time he reads it.

[/ QUOTE ]

No, you're cool...lol. I'm just going to Ceee my way out, too...lol.

[Doug Taylor]

As far as I remember, it's usually "...moderate turbulence reported at one-six thousand by a Beech Baron" unless I'm imagining things.

But considering the average pilots knowledge of what light/moderate/severe turbulence/chop, you've really got to use your judgement and make a decision.

You can err on the side of safety by building an expanded team of people to build a picture of the situation or you can throw caution to the wind and hope it's not really the faa-definition of moderate/severe turbulence and press on.

[Mr_Creepy]

Ah here I go posting one more time.

Lloyd! Nothing against you! Not pointing fingers at anyone!

Well,... I'm pointing my finger at inexperienced pilots who report turbulence incorrectly.

Back to your question though, I tend to think that turblulence is turbulence. A bigger plane may ride through it with less "drama" - but the in-flight indications will be the same. I'm not sure there is such a thing as an "almost moderate" turbulence level that will change the path and altitude of a C-172 but not do so with a B-737. I felt the bumps just as bad in the big one as the little one.

Just my limited experience with that one ...

[Bandit_Driver]

I would have to say I would CYA and follow what is in the company manual and divert unless, I could get a pirep from a larger aircraft in the same area that states something less than severe. Still a tough call...you are potentially damned if you do go (an someone gets hurt) and damned if you don't go and divert (then other airlines start landing there)..

[mtsu_av8er]

OK, John...you're right...that's what you like to hear.