Not understanding FAA PAR test question

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Da_Pilut@reddit

Think about being in a boat, trying row a rectangle in a river…. You have fight the current.

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Mediocre-Piano1192@reddit (OP)

That’s a very clever way to put it, I like that example a lot thank you

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What a crappy question. I didn’t understand at all what they were saying, because every turn in the diagram is 90 degrees. I assumed like the SAT convention that polygons are accurately portrayed. Actually a great many SAT questions (like a quarter) arr new questions being tested out. It is exactly to catch this sort of bad question and fix it eliminate it.

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SirKillalot@reddit

This question is not incorrect, and the figure is not inaccurate. Whether it's badly worded is up to opinion, I guess, but IMO pilots should be able to understand what it's asking for. Every turn in the diagram is to a *course* 90 degrees from the last one, but to correct for the wind the nose of the plane has to point somewhat north on both of the horizontal legs, making each turn either more or less than 90 degrees. Consider [this version of the diagram](https://imgur.com/a/boi7BDc) I modified in MS paint to show the heading required to fly each course. Now it should become obvious that the turns on the right side require less than 90 degrees of heading change to effect 90 degrees of course change, while the turns on the left side both require more.

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Recent-Day3062@reddit

Of course. What they find with the vast majority of SAT new questions is people aren’t clear what the questions is. For this one they didn’t throw in “account for wind” to start it. That would not have given much away but made the intent clear.

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My_name_is_not_Miles@reddit

It’s the same reason as corner 1. - Short answer: at corner 4 you are already crabbing into the wind and just had to turn into a straight headwind. More detailed answer: So let’s say the wind was REALLY strong and required a 45° crab to make it easy visualize & to calculate. At corner 1 you are headed straight northbound (360° heading) as you make turn 1 to leg 1-2 (west heading) it would require a 315° heading - 270° for the course +45° crab to adjust for the wind. Then on the 2-3 leg you’re heading straight southbound (180° heading) not wind correction here just a straight tail wind. — and the turn from the 1sᴛ leg was 135° (90° for the turn +45° for the wind correction =135°) Now once you’re @ turn #3 for the 3-4 leg you are turning from your heading of 180° (southbound) to a new heading of 090° (eastbound) but again on this leg you need to crab into the wind requiring and extra 45° to the left. - making your heading 45° (we get there by 090° for the desired track and this time minus 45° for wind correction) and your turn once again 135°. Finally coming to turn #4 for the 4-1 leg northbound. Now wind correction as this will be a straight headwind and we’re aiming for a northbound heading of 360° (you can think of it as a 0° heading if that easier) our current heading it again 45° to get to 360° (aka 0°) only requires a 45° turn. Or said another way we need to turn 90° left but we are already crabbing 45° and so only need to turn 45° more.

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SirKillalot@reddit

I think the easy way to solve questions like these (even if it's not the exact one here) is to visualize or draw out what the airplane's heading will be when it's established on each of the courses with an exaggerated wind correction angle. If you can draw [this picture](https://imgur.com/a/boi7BDc) in your head or on a notepad instead of the one they've given you, the answers will become obvious.

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82yukonXL@reddit

1-4

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Mountain-Box-5778@reddit

It’ll be 1 and 4. On the first turn u are turning north to north west since will turn shorter by crabbing into the wind. On turn 4 you are turning from a northeast heading to a north heading since u were crabbed to start.

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jsisson801@reddit

I love Reddit for lots of things, but not for this type of question…. Mostly right answers, and lots of wrong answers. Do you have a cfi you can ask, that’s where I’d go and trust their answers mostly

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Mediocre-Piano1192@reddit (OP)

Funnily enough I asked my CFI and his answer was that he knew for sure it was 2 or 3, knew it was 1 so just process of elimination it had to be corners 1 and 4. The question confused him as well, but don’t worry I’ve been studying a lot, I only came to reddit as a last resort as this is too specific to find online

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LostPilot517@reddit

Your CFI sounds like the product of ATP or other similar pilot factory.... It is definitely 1&4.

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jsisson801@reddit

Haha, 🤣 this has me rolling!

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CharAznableLoNZ@reddit

This question is asking you which turns would you turn less than a 90 for that turn. Since the wind requires the plane to crab to maintain a straight line two of the turns require more than 90 and the other two less than 90. Assuming the top is north. Flying from 1 > 2 you will be pointing slightly north to stay on a straight line. Flying from 2 > 3 you will be going with the wind. No correction is required. This is the fast leg. Flying 3 > 4 you will need to point lightly north to maintain a straight line. Flying 4 > 1 you're flying into the wind, no correction is required. Now thinking about how you will fly each leg, how would that change your turns? The two legs that are perpendicular to the wind required the correction. This means you have to turn more than 90 to apply that correction along with the turn. This about how far you have to turn to make the turn and apply any wind correction. Turn 2 goes from requiring a northern correction to no correction. This turn will be over 90. Turn 3 will require adding a northern correction to the turn. This will be over 90. Turn 4 already has some northern correction from the leg so you only have to turn a bit more to align with the wind. This is less than 90. Turn 1 you are already pointing north so the amount of turn required to align with the first leg is less than 90. A thing that could help is thinking of trying to swim a pattern in a river. You have to apply corrective angle to maintain the pattern.

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travesty01@reddit

Leg 3-4 will be crabbed into the wind direction, so that crosswind leg to upwind leg turn will be less than 90*

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humpmeimapilot@reddit

1/3 due to wind

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TravelerMSY@reddit

With no wind, the answer would be none of the corners, right?

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El_FigaroGold@reddit

Hated this question

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Bunslow@reddit

What the question means: "to keep a rectangular ground track, which corners would have heading changes less than 90deg?" It is, objectively, terribly written, completely unambiguous. But the only way to make logical sense of it is that they're trying to contrast course with heading, and asking about heading specifically.

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jemenake@reddit

I wrote a little webpage that let someone experiment with ground reference maneuvers (https://joe.emenaker.com/GroundReferenceSimulator/) The user interface is kinda clunky (you need to steer with your arrow keys, so don’t try this on your phone) The simulation start differently from the problem you posted, so you can either translate it in your head or you can turn the wind and plane to your liking. I wrote the simulator to help make the leap from flying the _box_ successfully to flying the circle. The circle is just the box with its corners cut because your turning rate is slower, but the heading of the aircraft at NSEW points is the same. Turn the wind up to just a little below the airspeed and it becomes quite obvious.

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Zestyclose_Big9544@reddit

Think heading, not track.

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absolutemadlad0@reddit

people are saying corners 3 and 4 but wouldn't it be 1 and 4? at corner 3 you should be turning more than 90°

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Mediocre-Piano1192@reddit (OP)

The correct answer is 1 and 4, I was asking about how 4 worked. I think people are just describing the path between 3 and 4, and how you need to turn more at corner 3 I don’t think they think the answer is 3

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absolutemadlad0@reddit

Got it, yea I see now

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BenTallmadge1775@reddit

1 & 4 1 because the turn will need to be less than 90 for a crab. 4 because the crab in place lessens the turn to N.

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Consistent-Trick2987@reddit

The diagram may be confusing. The line is your ground track. They’re asking how the nose of the airplane will be pointed to maintain that ground track. The wind is pushing you so you have to turn in more towards it to compensate.

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MEINSHNAKE@reddit

Draw the box out for yourself on a piece of paper and draw the aircraft on each leg and how they would be crabbed to fly a straight course accounting for the wind. The answer will make sense once you see it visually.

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Jwylde2@reddit

Corners 1 and 4. Wind is coming down the runway. Gotta keep that nose pointed in that direction. So the turn from departure to crosswind will be less than 90° to keep the nose into the wind. Since the turn from downwind to base will be more than 90° to keep the nose in the wind when flying base, the turn will be less than 90° when turning base to final.

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Frederf220@reddit

Consider the tracks are 360, 270, 180, 090 azimuth which need headings 360, 275, 180, 085 to fly. Then consider the subtractions to find the angle make each turn. Yet another way to look at it.

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ScathedRuins@reddit

on the leg between corner 3 and corner 4 your nose will be facing into the wind. call it heading 030 just as an example. so when you roll out on heading after corner 4 for will end up with a heading due north since the wind is directly on the nose. that’s about a 30 degree turn. assuming north is up here just for explanation’s sake now depending on the wind direction and strength the magnitude will change, but it’s always going to be less than a 90 degree turn turn since you will technically always have _some_ wind correction angle on the leg 3–>4

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LazinCajun@reddit

It’s the same reasoning — while flying to the East over the ground, the aircraft has to crab with its nose northward into the wind to compensate. However, on the north leg the aircraft points directly into the south wind. That’s an angle of less than 90 degrees

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Aviator8989@reddit

You are crabbing into the wind on the leg leading into turn 4. The crab angle is subtracted from the 90 degree turn.

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DollarBrand@reddit

You'd be crabbed over in position 4 due to wind correction to maintain that course. Like a tad bit, so when turning to 360 you'd need less than 90 degrees

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Hokie_Pilot@reddit

As you approach corner 4, you’re already crabbed into the wind (say 10 degrees to the north), then you when turn you’d make the extra 80 degrees, thus less than 90z

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SpamSushi206@reddit

When the plane is flying from point 3 to 4 it will be crabbed into the wind (to wind correction so you don’t get blown outwards) so when you make run 4 th then will be less than 90 due to already being angled inwards

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spartan224@reddit

Between 3 and 4 your nose would be pointed slightly more towards the wind in a “crabbed”manner. So when you turned into the upwind portion at corner 4 you would be turning less than 90 degrees

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Mediocre-Piano1192@reddit (OP)

Ohhh that makes so much sense I just learned about crabbing too, thank you!

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Sad-Umpire6000@reddit

Bewteen 3 and 4, you’re going to be crabbing into the wind. That will leave you needing less than 90 degrees to turn at 4.

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Repulsive-Frosting34@reddit

Corner 4 is less than 90 because the plane will be crabbed into the wind some. The simplest I can explain it is because the wind is off the left wing, the nose will be pointed left. And because me you're going to be turning left, you're already part of the way through the turn. If your brain thinks in headings - the plane will be tracking about a 270 track but crabbed to maybe 070-080 to hold that because the wind is pushing it. When it turns to the northerly 360, that is less than 90 degrees.

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rFlyingTower@reddit

This is a copy of the original post body for posterity: --- I understand how corner 1 is less than 90 degree turn, but I don’t understand how corner 4 is. If anyone could help me out that would be really helpful, thanks! --- Please downvote this comment until it collapses. Questions about this comment? [Please see this wiki post before contacting the mods](https://www.reddit.com/r/flying/wiki/index/rflyingtower/). --- I am a bot, and this action was performed automatically. If you have any questions, please [contact the mods of this subreddit](https://www.reddit.com/message/compose?to=/r/flying).

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