Penguinforce
Pre-takeoff checklist
I have my Commercial Checkride in one week from today. I’ve been flying lots and studying hard for it, and I would love to hear any “gotcha” questions or tough questions you faced on your commercial oral exam!
Commercial Oral Exam “Gotcha” Questions
- Thread starter Penguinforce
- Start date
Have you reviewed the ACS? If so, there shouldn’t be any surprises.
Penguinforce
Pre-takeoff checklist
I have already done this with my instructor and another pilot, and watched and answered alongside mock oral exams on YouTube as well in preparation. I know one person said he was asked the 3 different types of hydroplaning on his oral exams. So I’m looking for other oddball questions like that, that people may have been asked
MauleSkinner
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Will your airplane hydroplane on touchdown if the runway is wet enough to support it?
eman1200
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how much wood could a woodchuck chuck if a woodchuck could chuck wood, and the woodchuck was a commercial pilot?
Penguinforce
Pre-takeoff checklist
If enough moisture exists on the runway, then there is always the possibility that hydroplaning can occur whether it be from standing water causing dynamic hydroplaning or steam getting between the tire and pavement, that is created from the heat generated from the friction of the tire and the wet pavement that can cause reverse rubber hydroplaning
MauleSkinner
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Can a commercial pilot woodchuck Chuck more wood than a private pilot woodchuck could? If so, could obtaining a commercial certificate also be called up-chucking?
MauleSkinner
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Ok…let me clarify…will dynamic hydroplaning happen in your airplane on landing if the runway is wet enough to support it?
In other words, if you landed your airplane on a lake, would it do this?
Or this?
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Penguinforce
Pre-takeoff checklist
Not necessarily. Hydroplaning to a degree is dependent on braking action (assuming you’re not trying to land on a flooded runway). It’s also dependent on runway condition; if the runway is grooved or not for example.
MauleSkinner
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How is viscous hydroplaning dependent on braking action?
Penguinforce
Pre-takeoff checklist
Viscous hydroplaning is caused by a thin layer of water or oil getting between the tire and runway. So when landing you want to use light braking and rely more on aerodynamic braking to slow your aircraft down to decrease the effects of viscous hydroplaning
MauleSkinner
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So braking action is dependent upon hydroplaning, not the other way around.
Penguinforce
Pre-takeoff checklist
Correct. The amount of braking action a pilot should apply is dependent on the possibility and risk that hydroplaning could occur
MauleSkinner
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Ok, so let’s try another tack…how did this pilot ensure that his airplane would hydroplane?
So you haven’t actually done it. There’s no stress like paying a stranger up front for an oral exam with the outcome being an endorsement (or not) to take the practical.
Penguinforce
Pre-takeoff checklist
First off, thanks for sharing that because that is beyond cool!
But secondly, he is keeping the airspeed/ground speed of his aircraft high enough so that he doesn’t break the surface tension of the water which would’ve allowed the tires to “sink in” to the water, catch and likely flip or crash. By not breaking the surface tension, his tires are hydroplaning and to a degree, he’s kind of gliding over the water like it’s ice!
MauleSkinner
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So how fast is “fast enough,” and is your airplane “fast enough” when you land?
Penguinforce
Pre-takeoff checklist
I honestly didn’t know the exact speed so I looked it up and the answer is 9 times the square root of tire pressure is the speed at which hydroplaning can occur. So in my aircraft, it would be roughly 55 knots. So my aircraft’s landing speed would be fast enough for hydroplaning to occur
Penguinforce
Pre-takeoff checklist
Living in Denver, I’m not really used to having to deal with hydroplaning issues. Now I’m hoping I get asked about it after this discussion haha
Clip4
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Identify and explain the different types of hypoxia.
Penguinforce
Pre-takeoff checklist
The 4 types are hypoxic hypoxia, essentially not enough oxygen exists for the body (typically occurs at higher altitudes), hypemic hypoxia, which the the blood cells cannot carry the oxygen in the body, histoxic hypoxia, which is the individual cells cannot take in the oxygen delivered to them and is typically associated with recent alcohol consumption as well, and stagnant, which is where oxygen cannot be circulated in the bloodstream.
MauleSkinner
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and note that the formula you quoted is for a spinning tire…if the tire is stationary, like at the point of touchdown, the speed reduces to 7.7xsqrt(tire pressure), which is why the guy in the video probably has his brakes locked.
So you mentioned grooved runways earlier…how does that affect hydroplaning? And how about tire tread?
Edit: I got my terms mixed up…dynamic hydroplaning is what the formulas apply to.
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What is dry leasing?
What is a 91K
Can you take a job flying the owner of a plane in his plane?
Working for a company in their owned plane with company employees
How about if its just company cargo? Flying widgets from the factory to the buyer?
Working for a private individual flying their plane, but picking up their wife while the owner is not onboard
Can you do your own scenic tours in a rental right after you get your certificate? Why or why not?
What’s the difference between a 91 scenic tour and a 135 pax operation?
Can you get paid for flight hours as a aircraft salesmen on a demo flight from the factory with the buyer to his home 300nm away?
you land in the pt 91 plane you’re flying, you see a flat spot on the tire, when is this grounding vs when is this keep a eye on it?
You notice its grounding, who can change the tire?
The owner now put the plane on a 135 certificate, who can change the tire now?
Now that it’s on the 135, can you even fly the plane with your qualifications? IFR?
Can a 135 flight be operated pt 91? When?
What is a high mins airmen?
What are your o2 requirements non pressurized? Pressurized?
What is a MEL?
What is a opspec?
What is a GOM?
Do they carry the same weight as the FAR?
——
Bonus points that won’t be asked but should be known
How long should a pilot resume be?
Do you pay for a type rating for a job?
Name 5 items that you should always have (ie rubber band etc)
What is a 91K
Can you take a job flying the owner of a plane in his plane?
Working for a company in their owned plane with company employees
How about if its just company cargo? Flying widgets from the factory to the buyer?
Working for a private individual flying their plane, but picking up their wife while the owner is not onboard
Can you do your own scenic tours in a rental right after you get your certificate? Why or why not?
What’s the difference between a 91 scenic tour and a 135 pax operation?
Can you get paid for flight hours as a aircraft salesmen on a demo flight from the factory with the buyer to his home 300nm away?
you land in the pt 91 plane you’re flying, you see a flat spot on the tire, when is this grounding vs when is this keep a eye on it?
You notice its grounding, who can change the tire?
The owner now put the plane on a 135 certificate, who can change the tire now?
Now that it’s on the 135, can you even fly the plane with your qualifications? IFR?
Can a 135 flight be operated pt 91? When?
What is a high mins airmen?
What are your o2 requirements non pressurized? Pressurized?
What is a MEL?
What is a opspec?
What is a GOM?
Do they carry the same weight as the FAR?
——
Bonus points that won’t be asked but should be known
How long should a pilot resume be?
Do you pay for a type rating for a job?
Name 5 items that you should always have (ie rubber band etc)
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Bryce Bohlander
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When I did mine several years ago, the DPE asked questions based on question categories I answered incorrectly on the written. So review the queation categories you got questions wrong on and go from there. One I got wrong was on weather and turbulence. He said he knew the question I got wrong, and basically said to fly above the rotor cloud to have a good chance of avoiding the bad turbulence in mountain crossing. Thanked him for that tip. He then says "how in the hell did you get an airspace question wrong on this test? What's this (points to a sectional)?!" I replied thatnits a MOA. He says "good, let's go fly!" Good luck. If you're prepared and thoughtful in your answers you'll do just fine.
Jim Carpenter
Line Up and Wait
I've heard of an examiner asking, "How much does the aircraft battery weigh?" Not required memory knowledge, but you should know where to find such info.
A more realistic possibility, questions about flying with inoperative equipment. In my experience, examiners want a much more comprehensive understanding of the rules than regurgitation of 91.205 "TOMATOFLAMES." You should be familiar (again, not necessarily memorized) with AC91-67, https://www.faa.gov/documentlibrary/media/advisory_circular/ac_91-67.pdf. Wouldn't hurt to have a copy of that at hand. The flow chart on Chapter 2, Fig 2, page 8 is good for Part 91 ops without an MEL.
(Note, there is an updated version of this, AC91-67A, but I think the decision flow chart in the version above is better.)
A more realistic possibility, questions about flying with inoperative equipment. In my experience, examiners want a much more comprehensive understanding of the rules than regurgitation of 91.205 "TOMATOFLAMES." You should be familiar (again, not necessarily memorized) with AC91-67, https://www.faa.gov/documentlibrary/media/advisory_circular/ac_91-67.pdf. Wouldn't hurt to have a copy of that at hand. The flow chart on Chapter 2, Fig 2, page 8 is good for Part 91 ops without an MEL.
(Note, there is an updated version of this, AC91-67A, but I think the decision flow chart in the version above is better.)
MauleSkinner
Touchdown! Greaser!
I would also note that 91.213 is the starting point.
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I had that question on my private! I crapped the bed on that one.
- Joined
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- Ernie
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But which type?!Yes! That’s one of the signs of hypoxia
bbchien
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"BEST POST OF STRING!"
MauleSkinner
Touchdown! Greaser!
As long as one is willing to go beyond rote.
Penguinforce
Pre-takeoff checklist
Thanks for all the input and questions. I’m happy to announce I ended up passing my checkride today! Thanks again everyone!
KE5BM
Pre-takeoff checklist
Did you get any of the stump the chump questions like you feared?
I would love for there to be a discussion on these questions, Roller if you're so inclined. Your post definitely got me thinking about the head-space I need to be in for the near future.
Penguinforce
Pre-takeoff checklist
Most of it was pretty straight forward. I spent a ton of time studying commercial privileges and scenarios but we barely spent any time on that. The only tough question he asked me was how do I calculate minimum sink speed. I hadn’t a clue what the formula for that was but he had me look it up. I don’t think he expected me to know the answer off the top of my head. Otherwise, the oral went pretty smoothly!
MauleSkinner
Touchdown! Greaser!
Where did you find hat?
Penguinforce
Pre-takeoff checklist
Google xD
Zeldman
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How would you know if the compass is empty of fluid.??
Yes, this was asked by the examiner on my single engine commercial add on.
Answer: The glare shield will be all wet...
MauleSkinner
Touchdown! Greaser!
So it’s not actually in any of the documents listed in the ACS?
That my have worked for your exam but in real life my knee was all wet.
