Saturday, May 1, 2010

40 knot windshear ahead!

This chart made up part of our weather package for last night's flight. I circled the waypoint BDF (Bradford, Illinois). On this chart you'll see the culprit jet stream howling from the south-southwest at 150 knots. Each triangle represents 50 knots. The number 'one' depicts the forecast turbulence inside the dash line of moderate intensity up to 41,000 feet. The scalloped area just west of Lake Erie depicts isolated embedded Cbs (Thunderstorms) up to 36,000 feet. The solid black line shows our routing.

(Clicked on the chart for a better view)

As I write, heavy rain pelts on my office windows with thunder reverberating in the distance from thunderstorms I dodged just a few hours ago. As follower Tim commented on my last post, "Always an adventure, eh Doug?" Well here's the scoop:

It's been awhile since I flew out of LAX so finding Air Canada's flight planning area in the bowels of the airport proved to be a challenge. We immediately check out the weather radar because I knew the thunderstorms we deviated around a day ago would still be an issue. These babies have been a major road block/issue for thousands of flights. I rarely call flight dispatch but my meteorological senses were tingling. "We had flights pick their way through this with only 2C reported all day. Looks like you'll have to work your way around them and this is the best route I could come up with," were the words of encouragement I received from dispatch.

(Air Canada uses a rating from 1 to 6 for turbulence. 1. light chop 2. light turbulence 3. moderate chop 4. moderate turbulence 5. severe turbulence 6. extreme turbulence with letters A for occasional B intermittent and C continuous.) In theory the worst I can expect is continuous light turbulence. hmmmmm?

We launch with a full load (146 passengers plus two unsettled babies). For one brand new flight attendant this was her first flight on line. Turns out she was feeling queasy and this was during the smooth portion of the flight.

The flight moved along nicely. (We even scored two J class meals with cookies and ice cream. I must learn to say "no" to that stuff). Although I knew deteriorating conditions lurked ahead.
Albuquerque (New Mexico) ATC came on the radio and nonchalantly stated (may have been a combination of his southern drawl and being up at 3:00 a.m) to expect windshear of 40 knots in the next 50 miles.

At the time, we had a visiting flight attendant trying to stay awake and the f/o and her were discussing marital break downs. (A common topic of conversation among aircrew) I started hearing reports of turbulence from other aircraft so I became detached from the conversation. I get on the radio to fine tune the intensity, exact location and altitudes of this nasty meteorological phenomena. ATC kept saying it was mountain wave activity but to my knowledge no mountains existed, but I didn't want to correct him in the wee hours of the morning.

The visiting flight attendant notices my detachment (probably the same one my wife now and again detects) and exits, but not before I tell her to brief the in-charge turbulence will be up ahead. I discuss our options with the f/o. Our flight plan clearly depicts we will be penetrating the tropopause at the area of concern. (The tropopause is the boundary between the troposphere - the layer in which we live- and the stratosphere. It's where jet streams hang out and where turbulence can occur. Every airline pilot looks to where the "trop" is: above, below or in it). I suggest we descend to FL310, but we have to poke back up quickly in order to circumnavigate the thunderstorms downstream.

Everything is smooth. I watch the airspeed. It's steady. I watch. Then I notice a slight movement. The engines are sensing something as well - indicated by fluctuations. BAAAAMMMMM!!!! The airspeed literally jumps from MACH .76 to well into the overspeed barber pull. The master warning audio blares in the flight deck with red warning lights strobing in our eyes. The autopilot disengages, Captain Doug grabs the sidestick, but the aircraft still lurches 400 feet above where we are suppose to be. I know warnings will be going off in the ATC center. In a curt crisp voice, I tell the f/o, "request FL 310 now!" The controller is in some slow methodical conversation with another aircraft and we can't get a word in. I tell the f/0, "just butt in!"
We descend to FL310, but the airspeed is not increasing but decreasing to "green dot" speed. (Airbus talk for the the best lift/drag ratio). Captain Doug disengages the autothrust system to regain the speed. The first time in 15 years of flying Airbus.

After numerous follow up conversations with ATC things simmer down. I call the in-charge to get a report. No one hurt. We receive this note from dispatch:

Received from FIN XXX "Be advised 120 west of BDF, moderate to severe wind shift...gain of 40 knots overspeed for 3 second gain of 400 feet. Advised ATC. Will write an ASR (Air Safety Report)" Exactly what we encountered!

Now comes the thunderstorms. (For those who know of people claiming an airline pilot is overpaid - send them my way) :)

After numerous heading changes with occasional to continuous light turbulence we finally see tamer skies ahead. It's time to descend into YYZ. Captain Doug greases it on noise abatement runway, 15 left. I mumble to the f/o, "a good way to end it." He knew what I meant.

I set the park brake and open the door to listen to any concerns/comments from passengers. But two burly maintenance guys barge into the flight deck to get our take on things. This is an unusual practice because usually they wait until everyone exits. Apparently they thought the engines went into overspeed. A miscommunication.

Most passengers thanked me with elation. Some gestured of kissing the ground. One passenger paraphrased it nicely, "well captain you earned your pay tonight, thanks for getting us here safely."

On a lighter note many of our LAX flights tend to have the odd celebrity on board. For those enthralled with the T.V show the Bachelor, Jake Pavelka (a commercial pilot himself) was on board. I wanted to hear his take on things, but maintenance had me blocked.

Time to file an ASR and more sleep.


Tim said...

Ok, now THAT I HAVE seen in the sim (the windshear/overspeed). So, from overspeed to green dot? Yeah, been there, seen that. With real-world weather in the sim, including shear and gusts, you can certainly see some of that. Congrats on the greaser at YYZ! Smooth ending to a not-so-smooth flight!

Nathaniel said...

I think somebody deserves just a little more cookies and ice cream. Fascinating post.

From the Flight Deck said...

Tim. Well said, "smooth ending to a not so smooth flight." That's what I meant when I said, "a good way to end it" to my f/o. I have 24 hours to file an ASR but I'll wait until tomorrow. But I'm off to the Bahamas and back early tomorrow. Oh well, management doesn't work Sundays.

Captain Doug

From the Flight Deck said...

Nathaniel. Thanks for the feedback. Just finished dinner and cookies and ice cream would be great right now. But like I said in my post, I have to say "no" to that stuff. Pity!

Captain Doug

whywhyzed said...

On 792 (the noon flight from LAX-YYZ) on Friday we had Peter Gallagher from the O.C amd Bob Blumer from FoodTV on our flight.

You never know with LAX.

Lavi said...

Wow, great post Doug. Just to clear things up: the airplane climbed 400ft in 3 seconds? That sounds like quite the ride. As well, did you disengage the auto thrust in order to add thrust or reduce thrust? Sorry, not sure what the dotted green lines mean. Anyway, glad to hear you and your passengers made it safely onto solid ground. Captain Doug saves the day!

By the way, the word verification that I have to type here to make sure I'm not a robot read "unpoo". Interesting.

SimPilot264 said...

Hi Doug,

Quite a ride back. Was this the same weather system you had to dodge around on the way out? When you get the shear effects - up/down and increase/decrease in speed - is there usually a lateral shift also?

Re my own blog - in "suspension" mode due to a "jobsworth" in a company I did some business with a couple of years ago! It could be resolved by May 10/11, but I'll probably start again with a new i/d. I'll send you an e-mail.

Kind regards,


From the Flight Deck said...

Lavi. Good questions.

By the time, the autopilot disengaged and I took control we were at 35,400 feet.
The three seconds was what the other flight encountered, but I would say that's how long it took us. It truly did happen fast. It's on the top ten list of turbulence encounters for me or even the top five.

I disengaged the autothrust because the speed was decreasing during the descent. The speed was not increasing to where it was set. It turns out the engines have their own sensors and they look after things when the airplane goes into an overspeed situation.

"Unpoo" I concur. I know it rattled me a little.

I'm off to the Bahamas this morning where I'm told, "It's Better in the Bahamas." :)

Captain Doug

Ian said...


You have just proven beyond any doubt why those of us who have professional licences get paid well after the years of slog in the right hand seat. Grand job!

I am hoping for an uneventful crossing of the Atlantic shortly as I head westward - but scattered thunderstorms await out arrival in New Jersey...

If Chris St Clair is around I would hvae thoughr your practical experience of wind shear @ 40kts would be an excellent telly topic!

Cheers - Ian, about to get ready to take a 777 into the sky.

From the Flight Deck said...

whywhyzed. Yes, there's lots of celebrities going back and forth on the LAX flights. While flying as a passenger, I sat next to a famous DJ (Deep South?) touring the world playing music. He had super elite status and his wallet overfloweth. So much so, he bought my book. How was your flight back?


From the Flight Deck said...

Simpilot264. Yes, it's the same system. The thunderstroms are slowly inching eastward. They are moving with an upper trough which sure is moving slow. Hopefully, Captain Ian flying to New Jersey will get in before they hit. Some of them are topping at 50,000 to 55,000 feet. I just checked the TAF for KEWR and so far so good.

We did get a lateral shift on that particular encounter, because the winds broadsided us.

Received your email regarding your blog. Thanks

Captain Doug

From the Flight Deck said...

Ian. I just checked the TAF for EWR and I'm surprised they are not forecasting thunderbumpers especially with a temperature of 31c.

Windshear is an intriguing topic, but for the general public, it may scare the "you know what" out of them. :)

Just did a Nassau, Bahamas turn. The flights were relatively uneventful. Although YYZ ATC put us high on the approach. I was taken aback because lately they rarely do this. A case in point, never let your guard down.

A huge line up awaited us at Canadian customs. The f/o and I decided to butt ahead of the line. We were sent to secondary for a search.

I'm finally off for four and a half days.

Give that 777 of yours the "message." Enjoy Jersey!


Mark said...

Doug, you're off for 4.5 days? I guess you will hit the garden tomorrow and continue working outside on the new patio and steps....

Try not to get pulled over this week by the coppers!

Great post, very interesting

PS. I once flew on an Air Canada flight from Calgary to Montreal years ago. The whole WWF Wrester group was on the flight. A few of the guys couldn't use their first class seats becuase the armrests didn't go up and the seats weren't wide enough, so they got relegated to 2 economy seats at the back of the bus. Pretty scarry to see a WWF wrestler pissed off!


GreenPilot said...

GREAT story. I eat up this kind of thing Doug. hard to believe dispatch would give you that type of ominous sendoff though. is that pretty common up at the FL's?

thanks for sharing. keep writing.

From the Flight Deck said...

Greenpilot. The line of thunderstorms were a thorn to flight dispatch for days. I think he tried his best to plan a route with least resistance. It is forbidden to fly through an area of "observed" severe turbulence which of course is different than "forecasted" severe turbulence. And again, it was not the thunderbumpers causing the shear, but the strong jetstream. There was huge shear (change in wind speed) on the horizontal. As far as direction it shifted about 20 degrees.

I received a call from our fleet manager to recount my take on things. He mentioned our company flight said it was some of the roughest stuff they saw in their career.

I don't want to have many days like that.

Captain Doug

Daniel said...

Just back from a great trip to California so have taken a few flights. The landing getting back into Manchester (EGCC) was the smoothest I've ever experienced in heavy metal. I wanted to compliment the pilot but didn't really know what to say without sounding like some wannabe. "Nice landing, Captain" I guess would have been appreciated?

In the end he was busy with other things but it's not the first time I haven't said something when perhaps I should have...

From the Flight Deck said...

Daniel. Every pilot likes to hear, "nice landing." If they don't, they are lying. Most pilots have big egos, or so I'm told, so compliments are appreciated.

There's always next time, even if it's a snug landing. I remember landing in Bermuda with a wicked southwest crosswind. I put it down snugly, but one lady remark,
"that was a good landing because I know how windy it can be here." She pegged it.

Thanks for the post. I'm out the door to go flying. I'll be standing at the doorway after the flight looking for "nice landings." If it wasn't, I'll stay in the flight deck and make the
F/O said good bye. Kidding!

Captain Doug