Aircraft Dispatcher Exam: Lesson One — Aerodynamics and Aircraft Systems — Ailerons, Flight Controls and Trim Tabs

One of my 2018 goals that I know of already is to become a licensed aircraft dispatcher. The aircraft dispatcher exam (ADX) shares many of the same questions as the airline transport pilot (ATP) exam, as thirteen areas for testing are identical. In preparation for 2017 rolling into 2018, I will be posting a series of blog post lessons, which will include 10-20 questions each, the correct answers, and some discussion and explanations.

Aerodynamics and Aircraft Systems – Overview of Subsections

The Aerodynamics and Aircraft Systems section covers a lot of topics, called subsections.  Some of the questions may be basic private pilot stuff, but there are questions on turbine engine systems, de-ice, anti-ice, glass cockpit systems and more.  Below is the list of subsections and the number of questions in my question bank:

  • Ailerons, Flight Controls and Trim Tabs (14 questions)
  • Wing Lift Devices (20 questions)
  • Lift and Drag (20 questions)
  • Stall Speeds (14 questions)
  • Load Factor (6 questions)
  • Turns and Climbs (11 questions)
  • Stability and Loading (13 questions)
  • Takeoff and Landing Performance (14 questions)
  • Maximum Range (7 questions)
  • Propeller Pitch, Engine Performance and Turbochargers (6 questions)
  • Multi-Engine Airplane Operation (14 questions)
  • Turbine-Engine Operation (11 questions)
  • Compressor Stall (5 questions)
  • Mach Flight (12 questions)
  • Hydroplaning (8 questions)
  • Thrust Reversers (3 questions)
  • Aircraft Icing and Performance, De-icing, Anti-icing (20 questions)
  • Pitot-static and Altimeter Systems (5 questions)
  • Glass Cockpit Systems (9 questions)

Aerodynamics and Aircraft Systems – Ailerons, Flight Controls and Trim Tabs

Question 1.  What is the purpose of the servo tab?

a. Move the flight controls in the event of manual reversion.

b. Reduce control forces by deflecting the proper direction to move a primary flight control.

c. Prevent a control surface from moving to a full deflection position due to aerodynamic forces.

The correct answer is ‘b’ – Reduce control forces by deflecting the proper direction to move a primary flight control. Servo tabs reduce control forces by deflecting in the proper direction to move a primary flight control. You can read more about servo tabs on Wikipedia.

Question 2. When are inboard ailerons normally used?

a. Low-speed flight only.

b. High-speed flight only.

c. Low-speed and high speed flight.

The correct answer is ‘c’ – Low speed and high-speed flight. I don’t know the point of this question, but I guess that makes the answer easy to remember (for me). The question is there, I suppose, because some commercial aircraft have inboard ailerons, and some don’t. Airbus aircraft do not have inboard ailerons because they move the flaps differently (straight back as opposed to perpendicular to the hingeline, like a Boeing).

Question 3.  Precise roll control using a rudder on a transport category airline

a. can be effective when turbulence is encountered.

b. is difficult and therefore not recommended.

c. should be considered to assist the yaw damper.

The correct answer is ‘b’ – is difficult and therefore not recommended. Remember that differential lift for roll control is typically obtained by some type of ailerons or spoilers movement. Rudder is used to control yaw about the vertical axis. Using rudders primarily to achieve roll control can contribute to dihedral effect, which can lead to a few problems, including the tailwagging, side-to-side dutch roll.  In jets, we use a yaw damper to increase stability and prevent these tendencies.

Question 4. Which direction from the primary control surface does an elevator adjustable trim tab move when the control surface is moved?

a. Remains fixed for all positions

b. Opposite direction.

c. Same direction

The correct answer is ‘a’- Remains fixed for all positions. This question seemed like basic common sense for me, so I was able to come up with the answer immediately. Trim tabs remain in a fixed position relative to the control surface.

Question 5. Which direction from the primary control surface does a servo tab move?

a. Opposite direction.

b. Same direction.

c. Remains fixed for all positions.

The correct answer is ‘a’ – Opposite direction. Servo tabs work to reduce the control forces required from the pilot, and move in the opposite direction from the primary control surface.

Question 6.  When are outboard ailerons normally used?

a. High-speed flight only.

b. Low-speed flight only.

c. Low-speed and high-speed flight.

The correct answer is ‘b’ – Low-speed flight only. To remember the answer to this question, I think about this little diagram I found on the internet. The outboard aileron is called the low speed aileron.  Don’t  get confused though, remember question 2? Inboard ailerons are used for low-speed and high speed flight.

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Question 7. Which of the following is considered an auxiliary flight control?

a. Upper rudder.

b. Ruddervator

c. Leading-edge flaps.

The correct-answer is ‘c’- Leading-edge flaps.  I have never flown a V-tail airplane, so I had never heard of a “ruddervator” until this study session, but it is a hybrid of elevator and rudder, both primary flight controls. I’ve also never flown a split rudder airplane, but again, I know that rudders are primary flight controls. Flaps are NOT primary flight controls, they are secondary (along with trim devices). In the case of this question, auxiliary means the same thing as secondary. Leading edge flaps ae secondary or auxiliary flight controls.

Question 8. Which direction from the primary control surface does anti-servo tab move?

a. Remains fixed for all positions.

b. Same direction.

c. Opposite direction.

The correct answer is ‘b’ – Same direction. The key to answering this question correctly is reading it closerly. The Pilot’s Handbook of Aeronautical Knowledge (PHAK) says in chapter Five that anti-servo tabs move in the same direction as the primary control service.

Question 9. What is the purpose of an anti-servo tab?

a. Move the flight controls in the event of manual reversion.

b. Reduce control forces by deflecting in the proper direction to move a primary flight control.

c. Prevent a control surface from moving to a full-deflection position due to aerodynamic forces.

The correct-answer is ‘c’- Prevent a control surface from moving to a full-deflection position due to aerodynamic forces. Another question right out of PHAK, Chapter 5. Anti-servo tabs work to decrease the sensitive of the control surface, and preventing a surface from moving to a full-deflection position.

Question 10. Why do some airplanes equipped with inboard/outboard ailerons use the outboards for slow flight only?

a. Increased surface area provides greater controllability with flap extension.

b. Aerodynamic loads on the outboard ailerons tend to twist the wingtips at high speeds.

c. Locking the outboard ailerons in high-speed flight provides for variable flight control feel.

The correct answer is ‘b’ – Aerodynamic loads on the outboard ailerons tend to twist the wingtips at high speeds. This goes back to the diagram in question 6. On planes with both inboard and outboard ailerons (Boeings), the outboard ailerons tend to be locked into the neutral position during high-speed flight to avoid twisting the wingtips. This isn’t a real concern at lower speeds.

Question 11. What is the purpose of a control tab?

a. Reduce control forces by deflecting in the proper direction to move a primary flight control.

b. Prevent a control surface from moving to a full-deflection position due to aerodynamic forces.

c. Move the flight controls in the event of manual reversion.

The correct-answer is ‘c’- Move the flight controls in the event of manual reversion. Control tabs are linked directly to the pilot controls.

Question 12. Which of the following is considered a primary flight control?

a. Dorsal fin.

b. Elevator.

c. Slats.

The correct answer is ‘b’ – a question straight out of the Private Pilot Exam! This was an easy one – straight out of PHAK chapter 5.

Question 13. What is the purpose of an elevator trim tab?

a. Modify the downward tail load for various airspeeds in flight eliminating the flight-control pressures.

b. Provide horizontal balance as airspeed is increased to allow hands-off flight.

c. Adjust the speed tail load for different airspeeds in flight allowing neutral control forces.

The correct answer is ‘a’- Modify the downward tail load for various airspeeds in flight eliminating the flight-control pressures.  The answer to this question was simple to me, as I know from flying the Cessna, the elevator trim tab holds the elevator in proper position so that the pilot doesn’t need to put control pressure on the plane the whole flight.

Question 14:  Which of the following are considered primary flight controls.

a. Tabs.

b. Flaps.

c. Outboard ailerons.

The correct-answer is ‘c’- Outboard aileronsI know from my private pilot lessons that primary flight controls are elevators, ailerons, and rudders. This question is obviously designed to trick people who remember that not all planes have outboard ailerons. But it doesn’t matter. Tabs and flaps are not primary flight controls, and ailerons are primary flight controls (inboard or outboard).

November 12 Flight to Big Bear L35

On Sunday we got up early and flew to Big Bear, nestled in the San Bernardino Mountains at 6,750 feet. What a fun our flight and super yummy breakfast at the Barnstorm Restaurant.  Here is a little video of the takeoff out of Carlsbad.

 

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Ava’s Fourth Birthday

It’s been a hot minute since I’ve updated my blog, but I’m determined to get back to blogging on the regular, so much to share about flying, flight training, travel mom life, and even some books I’ve been reading, a la Jennifer Weiner and B.A. Paris.  Ava turned four last month and we had a great time celebrating at a Moana themed birthday party.  Here’s a little video recap of her fourth trip around the sun. I’m so proud to be her mama!

Understanding IFR Weather: AWOS-1, AWOS-2, and AWOS-3

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I know for the instrument checkride next month I will be asked about the different types of weather reporting. This is important to know, because as a pilot, you need to be able to not just interpret the weather, but also know what types of weather reports you need. At KCRQ (Carlsbad), there is an ATIS. At KOKB (Oceanside), there is an ASOS. F70 (French Valley) has an AWOS-3. So what’s an AWOS?  AWOS stands for Automatic Weather Observation System. It is a unit that measures and reports local weather at an airport to pilots.

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There are four basic levels of AWOS: 

  1. AWOS-A: Reports only the altimeter setting. 
  2. AWOS-1: Reports altimeter setting, wind data, temperature/dew point and density altitude. 
  3. AWOS-2: Reports the information provided by AWOS-1, plus the visibility. 
  4. AWOS-3: Provides the visibility provided by AWOS-2, plus cloud-ceiling data. 

For Part 121 or 135 operators, AWOS-3 is the only type of AWOS that’s acceptable without restriction. 

Instrument Checkride Prep: Reading Aviation Winds and Temperatures Aloft Forecasts

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On the instrument check ride next month, I know the examiner will be asking me about the Wind & Temps Aloft forecast. This is issued 4 times daily for different altitudes and flight levels.  The format is DIRECTION – SPEED – TEMPERATURE. If it says 9900 then that means light and variable. Wind direction is from true north, according to aviationweather.gov.

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Things get a little tricky when the wind is is about 100 or 200 knots. Just remember “Between 51 and 86.” 

When the wind speed is 100 knots or greater, wind direction is coded as a number between 51 and 86. And then you subtract 50 from that number – that’s your direction. And then you add 100 to the second set of numbers. That is your wind speed. Let’s practice: 

“751950”  

  • Direction (75-50) Winds coming from 250°
  • Speed (19 + 100) 119 knots  

Above 24,000 feet, the temperature is assumed to be negative. If this forecast was issued at 34,000, you would assume the temperature to be negative 50 degrees. 

Let’s try another one, from tonight’s forecast

At 39,000 feet over SAN: “771357” 

  • Direction=  (77-50) winds coming from 270°
  • Speed = (13 + 100) 113 knots 
  • Temperature = -57 degrees

another one, just for fun. at 39,000 feet over BLH: “761358” 

  • Direction= (76-50) winds coming  from 260°
  • Speed= (13+100) 113 knots 
  • Temperature -58 degrees 

All levels through 12,000 feet are true altitude (MSL). The levels 18,000 feet and above are pressure altitude. 

Instrument Checkride Prep: Reading and Interpreting the METAR

I’m taking the instrument check ride next month and I’m going to be blogging nightly on different topic in preparation for all of the stuff I think will come up on the oral part. I am preparing for lots of aviation weather talk, so at least the next week will be over those topics. I will have to explain things like the difference between a stable and an unstable atmosphere, what standard temperature and pressure values are, and the two basic ways that fog may form. 

aviationweather

One very basic thing I will have to do is hop on aviationweather.gov and read and interpret a METAR. The first thing I will do is going to aviationweather.gov and click on METAR – it’s in the upper left hand corner of the website. Then I will scroll down to near the bottom of the page – on the right, where it says “Request Metar Data”, and I’ll type in the identifier of my airport – in this case KCRQ. 

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The METAR reads: Data at: 0358 UTC 23 Mar 2016 KCRQ 230353Z AUTO VRB03KT 10SM CLR 15/10 A3004 RMK AO2 SLP169 T01500100

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 Here’s how I’d read this: Airport is KCRQ, Carlsbad, CA Time – 23nd of March at 03:58 Zulu Time. I convert the time and it’s the 22nd of march at 20:58 Pacific Daylight time. The AUTO, when it appears just after the time group, means that the observation is from an automated station. Winds are light and variable at 3 knots, visibility is 10 or more statute miles, sky is clear, Temperature is 15 degrees, Dew Point is 10 degrees. Remarks: A02 means the station has a precipitation discriminator. SLP stands for Sea Level Pressure, which is another measure of atmospheric pressure. The Last digits that start with a “T” are the he hourly air and dewpoint temperatures to the nearest 1/10 C degree.

Tomorrow night I think I will review the Winds and Temperature aloft chart, and what valuable information can be determined on there, like the most favorable altitude, areas of possible icing, temperature inversions, and turbulence.

What is WAAS (in Aviation)? Explaining it for the Instrument Checkride

In the instrument checkride (next month – eeeek!) I know I’m going to have to talk about instrument approaches, GPS approaches and will be prepared to explain how a GPS works.  And I’ll probably be asked about WAAS. What the heck is it? I know what WAAS is because I’ve been eyeing a ForeFlight Stratus for Echo Sierra – and it has WAAS!  

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 WAAS stands for Wide Area Augmentation System, and it’s a nice system of satellites and ground stations that give GPS signal corrections in a timely manner (every 5 seconds or better), to give better accuracy. Garmin says WAAS capable receiver can give position accuracy of better than 3 meters, 95% of the time. Foreflight says you frequently see 1 meter accuracy or better. Essentially, WAAS is intended to enable aircraft to rely on GPS for all phases of flight, including precision approaches to any airport within its coverage area. 

Another great thing about WAAS is almost around the clock availability. If you want to get technical, availability is the probability that a navigation system meets the accuracy and integrity requirements.  The WAAS specification mandates availability as 99.999% throughout the service area. This is equivalent to a downtime of just 5 minutes a year. That’s pretty awesome, especially considering before WAAS, GPS specs allowed system unavailability for as much as a total time of four days per year. 

IFR Checkride Prep: Alternate Airports and the 1-2-3 Rule

Screen Shot 2016-03-02 at 9.49.08 PMNext month I will be taking my Instrument Rating checkride! I am very excited, not because I have any desire to fly straight into some big puffy clouds, but because it is an important step in my progress of being a more experienced and qualified pilot. I’ve finished two big hurdles already, I have gotten my 50 hours cross country PIC time, including a few solo cross country flights, and I’ve passed the FAA written exam. I’m also about half way through the commercial ground school. I was planning on taking that written exam before the Instrument checkered, but I’m not sure if that will happen yet. In any event, I will be studying aviation every night. 

One question that I anticipate coming up on the checkered is “How do you know if you’ll need to list an alternate airport on your IFR flight plan?” And no, it’s not acceptable to just say, “I’ll list one anyway, just to be safe.” The examiner is going to give me a weather forecast at an airport and I’ll have to tell him whether or not I need an alternate. I will refer to the 1-2-3 rule of IFR flying. It’s pretty simple. 

From ONE hour before to ONE hour after your planned ETA at the destination airport, the forecast has to be at least 2,000 foot ceiling and 3 mile visibilities. If those weather minimums are met, than no alternate airport is required. But if the ceiling or visibility is less than TWO thousand feet and THREE miles, then you need an alternate. And there are some rules about your alternate, depending on the available instrument approaches. 

If an IAP is published for that airport, you must be able to land at the alternate minimums specified in the procedure, or if none are specified: 

(1) for a precision approach procedure: ceiling 600 feet and visibility 2 statue miles. 

(2) for a non precision approach procedure, ceiling 800 feet and visibility 2 statute miles. 

(3) If there is no instrument approach procedure published for your alternate airport, the ceiling and visibility minimums are those allowing descent from the MEA, approach, and landing, under basic VFR. In class Echo airspace below 10,000 feet MSL, basic VFR is 3 statute miles visibility and cloud clearance of 500 feet below, 1,000 feet above, and 2,000 feet horizontal. 

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Olivia Caridi of the Bachelor :: “I Wanna Talk Smart Things”

I love watching the Bachelor on Monday night, and I especially love some of the great quotes that come from these smart, beautiful women. You can’t make some of this stuff up! This week was no disappointment, it picked up right where the drama left off last week. Olivia Caridi is a news anchor / reporter, and when Bachelor Ben Higgins pulls her aside, she tells Ben she wants to talk smart things. Then they all head to Exuma Island of the Bahamas, where Ben takes Caila deep sea fishing. If you are a fan of the Bachelor, check out my friend Andrea’s Bachelor Recaps, every Tuesday over on http://andrealebeau.blogspot.com.