No matter how much a pilot's heart races at the thought of taking to the skies once again, he/she must temper this passion with the question, "Go or no go?" Already had two "no go's" this week! The weather has not been kind!I had scheduled a lesson for Monday evening at 4 p.m., but when I woke up in the morning and checked the TAF (Terminal Area Forecast) on http://www.aviationweather.gov/, it showed visibility 2 miles, cloud ceiling 1,000 overcast, and wind gusts up to 25 knots. VFR aircraft may only fly in 3 miles visibility, and the pilot must be able to be clear of clouds at all times (500 feet below, 1,000 feet above, and 2,000 feet horizontally). These clouds were too low, visibility too poor, and the wind gusts of 25 knots are a bit much for our little Cessna. I texted Tom with the weather report, and he said that he would check the new forecast when it comes out at 1800Z. And he did. No improvement. I was greatly disappointed, but we rescheduled the lesson for Tuesday at 1 p.m.
On Tuesday morning, I woke up with a start. Charged to the computer and checked the TAF. Visibility 6 miles in the afternoon, calmer wind, but a ceiling of only 1,000 feet. Tom and I had high hopes that the clouds would burn off in time for our lesson, but when I was pulling up to Atlantic, Tom texted me and told me to come to the API office. When I arrived, he pointed out that the ceiling (lowest cloud layer classifed as Broken or Overcast) had risen to 1,200 feet, but still not high enough for us. Sadness!
Met up with Tom and did some ground school work instead. Discussed the practical test standards which I must meet in order to earn the PPL. I will be tested using a combination of written tests, an oral exam, and a checkride in the airplane. Tom told me that the examiner is a stickler for details, but I must also establish the fact that I possess excellent judgment. If I were asked "What type of weather is required for VFR flight?", I would respond by quoting the VFR minimums according to regulation, but also explain that if a METAR shows weather that is better than minimums, but very close to those minimums, I would still wait to fly. Even if the weather at my departure airport is above minimums, I might encounter below-minimum weather after takeoff, which would in the least cause me to divert from my flight plan and cause inconvenience, but at most might result in an accident. A pilot must constantly ensure safety of the aircraft and passengers, and must possess the judgment to ensure that safety.
Covered the four turning tendencies generated by the physics of the airplane: P-Factor, Spiral Slipstream, Torque, and Gyroscopic Precession.
* P-Factor: When the propeller is turning with a high angle of attack, such as in a climb, the downstroke side of the propeller has a higher angle of attack than the upstroke side, and creates more thrust on the downstroke side. This tends to pull the plane to the left at high power and low airspeed. Very prevalent on takeoff. Countered with right rudder.
* Spiral Slipstream: The propeller causes a spiral of air to rotate about the airplane in flight, and this spiral of air strikes the vertical stabilizer, yawing the airplane to the left. Also prevalent at lower airspeeds. Countered with right rudder.
* Torque: According to Isaac Newton's third law, any action has an equal and opposite reaction. Since the propeller is turning clockwise (from the pilot's point of view), it also generates an opposite motion which tends to roll the entire airplane counter-clockwise. Countered with a little bit of right bank, although most modern airplanes are designed to account for this torque in level flight by centering the propeller shaft slightly to the right.
* Gyroscopic Precession: The spinning propeller acts as a gyroscope at the front of the aircraft. When the aircraft climbs, it creates downward (opposite) pressure on the shaft, which translates to forward pressure on the bottom of the propeller and a right-turn tendency as the force on the shaft is felt 90 degrees later in the propeller rotation. When the aircraft is pitching downward for a descent, the upward pressure on the shaft translates to a left-turn tendency. Countered with opposite rudder (left rudder in a climb, right rudder in a descent).
So, the ground school lesson was uneventful, but necessary. Bought four books: Private Pilot Practical Test Standards for Airplane Single Engine Land and Sea, FAR/AIM (Federal Aviation Regulations / Aeronautical Information Manual), Pilot's Handbook of Aeronautical Knowledge, and the Private Pilot Oral Exam Guide. I'm very impressed by the full color illustrations in the Aeronautical Knowledge handbook. I'm going to be doing a LOT of reading.
Are you ready for me to get back in the plane? Me, too!
Headed home; looked over all of my materials. Watched more of the DVD course; learning about ground reference maneuvers and turns around a point. Anxiously waiting for the weather to clear up. Tomorrow is another day.
- Airman Eric
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