AUTOPILOT PROS & CONS

[STICKMONKE]

I got my IFR rating 7 months ago. I use the KAP140 autopilot a lot. From
climb-out to MDA/DA. I find it really helps in my management of the plane
and the IFR flight. I am interested in comments regarding the pros and cons
of a heavy use/reliance on the autopilot.

[Jose]

> I got my IFR rating 7 months ago. I use the KAP140 autopilot a lot. From
> climb-out to MDA/DA. I find it really helps in my management of the plane
> and the IFR flight. I am interested in comments regarding the pros and cons
> of a heavy use/reliance on the autopilot.

I never use it. I don't feel like I'm flying if I don't have my hand on
the yoke. I don't fly IFR enough that I want to risk losing the
proficiency I have, and although it has been said that one is safer with
the autopilot on, I believe one =becomes= less safe relying on it.

Jose
--
The price of freedom is... well... freedom.
for Email, make the obvious change in the address.

[Jim Macklin]

An autopilot is very useful as long as it is used properly.
In VMC, use the autopilot to fly the departure, allowing you
more time to scan for traffic. This is very important in
night VMC. Use the autopilot at cruise to let you rest and
while checking on weather. Use the autopilot for some of
your approaches so you are proficient in the management of
the system. But hand fly enough so you are 100% proficient
because the autopilot can fail.

If you had a live copilot, you would share legs, treat the
A/P the same, use it as an aid not a crutch. Be sure to
read the entire POH supplement and know all the limitations
and failure modes.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"STICKMONKE" > wrote in message
...
|I got my IFR rating 7 months ago. I use the KAP140
autopilot a lot. From
| climb-out to MDA/DA. I find it really helps in my
management of the plane
| and the IFR flight. I am interested in comments regarding
the pros and cons
| of a heavy use/reliance on the autopilot.
|
|

[Thomas Borchert]

Stickmonke,

> I am interested in comments regarding the pros and cons
> of a heavy use/reliance on the autopilot.
>

As one data point: In Germany, single pilot IFR flying requires the
aircraft to have at least a two-axis autopilot (that is, including
altitude hold).

--
Thomas Borchert (EDDH)

[Mortimer Schnerd, RN]

STICKMONKE wrote:
> I got my IFR rating 7 months ago. I use the KAP140 autopilot a lot. From
> climb-out to MDA/DA. I find it really helps in my management of the plane
> and the IFR flight. I am interested in comments regarding the pros and cons
> of a heavy use/reliance on the autopilot.


I have always used an autopilot if it's available for cruise flight only. I
hand fly all climb outs and approaches. As a matter of fact, since nothing I
have access to these days has an autopilot, I hand fly the entire flight. <G>



--
Mortimer Schnerd, RN

[Sam Spade]

STICKMONKE wrote:

> I got my IFR rating 7 months ago. I use the KAP140 autopilot a lot. From
> climb-out to MDA/DA. I find it really helps in my management of the plane
> and the IFR flight. I am interested in comments regarding the pros and cons
> of a heavy use/reliance on the autopilot.
>
>
With a panel mount IFR GPS, you can easily fail to do a traffic watch or
perhaps properly control the airplane when not using an autopilot.

[Bob Noel]

In article >,
Thomas Borchert > wrote:

> As one data point: In Germany, single pilot IFR flying requires the
> aircraft to have at least a two-axis autopilot (that is, including
> altitude hold).

But is the pilot required to use it? :-)

--
Bob Noel
Looking for a sig the
lawyers will hate

[Thomas Borchert]

Bob,

> But is the pilot required to use it? :-)
>

Well, if you don't, "ve haf wais off makink yu!" ;-)

--
Thomas Borchert (EDDH)

[Matt Barrow]

"Mortimer Schnerd, RN" > wrote in message
...
> STICKMONKE wrote:
>> I got my IFR rating 7 months ago. I use the KAP140 autopilot a lot. From
>> climb-out to MDA/DA. I find it really helps in my management of the plane
>> and the IFR flight. I am interested in comments regarding the pros and
>> cons
>> of a heavy use/reliance on the autopilot.
>
>
> I have always used an autopilot if it's available for cruise flight only.
> I hand fly all climb outs and approaches. As a matter of fact, since
> nothing I have access to these days has an autopilot, I hand fly the
> entire flight. <G>
>
Cessna and most other "heavy metal" manufacturers, as well as such
publications as "Professional Pilot" recommend use of the autopilot
immediately after takeoff to enhance scanning for traffic. Since the
overwhelming majority of mid-air's occur in the airport area and during
climb out and descent, that makes good sense.

[Matt Barrow]

"Sam Spade" > wrote in message
news:Q5F6g.175210$bm6.21298@fed1read04...
>>
> With a panel mount IFR GPS, you can easily fail to do a traffic watch or
> perhaps properly control the airplane when not using an autopilot.

Why would a panel mount GPS make much difference, compared to a hand held,
or VOR/airways vector?

>

[Matt Barrow]

"STICKMONKE" > wrote in message
...
>I got my IFR rating 7 months ago. I use the KAP140 autopilot a lot. From
>climb-out to MDA/DA. I find it really helps in my management of the plane
>and the IFR flight. I am interested in comments regarding the pros and cons
>of a heavy use/reliance on the autopilot.
>
Just like the cruise control on your car, there's times to use and times not
to. For departure, it's highly recommended to enhance your concentration on
the traffic scan. Same for approaches. OTOH, don't forget how to handle
things when the AP goes tits up. At least you don't have the King
AP/FD-150...a POS.

Remember, too, that people have fallen asleep with the cruise on their cars
(and at cruise with the AP...been there, done that one :~( ).

On departure, use airspeed hold, rather than Rate of Climb if the 140 has
it. If not, monitor your AS/ROC.

[Roy Smith]

In article >,
"STICKMONKE" > wrote:

> I got my IFR rating 7 months ago. I use the KAP140 autopilot a lot. From
> climb-out to MDA/DA. I find it really helps in my management of the plane
> and the IFR flight. I am interested in comments regarding the pros and cons
> of a heavy use/reliance on the autopilot.

The only real con of the autopilot is that it's too easy to become
dependent on it and let your hand-flying skills degrade to the point there
you're in trouble if George quits. Turn it off every once in a while and
hand-fly to stay in shape.

Don't just click on the A/P and zone out. Take advantage of the workload
reduction it gives you to stay further ahead of the airplane. Pull out
those approach charts earlier and brief the approaches you might end up
doing. Get on the radio and talk to Flight Watch to find out what the
weather is up ahead. Update your flight planning to make sure that
re-route ATC gave you didn't eat into your fuel budget too much.

And, above all, keep up your instrument scan! If George wigs out and puts
you into an unusual attitude, you've still got to recognize it and recover.

[Sam Spade]

Matt Barrow wrote:
> "Sam Spade" > wrote in message
> news:Q5F6g.175210$bm6.21298@fed1read04...
>
>>With a panel mount IFR GPS, you can easily fail to do a traffic watch or
>>perhaps properly control the airplane when not using an autopilot.
>
>
> Why would a panel mount GPS make much difference, compared to a hand held,
> or VOR/airways vector?
>
I was referring to IFR operations with IFR equipment. A panel mount is
much more difficult to operate than a FMS/LNAV platform.

"VOR/Airways vector?" I am not sure I understand your question. Is it
one question or two?

Setting up a VOR airway is a much simpler task than programing an airway
on a non-airway-database panel mount. Once everything is set up and
underway there is little difference in the task of VOR or panel-mount
GPS navigation. But, everytime something significant has to be changed,
it requires more concentration and cross-check to program the panel
mount than a VOR set.

Vectors are vectors.

[Matt Barrow]

"Sam Spade" > wrote in message
news:lZJ6g.175221$bm6.68992@fed1read04...
> Matt Barrow wrote:
>> "Sam Spade" > wrote in message
>> news:Q5F6g.175210$bm6.21298@fed1read04...
>>
>>>With a panel mount IFR GPS, you can easily fail to do a traffic watch or
>>>perhaps properly control the airplane when not using an autopilot.
>>
>>
>> Why would a panel mount GPS make much difference, compared to a hand
>> held, or VOR/airways vector?
>>
> I was referring to IFR operations with IFR equipment. A panel mount is
> much more difficult to operate than a FMS/LNAV platform.

Okay, that makes sense (for someone not well versed in the GPS's operation).

>
> "VOR/Airways vector?" I am not sure I understand your question. Is it
> one question or two?

Two (either/or)

>
> Setting up a VOR airway is a much simpler task than programing an airway
> on a non-airway-database panel mount. Once everything is set up and
> underway there is little difference in the task of VOR or panel-mount GPS
> navigation. But, everytime something significant has to be changed, it
> requires more concentration and cross-check to program the panel mount
> than a VOR set.
>
> Vectors are vectors.

Sam, you're one of the most knowledgable people in here, but your
communications (writing) leaves much to be desired by those of us that don't
read minds (intentions, contexts).

[Doug]

They sure are nice on a long trip. I always fly my climbouts and
approaches by hand though. Don't get rusty at hand flying, whatever you
do. And learn your autopilot failure modes...

[Sam Spade]

Matt Barrow wrote:
> "Sam Spade" > wrote in message
> news:lZJ6g.175221$bm6.68992@fed1read04...
>
>>Matt Barrow wrote:
>>
>>>"Sam Spade" > wrote in message
>>>news:Q5F6g.175210$bm6.21298@fed1read04...
>>>
>>>
>>>>With a panel mount IFR GPS, you can easily fail to do a traffic watch or
>>>>perhaps properly control the airplane when not using an autopilot.
>>>
>>>
>>>Why would a panel mount GPS make much difference, compared to a hand
>>>held, or VOR/airways vector?
>>>
>>
>>I was referring to IFR operations with IFR equipment. A panel mount is
>>much more difficult to operate than a FMS/LNAV platform.
>
>
> Okay, that makes sense (for someone not well versed in the GPS's operation).
>
>
>>"VOR/Airways vector?" I am not sure I understand your question. Is it
>>one question or two?
>
>
> Two (either/or)
>
>
>>Setting up a VOR airway is a much simpler task than programing an airway
>>on a non-airway-database panel mount. Once everything is set up and
>>underway there is little difference in the task of VOR or panel-mount GPS
>>navigation. But, everytime something significant has to be changed, it
>>requires more concentration and cross-check to program the panel mount
>>than a VOR set.
>>
>>Vectors are vectors.
>
>
> Sam, you're one of the most knowledgable people in here, but your
> communications (writing) leaves much to be desired by those of us that don't
> read minds (intentions, contexts).
>
>
>
>
How have I failed to communicate?

[Matt Barrow]

"Sam Spade" > wrote in message
news:_oM6g.175224$bm6.117405@fed1read04...
> Matt Barrow wrote:
>> Sam, you're one of the most knowledgable people in here, but your
>> communications (writing) leaves much to be desired by those of us that
>> don't read minds (intentions, contexts).
>>
>>
>>
>>
> How have I failed to communicate?

Notice how many people are completely confounded by what you write.

You have to write to _the audience_, not to yourself.

[Brien K. Meehan]

The biggest "con" I've observed is that it sometimes gives the
passengers the impression that you're not working hard enough.

I actually had a passenger say to me, "What am I paying you all this
money for? This is easy, you're just pressing buttons! I could do
that myself!"

[Mark Hansen]

On 05/05/06 11:18, Brien K. Meehan wrote:
> The biggest "con" I've observed is that it sometimes gives the
> passengers the impression that you're not working hard enough.
>
> I actually had a passenger say to me, "What am I paying you all this
> money for? This is easy, you're just pressing buttons! I could do
> that myself!"
>

Well, it's the old TV repair mantra:

Turning one screw: $ 0.05
Knowing which screw to turn: $ 99.95

;-)

--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

[Robert Chambers]

Give him the yoke and disengage the a/p and say, "go on then"

Brien K. Meehan wrote:
> The biggest "con" I've observed is that it sometimes gives the
> passengers the impression that you're not working hard enough.
>
> I actually had a passenger say to me, "What am I paying you all this
> money for? This is easy, you're just pressing buttons! I could do
> that myself!"
>

[Michael]

Heavy use of the autopilot is not a problem. Reliance on the autopilot
is absolutely deadly unless you have multiply redundant autopilots with
redundant power sources. There's no problem in using the autopilot as
long as you're also getting plenty of time in the equivalent flight
conditions and are very comfortable in them. Basically, it's OK to use
the autopilot any time you would allow a child with emotional problems
who is good at playing flight simulator to fly the plane while you
watch. The degree of monitoring you should exercise should also be the
same.

Most pilots already get plenty of experience flying day-VMC in cruise,
so using the autopilot in those conditions is no big deal, just as it
would be no big deal to let any passenger fly under those conditions.
If you're one of those rare people who gets plenty of actual all the
time and feel very comfortable in the soup, there's no issue with using
it in the soup either. If you shoot so many approaches to minimums in
actual that you find the process boring, it's fine to let the autopilot
shoot the approach.

If you are struggling to get enough actual to stay proficient, and even
going under the hood, then why would you give any of that valuable IMC
time away to the autopilot? You need that time to keep your skills
sharp and hopefully develop them. You're paying for that time.

Realize that no GA autopilot on the market has the capability to
crosscheck gyros. Any of them can cause the ailerons to go to full
deflection smoothly but quickly. As long as you're always in a
position where you are confident you can recover from that safely,
there's no problem with using the autopilot. If you're in a position
where that's not true, why are you there?

If the reason is because you can't handle the workload (or are not
confident you can handle the workload), fine, turn on the autopilot.
Then make it a point to get more training/practice prior to your next
IMC flight. Otherwise, all you're doing is increasing the risk.

Personally, other than in training, I use the autopilot only in level
crusie in VMC, generally on long trips so I can rest. I never use it
in IMC because I don't feel like I get enough of it to stay sharp (I go
under the hood at least once a year for recurrent) so I'm not going to
give any away to the autopilot. If I ever feel like I'm losing it,
I'll turn it on. If I had to fly several hours of solid IMC in one day
single pilot, I would use it in level cruise, to reduce fatigue and
keep myself shart for the higher workload terminal and approach
operations.

Of course everything I said above is based on the idea of the
proficient pilot - someone who could easily pass his instrument
checkride in whatever plane he normally flies IFR without needing to
prepare for it. This does not describe most instrument rated private
pilots I've met. I suspect that has a lot to do with the abysmal
safety record of private IMC flight. I've only ever met a few who fit
this description, and most of them, even if they don't fly
professionally, hold professional ratings. The average instrument
rated private pilot I've met was probably at his best as an instrument
pilot the day he took his IFR checkride, and would need to practice
quite a bit to pass it again. For someone like that, I recommend
buying the best, most modern autopilot he can afford and using the it
as much as possible throughout the flight, since the autopilot is less
likely to screw up than he is - that is assuming he is not willing to
practice enough to bring his skills up to par and is unwilling to give
up flying IFR, both of which I consider better options.

Michael

[Travis Marlatte]

Degrading hand-flying skills while using the AP? I've got the solution to
that one! My AP ain't so good.

Only roll control and my plane takes rudder action to make anything happen.
Flying with the AP takes about as much hand-flying skills than without.
However, at least it won't let the roll get away from me, if I were to get
distracted for a few seconds. But, if I'm not paying attention, it will be
in a skid in no time as it tries to turn but can't without a little rudder
help.

With the AP on, I can spend more time watching outside or looking at charts
and glance at the turn coordinator and altimeter until I resume my normal,
full scan.

My AP is best when it's calm. Of course, in that situation, the plane flies
about the same no hands and no AP. When it's turbulent, I can hand fly
better than my AP. But it does lighten the workload until I start feeling
seasick with the wandering back and forth.
--
-------------------------------
Travis
Lake N3094P
KPWK

"Roy Smith" > wrote in message
...
> In article >,
> "STICKMONKE" > wrote:
>
>> I got my IFR rating 7 months ago. I use the KAP140 autopilot a lot. From
>> climb-out to MDA/DA. I find it really helps in my management of the plane
>> and the IFR flight. I am interested in comments regarding the pros and
>> cons
>> of a heavy use/reliance on the autopilot.
>
> The only real con of the autopilot is that it's too easy to become
> dependent on it and let your hand-flying skills degrade to the point there
> you're in trouble if George quits. Turn it off every once in a while and
> hand-fly to stay in shape.
>
> Don't just click on the A/P and zone out. Take advantage of the workload
> reduction it gives you to stay further ahead of the airplane. Pull out
> those approach charts earlier and brief the approaches you might end up
> doing. Get on the radio and talk to Flight Watch to find out what the
> weather is up ahead. Update your flight planning to make sure that
> re-route ATC gave you didn't eat into your fuel budget too much.
>
> And, above all, keep up your instrument scan! If George wigs out and puts
> you into an unusual attitude, you've still got to recognize it and
> recover.

[Sam Spade]

Matt Barrow wrote:

> "Sam Spade" > wrote in message
> news:_oM6g.175224$bm6.117405@fed1read04...
>
>>Matt Barrow wrote:
>>
>>>Sam, you're one of the most knowledgable people in here, but your
>>>communications (writing) leaves much to be desired by those of us that
>>>don't read minds (intentions, contexts).
>>>
>>>
>>>
>>>
>>
>>How have I failed to communicate?
>
>
> Notice how many people are completely confounded by what you write.
>
> You have to write to _the audience_, not to yourself.
>
>
It is tough to know the audience in a forum like this.

I work in an environment where a lot of this stuff is a given.

I guess here it could end up being article writing. That is not what
these Usenet forums are about.

Also, I have been accused by some here of being an "AH jail house
lawyer" so it is a no-win situation in some ways.

[Judah]

"STICKMONKE" > wrote in
:

> I got my IFR rating 7 months ago. I use the KAP140 autopilot a lot.
> From climb-out to MDA/DA. I find it really helps in my management of
> the plane and the IFR flight. I am interested in comments regarding
> the pros and cons of a heavy use/reliance on the autopilot.
>
>

PRO: A good autopilot will typically fly an approach as well or better than
a person. Also, it allows the pilot to have time to manage the other
aspects of the flight.

CON: Autopilots can fail. If you exclusively rely on the autopilot to fly
the plane, you quickly become the passenger, not the pilot. You need to
stay attentive and proficient enough that if the autopilot fails, you don't
kill yourself.

[scott moore]

Brien K. Meehan wrote:
> The biggest "con" I've observed is that it sometimes gives the
> passengers the impression that you're not working hard enough.
>
> I actually had a passenger say to me, "What am I paying you all this
> money for? This is easy, you're just pressing buttons! I could do
> that myself!"
>

You say "come on up, and do it yourself".

[Greg Farris]

In article . com>,
says...

>
>If you are struggling to get enough actual to stay proficient, and even
>going under the hood, then why would you give any of that valuable IMC
>time away to the autopilot? You need that time to keep your skills
>sharp and hopefully develop them. You're paying for that time.
>
>Realize that no GA autopilot on the market has the capability to
>crosscheck gyros. Any of them can cause the ailerons to go to full
>deflection smoothly but quickly. As long as you're always in a
>position where you are confident you can recover from that safely,
>there's no problem with using the autopilot. If you're in a position
>where that's not true, why are you there?
>
>If the reason is because you can't handle the workload (or are not
>confident you can handle the workload), fine, turn on the autopilot.
>Then make it a point to get more training/practice prior to your next
>IMC flight. Otherwise, all you're doing is increasing the risk.
>


That's a pretty well-stated, sane approach to how to manage real-time
risk vs loss of proficiency and over-reliance on automation. Well put.

GF

[Michael]

> How true. My KFC225 has failed about a dozen times in 4 years, most of
> them without any indication.

Yuck. I knew they were unreliable. I didn't know they were THAT
unreliable.

> On one occassion the red Disconnect button failed (this was after the
> AP drove the ailerons to full deflection) so the master disconnect had
> to be used.

This is the sort of thing I worry about when it comes to autopilots.
Ailerons go hard over at the wrong time, and that's all she wrote.

> All this makes a complete joke of TSO-129 certification, which
> obviously has no concept of software/hardware quality or reliability.

Eventually, you will come to accept that FAA certification only adds
cost, not value or safety. It's only obvious in those areas where you
know what's going on. In areas where you are ignorant, FAA rules can
seem like a good idea. They never are.

> I also hand fly a proportion of approaches, but not all because flying
> them (especially an ILS) with the AP is also something that needs to
> be done with the correct procedure and that needs practice too.

You know, I've shot a lot of approaches in IMC, including more than one
ILS to real mins (less than 300 ft and less than a mile vis) including
one in a plane I only got into that morning, with an HSI that had
failed and a compass that was unreadable due to a bad light. But the
ILS approach that scared me most was in VMC - with a Century 2000 A/P
flying it. It never seriously occurred to me that I would roll the
plane over just because I was flying with a partial panel at night in
low IMC in an unfamiliar airplane - I always had confidence that it
might not be pretty, but I would either put it on the runway right side
up or make a passable miss. But I knew for a fact that uncommanded
hard rolls are part of life with an autopilot - and frankly my
enthusiasm for low altitude aerobatics on instruments is very low, even
in good VMC. I certainly did not have confidence that I would
successfully recover from such an uncommanded roll - especially if the
disconnect were to fail as well, necessitating fumbling for the rarely
used master disconnect. At 300 AGL my fear got the best of me, I
switched off the AP, and completed the approach by hand - and again,
this was VMC. Risking an uncommanded hard roll at 300 AGL in IMC
strikes me as a last-resort kind of option.

I know the airlines do it - but they're doing it with substantially
better equipment that is maintained far more meticulously.

I have to ask - what was your altitude loss when the ailerons went hard
over and the A/P disconnect failed? What is your logic behind having
it engaged when you are lower than that (assuming you do have it
engaged then)?

Personally, you can't pay me enough to have the autopilot engaged on an
actual IMC approach. I quite agree with you that the procedures
involved require practice, and I do practice with it - under the hood
with a safety pilot I can really trust, and never below 800 AGL.

Michael

[Dan Luke]

"Peter" wrote:

>>CON: Autopilots can fail. If you exclusively rely on the autopilot to fly
>>the plane, you quickly become the passenger, not the pilot. You need to
>>stay attentive and proficient enough that if the autopilot fails, you don't
>>kill yourself.
>
> How true. My KFC225 has failed about a dozen times in 4 years, most of
> them without any indication.

My buddy has a KFC225 with a similarly dismal history. The avionics shop
tells him this is not unusual for that model. Not usual!!!

My S-Tec 50, a 2-axis, rate-based unit, has operated with only one glitch-- a
bad switch--in 700+ hours since installation. It's a much simpler piece of
gear, not as precise or as smooth in turbulence as the KFC225, but I'll take
reliability over capability every time.

--
Dan
C-172RG at BFM

[Michael]

> My S-Tec 50, a 2-axis, rate-based unit, has operated with only one glitch-- a
> bad switch--in 700+ hours since installation.

A friend of mine has a 50 in his Bo, and it hasn't fared as well as
yours. If went 'dead' - meaning no action on aileron control and no
annunciation - multiple times before the problem was resolved. Usually
by the time he got it to the A/P shop it was working again, and the
shop could not figure out what was wrong. Eventually it died for good.
It was a bad motor in the roll servo.

On the flip side, I once instructed a student in an Ovation who told me
his KFC-225 never hiccupped.

Michael

[Al]

"Michael" > wrote in message
ups.com...
>> My S-Tec 50, a 2-axis, rate-based unit, has operated with only one
>> glitch-- a
>> bad switch--in 700+ hours since installation.
>
> A friend of mine has a 50 in his Bo, and it hasn't fared as well as
> yours. If went 'dead' - meaning no action on aileron control and no
> annunciation - multiple times before the problem was resolved. Usually
> by the time he got it to the A/P shop it was working again, and the
> shop could not figure out what was wrong. Eventually it died for good.
> It was a bad motor in the roll servo.
>
> On the flip side, I once instructed a student in an Ovation who told me
> his KFC-225 never hiccupped.
>
> Michael

Some autopilot failures are very subtle. I was shooting a coupled ILS to
minimums with a King autopilot in a Mooney. After capturing the glideslope,
I noticed the rate was about 75'/min more than I was used to. As we got
closer to DH, the DME was still showing about 2 miles to the airport. I
leveled at DH, and while motoring along 200' above the houses, I tapped the
Vor/loc. The GS needle snapped to the top of the case. It was "stuck"
centered, and the autopilot
was literally flying the needle. Iron Mike, indeed.

Al

[Bill]

All the comments about monitoring for failures are worthy of
consideration. And staying current enough to cope with those
failures is essential. You need to be able to hand fly it.

That said, one of the common features of instrument training is
that stick wiggling is featured and evaluated.

The success factor in serious IFR travelling is being the captain--
the flight manager. Making the in-flight decisions. Key example:
Coping with weather.

Can be that stick wiggling interferes with concentrating on the.
flight management duties. A good autopilot is a key tool at times
like that.

Folks pooh-pooh coupled approaches. Those who have actually
flown them, especially under low-light, minimum conditions know that
good
runway alignment when breaking out is essential. I'm not as good
as the autopilot, so I let it handle those situations.

FWIW. Bill Hale
Chicken.

[Thomas Borchert]

Greg,

> OK - it may be off color a bit, or it may already have been published
> here (my apologies in either case) but have a look at this one :
>

Just saw it the other day in a movie theater. nice ad for a language
school.

--
Thomas Borchert (EDDH)

[Judah]

"Al" > wrote in
:

> Some autopilot failures are very subtle. I was shooting a coupled ILS
> to minimums with a King autopilot in a Mooney. After capturing the
> glideslope, I noticed the rate was about 75'/min more than I was used
> to. As we got closer to DH, the DME was still showing about 2 miles to
> the airport. I leveled at DH, and while motoring along 200' above the
> houses, I tapped the Vor/loc. The GS needle snapped to the top of the
> case. It was "stuck" centered, and the autopilot
> was literally flying the needle. Iron Mike, indeed.

Technically speaking, that wasn't an autopilot failure, it was a GS needle
failure. The results would have been nearly identical if you were hand-
flying. Although you might have noticed inconcistencies in airplane
response more quickly and fixed it earlier. Then again, you might have been
so busy keeping the needle centered that it would have gone unnoticed until
you flew your plane right through someone's living room.

Hard to say.

[Robert M. Gary]

The KAP 140 flys a better ILS than I can. It would be easy to forget
how to fly an ILS if you never hand flew one.

-Robert

[Robert M. Gary]

> I never use it. I don't feel like I'm flying if I don't have my hand on the yoke.

We have guys like that in CAP (most are 30 years older than me). The
problem is that those pilots cannot transition to the new G1000
aircraft because there is just no way to hand fly the plane, look for
traffic and exercise all the complex stuff the G1000 glass cockpit
provides. You really have to step back and manage the aircraft rather
than fly it. You need to know what the plane is doing and what it will
do next. The guys who are hand flying it are just keeping up and not
able to determine what the plane should do next. Of course the plane
can be flown just fine w/o the autopilot but passing the check ride
requires you to demonstrate using the G1000 features while airborne.

-Robert, CFI (G1000 instructor)

[Al]

"Judah" > wrote in message
. ..
> "Al" > wrote in
> :
>
>> Some autopilot failures are very subtle. I was shooting a coupled ILS
>> to minimums with a King autopilot in a Mooney. After capturing the
>> glideslope, I noticed the rate was about 75'/min more than I was used
>> to. As we got closer to DH, the DME was still showing about 2 miles to
>> the airport. I leveled at DH, and while motoring along 200' above the
>> houses, I tapped the Vor/loc. The GS needle snapped to the top of the
>> case. It was "stuck" centered, and the autopilot
>> was literally flying the needle. Iron Mike, indeed.
>
> Technically speaking, that wasn't an autopilot failure, it was a GS needle
> failure.

Correct.

The results would have been nearly identical if you were hand-
> flying. Although you might have noticed inconcistencies in airplane
> response more quickly and fixed it earlier.

Naw, If I'd set the plane up for the descent, and got it exactly right the
first time, with no additional trim, I'd be real suspicious...Never happened
before.

>Then again, you might have been
> so busy keeping the needle centered that it would have gone unnoticed
> until
> you flew your plane right through someone's living room.
>
> Hard to say.

It's really a matter of cross checking and a cynical attitude.

Al

[Roy Smith]

On the Century-2000 equipped Bonanzas I fly, there's an interesting
trim problem with the AP, which is basicly that it doesn't trim.

Engage the AP while you're being vectored for the ILS and let it
fly the approach, as you keep reducing power to slow down and then
track the GS. As you slow down, you should be dialing in nose-up trim
(and, indeed, the AP prompts you to do this, but if you're not paying
attention, you can miss the flashing light).

Now, at DH, click off the AP to hand-fly the landing. All of a
sudden, you've got a fistfull of yoke trying to pull your arms out of
their sockets until you get the trim fixed. Even worse if you didn't
see the runway and clicked off the AP to execute the missed.

Of course, the AP is performing as designed, and it's the pilot who's
unairworthy, but it's a common enough mistake that I've got to believe
it's a design flaw in the system. If nothing else, it should have a
more obvious alert than a small blinking light outside of your main
visual scan. Like maybe a mechanical arm that smacks you upside your
head with a rolled-up sectional while a synthesized voice says, "Trim
up, trim up".

[Jim Macklin]

The auto-pilot should be running the trim, the annunciation
is intended to be advisory. Using the electric trim will
disengage the auto-pilot. I'm guessing that you have a bad
relay.
It is not airworthy as it is, you might be able to placard
it in-op until you can get it in the shop. Read the POH FM
supplement for a description of the required pre-flight
tests, you may not be doing them properly and thus the A/P
won't engage.

--
James H. Macklin
ATP,CFI,A&P



"Roy Smith" > wrote in message
...
| On the Century-2000 equipped Bonanzas I fly, there's an
interesting
| trim problem with the AP, which is basicly that it doesn't
trim.
|
| Engage the AP while you're being vectored for the ILS and
let it
| fly the approach, as you keep reducing power to slow down
and then
| track the GS. As you slow down, you should be dialing in
nose-up trim
| (and, indeed, the AP prompts you to do this, but if you're
not paying
| attention, you can miss the flashing light).
|
| Now, at DH, click off the AP to hand-fly the landing. All
of a
| sudden, you've got a fistfull of yoke trying to pull your
arms out of
| their sockets until you get the trim fixed. Even worse if
you didn't
| see the runway and clicked off the AP to execute the
missed.
|
| Of course, the AP is performing as designed, and it's the
pilot who's
| unairworthy, but it's a common enough mistake that I've
got to believe
| it's a design flaw in the system. If nothing else, it
should have a
| more obvious alert than a small blinking light outside of
your main
| visual scan. Like maybe a mechanical arm that smacks you
upside your
| head with a rolled-up sectional while a synthesized voice
says, "Trim
| up, trim up".

[Sam Spade]

Robert M. Gary wrote:
>>I never use it. I don't feel like I'm flying if I don't have my hand on the yoke.
>
>
> We have guys like that in CAP (most are 30 years older than me). The
> problem is that those pilots cannot transition to the new G1000
> aircraft because there is just no way to hand fly the plane, look for
> traffic and exercise all the complex stuff the G1000 glass cockpit
> provides. You really have to step back and manage the aircraft rather
> than fly it. You need to know what the plane is doing and what it will
> do next. The guys who are hand flying it are just keeping up and not
> able to determine what the plane should do next. Of course the plane
> can be flown just fine w/o the autopilot but passing the check ride
> requires you to demonstrate using the G1000 features while airborne.
>
> -Robert, CFI (G1000 instructor)
>

I agree with everything you say, yet I wonder whether a single pilot can
effectively manage it all with an autopilot and also keep a good lookout
for traffic.

[Roy Smith]

In article <5u4ag.20816$ZW3.8687@dukeread04>,
Jim Macklin > wrote:
>The auto-pilot should be running the trim, the annunciation
>is intended to be advisory. Using the electric trim will
>disengage the auto-pilot. I'm guessing that you have a bad
>relay.

There is no electric trim. I believe it's an option, but our boxes
don't have it.

[Jim Macklin]

I've never seen a Bonanza without electric trim and an
autopilot installed. What you have seems to be just a wing
leveler with heading and [maybe] tracking.


--
James H. Macklin
ATP,CFI,A&P

"Roy Smith" > wrote in message
...
| In article <5u4ag.20816$ZW3.8687@dukeread04>,
| Jim Macklin > wrote:
| >The auto-pilot should be running the trim, the
annunciation
| >is intended to be advisory. Using the electric trim will
| >disengage the auto-pilot. I'm guessing that you have a
bad
| >relay.
|
| There is no electric trim. I believe it's an option, but
our boxes
| don't have it.

[Roy Smith]

In article <PG5ag.20818$ZW3.19044@dukeread04>,
Jim Macklin > wrote:
> I've never seen a Bonanza without electric trim and an
> autopilot installed.

Apparently not :-)

> What you have seems to be just a wing leveler with heading and
> [maybe] tracking.

Nope. It does heading, tracks nav, altitude hold, course intercepts,
and coupled ILS approaches. Once we get the kinks worked out of the
new add-on box, it'll be doing GPS roll steering too. We've got one
driven from a CDI, another with an HSI. It just doesn't have electric
trim. It's an option, and we don't have that option. Wish we did,
but we don't.

[Jim Macklin]

I would skip the fancy nav steering and coupling, you can
always use the heading bug to track the needle and get the
pitch trim ASAP. But, it isn't my airplane. A wing leveler
like Mooney installed is a big aid, but real altitude hold
and trim is just as important.

If you want to get spoiled, fly a $500,000 Sperry autopilot
in a King Air. I've flown a few hundred different Bonanzas,
from late 1940 models to the B36TC, if they had an
autopilot, [all the ones built after about 1965 that I flew
did] they had electric trim.

We did a Category II certification on the Beechjet and
encountered a problem caused by a poorly written flight test
schedule. The DER that was hired wrote a schedule that
called for the coupled approaches to be flown at a
stabilized speed of 1.3 Vso from the OM to landing or missed
approach. We could hand fly within the tolerances, but the
autopilot could not. We had to do extreme fore and aft CG
and the autopilot would get wild on the ILS. Came to find
out several things... FAR 25 requires that the airplane trim
function to 1.4 Vso, so 1.3 Vso might not be a trimable
speed, depending on CG. Also the autopilot was certified at
1.3 Vso +10, as far as those who did the original
certification could remember.
So we re-wrote the flight test schedule and the autopilot
flew well within the 95% 1 dot on all the approaches because
it was in trim at 1.3 Vso+10.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Roy Smith" > wrote in message
...
| In article <PG5ag.20818$ZW3.19044@dukeread04>,
| Jim Macklin > wrote:
| > I've never seen a Bonanza without electric trim and an
| > autopilot installed.
|
| Apparently not :-)
|
| > What you have seems to be just a wing leveler with
heading and
| > [maybe] tracking.
|
| Nope. It does heading, tracks nav, altitude hold, course
intercepts,
| and coupled ILS approaches. Once we get the kinks worked
out of the
| new add-on box, it'll be doing GPS roll steering too.
We've got one
| driven from a CDI, another with an HSI. It just doesn't
have electric
| trim. It's an option, and we don't have that option.
Wish we did,
| but we don't.

[Sam Spade]

Jim Macklin wrote:
>
>
> If you want to get spoiled, fly a $500,000 Sperry autopilot
> in a King Air. I've flown a few hundred different Bonanzas,
> from late 1940 models to the B36TC, if they had an
> autopilot, [all the ones built after about 1965 that I flew
> did] they had electric trim.

Try the autoflight in the 767 or L-1011, and would never look back at
the King Air.

[Jim Macklin]

But a J-3 or PA 18-150 is more fun than either.



"Sam Spade" > wrote in message
news:LJ9ag.177039$bm6.20988@fed1read04...
| Jim Macklin wrote:
| >
| >
| > If you want to get spoiled, fly a $500,000 Sperry
autopilot
| > in a King Air. I've flown a few hundred different
Bonanzas,
| > from late 1940 models to the B36TC, if they had an
| > autopilot, [all the ones built after about 1965 that I
flew
| > did] they had electric trim.
|
| Try the autoflight in the 767 or L-1011, and would never
look back at
| the King Air.

[Sam Spade]

Jim Macklin wrote:
> But a J-3 or PA 18-150 is more fun than either.

Now you're talking!! ;-)

A Super Cub with a Garmin 296.~

[karl gruber]

And a comfortable seat!
And a heater that heats both seats equally.


Karl
"Curator" N185KG

"Sam Spade" > wrote in message
news:OOmag.177086$bm6.21618@fed1read04...
> Jim Macklin wrote:
>> But a J-3 or PA 18-150 is more fun than either.
>
> Now you're talking!! ;-)
>
> A Super Cub with a Garmin 296.~

[Jim Macklin]

Even better, www.cubcrafters.com



"Sam Spade" > wrote in message
news:OOmag.177086$bm6.21618@fed1read04...
| Jim Macklin wrote:
| > But a J-3 or PA 18-150 is more fun than either.
|
| Now you're talking!! ;-)
|
| A Super Cub with a Garmin 296.~

[Jim Macklin]

RefrigiWear makes the heater redundant.
http://www.refrigiwear.com/

Good boots and socks, thick wool. Think winter motorcycle
gear.


"karl gruber" > wrote in message
...
| And a comfortable seat!
| And a heater that heats both seats equally.
|
|
| Karl
| "Curator" N185KG
|
| "Sam Spade" > wrote in message
| news:OOmag.177086$bm6.21618@fed1read04...
| > Jim Macklin wrote:
| >> But a J-3 or PA 18-150 is more fun than either.
| >
| > Now you're talking!! ;-)
| >
| > A Super Cub with a Garmin 296.~
|
|

[karl gruber]

I've owned two Super Cubs. One that I bought brand new in 1966 and picked it
up in Lock Haven.
It cost just under $12,000.

I prefer to fly in shirtsleeves, and certainly would never climb into a
space suit to fly. The PA-18-150, as delivered from the factory has an
excellent front set heater. It's the PAX that freezes. Although a little
tape around the doors makes it more bearable.

There are some things that Cubcrafters do to make the situation better, but
Piper never cared to change the airplane much.

Karl
ATP CFI ETC
"Curator" N185KG


"Jim Macklin" > wrote in message
news:WToag.21671$ZW3.19218@dukeread04...
> RefrigiWear makes the heater redundant.
> http://www.refrigiwear.com/
>
> Good boots and socks, thick wool. Think winter motorcycle
> gear.
>
>
> "karl gruber" > wrote in message
> ...
> | And a comfortable seat!
> | And a heater that heats both seats equally.
> |
> |
> | Karl
> | "Curator" N185KG
> |
> | "Sam Spade" > wrote in message
> | news:OOmag.177086$bm6.21618@fed1read04...
> | > Jim Macklin wrote:
> | >> But a J-3 or PA 18-150 is more fun than either.
> | >
> | > Now you're talking!! ;-)
> | >
> | > A Super Cub with a Garmin 296.~
> |
> |
>
>

[Michael]

> Doesn't anybody do proper modelling of the aircraft behaviour (such as
> is done for airliner flight simulators, in order to derive the
> equations which are then solved in the sim) and check that the control
> loop parameters of the AP provide a sufficient margin?

No. It's not done.

> There have been too many cases of APs going unstable under certain
> conditions.

I have a Twin Comanche with a Piper Autocontrol autopilot (single
axis), and I can esily force it into a divergent pitch oscillation
mode. All I have to do is let go of the controls in a trimmed
airplane, let it fall off into a spiral past about 30 degrees
(eventually it will, no matter how well trimmed and how smooth the
air), and then just turn on the autopilot in wing level mode. You
know, like pilots who lose it in IMC are told to do. The autopilot
will keep the wings level, but the plane will go into a divergent pitch
oscillation.

Gotta love it.

Michael

[Michael]

> I think when this happens in some very old AP, which used to work
> previously, it is probably because it used electrolytic caps for
> various time constants, and over the decades these dry out, so the
> derivative term goes up, the integral term goes down, and the
> stability goes out of the window.

That sounds great, but I had the Century test set available to me when
I installed the autopilot, and I used it (the Autocontrol is actually a
Century II private-labeled, which is obvious when you read the service
manual) and everything tested within limits. The autopilot actually
works fine - it does a good job of holding wings level or heading, and
a fair job of tracking the LORAN. Roll stability is fine regardless of
airplane attitude in which any roll mode is engaged. The problem
occurs in pitch.

> Anything modern should not suffer from this, and current stuff should
> do the control loop in software anyway.

I can make my friend's STEC do the same thing in his Bonanza. An
identical STEC in a Warrior won't do it. Neither one will do it if the
pitch mode is engaged, but in roll mode only it will happen in the Bo.

Michael

[Michael]

> Pitch stability is much harder in comparison and I wouldn't even know
> where to start. One would need to be a control systems expert.

Pitch stability isn't very difficult if you have pitch sensing and
pitch control. I guess I'm a little bit of a control systems expert
(I've taken control theory courses at the graduate level and designed
and built some oddball control systems) and I could do a pitch control
with no problem. So can the A/P manufacturers. The problem I
described doesn't occur with any 2-axis A/P that I know of, in any
airplane.

The problem is that roll and pitch are dynamically coupled (prove it to
yourself - apply roll input and the nose drops) and the coupling is
different between airplanes, and for a given airplane is likely a
function of mass, cg, inertial moment (controlled mostly by how far
outboard the fuel is), airspeed, angle of bank, etc. Without knowing
any of those things, it's pretty much a given that if there is a
divergent pitch mode (and many planes have one) the A/P will find it
one way or another. What bothers me is not that a given
airplane/autopilot combination can be forced into such a mode, but how
trivially easy it is. No effort has been made to suppress this
undesirable behavior.

If I were going to fix this problem, I would start by having the unit
read the bank at startup, and go into a recovery mode designed for the
airplane, probably involving stabilizing the angle of bank and then
slowly reducing it. Not saying that's a guaranteed fix, but it's
simple and IMO would probably work. BTW, this is simple enough to do
in an analog design, and pretty trivial in software. But there's no
incentive to do it - causing a divergent pitch oscillation by
overcontrol of the roll axis doesn't make an autopilot unairworthy - no
rules cover this.

It may make it unsafe if used in the manner often advocated, but unsafe
does not mean unairworthy (and vice versa).

Michael

[Michael]

> There are secondary effects but these are second order. If you apply
> roll, the main result will be roll. The pitch change should be small.

Think about this carefully. Imagine you have the plane trimmed for
straight and level flight. Now let go of the controls and allow the
plane to enter a spiral. Will the pitch change be small? Somehow I
doubt it. When an airplane rolls, the vertical component of lift is
reduced. This is a first order effect on pitch. The second order
effects modify it.

> I think that either there is more to this, or the manufacturers are
> not doing the most basic analysis of the stability margin.

Your latter conjecture is most likely correct. I once interviewed an
electrical engineer who worked for Meggitt. If he is at all typical,
they are simply not capable of doing the most basic analysis of the
stability margin (of course I did not hire him).

> The thing which suprised me, on the KFC225, was that the software does
> not detect an increasing error. So, if say a roll servo goes dead, it
> never realises it.

S-TEC's are the same. A friend of mine had a servo go intermittent,
and finally die. Never got any diagnostics.

> I even have a couple of videos of this. The unit
> even passes its power-up tests, including servo tests, with a totally
> dead servo.

I believe the only failure mode the KFC is designed to detect is a dead
open circuit. Some A/P's won't even do that.

> I realise this isn't on the same topic as control
> stability but if they don't get this right then .... ?

Your implication is that their design is not up to the standards you've
come to expect from a professional operation. And it's not.

> I often wonder just what "certification" really means in this
> business.

It means the paper is worth five times as much as the actual product.
It's obvious to you how poorly autopilots are designed because you have
a good understanding of the technology. If you believe that the
situation is different for other aircraft components, I have a bridge I
think you might be interested in purchasing.

Michael