Monday, May 7, 2012

Caution Wake Turbulance

It was just another nice spring afternoon in the Dallas Fort Worth area. The weather was nice, skies clear, winds mild out of the south at about 8-10 kts. We had to Taxi to runway 17c for take off. This is an east side runway, we park on the west side. You have to taxi across one of four bridges to access the east and west sides. After crossing the top of the zulu bridge we could see there was only a couple of planes ahead, so we started the number two engine.
a couple minutes later we reach the end of runway 17c. We don't even stop as the tower controller clears us to "line up and wait Runway 17c". An MD80, or super 80 is on the takeoff roll ahead of us. Again the controller calls with take off instructions and we don't stop.

It's my leg, the caption hands over control of the aircraft to me I advance to takeoff thrust and moments later we're airborne. This whole time I'm very aware of the close proximity to the 80. This whole time I'm considering things like his flight path, where the winds are and how close I am to him. SO whats the big deal? well wake turbulence is turbulence that forms behind an aircraft as it passes through the air.

Wingtip vortices occur when a wing is generating lift. Air from below the wing is drawn around the wingtip into the region above the wing by the lower pressure above the wing, causing a vortex to trail from each wingtip. Wake turbulence exists in the vortex flow behind the wing. The strength of wingtip vortices is determined primarily by the weight and airspeed of the aircraft. Wingtip vortices make up the primary and most dangerous component of wake turbulence.Wake turbulence is especially hazardous in the region behind an aircraft in the takeoff or landing phases of flight. During take-off and landing, aircraft operate at high angle of attack. This flight attitude maximizes the formation of strong vortices. In the vicinity of an airport there can be multiple aircraft, all operating at low speed and low height, and this provides extra risk of wake turbulence with reduced height from which to recover from any upset.
The MD80 is not as notorious as larger aircraft like the 757, and 767 for creating wake turbulence. However it still creates it. I have experienced wake turbulence being created by another regional jet a CRJ 700.
When we think about wake turbulence I think its most commonly thought of during the landing phase. However the strongest wingtip vortices are created when an aircraft is clean, heavy, and slow.
Clean meaning flaps up gear up. The take off climb phase is where this happens. Landing is Dirty (flaps, gear out) slow, and light (compared to take-off weight).

This image shows exactly what it looks like. This can be a very dangerous event. Shortly after 9/11 an airbus A300 crashed in New York. the CVR (cockpit voice recorder) recorded the FO who was the flying pilot say he was in the wake turbulence of a Boeing 747. Unfortunately he over controlled his aircraft to the point he caused structural failure to the aircraft, and they crashed.
A few Years before that a twin engine Baron was on approach to Indianapolis In airport, he flew the plane all the way to the runway, and moments before he would have touched down, his airplane rolled over and impacted in an inverted position, killing the pilot. He was following a B757, and caught the 757's wake.
In 1972 a Delta DC9 crashed after following a heavy DC10 into GSW Greater Southwest Airport killing the three occupants of the DC9. That crash prompted the FAA to create separation standards for aircraft following "Heavy's".
Now you know why my mind is focusing on this MD80. Just about the time I think we should be clear...bam, there it is. It was a light hit which caused the right wing to drop. Next your mind tries to think OK which part of the wake was that. remember it flows in a circular motion. Did we catch an edge that was moving away, or is that the leading edge entering into the whole circle. I believe that was the downward spiral of the wake and in a split second its confirmed.
Now we're inside the wake, we have the left wing drop and the right wing raise, we're starting to roll in the wake. It's time to get busy, It all happens very fast but seams like its an eternity. You want to maintain control, but not over control. Wingtip vortices drop towards the ground, so you don't want to level or go down, you want to continue your climb. Hold the plane level, climb and finally smooth air once again.
The great thing about flying, you always have to be prepared.
As I continued my climb up and away from DFW I couldn't help but think how the phrase Caution wake turbulence is so incredibly appropriate for aviation, and a career in aviation. I just finished my first year as an airline pilot. Honestly it has taken a lot to get used to. I am very fortunate, I have held a set schedule (Line) for several months now. However the schedule is still a little tougher on me then I thought it would be. I have been working 4 days trips, and have learned spending half the month in a hotel is the not most glamorous way to spend your time. Especially at the regional level. We do not have 24 hour overnights in Miami, Or LA or New York.
We have overnights as short as 9-10 hours. Last week I had an overnight in Monroe LA (I can feel your jealousy) we had 9hrs 59min from the time we got out of the airplane, to the time we took off the next morning. In that amount of time we had to catch a taxi to and from the airport to the hotel, check in, eat, shower, iron clothes, and lets not forget TRY to sleep, get up preflight the airplane and get ready to go again.
That is one reason the blog has suffered. Now when I'm home I have found the my Family time is of utmost importance. It does and will come first. I'm so blessed that I have a wonderful wife who supports me 100% and makes life on the road bearable.

Also in my Looooong one year career I have already entered in my first airline bankruptcy. Someone I have never met, yet I would consider him a friend and hope to meet in person someday Rand Peck (A life Aloft, if you do not read his blog you should. it inspired me to do this crazy airline adventure) gave me advice and tips before I ever went to airline training. One was to expect ups and downs (like bankruptcies).

I Don't even know where to start on this subject.In reality there is no where to start. we have NO information. The parent company, our company and our union will not tell us a thing. I believe the reality is it could easily go both ways. Either we come out a strong company and we grow, or they chop us off like we were just an unwanted parasite they never wanted and ALL of us start looking for a job. Either way, it's all good. I am a believer that when one door closes another opens. I'm already thinking about other doors anyway.

So where have I been in a year. Experience wise I have now been through two part 121 checking events. I have 550+ hours in a jet and I have learned a great deal about life as a airline pilot.
I do miss flying the smaller stuff.I do not regret making the move to the airlines, it has been an experience. Another chapter in my book of life. speaking of books, I think maybe its time to read Earnest Gann's "Fate is the hunter" again.

1 comment:

Paul said...

A good read! As I had wondered if you survived the bankruptcy I am glad you are still flying.