Month: January 2011

Blog

incognito

I recently took a trip with my good friend James, in a Piper Warrior. We decided to take a short flight from Sarasota to Vero Beach where we attended flight school together. He was recently checked out from a local FBO and we set out for an afternoon flight to have lunch.

It was a good day for VFR flying in Florida and it was to be my first flight back in a light airplane since I started flying for the airline. I was excited to get back in an airplane type that I spent so much time flight instructing in. It was also to be my first time returning to the airport where I instructed since leaving.

We completed the pre-flight together and set out to begin our taxi from the FBO ramp. We decided to split the duties as he would be the PIC, I would work the radios and read the checklists. An ideal model of our strict training and airline protocols.

“Ground, Cherokee 10155, taxi from FBO, VFR, southeast.”

Sarasota is a primary class Charlie airport and in my experience it varies by locale what procedure they want a VFR pilot to use. Some will request you contact clearance delivery for departure instructions, others simply want a direction, Fort Myers will ask if you even want radar services.

“Is there anything else you want to tell me?” Was my reply over the ground frequency. Not in a helpful tone. More so in a condescending, snarky tone.
“Information Foxtrot, sorry.”
“Anything else?”
“I have no idea what you want.”
We exchanged confused looks in the cockpit. We tried to determine between ourselves what he could possibly be looking for from us.

“Cherokee 10155, how about an altitude, and a destination?”
“Ok. K-V-R-B at three thousand five hundred.”
“Otherwise known to the aviation community as Vero Beach.”
Again, a very condescending and demeaning tone came through our headsets.
“After take-off fly heading 090 and maintain VFR at or below 1600. Contact departure on frequency 119.65 and squawk 5156.”
I read back his clearance and heard a reply.
“I didn’t hear a call sign, so I’m going to assume that was Cherokee 10155. Taxi to runway 14 via alpha.”
At this point I was irritated. I began to read back clearances and acknowledgments extremely slowly. We taxied to the runway and completed our run up checklists and departed without incident.

While cruising I took care of the navigation while James flew. Using a sectional chart and my experience as a flight instructor in Florida, we navigated towards the middle of the state. Unlucky for us, the Restricted areas north of Okeechobee were active today which required slight circumnavigation. We also fought a headwind on the way over which made for a longer flight than we expected. I began to think about what it would be like to be a student pilot in Sarasota. I put myself in the shoes of a new student with a typical case of anxiety associated with radio transmissions. There is a very real sense of exposure when a student pushes that mic button. They’re attempting to communicate in a language and way that can often feel foreign and strange. Overcoming this anxiety is a key step in a students training and sometimes takes quite some time and practice to achieve.

As instructors it is our job to facilitate the learning process. Sometimes outside factors can dilute and dismantle this process. I often heard instructors state on the frequency that the student made a mistake, or that they made a mistake because the student did something. What instructors don’t realize is they just violated trust between the student and themselves. I only mention this because had this situation occurred with my student, I would have taken over the radio communications and encouraged the student to continue. I would have followed with a phone call to the tower.

I got the feeling that this controller was very familiar with the flight training that occurs from this FBO. He must also be familiar with the fact that there are many new students coming from this FBO, however that shouldn’t change his tone of communication. I would have requested his preference of communication for a VFR flight out of the Charlie airspace. I might have added how his tone and language have drastic impacts on new students but I don’t know if it would have done any good.

I guess my overall impression after this flight was you don’t always know who’s behind the mic, but you shouldn’t judge the pilot by the aircraft type.

Flying the Line

stick shaker

One of the stall warning indicators the airplane is equipped with is the stick shaker. It helps provide a ‘WAKE UP’ warning to an impending stall. It literally creates vibration in the yoke control that simulates a car on a dirt road feeling. The mechanism that creates it is loud, while holding the yoke with it active it will shake your entire arm.

There is no mistaking what is occurring when you feel and hear the shaker activate.

Recently during a departure from a hub airport, we were cleared for take off immediately following an Airbus 319. You’d be surprised how close they clear us for take off normally, however during this departure they were stacking us pretty close.

This specific hub airport utilizes RNAV(Area Navigation, more commonly known as GPS) departure procedures for all RNAV capable aircraft. This means that the flight path for 99% of the traffic departing the airport is within one tenth of a mile of each other. With adequate lateral and vertical separation it’s never really a problem. During this departure we had significantly less lateral separation, however still beyond the minimum required.

Around 1500 feet above the ground we encountered the wake turbulence from the Airbus.

Predictable.

Wake turbulence is defined as a byproduct of induced drag. As airflow over the wing passes over the tip of the wing, it rolls over as it’s mixed with the air from under the wing. There is a small amount of span-wise flow from the air under the wing that creates a rotational vortex. These vortices flow outward and down from the wing tips of the aircraft. Since these are created as a byproduct of induced drag, the heavier the aircraft, the more intense the vortices. There are other factors that create more wake turbulence such as clean and slow aircraft. Clean referring to lack of high lift device deployment such as flaps or slats. Without those devices employed a higher angle of attack is required for flight which increases lift production, which increases induced drag. Slow aircraft require more angle of attack as the amount of lift generated is directly proportional to the indicated airspeed of the wing.

Put all of these factors together and you can see that during take-off, you have the highest amount of wake turbulence creation after take-off.

Small vibrations of what normal light turbulence feels like first. The captain is hand flying the aircraft throughout the climb. One of the signs of wake turbulence is the rotation force exerted on the aircraft that requires aileron input to keep the wings level. That happened next.

Another stall warning and protection device our aircraft uses is a pitch limit indicator. It shows how close to the stalling angle of attack the aircraft it currently at. It immediately showed that we were less than 3 degrees from stalling angle of attack. Simultaneously the stick shaker activated.

The entire event lasted less than 5 seconds.

I spent years teaching students about the dangers of wake turbulence and the techniques to avoid it. This made me realize I need to be more vigilant about it. Almost every take off and landing we hear ‘caution wake turbulence’ because we’re either landing behind or taking off behind a heavy airplane. Perhaps that dumbs it down a little or dilutes the seriousness of it.

Land above and beyond, rotate before and climb above.