13 Hours, 2 Notices of Discontinuance, 1 Temporary Airman Certificate

flyingsailor

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FlyingSailor
Thought I’d post a write up on my last checkride.

Earned my CFII (as my initial with the FSDO) back in ’09, and then promptly stopped flying for 5 years due to work. Finally decided to start again and work on my CFI SE addon. Decided to do the ride in 2 a/c (an Arrow and 172) which worked out quite well. Practicing/Studying for the addon was a lot more difficult than the CFII (likely due to being so rusty you’d need a tetanus shot before looking at my logbook).

Finally scheduled the checkride. The DPE is very well known, and I was more worried about disappointing my recommending instructor or the DPE by doing something boneheaded, than I was about passing/failing the ride. The week leading up to the ride, the stress began to build. I kept researching everything, trying to be at least conversant/able to teach 2 or 3 layers deep on every topic, and know where to go for deeper.

After talking to the DPE, we settled on a time and he said he wanted me to teach a maneuver on the ground that we’ll fly in the air. We settled on eights-on-pylons. I know it isn’t required for the add-on, but didn’t want to start out by arguing with the DPE on the phone. Besides, figured given the amount of time since doing the CFII ride, it’d be good practice. Started dissecting the eights-on-pylons maneuver from every angle. Besides knowing it cold, started thinking of what questions he (or a student) could possibly ask. That’s when I went down the proverbial rabbit hole. I thought of the question “Where does 11.3 come from in the pivotal altitude equation”? (I’m an engineer by education)

The DPE doesn’t like travelling up to our airport (usually it’s a fly to him for the ride event as he doesn’t like the horrendous traffic), but makes exceptions for people doing rides with different a/c on same day. With that, started watching the weather and began growing a little concerned. Forecast was for wx to be acceptable for a CFI ride, so held my breath. Left the house at 0600, met him at the airport, and of course the wx ended up being worse than forecasted. Decided to at least knock the oral out and see if the wx lifts.

Oral was relatively un-eventful. After going through both aircraft’s logbooks, spent a lot of time on “how to” and “what would you be looking for” questions. Such as “how would you teach collision avoidance here and at an uncontrolled field”? A couple questions on airspace and “how would you teach local airspace to a new PPL student? OK, how about a commercial pilot?” (Since we’re a Class D, under a B, inside the DC SFRA). “If you’re sending a student to XYZ airport, what would you be concerned with/be looking for, in their pre-flight planning”?”

Couple questions that I brain-farted in my ability to describe/teach (I’m horrible at drawing). For example, in explaining governors and oil-pressures, rather than push an already poor drawing/presentation, whipped out my iPad, found a good cutaway drawing of one, then was able to teach off that drawing much more effectively than my stick-figure approach.

Finally came the Eights-on-Pylons lesson. Pulled out my plane model and a small whiteboard, and taught the maneuver. Rather than lecture, would ask questions as I’m teaching it make sure “the student” was understanding the concepts. He never asked when I said “divide by 11.3”. Wasn’t going to let all that work I did go to waste, so I worked in a question about it. He honestly didn’t know and it felt a bit refreshing to be able to stump a DPE. So the last part of the lesson was a trigonometry/algebra lesson, going through the derivation to arrive at the 11.3 (actually 11.299). When I was done, he insisted on a copy of the derivation (he likes to keep little things like this for future checkrides). So, if you’re going for your CFI ride and get asked where does 11.3 come from… I’m sorry, that was me.

Overall the oral was really laid back. It seemed more of a professional discussion that drifted in and out of explaining things to a student and explaining things to another aviation professional. With it all over, went to look at the wx.

Airport was now IMC. Decided to wait an hour and see what happens. After an hour, no change in the wx, so we “called it” and he issued a notice of discontinuance. After that, we still stayed around and chatted for an hour or two. During that time the field went from IFR to Marginal, so it was lifting. Looking outside, it seemed it got better, so tuned the ATIS and ceiling was now 1800 and 10SM (which matched what we were seeing)…jackpot. He grabbed his bag and said “Let’s go!”.

The aircraft was already pre-flighted. On the walk out he asked a couple questions, we got in, ran through the startup, and he taxied to the runup area. He asked me to demo a soft-field takeoff/landing. Did a short field after that, then on the final time around on the downwind, there was confusion with tower on where exactly traffic was on final for our runway. I said I don’t quite like this, and told tower I wanted to do a right 360. DPE liked that and things ended up working out.

While we were in the pattern, looking out to the west, the wx actually appeared to be lifting. Once we landed, discussed how to proceed. Since the he lived to the SW and wanted to get home to beat the traffic, agreed that he’d start heading home, I’d fly the 172 out to a field closer to where he lived, meet him there and we’d continue the checkride.

In case things didn’t work out, he went in to issue a second notice of discontinuance (to update the info for what we just did).

Launched in the 172 and headed out to meet him. On the way there, wx looked like it was closing back in (nothing was as forecast that day). Landed and met him at the airport. We both agreed that we’ll keep a close eye on the weather and get as much as we can get done (ceilings were dropping). I had no issues ending the checkride with a third notice and having to file to get back home if it came to that. We both agreed and launched, pretty much planning on just doing the low-altitude stuff.

On the climbout, I’m not kidding when I say about a 6NM radius area opened up with ceilings 6k+ and a little sunshine. We immediately took advantage of it. He asked for a Chandelle to the left, which I did. Was a bit sloppy (I even mentioned that), he said “OK, let’s do one to the right”. That one I nailed. After that, asked for an emergency decent into a simulated emergency approach and landing.

Once down closer to the ground, did eights-on-pylons with a “after this morning, I’m expecting these to be perfect”. They went fine, then headed back to the airport for some takeoffs/landings. Short Field, Go-Around, Slips, and during the short field takeoff asked what I’d do if I lost my engine while we were climbing out. On the base-final turn (where I was going to slip) he started asking a couple technical questions on how things worked. Told him “good question, let’s discuss it once we land” (obviously the ‘distraction’).

Landed, taxied to the FBO and he congratulated me. He Fired up IACRA to do the paperwork and I pulled out the iPad to file back into the SFRA, looking at the latest radar. We chatted for a bit and I respectfully hinted that I needed to leave (wx had decided to nose dive again, with a wall of nastiness heading this way). After getting the temporary airman cert, again shook hands, I thanked him and headed out.

Managed to get back into the SFRA with no delay, parked the plane, and about 10 minutes after securing everything, skies opened up in a massive downpour.

Got home around 1900. 13 hours, 2 notices of discontinuance and a temporary airman certificate after leaving the house that morning.

Things I learned:

- The CFI checkride isn’t about what you know (you already have a commercial certificate), but more about presentation, professionalism, and decision making.
- Be able to scale the complexity of subjects while presenting them. How you address/present information to a brand new student vice someone who is experienced.
- Have a sense of humor.
- If you don’t know, or if you “think”, look it up, but couch it with “I think it’s this, but let’s check”.
- Don’t be afraid to move out of the “teaching” mode, into the flying “we’ll discuss later” mode if circumstances dictate.
- When you talk to the DPE before the ride, always ask if they’d like Coffee/Tea, Donuts, Muffins.. $5 at Dunkin Donuts goes a long way (though my DPE declined). Bring a couple bottles of water and offer one to the DPE for the flight.

Now on to getting the Multi PIC hours for the MEI.
 
Congrats ,was one long day,nice write up.
 
Congratulations!

(I think you owe us the derivation of 11.3!)
 
Sounds like the lessons you learn as a private student always come in handy -biggest lesson I learned was patience. It sounds like you had plenty of it (and a DPE with a pretty good attitude.)
 
Nice to see another local; congrats and welcome to PoA.
 
So, I guess it's not just us private pilots who get the nerves on check rides.

Thanks for the write-up. Quite informative.
 
Was that Jerry you flew with? Good guy. Like you, I started with my CFII back in 2004 and waited 9 years before doing my MEI a year ago, and then finally my CFI-ASE this past spring. Advantage of doing MEI first was needing only one plane for the single engine; the MEI takes care of the complex requirement.
 
Was that Jerry you flew with? Good guy. Like you, I started with my CFII back in 2004 and waited 9 years before doing my MEI a year ago, and then finally my CFI-ASE this past spring. Advantage of doing MEI first was needing only one plane for the single engine; the MEI takes care of the complex requirement.

Yeah, it was Jerry. Very professional and down to earth. I learned quite a bit from him during the ride (even though he wasn't actually teaching) :)
 
Congratulations, welcome to POA and great write up.

I too am anxious to read the 11.3 write up.
 
I too am anxious to read the 11.3 write up.

Posted a reply to a previous post with a link to a PDF that I scanned of my cheat sheet. Appears it needs to be approved by an admin (guess due to the links).

I'll work on a post which contains the derivation. Has a couple graphics and equations.
 
Nice write up, thanks. I'm going for my CFI ride in a couple of weeks, so this was helpful. I'd like to see the 11.3 write up as well.
 
Sorry for the delay. Needed to create some graphics and write some equations to post on a forum, which took some time. (Note only thing worse than my drawing ability is my computer drawing ability).

My apologies, but a mis-statement. There is no derivation for 11.3 per se, as it’s just a conversion factor. The derivation is more related to how you arrive at the traditional:


eqn1.jpg



And then explain how 11.3 and 15 falls out of that?

Remember from high school trigonometry class, that the tangent of an angle in a right triangle:


triangle1.jpg


Can be defined as:

eqn2.jpg


Let's flip the triangle, change the names of the triangle legs, and throw a picture of an airplane in to help visualize:

triangle2.jpg


Thus we can rewrite the tangent of the angle as:

eqn3.jpg


Now, let’s take a look at a circle with a certain radius (let’s call it ‘r’). Going back to Physics 101, Centripetal Force (cf), which is the force required to follow a fixed curve (and is opposite of Centrifugal Force):


circle.jpg



Centripetal Force (cf) in Newtons is defined as:

eqn4.jpg


Where m is the mass of the object, V is the velocity of the object in meters/sec, and r is the radius (in meters) of the arc or circle.

[FONT=&quot]Let’s add the two shapes together and we get a cone. Throw the airplane in there for reference and starts to look like what we’re doing around our pylons:[/FONT]

cone.jpg



We need to talk a bit about gravity (will get to why in a moment). Recall that the weight of an object is the mass of an object multiplied by acceleration. Since we're talking gravity, the acceleration if the standard gravitational acceleration constant of 9.806 meters/sec/sec.

Since we known that the thing that keeps airplanes in the air (other than money) is lift. Also, we know that in steady state, non-accelerated level flight, lift is equal (and opposite) to gravity. However, we're going to be turning around a pylon, so we need to take the next step and start talking about horizontal and vertical components of lift.

Let's draw an airplane in a bank, and throw a triangle in for good measure:


horizontallift.jpg


[FONT=&quot]As you can see, the tangent of the bank angle is equal to the horizontal component of lift divided by the weight of the aircraft. If the airplane is turning around a pylon in a given bank, then the amount of force required to keep it along an arc of a specific radius is the horizontal component of lift....or.....centripetal force.


So, the tangent of the bank angle is equal to centripetal force (cf) divided by the weight (W) of the aircraft, or written as:

eqn5.jpg

[/FONT]
[FONT=&quot][FONT=&quot]However, if we plug in the equation for centripetal force, and plug in the equation for weight, we get:[/FONT]

eqn6.jpg

[/FONT]
Which, using basic algebra, reduces to:


eqn7.jpg


Now... if:

eqn8.jpg
and
eqn9.jpg


And we're trying to find an equation to determine altitude (or height), let's set both equations equal to each other, and solve for h (height of the cone):

eqn10.jpg
which reduces to:
eqn11.jpg


Look familiar?

Thus the pivotal altitude (h) is equal to:

eqn12.jpg


So, in order to convert to something usable in the cockpit, let's do knots first. Since this is a conversion. we'll assume 1 knot. Since 1 knot is 1 Nautical Mile (6076 ft) per Hour (3600 seconds), the equation is in seconds, and we are concerned about feet vice meters, we take the inverse of the above equation with the 1 kt in the desired units. Thus:

eqn13.jpg


= 0.0885756

Taking the inverse:

eqn14.jpg


For mph, 1 mph is 1 statute mile (5280 ft) per hour (3600 seconds). Same equation:

eqn15.jpg


= 0.06688

Taking the inverse:

eqn16.jpg


There you go. So yea, got a little bit down the rabbit hole when prepping for my ride.
 
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Wonderful write-up! The 11.3 explanation is very interesting as well. Hopefully I get some bad weather and can stay in and read it thoroughly to understand it sufficiently enough to teach. Well done and congratulations!
 
Fascinating explanation. Although, is that really something you should have asked? Is that really something you thought the DPE would know.

I'm always trying to draw the line between technical knowledge and practical information. I too am of the engineering background, and think taylor series are amazing for solving integrals which otherwise wouldn't be easy to solve on their own. But I do not concern myself with the proof because I use this as applied knowledge--not a rigorous attestation. I mean, you used 9.806 for the acceleration due to g. Even in demanding physics courses, we've only ever used 9.8m/s^2--less than a tenth of one percent difference.
 
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