compass turns with high mounted compass (Cessna 152)

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.

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/

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.

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.

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 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 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.