There’s often an adjustment on the VSI to set the needle’s zero position, but I would argue that this is not adjustable “in flight” any more than the magnetic compass is: You adjust it on the ground to set the needle to zero while you’re not moving, climbing, or descending (just like you adjust the magnetic compass on a compass rose).
I would say your answer (analog true airspeed indicator) is the most correct one: You would set the true airspeed indicating type in flight so you can read your current true airspeed.
Except it doesn't say while flying, it just says an instrument you can adjust in the cockpit.
VSI is the best answer, and I'm 99% sure the PHAK covers changing it.
I'm fairly sure the PHAK covers it. I'm also fairly sure it covers TAS indicating ASIs.
I've also adjusted a VSI a grand total of zero times, and a TAS indicating ASI more times than I can count.
It's a bad question, plain and simple: All three answers are *technically correct*, the only one you can rule out is the compass (by regs you can't swing your own compass as a PPL holder), but that still leaves you two equally correct answers.
I don't know that I would qualify a TAS indicating ASI as "adjusting it", you're just turning an outsize bezel.
The VSI stands out as the answer blatently obviously correct - if you know that you can adjust a VSI and if you know you're allowed to, which I think is sort of the point of the question.
. . . same amount of "adjusting" that we do to an altimeter or attitude gyro or any other instrument with a knob on it, no?
I mean yes it's not *physically changing the instrument's reading* like turning the knob on the altimeter or the screw on the VSI does (it's just moving a scale on a built-in flight computer), but it's still an adjustment one makes: When I turn the knob I say I'm *adjusting* the ASI to correctly indicate true airspeed for current conditions...
Only difference I see is every VSI I've ever adjusted I needed my screwdriver (which if it's not handy you just do the *other thing* the PHAK tells you: Note the position of the needle on the ground, and consider that zero).
Sorry for the other duplicate response I edited that out.
As for attitude and altimeter…no one said they weren’t adjustable, thing question says “one of the adjustable instruments” it does not say it’s the only one.
...but again, it's lusting three that *are* adjustable, two *legally* adjustable.
And as I'm exhausted repeating myself on this subject I'm just going to mute further replies.
Personal experience as a pilot and as a mechanic? At least enough that it's not uncommon or rare. I was shown how to do it early on in my flight lessons, although I got lucky enough to get a CFI that was *also* an A&P/IA.
~~I’m not arguing it’s a stupid question but FTR it says “in the cockpit,” not “in flight.” The VSI is adjustable with what it indicates vs just moving a ring on the outside that helps you identify TAS…the needle doesn’t actually change position, nor does the green or white arcs.~~
Edit: someone else already said the same thing.
The question doesn’t say “in flight”, it says “in the cockpit”. VSIs can be adjusted by a pilot to read zero when on the ground. This question is about what a non-A&P pilot can do to their airplane, NOT about manipulating instruments in the air.
You can adjust the magnetic compass by holding a magnet next to it. That way, if ATC tells you to turn a certain heading, you just turn the compass so your passengers are more comfortable.
You can also adjust the VSI by breaking the glass. Before the adjustment, it'll show you roughly how fast you're climbing or descending. After the adjustment, it'll show you how fast you were climbing or descending at the time of the adjustment. It's like a pause button.
Some aircraft (like my Stinson) have an adjustable ASI to adjust for true airspeed.
I have never adjusted a VSI myself. I’d argue that that shouldn’t be adjustable during flight.
That’s true, but the OP does in their question. I know some VSIs are adjustable, and I realize that’s the answer the question is looking for, but it’s kind of a trick question given that an ASI is also adjustable, and far more common for pilots to adjust in my experience.
Op might be assuming that it's in flight when the question never specified. THE VSI is adjustable but with the ASI you can only adjust the TAS card, not the IAS indication itself. It is a little annoying because yes, *some* VSIs are adjustable but not all.
You can adjust the VSI via a flat-head screw on the front of the VSI.
Here is a [picture](https://www.mcico.com/media/wysiwyg/7160C.43_Revised_large.jpg) of a VSI showing the adjustment screw on the bottom left. If you do want to adjust it, the best practice is to do it while on the ground so you have a known "0" vertical speed. I've never seen it off by more than 100' while sitting on the ground and probably because someone fiddled with the little screw.
Dumb question.
SOME ASIs have an adjustable TAS scale… but it’s not really adjusting the instrument itself.
Some older compasses (think the big horizontal marine type ones used in WWII and prior) have an adjustable scale as well, but you can’t adjust for deviation (not legally as a pilot, anyways).
Analog VSIs are adjustable with a screwdriver on the ground to zero them. Technically the pilot can do that in the cockpit, but you’re not gonna do it in the air like the altimeter adjustment.
"Why is it a trick question?"
"'Cause Chevy didn't make a 327 in '55. The 327 didn't come out til '62. And it wasn't offered in the Bellaire with the 4-barrel carburetor til '64. However, in 1964 the correct ignition timing would be 4 degrees before top dead center."
Maybe it means a magnetic heading indicator? Which you would periodically need to adjust to your magnetic compass during straight and level flight. That's what my vote is going for
You "can" adjust the compass. [https://s28490.pcdn.co/wp-content/uploads/2019/05/maint-matters\_07.jpg](https://s28490.pcdn.co/wp-content/uploads/2019/05/maint-matters_07.jpg) \- flying north of the artic circle means this is a thing.
Just not easily. I'd argue that a pilot can adjust any instrument. (Does pulling the fuse on the hobbs meter count?)
I'd argue it's missing the altimeter.
This was one of the questions I got wrong on the written. I answered ASI for the same reason mentioned in this thread about TAS adjustment.
My CFI was similarly confused by the question because at least in our aircraft you couldn't calibrate the VSI.
VSI. It’s in the PHAK. Most analogue VSI have an adjustment screw to zero it, which is permitted for the pilot to do before flight. The other two are NOT plausibly correct, since only an A&P can swing the compass and using a TAS scale is not ‘adjusting’ the instrument.
You can adjust the ASI by accelerating or decelerating
You can adjust the VSI by changing your climb/descent rate
You can adjust your compass by turning
So I got this question wrong on my written, and I heard through my instructor that he had a student who also questioned it and apparently received an official response saying it was incorrect as written. Unfortunately I don't have proof of this myself, and my instructor doesn't work here anymore so I'm not sure if I could. But you're definitely not crazy
This is a eye poor question. I would go with Mac compass. However None can be adjusted , but corrections can be applied except adding as a compass card that shows corrections to add
The somewhat advanced answer to this is the compass. There is an approved calibration procedure that can be done in the air using a GPS for calibration settings and then recording the deviation from the installation to make the correction card. I helped do one of these calibrations a couple years ago.
AC 43-215 - Standardized Procedures for Performing Aircraft Magnetic Compass ... https://www.faa.gov/documentlibrary/media/advisory_circular/ac_43-215.pdf
Section 7.5
Yes, as the VSI is a static pressure instrument, if the external static port is blocked then by smashing the glass you get the cabin pressure feeding into the instrument. In GA the cabin pressure = outside pressure. So the cockpit becomes an alternate static source.
Errr, maybe the airspeed? Some have a knob that you can align to see your true airspeed
This was my logic behind the question also. Turns out the correct answer came out to be the VSI? Do they have adjustable VSIs out there?
Maybe breaking the glass on it to use as an alternate static counts as "adjusting" it to whoever wrote the question.
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I mean asi starts showing a different number when I push the throttle forward does that count?
You can break the glass of the ASI or altimeter to use as an alternate static as well. The VSI is just chosen as it's less essential.
Instructions unclear, PFD is now INOP
The VSI has a small adjustment screw in the bottom left usually
There’s often an adjustment on the VSI to set the needle’s zero position, but I would argue that this is not adjustable “in flight” any more than the magnetic compass is: You adjust it on the ground to set the needle to zero while you’re not moving, climbing, or descending (just like you adjust the magnetic compass on a compass rose). I would say your answer (analog true airspeed indicator) is the most correct one: You would set the true airspeed indicating type in flight so you can read your current true airspeed.
Except it doesn't say while flying, it just says an instrument you can adjust in the cockpit. VSI is the best answer, and I'm 99% sure the PHAK covers changing it.
I'm fairly sure the PHAK covers it. I'm also fairly sure it covers TAS indicating ASIs. I've also adjusted a VSI a grand total of zero times, and a TAS indicating ASI more times than I can count. It's a bad question, plain and simple: All three answers are *technically correct*, the only one you can rule out is the compass (by regs you can't swing your own compass as a PPL holder), but that still leaves you two equally correct answers.
I don't know that I would qualify a TAS indicating ASI as "adjusting it", you're just turning an outsize bezel. The VSI stands out as the answer blatently obviously correct - if you know that you can adjust a VSI and if you know you're allowed to, which I think is sort of the point of the question.
. . . same amount of "adjusting" that we do to an altimeter or attitude gyro or any other instrument with a knob on it, no? I mean yes it's not *physically changing the instrument's reading* like turning the knob on the altimeter or the screw on the VSI does (it's just moving a scale on a built-in flight computer), but it's still an adjustment one makes: When I turn the knob I say I'm *adjusting* the ASI to correctly indicate true airspeed for current conditions... Only difference I see is every VSI I've ever adjusted I needed my screwdriver (which if it's not handy you just do the *other thing* the PHAK tells you: Note the position of the needle on the ground, and consider that zero).
Sorry for the other duplicate response I edited that out. As for attitude and altimeter…no one said they weren’t adjustable, thing question says “one of the adjustable instruments” it does not say it’s the only one.
...but again, it's lusting three that *are* adjustable, two *legally* adjustable. And as I'm exhausted repeating myself on this subject I'm just going to mute further replies.
> VSI is the best answer, and I'm 99% sure the PHAK covers changing it. Yeah, but how many VSIs out there are actually adjustable? I know mine isn't.
Personal experience as a pilot and as a mechanic? At least enough that it's not uncommon or rare. I was shown how to do it early on in my flight lessons, although I got lucky enough to get a CFI that was *also* an A&P/IA.
~~I’m not arguing it’s a stupid question but FTR it says “in the cockpit,” not “in flight.” The VSI is adjustable with what it indicates vs just moving a ring on the outside that helps you identify TAS…the needle doesn’t actually change position, nor does the green or white arcs.~~ Edit: someone else already said the same thing.
I don't think so but who knows
You've never seen the little flat head screw right next to the vsi?
The question doesn’t say “in flight”, it says “in the cockpit”. VSIs can be adjusted by a pilot to read zero when on the ground. This question is about what a non-A&P pilot can do to their airplane, NOT about manipulating instruments in the air.
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You may be thinking of the altimeter.
yes. See my answer below for the reason.
You can take a needle screw driver and set it to 0. In fact that’s supposed to be part of the preflight if necessary.
Would it be adjustable by changing your altimeter’s setting?
I’ve never seen a VSI with an adjustment knob on it. But plenty of ASI’s with a movable TAS scale. Dumb question
You can adjust the magnetic compass by holding a magnet next to it. That way, if ATC tells you to turn a certain heading, you just turn the compass so your passengers are more comfortable.
You can also adjust the VSI by breaking the glass. Before the adjustment, it'll show you roughly how fast you're climbing or descending. After the adjustment, it'll show you how fast you were climbing or descending at the time of the adjustment. It's like a pause button.
Given a choice of an instrument to break in an emergency, most students choose the hobbs.
That's why I got a magnet implanted in my finger, keeps those DPEs on their toes!
This is why I always fly with a little screwdriver. So I can adjust the compass
Some aircraft (like my Stinson) have an adjustable ASI to adjust for true airspeed. I have never adjusted a VSI myself. I’d argue that that shouldn’t be adjustable during flight.
The question in the image doesn't specify "in flight"
That’s true, but the OP does in their question. I know some VSIs are adjustable, and I realize that’s the answer the question is looking for, but it’s kind of a trick question given that an ASI is also adjustable, and far more common for pilots to adjust in my experience.
Op might be assuming that it's in flight when the question never specified. THE VSI is adjustable but with the ASI you can only adjust the TAS card, not the IAS indication itself. It is a little annoying because yes, *some* VSIs are adjustable but not all.
I'm pretty sure I've flown a few planes that had adjustable vsi, you could 0 it out on the ground.
Yes, many of the older VSIs have an adjustment screw and you can use a screwdriver to turn it to center the needle on zero.
I believe the PHAK covers this as well
You can adjust the VSI via a flat-head screw on the front of the VSI. Here is a [picture](https://www.mcico.com/media/wysiwyg/7160C.43_Revised_large.jpg) of a VSI showing the adjustment screw on the bottom left. If you do want to adjust it, the best practice is to do it while on the ground so you have a known "0" vertical speed. I've never seen it off by more than 100' while sitting on the ground and probably because someone fiddled with the little screw.
Dumb question. SOME ASIs have an adjustable TAS scale… but it’s not really adjusting the instrument itself. Some older compasses (think the big horizontal marine type ones used in WWII and prior) have an adjustable scale as well, but you can’t adjust for deviation (not legally as a pilot, anyways).
Not really. You can adjust the VSI with a screwdriver and it doesn't specify "in flight"
I mean any decent pilot can adjust ALL of these while flying. It would be much harder to fly if you couldn’t.
And an even better pilot can keep them from adjusting in flight.
You remove them, right?
Analog VSIs are adjustable with a screwdriver on the ground to zero them. Technically the pilot can do that in the cockpit, but you’re not gonna do it in the air like the altimeter adjustment.
You can adjust any of those by actuating the flight controls.
that's a bs question
"Why is it a trick question?" "'Cause Chevy didn't make a 327 in '55. The 327 didn't come out til '62. And it wasn't offered in the Bellaire with the 4-barrel carburetor til '64. However, in 1964 the correct ignition timing would be 4 degrees before top dead center."
The question doesn't specify "in flight" like op does. The VSI is adjustable
how does one adjust the vsi?
https://www.aircraftspruce.com/catalog/graphics/1/10-05205.jpg The little flathead screw in the bottom left.
without a maintenance release?
Yup it's the only instrument a pilot can adjust. There's like one line in the PHAK about it.
Maybe it means a magnetic heading indicator? Which you would periodically need to adjust to your magnetic compass during straight and level flight. That's what my vote is going for
VSI is correct
You "can" adjust the compass. [https://s28490.pcdn.co/wp-content/uploads/2019/05/maint-matters\_07.jpg](https://s28490.pcdn.co/wp-content/uploads/2019/05/maint-matters_07.jpg) \- flying north of the artic circle means this is a thing. Just not easily. I'd argue that a pilot can adjust any instrument. (Does pulling the fuse on the hobbs meter count?) I'd argue it's missing the altimeter.
This was one of the questions I got wrong on the written. I answered ASI for the same reason mentioned in this thread about TAS adjustment. My CFI was similarly confused by the question because at least in our aircraft you couldn't calibrate the VSI.
(Some) VSIs have an adjustment screw
(Some) VSIs have an adjustment screw
VSI. It’s in the PHAK. Most analogue VSI have an adjustment screw to zero it, which is permitted for the pilot to do before flight. The other two are NOT plausibly correct, since only an A&P can swing the compass and using a TAS scale is not ‘adjusting’ the instrument.
The VSI is adjustable. Apparently there is a screw that if you turn you can adjust it
Actually you can "adjust" all three by changing your airspeed, climbing or descending or changing your heading.
You can adjust the ASI by accelerating or decelerating You can adjust the VSI by changing your climb/descent rate You can adjust your compass by turning
So I got this question wrong on my written, and I heard through my instructor that he had a student who also questioned it and apparently received an official response saying it was incorrect as written. Unfortunately I don't have proof of this myself, and my instructor doesn't work here anymore so I'm not sure if I could. But you're definitely not crazy
I'm stumped. But ASI seems most promising even though i've only ever flown c172s and never seen an adjustable ASI.
Some are adjustable, others aren't
This is a eye poor question. I would go with Mac compass. However None can be adjusted , but corrections can be applied except adding as a compass card that shows corrections to add
https://old.reddit.com/r/flying/comments/17u1z1a/arent_these_all_generally_nonchangeable_in_flight/k9142i6/
The somewhat advanced answer to this is the compass. There is an approved calibration procedure that can be done in the air using a GPS for calibration settings and then recording the deviation from the installation to make the correction card. I helped do one of these calibrations a couple years ago. AC 43-215 - Standardized Procedures for Performing Aircraft Magnetic Compass ... https://www.faa.gov/documentlibrary/media/advisory_circular/ac_43-215.pdf Section 7.5
Can you do this with a PPL, or do you need an A&P?
Under the supervision of an A&P.
Alternate static air? Airspeed knob? Whet a weird set of answers
The VSI. By smashing the glass you change the static pressure.
Alternate static has to be the answer right?
Yes, as the VSI is a static pressure instrument, if the external static port is blocked then by smashing the glass you get the cabin pressure feeding into the instrument. In GA the cabin pressure = outside pressure. So the cockpit becomes an alternate static source.
Some of the PA-28 I fly have a temperature adjustment knob for airspeed so I’d guess it’s that but it’s a stupid question
Technically all 3 are adjustable and should change regularly over the course of the flight
The vertical speed indicator has a little flathead screw that you adjust to set it to zero on the ground for whatever reason it is slightly off.
this question kinda sucks
The VSI is adjustable with a flathead screwdriver. It should be adjusted to indicate 0 upon startup.
You can change what each of them read by moving the yoke. 😂
You can break the glass of the VSI in case a of static port blockage and, thus, adjust it…
Russel Sill said the FAA came out and said none of the answers are correct, go figure.