Ground school teaches student pilots everything they need to know about flying an airplane, regulations, and safety of flight. However, until the student actually experiences the lessons taught in ground school, they cannot relate to the material. For example, we learned in class about light gun signals. The light gun signals are different colored lights which the tower flashes towards an airplane, with an inoperative radio, to communicate. The signals instruct the pilot if it’s safe to land, to continue circling, or other instructions the pilots must be ready for. However, until a pilot actually has a broken radio, and needs to communicate by light gun signals, it can be hard for him or her to imagine what that experience would be like.
Something which I recently experienced firsthand, which is taught over and over again in the classroom, is wake turbulence. While an airplane is generating lift, it generates wake turbulence. This turbulence is invisible, but can damage an airplane greatly. The turbulence rotates from the bottom of each wingtip, to the outside of the wingtip, then back over the wing. While looking at an airplane from the rear, the right wingtip creates a counterclockwise vortex, while the left wingtip generates a clockwise vortex. These vortices trail the plane and sink below the aircraft’s flight path. Planes from as large at the space shuttle, to training airplanes like the Piper I use, all generate wake turbulence, however it is the size of the plane which dictates the strength of the turbulence. As you may have guessed, the larger and heavier the plane, the greater the wake turbulence. Planes which are heavy, clean (meaning no landing gear or flaps extended) and slow, produce the greatest wake turbulence.
The day I got firsthand experience of wake turbulence was on a nice clear day, when I was practicing touch and goes. My instructor and I decided to fly over to MacArthur Airport (check out the airports I’ve flown to, to see what MacArthur looks like) to practice landings so I can get use to flying to different paces. There are 4 runways there, but only one of the runways can facilitate the takeoffs, and landings of the heavy Boeing 737’s, which are operated by Southwest Airlines. (It is common to see 737’s flying in and out of MacArthur, while training there.) After I had done 5 or 6 touch and goes, the tower instructed me to change the runway which I would be using. I radioed back my change of course for the new runway. The reason for this (which I was about to find out) was because a Southwest jet needed to use the longer runway, which I had been using, for a takeoff. It was a little tricky getting into the downwind for the new runway assignment because the two runways, the first runway I used and the new one, are perpendicular of one another. This caused my downwind leg to be almost 2 miles wide. My instructor told me that the wide downwind leg wasn’t a concern so I continued. I entered base at the proper spot, and then eventually turned to final. The turn to final ended up being about 4 miles out, so I had a clear view of the whole airport, and all its’ runway surfaces. The runway I was using was parallel with another runway, which was also in use, and I could see the first runway I had been using now had a large orange and blue 737 sitting at the one end. Because the final was so long, I had expected the 737 to takeoff before I was close to my runway’s threshold. However, at the mile and a quarter mark, the tower radioed to me to caution for wake turbulence from the departing 737, and at that moment, the 737 started rolling down the runway. (The threshold of the runway I was using is located about 4/5ths, down the runway of the perpendicular runway, which the 737 was using. The two runways don’t intersect; however, the far edge of the 737’s runway is where my runway started.) I acknowledged the wake turbulence warning and watched the 737 pick up speed. The jet rotated almost directly in front of me, while I was about a mile away from my runway. This may sound like a close call, but when on final, the airspeed is slow enough that this distance is sufficient for both airplanes to continue flying normally. Because the rotation of the 737 occurred in front of me, my instructor told me not to worry about the wake turbulence of the heavy jet. We expected that because the wake sinks below the airplane, we would miss it. We were wrong. While at an altitude of about 80 feet, and a speed of 70 knots, we hit the wake turbulence. My little piper warrior shuttered and dropped 50 feet in less than a second. The force caused my instructor to instinctually grab the control. I was less than 10 seconds away from wheels on the runway when we hit the 737’s wake. Because my Warrior dropped dramatically from the wake, my head hit the roof of the cockpit and my headset flew off. After only a second or two, I knew what had happened. My instructor knew it sooner than me and was already realigning our plane with the runway. He knew that the encounter with the wake threw me off. However, I was still able to land the plane myself for another touch and go.
What both my instructor and I didn’t take into account was the wind. Planes generally take off into the wind in order to produce lift more easily that with a tailwind. However, since the 737 was taking off into a crosswind, (I was doing touch and goes into a head wind) the wind blew its’ wake into my flight path. I would say it was the first major “non-planned” lesson of my flying career, and one that I’ll never forget!
Something which I recently experienced firsthand, which is taught over and over again in the classroom, is wake turbulence. While an airplane is generating lift, it generates wake turbulence. This turbulence is invisible, but can damage an airplane greatly. The turbulence rotates from the bottom of each wingtip, to the outside of the wingtip, then back over the wing. While looking at an airplane from the rear, the right wingtip creates a counterclockwise vortex, while the left wingtip generates a clockwise vortex. These vortices trail the plane and sink below the aircraft’s flight path. Planes from as large at the space shuttle, to training airplanes like the Piper I use, all generate wake turbulence, however it is the size of the plane which dictates the strength of the turbulence. As you may have guessed, the larger and heavier the plane, the greater the wake turbulence. Planes which are heavy, clean (meaning no landing gear or flaps extended) and slow, produce the greatest wake turbulence.
The day I got firsthand experience of wake turbulence was on a nice clear day, when I was practicing touch and goes. My instructor and I decided to fly over to MacArthur Airport (check out the airports I’ve flown to, to see what MacArthur looks like) to practice landings so I can get use to flying to different paces. There are 4 runways there, but only one of the runways can facilitate the takeoffs, and landings of the heavy Boeing 737’s, which are operated by Southwest Airlines. (It is common to see 737’s flying in and out of MacArthur, while training there.) After I had done 5 or 6 touch and goes, the tower instructed me to change the runway which I would be using. I radioed back my change of course for the new runway. The reason for this (which I was about to find out) was because a Southwest jet needed to use the longer runway, which I had been using, for a takeoff. It was a little tricky getting into the downwind for the new runway assignment because the two runways, the first runway I used and the new one, are perpendicular of one another. This caused my downwind leg to be almost 2 miles wide. My instructor told me that the wide downwind leg wasn’t a concern so I continued. I entered base at the proper spot, and then eventually turned to final. The turn to final ended up being about 4 miles out, so I had a clear view of the whole airport, and all its’ runway surfaces. The runway I was using was parallel with another runway, which was also in use, and I could see the first runway I had been using now had a large orange and blue 737 sitting at the one end. Because the final was so long, I had expected the 737 to takeoff before I was close to my runway’s threshold. However, at the mile and a quarter mark, the tower radioed to me to caution for wake turbulence from the departing 737, and at that moment, the 737 started rolling down the runway. (The threshold of the runway I was using is located about 4/5ths, down the runway of the perpendicular runway, which the 737 was using. The two runways don’t intersect; however, the far edge of the 737’s runway is where my runway started.) I acknowledged the wake turbulence warning and watched the 737 pick up speed. The jet rotated almost directly in front of me, while I was about a mile away from my runway. This may sound like a close call, but when on final, the airspeed is slow enough that this distance is sufficient for both airplanes to continue flying normally. Because the rotation of the 737 occurred in front of me, my instructor told me not to worry about the wake turbulence of the heavy jet. We expected that because the wake sinks below the airplane, we would miss it. We were wrong. While at an altitude of about 80 feet, and a speed of 70 knots, we hit the wake turbulence. My little piper warrior shuttered and dropped 50 feet in less than a second. The force caused my instructor to instinctually grab the control. I was less than 10 seconds away from wheels on the runway when we hit the 737’s wake. Because my Warrior dropped dramatically from the wake, my head hit the roof of the cockpit and my headset flew off. After only a second or two, I knew what had happened. My instructor knew it sooner than me and was already realigning our plane with the runway. He knew that the encounter with the wake threw me off. However, I was still able to land the plane myself for another touch and go.
What both my instructor and I didn’t take into account was the wind. Planes generally take off into the wind in order to produce lift more easily that with a tailwind. However, since the 737 was taking off into a crosswind, (I was doing touch and goes into a head wind) the wind blew its’ wake into my flight path. I would say it was the first major “non-planned” lesson of my flying career, and one that I’ll never forget!
