Mental dump of questions for PPL & CPL level

[photofly]

Not answered

When learning the technique for "short-field landing over an obstacle", students are instructed to use a steeper glide path than usual (since you need to clear the obstacle).

I'm wondering about short-field landings WITHOUT an obstacle... is it still recommended to use a steeper glide path than you would for a normal approach?

The glide path doesn't make much difference if you don't have an obstacle to clear. Touch down close to the threshold no faster than the recommended speed, and use (up to) maximum braking.

Remember from a practical point of view that any runway sufficiently short that you are in doubt as to your ability to stop the aircraft before the other end is almost certainly too short to permit you to take off again, and so you probably don't want to plan to land there.

[photofly]

ROC-A is not a radio station licence. (It's neither a licence not is it for a station.) There are no renewal fees.

Oh I see... so in this context when they say "license" they are not referring to something that is held by an individual person... they are referring to a license that allows the station to be operated by SOMEONE, regardless of who that someone is.....

They're referring exactly and only to a piece of paper with the words "Radio Station Licence" printed at the top. If your piece of paper doesn't say "Radio Station Licence" they are not referring to it.

The ROC-A is the "Restricted Operator Certificate - Aeronautical".

If you want to interpret official publications you have to pay close attention to the words they use. They're (usually) very carefully chosen.

[photofly]

Does anyone know where the aileron type and flap type for a 172 would be published? The POH for the 172S does not contain this information.

The 172S I train on has frise differential ailerons and single-slotted fowler flaps. I know this from word-of-mouth and observing the airframe of the aircraft for myself. However, since this kind of question comes up on flight tests, I would like to know where I can see it published.

You can look in places like "From the Ground Up" to see the different flap configurations, and what Frise ailerons are. Cessna doesn't publish a document that says "we use Frise-type ailerons with differential travel on the C172". Anyone else who puts this in print is simply observing the aircraft (like you do) and writing down their observations. Their word carries no more weight than yours.

If you need to discuss the point on a flight test, you can simply show the examiner the features of the ailerons that make them Frise-type. You don't need to back up your observations with an official publication.

[mckenziepiping]

Answered

When you turn up the "squelch" knob, you are raising the minimum threshold for a signal to be transmitted to your headset.

What I'm wondering is this: Does squelch eliminate low amplitude (volume) signal? Or does it eliminate low clarity signal?

For example, let's say you hear noise so you turn up the squelch to make the noise disappear. If that same noise were somehow to become louder, would it then make it into the headset? Or would it still be blocked since it's "noise"...?

If I fully understood how the diodes/resistors/inductors/capacitors/coils/etc. of a radio worked, the answer would probably be obvious, but fail that, perhaps someone can give me an operational answer rather than an electrical engineering one....

[Posthumane]

Most radios don't distinguish valid signal (voice) from background noise other than by signal amplitude. The squelch is just a signal strength threshold, both on your radio and your intercom if it has adjustable squelch. If you put your microphone up to a vent the rushing air will break squelch on the intercom and it will come through even though it's just noise, whereas some radio tramsissions that are weak enough to just be on the threshold will cut in and out even though they are obviously voice.

The exception is some modern digital radios/intercoms do some signal processing to actually filter out background noise, but most of those don't have a simple squelch knob that you have to adjust.

[photofly]

For example, let's say you hear noise so you turn up the squelch to make the noise disappear. If that same noise were somehow to become louder, would it then make it into the headset? Or would it still be blocked since it's "noise"...?

The squelch control on the radio shuts off the output when the signal strength is below the adjustable threshold.

The signal strength is only one component in determining how loud you hear something: you can have a strong signal (carrier) modulated with a very quiet audio (as if another pilot nearby has their microphone too far away from their mouth). That will still pass the squelch.

Most aviation radios have an automatic gain control so that whenever a signal gets past the squelch it's demodulated then amplified so you hear it at roughly constant volume.

So the answer to your question depends on what exactly you mean by "the same noise were to become louder". If the noisy radio signal is picked up with higher signal strength then it will open the squelch gate and you'll hear it.

The squelch control knows nothing from "clarity" - that's a human thing. But a weaker signal is both less likely to make it through the squelch gate, and also less likely to be clear.

[Mercator]

Ok so then it's not the RPM that determines whether or not the engine may get damaged - it's the %power?

A) RPM PRODUCES POWER

So is it meaningless for the "normal operation" column to indicate 2100 - 2700 at 10 000ft since you wouldn't be able to achieve that RPM anyway? A publishing oversight, perhaps?

A) POH NUMBERS ARE IN A RANGE, YOU CAN ACHIEVE 2700 RPM AND MORE IN A FULL POWER DESCENT AT ANY ALTITUDE

Ok so the fact that the range 2100 - 2700 is in the "normal operation" column does not mean that every setting within that range is "ok"? I would have thought "normal operation" means "use any settings prescribed here and it's safe"

A)EVERY SETTING IN THAT RANGE PRODUCE A CORRESPONDING SPEED TAS , FUEL BURN AND POWER.
USE IT AS YOU LIKE, BUT DON'T REDLINE
EVERY SETTING IS OK, DO NOT EXCEED 2700.DEPENDS IF YOU WANT TO DO A 50nm TRIP IN 30 mins or 2 hours.

[mckenziepiping]

ROC-A is not a radio station licence. (It's neither a licence not is it for a station.) There are no renewal fees.

Oh I see... so in this context when they say "license" they are not referring to something that is held by an individual person... they are referring to a license that allows the station to be operated by SOMEONE, regardless of who that someone is.....

They're referring exactly and only to a piece of paper with the words "Radio Station Licence" printed at the top. If your piece of paper doesn't say "Radio Station Licence" they are not referring to it.

The ROC-A is the "Restricted Operator Certificate - Aeronautical".

If you want to interpret official publications you have to pay close attention to the words they use. They're (usually) very carefully chosen.

Had I seen such a document called a "Radio Station License" at some point in my life, perhaps this confusion would not have arisen. Until now, I've NEVER seen the word "license" used with this kind of meaning (e.g. Driver's License, Hunter's License, Fishing License, Pilot's License, etc. etc....) so naturally, the term "Radio Station License" lends itself to the interpretation as being something that enables someone to carry out a certain task. Specifically, I thought that "Radio Station License" was, perhaps, a "category" within which you could find the ROC-A. Of course, now I realize that it's a license belonging to a piece of equipment. I'm just pointing out that my misunderstanding did not necessarily result because I didn't "pay close attention to the words".

[mckenziepiping]

Does anyone know where the aileron type and flap type for a 172 would be published? The POH for the 172S does not contain this information.

The 172S I train on has frise differential ailerons and single-slotted fowler flaps. I know this from word-of-mouth and observing the airframe of the aircraft for myself. However, since this kind of question comes up on flight tests, I would like to know where I can see it published.

You can look in places like "From the Ground Up" to see the different flap configurations, and what Frise ailerons are. Cessna doesn't publish a document that says "we use Frise-type ailerons with differential travel on the C172". Anyone else who puts this in print is simply observing the aircraft (like you do) and writing down their observations. Their word carries no more weight than yours.

If you need to discuss the point on a flight test, you can simply show the examiner the features of the ailerons that make them Frise-type. You don't need to back up your observations with an official publication.

Ok great, I actually chased down one of our instructors yesterday and got the same answer over the phone!

[mckenziepiping]

Most radios don't distinguish valid signal (voice) from background noise other than by signal amplitude. The squelch is just a signal strength threshold, both on your radio and your intercom if it has adjustable squelch. If you put your microphone up to a vent the rushing air will break squelch on the intercom and it will come through even though it's just noise, whereas some radio tramsissions that are weak enough to just be on the threshold will cut in and out even though they are obviously voice.

The exception is some modern digital radios/intercoms do some signal processing to actually filter out background noise, but most of those don't have a simple squelch knob that you have to adjust.

Ok this really clears things up.... I am still wondering about one thing though, regarding the use of squelch. I get that its primary use is to eliminate noise, but I'm wondering whether it would be advisable to also use it as a means of "muting" far away transmissions that couldn't possibly affect you? For example, I've flown at a few smaller airports where the frequency in use (be it ATF, UNICOM, MF, AU, etc.) is extremely congested because you hear all the transmissions from like 10 other airports that are all beyond 50nm away. It's very annoying and hazardous, especially when you're doing something that requires a radio call but you cannot make it without stepping on a bunch of other people. So I'm wondering what you guys think of the practice of using squelch as a way to suppress irrelevant/faraway transmissions....? Or would this be dangerous since it might inadvertently suppress someone who's in the circuit with you just because they have a shitty radio?

[mckenziepiping]

For example, let's say you hear noise so you turn up the squelch to make the noise disappear. If that same noise were somehow to become louder, would it then make it into the headset? Or would it still be blocked since it's "noise"...?

The squelch control on the radio shuts off the output when the signal strength is below the adjustable threshold.

The signal strength is only one component in determining how loud you hear something: you can have a strong signal (carrier) modulated with a very quiet audio (as if another pilot nearby has their microphone too far away from their mouth). That will still pass the squelch.

Most aviation radios have an automatic gain control so that whenever a signal gets past the squelch it's demodulated then amplified so you hear it at roughly constant volume.

So the answer to your question depends on what exactly you mean by "the same noise were to become louder". If the noisy radio signal is picked up with higher signal strength then it will open the squelch gate and you'll hear it.

The squelch control knows nothing from "clarity" - that's a human thing. But a weaker signal is both less likely to make it through the squelch gate, and also less likely to be clear.

Ah yes, I had learned about carriers and how AM/FM work but that was years ago so I couldn't readily see how that applies to this situation...

I don't think I've ever experienced automatic gain control since I always find myself frantically spinning volume knobs according to who's speaking.

I guess when I said "louder" I meant the carrier's source got closer to you... but at any rate, after reading everything that's been said here, I have my answer now.

[mckenziepiping]

Ok so then it's not the RPM that determines whether or not the engine may get damaged - it's the %power?

A) RPM PRODUCES POWER

So is it meaningless for the "normal operation" column to indicate 2100 - 2700 at 10 000ft since you wouldn't be able to achieve that RPM anyway? A publishing oversight, perhaps?

A) POH NUMBERS ARE IN A RANGE, YOU CAN ACHIEVE 2700 RPM AND MORE IN A FULL POWER DESCENT AT ANY ALTITUDE

Ok so the fact that the range 2100 - 2700 is in the "normal operation" column does not mean that every setting within that range is "ok"? I would have thought "normal operation" means "use any settings prescribed here and it's safe"

A)EVERY SETTING IN THAT RANGE PRODUCE A CORRESPONDING SPEED TAS , FUEL BURN AND POWER.
USE IT AS YOU LIKE, BUT DON'T REDLINE
EVERY SETTING IS OK, DO NOT EXCEED 2700.DEPENDS IF YOU WANT TO DO A 50nm TRIP IN 30 mins or 2 hours.

Hmmmmmmmm ok I think I get it, but there's still something blocking me somewhere. I'd say let's leave this one alone for now and I'll bring this into school since a face-to-face conversation is sometimes better than posting on a forum. I understand everything everyone has said on the matter, I just feel there's an aspect of my question that I've unable to clearly express. Or perhaps my question is rooted in such stupidity that nobody can see where I'm coming from. In such cases, it's best for me to bring this to someone who knows me and knows how I think.

[mckenziepiping]

Answered

Another one about taxiing in a crosswind... what do you do if the x-wind is NOT quartering but it's exactly 90 degrees to one side? Would that be a turn into wind, away from the wind, or just keep the ailerons flush with the wing...?

[photofly]

Neutral controls

[mckenziepiping]

Answered

Does anyone have any recommendations about how to practice the skill of locating oneself on a VNC, aside from actually renting an airplane and doing it?

The reason I ask is because I often have trouble when planning and executing a diversion since:
- "yellow dot towns" tend to be indistinguishable from small forests since there are no prominent buildings and the trees in the towns tend to hide the houses unless you're very close
- comparing roads you see out the window to those shown on a VNC is a challenge since only a very small fraction of the roads are depicted on the VNC, so when you see one road on the VNC and then look out the window, it's very hard to tell which of 10 possible roads you're looking at on the map
- many other reasons I can't quite recall at the moment

So I'm wondering if this is a skill that can be practiced on the ground? Going into a simulator or an FTD is not helpful in this regard since the maps are never quite detailed enough... somehow I've never had issues with maps when it comes to video games, navigating foreign cities, orienteering, etc., and yet I'm awful when an instructor asks me to pinpoint where I am on the map at any given moment....

So has anyone heard of tools/mental exercises for improving this skill? Or is this one of those "you either got it or you don't" situations....?

[photofly]

yet I'm awful when an instructor asks me to pinpoint where I am on the map at any given moment....

It's much much easier to stay un-lost than to become un-lost. So when your instructor asks where you are on the chart, the correct thing to do is to check your watch, see how many minutes since your last known position, do the mental arithmetic to multiply your miles per minute by how many minutes have passed, and project forward along your track line on the chart to determine where you are. This applies to diversions as much as planned cross-country routes, and you should be able to pinpoint yourself to within a very small area without seeing the ground at all.

From there you verify your calculated position by looking out of the window: look for (at least) three confirming features on the ground. The shape of a road, or if there are very few roads, small towns or towers then the existence of a road town or tower, or a water feature, or a railroad line, whatever you have available.

This is the skill of confirming your position, and it's not the same as finding yourself on a chart, which can be a very tricky thing to do.

You will note from the flight examiners' handbook that you are not expected to be able to locate yourself at the beginning of a diversion; the examiner is required to assist you to find your location on the chart before beginning the exercise.

[7ECA]

The easiest way to know your location, is to keep track of it at all times. Have your map folded in such a way as to display where you will be going (or likely going), and once you are in the air, take a look outside, and place your finger on said location on the map. Then as you fly, move your finger along the map.

When over a noticeable landmark(s), confirm your location via the map, circle it on the map, and write down the time. Then continue to trace out on the map with your finger where you are.

Foreflight, GPS, and all the other gadgets/toys, have made it really easy to know exactly where you are all the time. The best thing an instructor can do for their students, is to "fail" said gadget or toy from time to time, and get the student to figure out where the hell they are.

[Posthumane]

Ok this really clears things up.... I am still wondering about one thing though, regarding the use of squelch. I get that its primary use is to eliminate noise, but I'm wondering whether it would be advisable to also use it as a means of "muting" far away transmissions that couldn't possibly affect you? For example, I've flown at a few smaller airports where the frequency in use (be it ATF, UNICOM, MF, AU, etc.) is extremely congested because you hear all the transmissions from like 10 other airports that are all beyond 50nm away. It's very annoying and hazardous, especially when you're doing something that requires a radio call but you cannot make it without stepping on a bunch of other people. So I'm wondering what you guys think of the practice of using squelch as a way to suppress irrelevant/faraway transmissions....? Or would this be dangerous since it might inadvertently suppress someone who's in the circuit with you just because they have a shitty radio?

I wouldn't recommend using squelch to block out radio traffic from other nearby airports. While reception strength is generally proportional to the distance between the transmitter and receiver, in the real world there are a few other factors that affect it: the geometry of the antennas on the transmitting and receiving aircraft, terrain, etc. You could have a stronger signal from an aircraft that is several miles away at the same altitude compared to one that is closer but at a different altitude and on a different heading. In my aircraft I can often clear up a weak signal from a distant station by banking the plane slightly one way or the other. Also keep in mind that you may have an aircraft approaching the airfield from 15-20 miles away and calling inbound, which may be important to you. Best to get in the habit of listening to all radio traffic and deciding which is important to you.

[mckenziepiping]

What is this "distance AGL" column...? It's odd to find this in a "VFR Weather Minima" table. Is this saying that, under all weather conditions, you mustn't fly below 500AGL within a control zone?

[photofly]

Correct. Except for taking off and landing, or when cleared for SVFR, you must maintain at least 500AGL within a control zone.

Could you down-scale your photos?

[torquey401]

FTG
"Minimum VFR Flight Altitudes"

Built Up Areas - Except when landing or taking off, the minimum altitude at which an aircraft in VFR flight may be flown over the built up area of any community or any open air assembly of people is an altitude that, in an emergency would permit the landing of the aircraft without creating a hazard to persons or property on the ground. In no case can the altitude be less than 1000 feet above the highest obstacle within a radius of 2000 feet from the aircraft.

Areas Not Built Up - minimum altitude is 500 feet above highest obstacle within a radius of 500 feet from the aircraft.

Non Populous Areas Or Open Water - Provided no hazard is created for people or property on the ground, an aircraft may be flown at lower altitudes so long as it is at least 500 feet from any person, vessel or structure.

[danishroy]

Im doing the instrument part of my ppl ground school. I was reading about the turn coordinator and the turn and slip coordinator. I am confused by the difference between the two? Can anyone explain it to me? I read the presentation a couple times and still dont get it fully.

[photofly]

FTG
"Minimum VFR Flight Altitudes"


Areas Not Built Up - minimum altitude is 500 feet above highest obstacle within a radius of 500 feet from the aircraft.

This is pure fantasy by whoever wrote the FTG and does not appear in the CARs.

[Shiny Side Up]

FTG
"Minimum VFR Flight Altitudes"


Areas Not Built Up - minimum altitude is 500 feet above highest obstacle within a radius of 500 feet from the aircraft.

This is pure fantasy by whoever wrote the FTG and does not appear in the CARs.

Minimum Altitudes and Distances

602.14 (1) [Repealed, SOR/2002-447, s. 2]

(2) Except where conducting a take-off, approach or landing or where permitted under section 602.15, no person shall operate an aircraft

(a) over a built-up area or over an open-air assembly of persons unless the aircraft is operated at an altitude from which, in the event of an emergency necessitating an immediate landing, it would be possible to land the aircraft without creating a hazard to persons or property on the surface, and, in any case, at an altitude that is not lower than

(i) for aeroplanes, 1,000 feet above the highest obstacle located within a horizontal distance of 2,000 feet from the aeroplane,

(ii) for balloons, 500 feet above the highest obstacle located within a horizontal distance of 500 feet from the balloon, or

(iii) for an aircraft other than an aeroplane or a balloon, 1,000 feet above the highest obstacle located within a horizontal distance of 500 feet from the aircraft; and

(b) in circumstances other than those referred to in paragraph (a), at a distance less than 500 feet from any person, vessel, vehicle or structure.

One could easily see where they have maybe slightly mis-read (b). I'm assuming that by FTG one is referring to the FTM.

[photofly]

Yes, FTM. But see the US rules for something similar to what was quoted from the FTM.