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)
(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.