Altimeter Setting

Rolf,

From the inception of the club to about 5 years ago, we flew and
taught AGL only. No self respecting power pilot would fly AGL.
Flying AGL is a crutch intended to help new pilots. But It is better
to learn it right from the get-go than to have to relearn it later and
maybe getting into an accident.

So about 5 years ago my Club's flight chair said that flying AGL was
wrong, dangerous and (if I am not mistaken) illegal. So the board
made an edict and we changed overnight at the start of a season. We
marked all altimeters in club ships "MSL Only Club Policy". There was
some, but not a tremendous amount of, consternation ... such as "But
it is so flat around here." or "But I always land back home."

We did have one incident related to the AGL/MSL switch that might be a
good to read about. One day yours truly flew a club ship and set the
altimeter to MSL. The next pilot was an die hard AGL'er. The AGL'ers
were used to finding the altimer not quite at zero due to barometric
changes and would "tweak" the altimeter to zero at the start of each
flight. Our field elevation is 888 feet. So the next pilot tweaks
the altimeter to "zero" but instead of subtracting 888 feet (by moving
the hands CCW), he tweaks it CW and adds 112 feet! Can you see where
this is going?

He then takes a tow to what he thinks is 3,000 feet AGL but is only
really at 2,000 feet AGL. The tow pilot doesn't think much about it
as people get off tow early all the time. About to enter the pattern
the AGL'er thinks, "Gee, the ground seems to be kind of large
today ... but I am still at 1500 feet AGL so I'm must be OK." He then
almost lands short as he was 1,000 feet lower than he thought. End of
story? Nah.

The AGL'er gets back on the ground and complains that the altimeter
must be wrong. We look at the altimer and see that it is showing
1,000 feet. Putting 2+2 together we figured out what he did. So get
this ... an old timer CFIG says it was my fault as I should have reset
the altimeter to zero when I got out. Sorry, wrong-o. Who was the
PIC on the second flight? The AGL'er of course. It is his
responsibility to ensure that the instrumentation is set correctly,
not mine. Can you tell that it still grates a bit? Ok, I feel better
now.

Anyway, my suggestions are to;

1) Do it!
2) Convert "big bang" all at once, not by dribs and drabs or over a
"transition" period.
3) Mark the altimeter with an "MSL Only" sign to reenforce the new
policy each time a pilot climbs into the cockpit.

Good luck, John DeRosa

PS Early in my soaring career, I remember flying at a commercial
operation while on a business trip and was told to set the altimeter
to MSL. I started sweating worrying about all the math I would need
to calculate in my head. Luckily I was in Miami at the time and the
field elevation was all of 20 feet - not much of a problem.

On 5/31/2010 8:06 PM, ContestID67 wrote:


He then takes a tow to what he thinks is 3,000 feet AGL but is only
really at 2,000 feet AGL. The tow pilot doesn't think much about it
as people get off tow early all the time. About to enter the pattern
the AGL'er thinks, "Gee, the ground seems to be kind of large
today ... but I am still at 1500 feet AGL so I'm must be OK." He then
almost lands short as he was 1,000 feet lower than he thought. End of
story? Nah.

The poor guy couldn't tell the difference between 500' AGL and 1500' AGL
by looking out the window? Sounds like it was time to retire his wings.

On May 31, 11:22*pm, Greg Arnold wrote:
On 5/31/2010 8:06 PM, ContestID67 wrote:



He then takes a tow to what he thinks is 3,000 feet AGL but is only
really at 2,000 feet AGL. *The tow pilot doesn't think much about it
as people get off tow early all the time. *About to enter the pattern
the AGL'er thinks, "Gee, the ground seems to be kind of large
today ... but I am still at 1500 feet AGL so I'm must be OK." *He then
almost lands short as he was 1,000 feet lower than he thought. *End of
story? *Nah.

The poor guy couldn't tell the difference between 500' AGL and 1500' AGL
by looking out the window? *Sounds like it was time to retire his wings..

Here's a good one. I usually fly out of a busy general aviation
airport right on the edge of Class C airspace. We are surrounded by
mountains, talk to power planes and controllers, and fly cross country
a lot, so we always use MSL. Recently I spent a sunny afternoon down
at the local gliderport where they do a lot of training. I took a tow
to the ridge and got off at about 3,200 (MSL). Much later that
afternoon, the owner was up flying so I asked someone what I owed for
the tow. They asked me how high I went and I said "3,200 feet." A
quick look at the handy chart on the wall told me what I owed them for
"3,200 feet" and I happily paid and left. On the drive home I was
musing about how the price of tows was always going up, but who cares
when the planes and gadgets cost so damned much. Then it hit me WHY
they were going up. The gliderport uses AGL for training AND to
calculate the tows to simplify the billing, and I hadn't deducted the
field elevation when I told him "3,200 feet." I had bought about 800
feet of it sitting at the end of the runway waiting to hook up. All
I could do was laugh at myself, and they are welcome to the tip for
all they do for all of us. At least I hadn't scratched around cross
country for two hours with my gear down like I usually do... Now THAT
****es me off!

Don

In article
,
ContestID67 wrote:

We did have one incident related to the AGL/MSL switch that might be a
good to read about. One day yours truly flew a club ship and set the
altimeter to MSL. The next pilot was an die hard AGL'er. The AGL'ers
were used to finding the altimer not quite at zero due to barometric
changes and would "tweak" the altimeter to zero at the start of each
flight. Our field elevation is 888 feet. So the next pilot tweaks
the altimeter to "zero" but instead of subtracting 888 feet (by moving
the hands CCW), he tweaks it CW and adds 112 feet! Can you see where
this is going?

I did pretty much the same thing in my MSL-only club. Atmospheric
pressure had changed by 6-700ft from the last time the plane had flown,
and I did the nearest-thousand thing you describe. Even better, I
actually managed to do this twice in a row in our ASK-21! Discovered it
when I got off tow. Casually asked my passenger what his altimeter said,
and this discovered I'd managed to screw up both of them. Easy fix in
the air once I realized what I'd done.

Watch that thousands hand when you set your altimeter, and know what
your altitudes look like outside the cockpit!

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

On May 31, 11:06*pm, ContestID67 wrote:
Rolf,


So about 5 years ago my Club's flight chair said that flying AGL was
wrong, dangerous and (if I am not mistaken) illegal. *

The "legal" issue is a slippery slope. Newbies to the sport (and I
still consider myself one) may take everything their instructor says
as the bible. Seems like learning and adhering to the FARs is a
critical part of soaring. If we're taught to break certain FARs from
the get go, what is the lesson there?

Rob

On Jun 2, 10:43*am, Rob wrote:
On May 31, 11:06*pm, ContestID67 wrote:

Rolf,

So about 5 years ago my Club's flight chair said that flying AGL was
wrong, dangerous and (if I am not mistaken) illegal. *

The "legal" issue is a slippery slope. *Newbies to the sport (and I
still consider myself one) may take everything their instructor says
as the bible. *Seems like learning and adhering to the FARs is a
critical part of soaring. *If we're taught to break certain FARs from
the get go, what is the lesson there?

Rob

That maybe you have the wrong instructor.
UH

On Jun 2, 10:57*am, wrote:
On Jun 2, 10:43*am, Rob wrote:

On May 31, 11:06*pm, ContestID67 wrote:

Rolf,

So about 5 years ago my Club's flight chair said that flying AGL was
wrong, dangerous and (if I am not mistaken) illegal. *

The "legal" issue is a slippery slope. *Newbies to the sport (and I
still consider myself one) may take everything their instructor says
as the bible. *Seems like learning and adhering to the FARs is a
critical part of soaring. *If we're taught to break certain FARs from
the get go, what is the lesson there?

Rob

That maybe you have the wrong instructor.
UH

Perhaps, but the student is the wrong person to judge the
professionalism of the instructor. I seem to recall that as one
of the 1 hour sessions in my last CFI clinic, after all. All of us
instructors do have the duty to be professional about what we're
teaching.

When I started flying many years ago the glider operation used
QFE since we were only doing local flying. It was pointed out at some
point that we would have to convert to doing it the proper way, but
that
pattern ops were easier to teach that way. Later I moved to
a club environment that pretty much used QNH. I took my flight test
there and it was pointed out that you had to switch over to QNH
before you could take the test. After that, I moved to yet another
club that was mostly using QFE, but after several years Tom came to
visit, and we've used QNH since then. I have to say that it never
really
bothered me as to which setting was in use.

Whenever going cross country, of course, I have always used QNH and,
for that matter,
I never look at my altimeter once I'm established on downwind, anyway.
At the very first place we used Tom's landing checklist that ended
with
"ignore the altimeter", and that's stuck with me all along. I fly
at least 80 flights a year as a primary instructor, and truthfully I
can't tell
you at what altitude we turn base or final. I judge those turns
entirely
by angle.

-- Matt