I'm just starting out my instrument training in a Cessna 152 that has a
compass mounted at the top of the windshield. Here's a sample picture for
those who have never seen it, http://www.airliners.net/open.file/643201/M

Can anyone tell me if it's still possible to do compass turns under the hood
with this kind of setup? I've seen a lot of planes with high mounted
compasses, so I imagine this isn't a new question.

- Ray

Ray,

It depends on you. Next time you are in the plane with a hood (or
substitute) on see if you can see the compass. That should answer your
question.

Most people can manage that.

Daniel

"Ray" > wrote in message
...
> I'm just starting out my instrument training in a Cessna 152 that has a
> compass mounted at the top of the windshield. Here's a sample picture for
> those who have never seen it, http://www.airliners.net/open.file/643201/M
>
> Can anyone tell me if it's still possible to do compass turns under the
> hood
> with this kind of setup? I've seen a lot of planes with high mounted
> compasses, so I imagine this isn't a new question.
>
> - Ray
>
>

I think the problem is that, with a high-mounted compass, you are
looking out the window every time you look at the compass. I'm not
sure how examiners deal with this.

On 1 Apr 2005 06:26:48 -0800, "paul kgyy" > wrote:

>I think the problem is that, with a high-mounted compass, you are
>looking out the window every time you look at the compass. I'm not
>sure how examiners deal with this.


Some examiners don't care.

Others will just tell you your compass heading whenever you ask for
it.

Unrelated response to your specific question.... do they have a dual
com/nav stack in the 152? I ask, because all the 152 trainers I've seen at
my FBO only have one com and one nav. I would think that adding another
stack would only serve to further reduce the marginally okay max load capy
of the 152?

--
--
=-----
Good Flights!

Cecil
PP-ASEL-IA
Student - CP-ASEL

Check out my personal flying adventures from my first flight to the
checkride AND the continuing adventures beyond!
Complete with pictures and text at: www.bayareapilot.com

"I fly because it releases my mind from the tyranny of petty things."
- Antoine de Saint-Exupery -

"We who fly, do so for the love of flying. We are alive in the air with
this miracle that lies in our hands and beneath our feet"
- Cecil Day Lewis -
"Ray" > wrote in message
...
> I'm just starting out my instrument training in a Cessna 152 that has a
> compass mounted at the top of the windshield. Here's a sample picture for
> those who have never seen it, http://www.airliners.net/open.file/643201/M
>
> Can anyone tell me if it's still possible to do compass turns under the
> hood
> with this kind of setup? I've seen a lot of planes with high mounted
> compasses, so I imagine this isn't a new question.
>
> - Ray
>
>

Ask the CFI to tell you when you hit the compass heading
you want to start your rollout on. Talk thru your logic for
selecting this heading. (compensating for lead/lag of the
compass)


"Ray" > wrote in message
...
> I'm just starting out my instrument training in a Cessna 152 that has a
> compass mounted at the top of the windshield. Here's a sample picture for
> those who have never seen it, http://www.airliners.net/open.file/643201/M
>
> Can anyone tell me if it's still possible to do compass turns under the
> hood
> with this kind of setup? I've seen a lot of planes with high mounted
> compasses, so I imagine this isn't a new question.
>
> - Ray
>
>

Compass turns are not required by the PTS. In my opinion, teaching and
practicing compass turns is a complete waste of time that could be more
profitably spent on more practical maneuvers. OTOH, timed turns make
perfectly good sense.

Imagine that you are an instrument-rated pilot flying on a dark and stormy
night. Your vacuum pump fails (or your vacuum-operated attitude
indicator/heading indicator fails). Your wife is scared, your kids are
crying, the turbulence is moderate to extreme, and you are trying to
remember whether to lag or lead the rollout by...the latitude? One-half the
latitude? Can't remember, and the situation is not getting any better.

Compare that with simply rolling into a standard rate turn (still hard to
maintain in turbulence) and watching the seconds tick by. BTW, nobody
expects you to roll out anywhere close to a desired heading when conditions
are really bad.

Bob Gardner

"paul kgyy" > wrote in message
oups.com...
>I think the problem is that, with a high-mounted compass, you are
> looking out the window every time you look at the compass. I'm not
> sure how examiners deal with this.
>

> I think the problem is that, with a high-mounted compass, you are
> looking out the window every time you look at the compass. I'm not
> sure how examiners deal with this.

From the Instrument Rating PTS:

Applicants may have an unfair advantage during performance of the TASK using
the backup flight instruments during an instrument approach due to the
location of the magnetic compass in some aircraft. When crosschecking the
magnetic compass heading, a view of the runway or other visual clue may be
sighted. It is the examiner's responsibility to determine if the applicant is
receiving visual clues from outside the cockpit. If an examiner feels that the
applicant is receiving visual clues, the examiner may devise other options to
limit the applicant's view. By no means shall the examiner limit his or her
view as the safety pilot.

> Compass turns are not required by the PTS. In my opinion, teaching and
> practicing compass turns is a complete waste of time that could be more
> profitably spent on more practical maneuvers. OTOH, timed turns make
> perfectly good sense....
>
> Compare that with simply rolling into a standard rate turn (still hard to
> maintain in turbulence) and watching the seconds tick by. BTW, nobody
> expects you to roll out anywhere close to a desired heading when conditions
> are really bad.

Yes, compass turns are not in the new PTS. However, I think that it's still a
skill worth learning. I prefer (and teach) using timing for small turns
(heading change 60 degrees or less), and the compass for larger turns. All
you really need to remember is that if the desired heading is north, you roll
out early, and if the desired heading is south, you go past it before rolling
out. This gets you close, and then you used a small timed turn to get closer.
I really think this is easier than trying to figure out the time required for
say, a right turn from 320 to 180. There's also the effect of the turn
coordinator calibration.

But I wouldn't insist on compass turns if the pilot makes acceptable timed
turns.

I'm with Gardner on this one.

compass turns are a complete waste of time and money.

Use a clock. Forget lead, lag, accelerate north, decelerate south,
and all the rest of the anal aviation gobbledygook..





On Fri, 01 Apr 2005 16:28:32 GMT, "OtisWinslow"
> wrote:

>Ask the CFI to tell you when you hit the compass heading
>you want to start your rollout on. Talk thru your logic for
>selecting this heading. (compensating for lead/lag of the
>compass)
>
>
>"Ray" > wrote in message
...
>> I'm just starting out my instrument training in a Cessna 152 that has a
>> compass mounted at the top of the windshield. Here's a sample picture for
>> those who have never seen it, http://www.airliners.net/open.file/643201/M
>>
>> Can anyone tell me if it's still possible to do compass turns under the
>> hood
>> with this kind of setup? I've seen a lot of planes with high mounted
>> compasses, so I imagine this isn't a new question.
>>
>> - Ray
>>
>>
>

> Unrelated response to your specific question.... do they have a dual
> com/nav stack in the 152? I ask, because all the 152 trainers I've seen
at
> my FBO only have one com and one nav. I would think that adding another
> stack would only serve to further reduce the marginally okay max load capy
> of the 152?

Hi Cecil - the plane is 65610 with West Valley out of Palo Alto (
http://www.wvfc.org/craft/65610.html ), and it does have dual nav/com with
glideslope and an inop ADF. All this adds about 80 or so pounds to the
empty weight. The max load is decreased, but the performance is more than
compensated for by the sparrowhawk conversion. I'm a fair bit lighter than
the FAA "standard passenger" - so I can barely fly with my instructor and
full fuel.

After doing my PP in 152's, I had originally planned on doing my instrument
in 172SPs in order to become proficient with the autopilot and GPS
approaches - which I figure I'll be much more likely to use in 'real life'
IFR flight. However, I'm a grad student with a pretty tight budget - and
there's a $50/hour wet difference between the 152 and 172SPs. I told my
instructor that I wanted to spend at least some of my instrument training in
the cheaper 152, and his response was basically "why not do all of it in the
152, after you finish the checkride it'll only take a couple lessons for you
to learn the GPS and autopilot, and this will save you thousands of
dollars." Sound's good to me!

- Ray

On 2005-04-01, > wrote:
> Some examiners don't care.
>
> Others will just tell you your compass heading whenever you ask for
> it.

I always thought that was funny, since the hardest thing for me about
the mag compass is reading it.

When I practiced compass turns I did it by looking at the mag compass,
even though I could see outside. The skill I was trying to learn wasn't
attitude instrument flying at that point.

--
Ben Jackson
>
http://www.ben.com/

I still think you are wasting your time and that of your students. Compass
turns are not practical...that's why they haven't been in the PTS for a long
time; it's not just a change in the most recent PTS. Turn coordinator
calibration is a non-issue, except for CFII checkrides. So you aim for 270
and end up with 250...is this life-threatening? Easy to fix, and absolutely
no one will notice.

Anyone who cannot pick two headings off of the heading indicator, count the
number of ten-degree/45-degree tick marks between them, and divide by three
may not be intellectually suited to aviation.

Bob



"Barry" > wrote in message ...
>> Compass turns are not required by the PTS. In my opinion, teaching and
>> practicing compass turns is a complete waste of time that could be more
>> profitably spent on more practical maneuvers. OTOH, timed turns make
>> perfectly good sense....
>>
>> Compare that with simply rolling into a standard rate turn (still hard to
>> maintain in turbulence) and watching the seconds tick by. BTW, nobody
>> expects you to roll out anywhere close to a desired heading when
>> conditions are really bad.
>
> Yes, compass turns are not in the new PTS. However, I think that it's
> still a skill worth learning. I prefer (and teach) using timing for small
> turns (heading change 60 degrees or less), and the compass for larger
> turns. All you really need to remember is that if the desired heading is
> north, you roll out early, and if the desired heading is south, you go
> past it before rolling out. This gets you close, and then you used a
> small timed turn to get closer. I really think this is easier than trying
> to figure out the time required for say, a right turn from 320 to 180.
> There's also the effect of the turn coordinator calibration.
>
> But I wouldn't insist on compass turns if the pilot makes acceptable timed
> turns.
>

I couldn't agree more with you and Bob. I can turn a lot more accurately
with a stop watch than a mag compass. But his question wasn't about
the merits of each .. it was about using the compass when it's outside
the viewing area of the hood. That would also be a factor when setting
the DG prior to starting an approach. To which I still say .. have the
CFI/safety pilot read it for you.


> wrote in message
...
> I'm with Gardner on this one.
>
> compass turns are a complete waste of time and money.
>
> Use a clock. Forget lead, lag, accelerate north, decelerate south,
> and all the rest of the anal aviation gobbledygook..
>
>
>
>
>
> On Fri, 01 Apr 2005 16:28:32 GMT, "OtisWinslow"
> > wrote:
>
>>Ask the CFI to tell you when you hit the compass heading
>>you want to start your rollout on. Talk thru your logic for
>>selecting this heading. (compensating for lead/lag of the
>>compass)
>>
>>
>>"Ray" > wrote in message
...
>>> I'm just starting out my instrument training in a Cessna 152 that has a
>>> compass mounted at the top of the windshield. Here's a sample picture
>>> for
>>> those who have never seen it,
>>> http://www.airliners.net/open.file/643201/M
>>>
>>> Can anyone tell me if it's still possible to do compass turns under the
>>> hood
>>> with this kind of setup? I've seen a lot of planes with high mounted
>>> compasses, so I imagine this isn't a new question.
>>>
>>> - Ray
>>>
>>>
>>
>

Well, if you do timed turns and forget all the other nonsense, you
only need to know the heading when the aircraft is straight and level.

Looking at a bouncing compass during a turn in the clouds and burning
up a bunch of brain cycles at the same time figuring leads and lags
and accelerations and decelerations with your attention diverted from
the instrument panel, is asking for trouble, if you ask me. When your
eyes return to the panel, you will probably find the altitude
decreasing rapidly and your airseed increasing rapidly, and then you
get to do partial panel unusual attitude recovery for real. By this
time ATC is probably on your case about your altitude, and you are
wishing you were somewhere else.

How about instead (1) look at the compass and note your heading (2)
use a compass rose (10 seconds per number on the rose) to calculate
the time for your desired turn (4) concentrate on a nice smooth,
level turn (5) check your heading after the rollout and (6) tidy up
the error, if any.

Not nearly as gee-whiz as all the compass gobbledygook, but a whole
lot safer, if you ask me.





On Fri, 01 Apr 2005 14:06:30 -0600, Ben Jackson > wrote:

>On 2005-04-01, > wrote:
>> Some examiners don't care.
>>
>> Others will just tell you your compass heading whenever you ask for
>> it.
>
>I always thought that was funny, since the hardest thing for me about
>the mag compass is reading it.
>
>When I practiced compass turns I did it by looking at the mag compass,
>even though I could see outside. The skill I was trying to learn wasn't
>attitude instrument flying at that point.

On Fri, 1 Apr 2005 12:56:39 -0800, "Bob Gardner" >
wrote:

>I still think you are wasting your time and that of your students. Compass
>turns are not practical...that's why they haven't been in the PTS for a long
>time; it's not just a change in the most recent PTS. Turn coordinator
>calibration is a non-issue, except for CFII checkrides. So you aim for 270
>and end up with 250...is this life-threatening? Easy to fix, and absolutely
>no one will notice.
>
>Anyone who cannot pick two headings off of the heading indicator, count the
>number of ten-degree/45-degree tick marks between them, and divide by three
>may not be intellectually suited to aviation.
>
>Bob
>
>

Amen. But why do any dividing at all? Each number on a compass rose
is 10 seconds. Count the numbers between your present heading and
the desired heading (just go "ten,twenty, thirty...") and interpolate
the overage/underage, and you'll be very close when you roll out,
with probably one more little turn to tidy up.

But you are absolutely right about the compass turn stuff. It's damn
near as ridiculous as parallel, teardrop and direct entries. Or
"reverse sensing". But let's not go there...


>
>"Barry" > wrote in message ...
>>> Compass turns are not required by the PTS. In my opinion, teaching and
>>> practicing compass turns is a complete waste of time that could be more
>>> profitably spent on more practical maneuvers. OTOH, timed turns make
>>> perfectly good sense....
>>>
>>> Compare that with simply rolling into a standard rate turn (still hard to
>>> maintain in turbulence) and watching the seconds tick by. BTW, nobody
>>> expects you to roll out anywhere close to a desired heading when
>>> conditions are really bad.
>>
>> Yes, compass turns are not in the new PTS. However, I think that it's
>> still a skill worth learning. I prefer (and teach) using timing for small
>> turns (heading change 60 degrees or less), and the compass for larger
>> turns. All you really need to remember is that if the desired heading is
>> north, you roll out early, and if the desired heading is south, you go
>> past it before rolling out. This gets you close, and then you used a
>> small timed turn to get closer. I really think this is easier than trying
>> to figure out the time required for say, a right turn from 320 to 180.
>> There's also the effect of the turn coordinator calibration.
>>
>> But I wouldn't insist on compass turns if the pilot makes acceptable timed
>> turns.
>>
>

I agree. Nothing like inserting high workload items such as compass turns
into situations where stress has created tunnel vision.

Bob

> wrote in message
...
> On Fri, 1 Apr 2005 12:56:39 -0800, "Bob Gardner" >
> wrote:
>
>>I still think you are wasting your time and that of your students. Compass
>>turns are not practical...that's why they haven't been in the PTS for a
>>long
>>time; it's not just a change in the most recent PTS. Turn coordinator
>>calibration is a non-issue, except for CFII checkrides. So you aim for 270
>>and end up with 250...is this life-threatening? Easy to fix, and
>>absolutely
>>no one will notice.
>>
>>Anyone who cannot pick two headings off of the heading indicator, count
>>the
>>number of ten-degree/45-degree tick marks between them, and divide by
>>three
>>may not be intellectually suited to aviation.
>>
>>Bob
>>
>>
>
> Amen. But why do any dividing at all? Each number on a compass rose
> is 10 seconds. Count the numbers between your present heading and
> the desired heading (just go "ten,twenty, thirty...") and interpolate
> the overage/underage, and you'll be very close when you roll out,
> with probably one more little turn to tidy up.
>
> But you are absolutely right about the compass turn stuff. It's damn
> near as ridiculous as parallel, teardrop and direct entries. Or
> "reverse sensing". But let's not go there...
>
>
>>
>>"Barry" > wrote in message
...
>>>> Compass turns are not required by the PTS. In my opinion, teaching and
>>>> practicing compass turns is a complete waste of time that could be more
>>>> profitably spent on more practical maneuvers. OTOH, timed turns make
>>>> perfectly good sense....
>>>>
>>>> Compare that with simply rolling into a standard rate turn (still hard
>>>> to
>>>> maintain in turbulence) and watching the seconds tick by. BTW, nobody
>>>> expects you to roll out anywhere close to a desired heading when
>>>> conditions are really bad.
>>>
>>> Yes, compass turns are not in the new PTS. However, I think that it's
>>> still a skill worth learning. I prefer (and teach) using timing for
>>> small
>>> turns (heading change 60 degrees or less), and the compass for larger
>>> turns. All you really need to remember is that if the desired heading
>>> is
>>> north, you roll out early, and if the desired heading is south, you go
>>> past it before rolling out. This gets you close, and then you used a
>>> small timed turn to get closer. I really think this is easier than
>>> trying
>>> to figure out the time required for say, a right turn from 320 to 180.
>>> There's also the effect of the turn coordinator calibration.
>>>
>>> But I wouldn't insist on compass turns if the pilot makes acceptable
>>> timed
>>> turns.
>>>
>>
>

On Fri, 01 Apr 2005 21:50:10 GMT, wrote:

> But you are absolutely right about the compass turn stuff. It's damn
> near as ridiculous as parallel, teardrop and direct entries. Or
> "reverse sensing". But let's not go there...

cfeyeeye,

Agree with everything but reverse sensing.

I hear on ATIS a lot at JAN for approaches, expect back course 16 right
(16L is closed), so learning to "pull the needle in" is important in this
neck of the woods.

Allen

On Fri, 1 Apr 2005 20:04:53 -0600, A Lieberman >
wrote:

>On Fri, 01 Apr 2005 21:50:10 GMT, wrote:
>
>> But you are absolutely right about the compass turn stuff. It's damn
>> near as ridiculous as parallel, teardrop and direct entries. Or
>> "reverse sensing". But let's not go there...
>
>cfeyeeye,
>
>Agree with everything but reverse sensing.
>
>I hear on ATIS a lot at JAN for approaches, expect back course 16 right
>(16L is closed), so learning to "pull the needle in" is important in this
>neck of the woods.
>
>Allen


There is no such thing as "reverse sensing". Instruments don't change
the way they sense.

There is only "reverse thinking".

But let's not get started on that.

> There is no such thing as "reverse sensing". [...]
> There is only "reverse thinking".

There's also "reverse polish notation".

Jose
--
Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.

On Fri, 1 Apr 2005 02:33:35 -0800, "Ray" > wrote:

>I'm just starting out my instrument training in a Cessna 152 that has a
>compass mounted at the top of the windshield. Here's a sample picture for
>those who have never seen it, http://www.airliners.net/open.file/643201/M
>
>Can anyone tell me if it's still possible to do compass turns under the hood
>with this kind of setup? I've seen a lot of planes with high mounted
>compasses, so I imagine this isn't a new question.
>

What is a compass turn?

I've done timed turns, (my instructors wouldn't even let me call it a
compass turn) but you can't do a turn while under the hood or in
actual while watching the compass. It'll even go the wrong way at
times and it'll change directions when you speed up or slow down when
on anything other than a north or south heading.

You look at the compass, figure how long to make a standard rate turn
(3 degrees per second), figure how many degrees to turn and then how
many seconds. Make the turn for how ever many seconds, roll out and
then check the compass to see how close you came to getting it right.

Short hand method... standard rate is 360 degrees in 2 minutes, 180
degrees in one minute, 90 degrees in 30 seconds, 45 degrees in 15
seconds and 10 degrees in roughly 3 seconds, or 30 degrees in 10
seconds. If you memorize these basic numbers you will be able to work
out any turn time in your head.

If you are referring to flying with a DE and will they let you use the
compass mounted way up there, the odds are no, but they will give you
the heading at the start and stop of the turn.

BTW, I find a vertical card compass "on the glare shield" to be great,
but the ones mounted at the top of the windshield to be a royal pain
when under the hood. They aren't quite so bad in actual, but I prefer
the compass closer to the rest of the instruments.

The new glass panels with all the flight instruments are great and
very easy to use although some pilots just can't seem to get used to
them. I find them to be natural. OTOH I don't think we'll see many
150s with glass panels soon <:-)) They'd be worth more than the
airplane.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
>- Ray
>

On Fri, 1 Apr 2005 02:33:35 -0800, "Ray" > wrote:

>I'm just starting out my instrument training in a Cessna 152 that has a
>compass mounted at the top of the windshield. Here's a sample picture for
>those who have never seen it, http://www.airliners.net/open.file/643201/M
>
>Can anyone tell me if it's still possible to do compass turns under the hood
>with this kind of setup? I've seen a lot of planes with high mounted
>compasses, so I imagine this isn't a new question.
>

What is a compass turn?

I've done timed turns, (my instructors wouldn't even let me call it a
compass turn) but you can't do a turn while under the hood or in
actual while watching the compass. It'll even go the wrong way at
times and it'll change directions when you speed up or slow down when
on anything other than a north or south heading.

You look at the compass, figure how long to make a standard rate turn
(3 degrees per second), figure how many degrees to turn and then how
many seconds. Make the turn for how ever many seconds, roll out and
then check the compass to see how close you came to getting it right.

Short hand method... standard rate is 360 degrees in 2 minutes, 180
degrees in one minute, 90 degrees in 30 seconds, 45 degrees in 15
seconds and 10 degrees in roughly 3 seconds, or 30 degrees in 10
seconds. If you memorize these basic numbers you will be able to work
out any turn time in your head.

If you are referring to flying with a DE and will they let you use the
compass mounted way up there, the odds are no, but they will give you
the heading at the start and stop of the turn.

BTW, I find a vertical card compass "on the glare shield" to be great,
but the ones mounted at the top of the windshield to be a royal pain
when under the hood. They aren't quite so bad in actual, but I prefer
the compass closer to the rest of the instruments.

The new glass panels with all the flight instruments are great and
very easy to use although some pilots just can't seem to get used to
them. I find them to be natural. OTOH I don't think we'll see many
150s with glass panels soon <:-)) They'd be worth more than the
airplane.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
>- Ray
>

On 1 Apr 2005 06:26:48 -0800, "paul kgyy" > wrote:

>I think the problem is that, with a high-mounted compass, you are
>looking out the window every time you look at the compass. I'm not
>sure how examiners deal with this.

When I took the instrument flight test, I asked the DE about it. He
asked me if I could see out when doing that. I replied, "I wear
bifocals. If you mean can I see any thing the answer is no, but if
you mean can I see light and dark and I could probably figure out
where the horizon was if the conditions were just right. If they
weren't just right I would probably come up with a false horizon". He
said not to worry, he'd just give me readings when appropriate.

Whether he read the vertical card compass on the glare shield for me,
or I read it made no difference to me. Actually it was probably
easier as I didn't have to look up away from the panel. Compasses
that are not very close to your flight instruments are a royal pain in
the real world.

Whether they let you look at it, or not should make no difference to
you. You know how to make timed turns and they are *not* going to
have you make turns while watching the compass. I seriously doubt any
one in their right mind would even ask for it in VFR conditions. They
just want the student to be aware of the quirks of a magnetic compass.
I've never head of them expecting the student to make turns with one.
However if I had to use the compass I'd cheat by getting the heading,
then rolling into the turn and ignoring what the compass was doing.
Just remember that 2 minute standard rate turn, one minute for a 180,
half a minute for 90, 15 seconds for 45. you can interpolate for
anything in between.

Timed turns are not the same thing.

Even VFR you should be looking at the compass to get a heading, make
the turn for so many seconds, roll out and then check the compass
again. If you are VFR, who cares if you miss the heading, you make a
correction and check again.

I had an instructor cover up everything except the TC, air speed, and
altimeter to see how long I could fly a straight course. After five
minutes, he said, never mind...we were still on course. <:-))

Now when he had me close my eyes and fly, I lasted about a minute and
a half before "we had to recover". (mainly due to the plane being
well trimmed and rigged and little to do with any skill of mine) He
said he saw very few students who managed more than 15 to 20 seconds.
I admitted I was letting the plane do most of the flying with me just
nudging the controls from time to time.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com