Turn on your autopilot...
Michael
they blunder into IMC inadvertently is to turn on the autopilot if
they have one. The reason is obvious - an autopilot, assuming it
works properly, will maintain wings level in the clouds whereas an
untrained person may not. Makes sense, right?
I've never owned a plane with an autopilot, and when I did
inadvertently blunder into IMC I kept the plane under control and flew
RADAR vectors based on the training all private pilots get in basic
attitude instrument flying. But what if I had an autopilot?
Recently I installed an Autocontrol III in my Twin Comanche. I tested
it in both wing level mode and heading hold mode (it has no altitude
hold) and I was satisfied that it would be a good tool for reducing my
workload at night or in IMC. But would it help the untrained pilot in
IMC?
So I tested it under nearly ideal conditions. I had the plane loaded
about 400 lbs under gross, and with the cg toward the forward part of
the envelope for good stability. I slowed the plane to about 120 kts,
trimmed it up, and released the controls at a safe altitude. I wanted
to see what would happen. For a minute or so, the plane wandered in
heading but continued to hold altitude (plus or minus a bit - there
were some bumps) and wings mostly level. Eventually, of course, it
got a wing lifted by a bump, and off it went into a graveyard spiral.
At 50 degrees of bank, the speed had built to about 160 kts and the
descent rate was over 1000 fpm. I decided that this was a classic
nose-low unusual attitude. So I engaged the autopilot in wing leveler
mode.
Immediately and smoothly, the autopilot leveled the wings. So far, so
good. The airplane immediately began to climb and slow down. "Wow,
this actually works!" I thought. Not so fast. The airplane blew
right through its trim speed, and the nose kept coming up. The wings
did stay approximately level, and the heading stayed pretty constant,
but airspeed bled off. I put my hand on the throttles, sensing what
was coming. Sure enough, I was slowing right through red line. The
power setting I used was low enough for a power-on stall, and the
altitude was high enough, so I kept my feet lightly on the rudders,
ready to recover. The plane slowed through 65 mph (power-off stall is
over 70) and then nosed down and dove. At the bottom of the dive, I
think it may have been doing even more than 160 kts - but then it
began to climb again. At the top, I felt the bite of the stall, but
before I could take action the nose dropped again. Still the wings
were level.
As the nose began to drop again, I lost my nerve. As the nose crossed
the horizon, I held the yoke for a few seconds to hold that attitude.
Then I let go. The plane flew, holding wings level and maintaining
altitude reasonably well in the bumps.
Maybe it's a good thing I had the instrument rating and the confidence
to use it before I had an autopilot...
Michael
Andrew
autopilots gets its information from. With a systems failure in IMC,
turning on the autopilot could make things worse.
Robert Hall
turn the autopilot "on"?
Regards,
Robert Hall
ELLX
"Andrew" <nos...@nospam.nos> wrote in message
news:DHQD8.80122$9F5.4...@typhoon.austin.rr.com...
Ron Natalie
Robert Hall wrote:
>
> ??? If you have a systems failure, can you explain to me how you would even
> turn the autopilot "on"?
>
Depends what system failed. If your HSI has gone loopy and it's feeding
the autopilot, you certainly wouldn't want to engage it.
JerryK
problem to a pitch problem. That would seem to be a benefit. I suppose the
better solution would be to have an A/P with heading and altitude holds.
"Michael" <crwd...@hotmail.com> wrote in message
news:449a3d6e.02051...@posting.google.com...
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Dudley Henriques
"Ron Natalie" <r...@sensor.com> wrote in message
news:3CDFDFFD...@sensor.com...
Agreed!!! and let's not forget the AP kickout limits!!! :-))))
As with everything else connected to flying, a general statement about black
and white might not be a good approach to fully understanding the issue. It
all depends as you say, on the type of equipment....the condition of the
equipment....and the experience of the individual pilot involved in the
situation.
I for one, prefer the approach that shies away from these "life saving"
suggestions, and I lean heavily in the direction of encouraging pilots to
get the practice and experience needed to handle these situations manually,
using any equipment available as an aid rather than a cure!
The last thing I want a pilot to start believing is that if he flies into
instrument weather, all he has to do is turn on the Autopilot, and
everything will be peaches and cream. That just isn't the best way to go.
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/Certificated Flight Instructor
Retired
Maurice Givens
Michael, I think the point is to engage the AP BEFORE you get into a
graveyard spiral. That will keep the wings level and the
non-instrument pilot out of the sprial.
Robert M. Gary
1) Turn off ram air (in case of ice)
2) Turn off the autopilot. These rate based autopilots will
often turn the wrong direction, making things worse when they
encouter turbulance that gets the plane out of coordination.
Its *much* earier to hand fly the plane in IMC than use the autopilot.
However, I'm instrument rated too, I'm not sure what the VFR guy would be
best doing.
crwd...@hotmail.com (Michael) wrote in message news:<449a3d6e.02051...@posting.google.com>...
Matt
correctly?
Matt
"Michael" <crwd...@hotmail.com> wrote in message
news:449a3d6e.02051...@posting.google.com...
Dudley Henriques
"Robert M. Gary" <rm...@my-deja.com> wrote in message
news:4252c371.0205...@posting.google.com...
> However, I'm instrument rated too, I'm not sure what the VFR guy would be
> best doing.
The universal answer to the issue of handling any weather situation is being
prepared, whether your instrument rated or just a VFR pilot attempting a
simple 180 out. This doesn't mean relying on an Autopilot, or learning a
bunch of "canned saves." It means taking the time to learn it right from the
very beginning. It's always been this way, it's this way now, and it will
always be this way. Pilots looking for "quick cures" to replace the time
they should have spent learning to do it right, are accidents waiting to
happen. I've been teaching people to fly airplanes for many years. I've
NEVER come across a pilot good enough to obtain a Private Certificate who
was bad enough he/she couldn't be taught to make a manually executed 180
degree turn on instruments without Autopilot! If a VFR pilot wants to use
Autopilot for this, fine. I'm a great fan of using what you have available.
I'd also expect this pilot to be savvy enough to be monitoring the raw data
during this 180, and be completely capable of kicking out that Autopilot and
completing the turn manually the INSTANT he/she confirmed something not
cross checking correctly.
Non instrument rated pilots flying VFR in today's world can no longer enjoy
the "luxury" of not being capable of elementary instrument skills......and I
mean CAPABLE, not just the lip service!
Newps
Joe Maj
> they blunder into IMC inadvertently is to turn on the autopilot if
> they have one. The reason is obvious - an autopilot, assuming it
> works properly, will maintain wings level in the clouds whereas an
> untrained person may not. Makes sense, right?
>
instruction booklet last night. It says nothing about using the AP to
bail you out of a loss of control.
The autopilot limits are bank 20 degrees, pitch 15 degrees. The manual
says the autopilot won't lock on a pitch out of limits when engaged
but doesn't mention anything about bank angle.
I'll just have to go out and try some steep banks and see what
happens.
I guess the message is to turn on the autopilot before you get out of
control.
Julian Scarfe
449a3d6e.02051...@posting.google.com, "Michael"
<crwd...@hotmail.com> wrote:
> As the nose began to drop again, I lost my nerve. As the nose crossed
> the horizon, I held the yoke for a few seconds to hold that attitude.
> Then I let go. The plane flew, holding wings level and maintaining
> altitude reasonably well in the bumps.
>
> Maybe it's a good thing I had the instrument rating and the confidence
> to use it before I had an autopilot...
What's the principle of the pitch/altitude hold on the Autocontrol III? Does
it work entirely on static pressure? Is there a way of engaging a roll mode
without engaging a pitch mode?
Or is that what you did? If the aircraft goes into a diverging phugoid
without any pitch input, I'd suggest that there's something wrong with its
stability characteristics, autopilot or not.
Julian Scarfe
Michael
> 1) Turn off ram air (in case of ice)
Ram air? Can you please explain?
> 2) Turn off the autopilot. These rate based autopilots will
> often turn the wrong direction, making things worse when they
> encouter turbulance that gets the plane out of coordination.
This was an attitude based autopilot.
> Its *much* earier to hand fly the plane in IMC than use the autopilot.
I don't find using an autopilot difficult. I also find it a useful
tool for flying. It's great to be able to take your hands off the
yoke and have them both available to refold a map or flip open to the
right page in the book of plates. It makes the operation happen much
faster, with less total distraction. I was never comfortable with the
idea of an autopilot as a substitute for being able to fly the gauges,
and I'm even less comfortable with the idea now.
Michael
Michael
> problem to a pitch problem. That would seem to be a benefit.
Maybe, maybe not. I find that making changes in pitch while letting
the autopilot control bank is not very intuitive.
> I suppose the
> better solution would be to have an A/P with heading and altitude holds.
Actually, I have heading hold - but holding heading was never the
problem. Once the wings were level the heading stayed pretty much on.
Maybe altitude hold would have made a difference.
Personally, I think the better solution is to recover from the unusual
attitude by hand, and only use the autopilot when fully in control of
the situation.
Michael
Julian Scarfe
>> Two things I do before entering IMC..
>> 1) Turn off ram air (in case of ice)
On 14/5/02 16:18, in article
449a3d6e.02051...@posting.google.com, "Michael"
<crwd...@hotmail.com> wrote:
> Ram air? Can you please explain?
It's a backup technique for stopping the engine on a Mooney... :-)
It bypasses the air filter and allows air directly to the engine. It's
supposed to give you an extra inch of MP. In practice, I've found you get
less than 1/2". It's also a trap for the unwary in icing conditions.
Julian Scarfe
Michael
> it work entirely on static pressure? Is there a way of engaging a roll mode
> without engaging a pitch mode?
There is no pitch on an Autocontrol III (it's basically a Century II).
> Or is that what you did? If the aircraft goes into a diverging phugoid
> without any pitch input, I'd suggest that there's something wrong with its
> stability characteristics, autopilot or not.
An aircraft is required to demonstrate static stability in smooth air
with a given (relatively small) upset ONLY. I doubt there is any
requirement to demonstrate dynamic stability with a 40 kt airpseed
disturbance.
Michael
Mike Weller
<julian...@innoviatech.com> wrote:
>It bypasses the air filter and allows air directly to the engine. It's
>supposed to give you an extra inch of MP. In practice, I've found you get
>less than 1/2". It's also a trap for the unwary in icing conditions.
>
>Julian Scarfe
>
Man, you're not kidding. I owned a Mooney 20F and I loved the ram
air. However, it didn't take 3 rain drops to make the engine cough.
Mike Weller
Julian Scarfe
news:449a3d6e.02051...@posting.google.com...
> An aircraft is required to demonstrate static stability in smooth air
> with a given (relatively small) upset ONLY. I doubt there is any
> requirement to demonstrate dynamic stability with a 40 kt airpseed
> disturbance.
OK, that makes sense, but it is a little worrying. If a pilot without
instrument experience were to make a manual recovery from a similar unusual
attitude, I think the chances of doing better than no-pitch-input would be
slim.
FWIW I'll try some stability experiments in our aircraft some time and
report the results.
Julian Scarfe
Robert M. Gary
> > Two things I do before entering IMC..
> > 1) Turn off ram air (in case of ice)
>
> Ram air? Can you please explain?
It allows the air to enter the engine without having to go
through a filter and make any turns. It uses the pressure of the air
coming at you to add MP. If the cowl were better designed you wouldn't
need it. In a pre-J Mooney this adds about a full inch of MP, in the
J and post J Mooneys appears to be just for drag (covering it up actually
gives you more speed than using it in the post Js).
> > Its *much* earier to hand fly the plane in IMC than use the autopilot.
>
> I don't find using an autopilot difficult.
It just depends on the autopilot. Mine is rate based and most of the time
in turb. it turns the wrong way and I end up fighting it.
Dan Luke
> It just depends on the autopilot. Mine is rate based and most of the
time
> in turb. it turns the wrong way and I end up fighting it.
What kind is it? Mine's a rate based S-Tec and lateral control doesn't
cause me a problem in turbulence.
The altitude hold is a bit too aggressive to use when things get bumpy,
though.
--
Dan
N9387D at BFM
Roger Halstead
"Dudley Henriques" <dhenr...@earthlink.net> wrote in message
news:BjSD8.7702$Nt3.6...@newsread2.prod.itd.earthlink.net...
>
> "Ron Natalie" <r...@sensor.com> wrote in message
> news:3CDFDFFD...@sensor.com...
> >
> >
> > Robert Hall wrote:
> > >
> > > ??? If you have a systems failure, can you explain to me how you would
> even
> > > turn the autopilot "on"?
> > >
> >
> > Depends what system failed. If your HSI has gone loopy and it's
feeding
> > the autopilot, you certainly wouldn't want to engage it.
>
> Agreed!!! and let's not forget the AP kickout limits!!! :-))))
Mine works just fine without the vacuum system as it works off the TC and
rate, but.... many autopilots do not "just turn on", but take a bit to go
through recognizing the current attitude and whether any change is being
made.
One of the last things you want to be doing is trying to get the autopilot
to work *after* having run into IMC. You'd be diverting attention away from
what you should be doing which is flying the airplane.
Now, "were it me", I'd have the autopilot on anyway. Beautiful blue sky and
I hand fly, but if it's getting busy and the visibility is not the greatest
the autopilot is on once the aircraft is stabilized after take off. Once
level, I engage the altitude hold.
One thing I don't want to be doing is trying to get the thing set up after
things have gotten sticky. Yes, I turn it on during climb out in IMC, (but
I've already planened on doing so well ahead)
A good autopilot is a great thing to have in a slipery airplane, or when
single pilot IMC, but they can put the pilot into some unusual attitudes far
faster than most would believe.
As Dudley said, "Don't use the autopilot as a crutch, but rather work on
procedures and do your best to stay out of situations where you think the
autopilot maight save your bacon. It could just as easily fry it instead.
Although he worded it much better than I.
Roger (K8RI EN73)
WWW.RogerHalstead.com
N833R, World's Oldest Debonair? S#CD-2
Roger Halstead
"Maurice Givens" <maurice...@ieee.org> wrote in message
news:eb93cce8.02051...@posting.google.com...
> crwd...@hotmail.com (Michael) wrote in message
news:<449a3d6e.02051...@posting.google.com>...
> > One piece of advice that non-instrument pilots are always given should
> > they blunder into IMC inadvertently is to turn on the autopilot if
> > they have one. The reason is obvious - an autopilot, assuming it
> > works properly, will maintain wings level in the clouds whereas an
> > untrained person may not. Makes sense, right?
Not necessiarily.
> >
> > I've never owned a plane with an autopilot, and when I did
> > inadvertently blunder into IMC I kept the plane under control and flew
> > RADAR vectors based on the training all private pilots get in basic
> > attitude instrument flying. But what if I had an autopilot?
> >
> > Recently I installed an Autocontrol III in my Twin Comanche. I tested
> > it in both wing level mode and heading hold mode (it has no altitude
> > hold) and I was satisfied that it would be a good tool for reducing my
> > workload at night or in IMC.
But would it help the untrained pilot in
> > IMC?
Probably if all wrks right and it's on *before* it's needed.
> >
> > So I tested it under nearly ideal conditions. I had the plane loaded
> > about 400 lbs under gross, and with the cg toward the forward part of
> > the envelope for good stability. I slowed the plane to about 120 kts,
> > trimmed it up, and released the controls at a safe altitude. I wanted
> > to see what would happen. For a minute or so, the plane wandered in
> > heading but continued to hold altitude (plus or minus a bit - there
> > were some bumps) and wings mostly level. Eventually, of course, it
> > got a wing lifted by a bump, and off it went into a graveyard spiral.
One of the first things we do in case of turbulence is to slow to Va and
turn the autopilotoff.
In mine, I'd not even attempt to recover from an unusual attitude using the
AP and it reacts far faster than I do.
*Possibly* using heading hold and then getting the altitude under control
you could use the AP for an unusual attitude recovery, but a dangerous way
to try to recover..At least the system in my plane could do damage from an
unusual attitude with a speed much over Va.
Far, far, better to learn to hold heading and altitude under the hood and
stay proficient at it, even if not rated...However, if not rated I'd sure be
working on that if I flew many cross countries. If you fly enough and far
enough the weather will either sneak up on you, or change abruptly from
beautiful clear sky to thunderstorms all over the place.
Most of us tend to think of the weather as moving front or line. Tain't
necessiarily so. Fronts can stop, they can back up, they can fragment, or
split, they can join, or they can materialize where there was none before.
Very large areas can go from that blue sky to severe weather in just five
minutes. I've seen it happen as most any pilot who flys often, or far, has.
--
Roger (K8RI EN73)
WWW.RogerHalstead.com
N833R, World's Oldest Debonair? S#CD-2
> > At 50 degrees of bank, the speed had built to about 160 kts and the
Michael
> > It just depends on the autopilot. Mine is rate based and most of the
> time
> > in turb. it turns the wrong way and I end up fighting it.
>
> What kind is it? Mine's a rate based S-Tec and lateral control doesn't
> cause me a problem in turbulence.
> The altitude hold is a bit too aggressive to use when things get bumpy,
> though.
I have a feeling this may depend both on the airplane and the
autopilot. A Mooney is a lot slicker than a 172RG, and I think it's
pretty well established that a faster, slicker airplane is harder to
fly on the turn coordinator than a slower, draggier airplane. It
would make sense that it would be harder for an autopilot as well.
Yet a proficient pilot at his best CAN do it, and so would a really
good rate-based autopilot is my guess.
Michael
Robert M. Gary
Its a Pathfinder. When the plane hits turb, the turn coordinator kicks
the opposite way (since its uncoordinated) and the autopilot dutifully follows.
Michael
See, I'm paranoid. I believe in survival through paranoia. I've had
all sorts of things quit on me - engines, gyros, generators - and
always managed to get a safe landing out of the deal. To me, an
autopilot is a lot like a mentally ill kid who has flown lots of
flight simulator. If all is well, he can keep the wings level with
the best of them. He'll chase needles, not having had any real flight
instruction, but he's quick and practiced so he'll keep them pretty
close to centered most of the time.
However, he might get upset for some reason and just throw the yoke
hard over with no warning. See what I'm getting at? You have to
watch him all the time.
A well designed autopilot system is easy to monitor. For example, my
airplane has dual attitude gyros and dual vacuum pumps. The
probability of losing both attitude indicators simultaneously is thus
about nil. The attitude gyro the autopilot uses is on the right side
of the panel. While the autopilot is flying, the short scan is
between the pilot's side attitude gyro, the altimeter, and whatever
heading/track reference the autopilot is NOT using.
If the autopilot is in heading hold mode, the heading reference is the
GPS and/or LORAN and/or the vertical card compass. If it's nav
tracking the LORAN, the heading reference is the DG and/or the GPS
and/or the vertical card compass. Those are backups. The primary
reference is the AI. It tells me what's happening at a glance. If it
shows a significant departure from straight and level flight, I can
immediately drop what I'm doing and crosscheck to determine why.
A combination of a well designed system and procedures optimized to
that system maximize safety. In my opinion, what I have is about as
good as it gets for an aircraft that won't set you back six figures.
If I could have figured out a better way to do it without spending a
fortune, I would have.
One of the most disturbing trends I have seen in recent years is the
increase in the functionality of GA autopilots without an increase in
redundancy.
Fact is, silicon is cheap. If I wanted to (and if the specter of
certification did not stand in my way) I could tap into the nav
coupler of my existing autopilot, interface it to a cheap computer and
my handheld GPS, and I would have an autopilot of arbitrary
sophistication, limited only by my ability to write software. It
could fly holds, it could do any sort of intercept, it could fly the
entire flight from takeoff to short final (assuming I added pitch)
without operator intervention - provided nothing went wrong.
Something eventually will.
The autopilot I have is old analog technology. It is very similar to
what you see on transport category aircraft of the same era - 35 years
ago. Had I gone with an Altimatic III rather than an Autocontrol III,
I would have had all the capabilty my friend the 727 captain has at
work.
Today's transport category aircraft have much more automation - but
they also have much more redundancy. The autopilots monitor multiple
gyros and detect the failed ones. It's not like letting the mentally
ill kid self-trained on flight sim fly anymore - you don't have to
watch them all the time. The modern high end GA autopilot has most or
all of the same functionality of a transport category autopilot - but
there are two problems. First, it lacks redundancy. It's still
dependent on a single primary attitude or rate gyro, and there is no
monitoring of angular velocity on that gyro. I always laugh at the
little red flags on GA gyros - they are worthless. They indicate the
presence of vacuum or electricity only - the gyro can come to a
complete stop without flagging out (yes I have seen this!). The
second problem is the pilot. The transport category pilot is
routinely tested on his ability to recognize autopilot malfunctions
and hand-fly the aircraft in IMC in the event of such malfunctions,
with a high degree of realism. The GA pilot usually is not.
So to summarize - we have the same high functionality lulling the
pilot into a false sense of security, while the lack of redundancy and
lack of training makes the whole operation unsafe.
The result?
Just a couple of months ago an autopilot failure in a privately owned
Cheyenne killed the pilot-owner and his wife.
Michael
Dan Luke
> I have a feeling this may depend both on the airplane and the
> autopilot. A Mooney is a lot slicker than a 172RG, and I think it's
> pretty well established that a faster, slicker airplane is harder to
> fly on the turn coordinator than a slower, draggier airplane. It
> would make sense that it would be harder for an autopilot as well.
> Yet a proficient pilot at his best CAN do it, and so would a really
> good rate-based autopilot is my guess.
Mmmm... good point.
In practice, using the AP in turbulence makes me uncomfortable. I get
that "behind the airplane" feeling and vertigo starts trying to sneak up
on me. I think hand flying in turbulence keeps the scan sharper when you
really need it.