Re: Backup gyros - which do you trust?

[Dan Luke]

"Steve House" wrote:
> I've been reading with interest the several threads where a number of
people
> have strongly pointed out the advantages of a backup electric AI to
supplant
> a vacum driven main AI. But I'm reminded of the saying "A man with a good
> watch always knows what time it is. A man with two watches is never
sure."

This is a very interesting issue, to me. Reading the records of IMC
loss-of-control accidents is very unsettling to this single pilot IFR flyer
because of the cases where there *was* backup attitude instrumentation
available. Even when there wasn't, the pilots usually had at least the turn
coordinator to help keep the aircraft upright. It is too simple to chalk up
all these accidents simply to lack of proficiency. There is something else
going on - some human factors issue that has not been properly identified. I
suspect it may be related to task saturation. If so, instrument panel
clutter could be a contributing factor.

> So I'm toodling along in IMC with no outside horizon reference and I see
my
> two AIs don't agree with each other. How do I determine which to trust?
If
> I had a third, I could go with a 2 of 3 voting strategy of course, but
with
> only two, what do you do to decide which is operating properly and which
one
> has faulted? Obviously I can look for consistency with other
instruments -
> does my DG or Turn indicator show I'm turning, does the VSI show a climb
or
> descent - but what would be the best strategy given the various ways
vacuum
> or electric driven instruments can fail?

My strategy is to include a yoke-mounted GPS displaying a synthetic HSI in
my scan. This works wonderfully well in training, but I am not sure how well
I would do in a real situation where my AI suffered a gradual failure.
--
Dan
C172RG at BFM

[Sydney Hoeltzli]

Dan Luke wrote:

> This is a very interesting issue, to me. Reading the records of IMC
> loss-of-control accidents is very unsettling to this single pilot IFR flyer
> because of the cases where there *was* backup attitude instrumentation
> available. Even when there wasn't, the pilots usually had at least the turn
> coordinator to help keep the aircraft upright. It is too simple to chalk up
> all these accidents simply to lack of proficiency. There is something else
> going on - some human factors issue that has not been properly identified.

Concur. I, too, don't think it's entirely lack of proficiency. I think
there are pilots who have training and proficiency, who, in the words
of my CFI, "ought to be able to do it", who don't. And clearly backup
AI is no panacea.

>> Obviously I can look for consistency with other instruments -
>>does my DG or Turn indicator show I'm turning, does the VSI show a climb
>>or descent - but what would be the best strategy given the various ways
>>vacuum or electric driven instruments can fail?

Having an inventive CFI who has little habits like mind-f***ing
me into doubting my AI while palming the TC fuse, I think the best
strategy is delimited above. *Instrument cross check is essential*

Rod Machado's "Instrument Pilot Survival Manual" delineates something I
haven't seen elsewhere:

Turn triangle of agreement: AI, TC, compass
Pitch triangle of agreement: AI, VSI, alt static on/off

The point is to deliberately cross-check instruments
which depend upon independent power sources.

The problem (for me anyway) in training is that my compass is
mounted on the windshield bow and it's impossible to keep it
in my scan in VMC under the hood w/out extensive "cheating".

I also think Machado's under-utilizes ASI and hearing. I
think the reasoning is that there are three sources of ASI
failure and only two for VSI, one of which alt static
eliminates. But when forced to fly instruments without static
instruments, I found hearing was a fairly precise means of
pitch control (at constant power for a fixed-pitch prop)

Interested to see what others say: this topic should elicit a
lot of opinions.

Cheers,
Sydney

[Big John]

Dan and others

Full panel makes it easier for a qualified pilot to fly IFR. I doubt
a properly trained pilot is over whelmed by task saturation. There may
be lots of guages in the cockpit but only a few are included in your
primary scan on IFR.

How many pilots today practice partial panel and can fly it when
required? Not many I'd say. Never hear it discussed in any avation
groups any more as failure rate of gyro's is very small..

With single or dual gyro flight instrumnts and the problem of knowing
which one to believe all you have to do is check your partial panel
instruments to identify the correct gyro.

All of this takes understanding of IFR flying and partital panel
practice anticipating a gyro failure. Instrument (gyro) failures are
emergencies that can kill you if not proficient on partial panel.

How many GA pilots today could make even a NDB approach partial panel
much less a ILS or GPS approach?

Many areas of flyng have high risk. One can only try to stay ahead of
the airplane (and system) to reduce risk.

Fly safe and a nice day to all.

Big John



On Sun, 13 Jul 2003 07:35:24 -0500, "Dan Luke"
> wrote:

>"Steve House" wrote:
>> I've been reading with interest the several threads where a number of
>people
>> have strongly pointed out the advantages of a backup electric AI to
>supplant
>> a vacum driven main AI. But I'm reminded of the saying "A man with a good
>> watch always knows what time it is. A man with two watches is never
>sure."
>
>This is a very interesting issue, to me. Reading the records of IMC
>loss-of-control accidents is very unsettling to this single pilot IFR flyer
>because of the cases where there *was* backup attitude instrumentation
>available. Even when there wasn't, the pilots usually had at least the turn
>coordinator to help keep the aircraft upright. It is too simple to chalk up
>all these accidents simply to lack of proficiency. There is something else
>going on - some human factors issue that has not been properly identified. I
>suspect it may be related to task saturation. If so, instrument panel
>clutter could be a contributing factor.
>
>> So I'm toodling along in IMC with no outside horizon reference and I see
>my
>> two AIs don't agree with each other. How do I determine which to trust?
>If
>> I had a third, I could go with a 2 of 3 voting strategy of course, but
>with
>> only two, what do you do to decide which is operating properly and which
>one
>> has faulted? Obviously I can look for consistency with other
>instruments -
>> does my DG or Turn indicator show I'm turning, does the VSI show a climb
>or
>> descent - but what would be the best strategy given the various ways
>vacuum
>> or electric driven instruments can fail?
>
>My strategy is to include a yoke-mounted GPS displaying a synthetic HSI in
>my scan. This works wonderfully well in training, but I am not sure how well
>I would do in a real situation where my AI suffered a gradual failure.

[James Robinson]

Dan Luke wrote:
>
> It is too simple to chalk up all these accidents simply to lack of
> proficiency.

I was just reading the NTSB report of the King Air that crashed in
Colorado, attributed to spatial disorientation after a partial panel
failure. It seems representative of the problem. The facts are
chilling:

- IMC, alt. 23,200 ft.
- Two person cockpit.
- Experienced pilot - 5117 hours total, 2520 in type.
- Partial panel loss due to AC power failure.
- Failure immediately indicated by flags on affected instruments.
- Remaining instruments, powered by vacuum:
Left - airspeed, turn/slip,
Right - airspeed, turn/slip, altimeter, attitude.
- Aircraft began gently increasing turn within one minute of failure.
- Time between instrument loss and impact - one minute, 33 seconds
- Flight path consistent with graveyard spiral

http://www.ntsb.gov/publictn/2003/AAR0301.pdf

> There is something else going on - some human factors issue that
> has not been properly identified. I suspect it may be related to
> task saturation. If so, instrument panel clutter could be a
> contributing factor.

One comment in the report was that the pilot might have had a tendency
to focus on a single problem, and mot paid attention to other things.
He could have been trying to troubleshoot the electrical problem, and
not handed control over to the copilot, who would have had a better view
of the remaining functional instruments.

In any event, it is amazing how quickly the pilot lost control of the
aircraft, considering how this should have been fairly routine: If an AC
inverter had failed, then the changeover to the remaining inverter is
accomplished with a simple flip of a switch, and should have been almost
a reflexive action. The failure would have been immediately obvious, so
it wasn't one of those insidious failures that people don't notice at
first. An experienced IFR pilot should have been aware of the need to
maintain attitude and yet lost control almost immediately. In reading
the report, it seems like such an avoidable accident, yet...

[Sydney Hoeltzli]

Big John wrote:

> How many pilots today practice partial panel and can fly it when
> required?

Dunno. We sure do.

> Never hear it discussed in any avation
> groups any more as failure rate of gyro's is very small..

Couldn't prove the latter by me (2 per 1000 hrs). Then there's
the dry vacuum pump (1 per 1000 hrs). Not meaningful as statistics
of course.

> How many GA pilots today could make even a NDB approach partial panel
> much less a ILS or GPS approach?

I'm confused here -- the implication seems to be that you feel
an NDB approach would be easier partial-panel than an ILS or
GPS approach. If I'm interpreting you correctly, why?

Thanks,
Sydney

[Sydney Hoeltzli]

James Robinson wrote:

> One comment in the report was that the pilot might have had a tendency
> to focus on a single problem, and mot paid attention to other things.
> He could have been trying to troubleshoot the electrical problem, and
> not handed control over to the copilot, who would have had a better view
> of the remaining functional instruments.

This is poor CRM if it is the case.

Did the report say anything about the training of the pilots? I
woulda thought they did regular sim stuff, where I assume the
instructors put you through the wringer on various failues.

> The failure would have been immediately obvious, so
> it wasn't one of those insidious failures that people don't notice at
> first. An experienced IFR pilot should have been aware of the need to
> maintain attitude and yet lost control almost immediately. In reading
> the report, it seems like such an avoidable accident, yet...

Yeah, that's what gets me about so many of these.

Sydney

[Sydney Hoeltzli]

Julian Scarfe wrote:

> http://www.dft.gov.uk/stellent/groups/dft_control/documents/contentservertemplate/dft_index.hcst?n=5232&l=4
>
> tells a similarly chilling story of a Bandeirante that lost one of its two
> AIs resulting in a loss of control.

What do you think of the conclusions? They seem to be:
1) prevent AIs from failing
2) since 2 AIs weren't enough to keep the plane upright (combined
with 2 turn and banks, 2 of every other instrument), require
passenger planes to have 3

(agree, chilling)
Sydney

[Big John]

Sidney

NDB approach is a non precision approach. Takes less Partial Panel
proficiency.

ILS is a precision approach.

GPS could be either a precession or non precision approach depending
on configuration. Eventually all will be precession.

You can flop around on a NDB approach with it's higher minimums easier
on partial panel than you can on a precision ILS.

On instruments, it is hard enough with full panel to fly precision IFR
especially if the ILS beams have splits in them and the needles bounce
from stop to stop at minimums. We used to practice at Scramento and
never felt comfortable making the ILS approach there due to erratic
needle movements on final.

Does that explain my feelings enough?

It's been so many years since I made a real partial panel approach.
It was a Radio Range (A/N) approach as I recall. Hit cone of silence,
turned to heading to field, let down to minimum altitude and flew the
time (minutes and seconds) to field. All the pilots wore those fancy
chronometers to time from cone of silence to field for instrument
approaches in those days :o)

Some still wear along with the white scarf :o)

People laughed at the white scarf but in a fighter when it was hot you
could rub the skin off your neck looking for enemy aircraft. The soft
(silk) white scarf made it easier to keep your head on a swivel like
they told you. First time you were jumped and didn't see them coming
they didn't have to tell you again to keep a look out behind you if
you survived that first combat mission :o)

Good flying Sydney

Big John

If you are seriously going to fly IFR than all of your landings should
be from practice instrument approaches. This is what we did in the Air
Defense Command. One out of a hundred would be a straight VFR landing.
When Wx was bad we were right at home since we had been flying the
approach each flight each day. Even if you don't use a hood, the
procedures and communications become a piece of cake.


----clip----

How many GA pilots today could make even a NDB approach partial panel
much less a ILS or GPS approach?

I'm confused here -- the implication seems to be that you feel
an NDB approach would be easier partial-panel than an ILS or
GPS approach. If I'm interpreting you correctly, why?

Thanks,
Sydney

[Sydney Hoeltzli]

Big John wrote:

> NDB approach is a non precision approach. Takes less Partial Panel
> proficiency.

I'm quite aware of what is and isn't a precision approach.

What I don't understand is why you feel it's easier to fly an
NDB approach than an ILS approach partial-panel.

It seems to me that the NDB approach most strongly requires
accurate heading information. The course to be flown can not
be determined from the position of the ADF needle alone, it
can only be determined by comparing the ADF bearing to heading.
If your only source of heading info is a compass dancing wildly
as you bounce around, this gets "too interesting"

On an ILS or GPS approach, OTOH, it seems to me that the
course to be flown can be determined from the CDI position
alone. Needle left, turn left etc.

> You can flop around on a NDB approach with it's higher minimums easier
> on partial panel than you can on a precision ILS.

I don't understand this at all. Yes, the ILS becomes increasingly
sensitive as one descends closer to DH. But, if the wx is such
that the 800 ft minimums (or 600, or whatever they are) on an
NDB approach will get one in, one need not fly the ILS minimums
but can "flop around" on the less sensitive portion.

OTOH, if the wx is really crappy, all the flopping around on an
NDB you might care to do won't help you.

> On instruments, it is hard enough with full panel to fly precision IFR
> especially if the ILS beams have splits in them and the needles bounce
> from stop to stop at minimums. We used to practice at Scramento and
> never felt comfortable making the ILS approach there due to erratic
> needle movements on final.

I've never experienced anything like this. Is this a Cat II or III
ILS?

> Does that explain my feelings enough?

Not really I'm afraid. I must say the view that partial panel
NDB approachs are the most difficult seems to be held by many
of the local DEs, who will require a partial-panel NDB if there
is an ADF installed in the plane.

> It's been so many years since I made a real partial panel approach.
> It was a Radio Range (A/N) approach as I recall. Hit cone of silence,
> turned to heading to field, let down to minimum altitude and flew the
> time (minutes and seconds) to field. All the pilots wore those fancy
> chronometers to time from cone of silence to field for instrument
> approaches in those days :o)

Whew...is this the sort of approach being described in "Fate is
the Hunter"? How would you handle adjusting groundspeed vs. time?
Would you guesstimate your groundspeed from time between waypoints
before initiating descent, would someone on the ground give you
winds from which you'd calculate groundspeed? Would you adjust
power to always fly the same groundspeed, or adjust time? Sorry
for all the naive questions, but pilots who actually flew radio
range approaches are few and far between.

These days, if I time an approach where I could use DME to define
the MAP my instructor beats me with a board "timing is the least
accurate way to determine the MAP! Never depend upon time if
there's another way!" And he's not a young whippersnapper
either.

Appreciate your comment re practice instrument approaches.

Cheers,
Sydney

[Big John]

Sidney

On Mon, 14 Jul 2003 05:10:26 GMT, Sydney Hoeltzli
> wrote:

>Big John wrote:
>
>> NDB approach is a non precision approach. Takes less Partial Panel
>> proficiency.

>I'm quite aware of what is and isn't a precision approach.
>
You ask and I gave a straight forward answer. Why did you parse my
answer and get snippy???? If you didn't want to know, why ask?

Are you trying to tell me it's not easier to fly a PP NDB approach
than a PP ILS?

>What I don't understand is why you feel it's easier to fly an
>NDB approach than an ILS approach partial-panel.

How many times have you flown a hard IFR partial panel NDB or ILS
approach? Are you making your statements from reading a book or from
bar talk? If you don't want to take advice from someone who has been
there and done that then use your own procedure. There are many ways
to fly an airplane, some better and more safe than others but only the
individual can make the decision of what is right for him/her within
the rules and their experience level.

It's too bad we are not closer and I could jump in and let you
demonstrate to me how easy it is to fly PP without killing us.

>It seems to me that the NDB approach most strongly requires
>accurate heading information. The course to be flown can not
>be determined from the position of the ADF needle alone, it
>can only be determined by comparing the ADF bearing to heading.
>If your only source of heading info is a compass dancing wildly
>as you bounce around, this gets "too interesting"
>
A NDB can be flown with very sloppy heading control. Use whisky
compass outbound in pattern and just point the needle at 360 degrees
(top of dial) in bound. After needle swing you can use time and
distance and compass heading to field letting down to minimums.

>On an ILS or GPS approach, OTOH, it seems to me that the
>course to be flown can be determined from the CDI position
>alone. Needle left, turn left etc.

I'd like to see you PP trying to use GPS to make an approach. It's
hard enough to keep the airplane flying PP without using the benefits
of GPS. Not saying it can not be done but I'd bet against anyone doing
it successfully and win a bundle. Could throw an Irish Wake with
dancing and drink galore.

Another post pointed out an individual practicing using his back up AI
across the panel and got vertigo. He probably was moving his head back
and forth which gives you vertigo when on instruments, Your scan is
only with your eye balls or you will probably get vertigo.

>> You can flop around on a NDB approach with it's higher minimums easier
>> on partial panel than you can on a precision ILS.
>
>I don't understand this at all. Yes, the ILS becomes increasingly
>sensitive as one descends closer to DH. But, if the wx is such
>that the 800 ft minimums (or 600, or whatever they are) on an
>NDB approach will get one in, one need not fly the ILS minimums
>but can "flop around" on the less sensitive portion.

True. If you have NDB minimums and only an ILS then you can probably
get down using the ILS assuming you are proficient enough to fly the
two needles and all the PP instruments required to just keep the bird
airborne.
>
>OTOH, if the wx is really crappy, all the flopping around on an
>NDB you might care to do won't help you.
>
Again. Want to see you make a IFR PP ILS. Doubt if I could when I was
able to fly the box the bird came in. It's very hard and very
dangerous.

> On instruments, it is hard enough with full panel to fly precision IFR
>> especially if the ILS beams have splits in them and the needles bounce
>> from stop to stop at minimums. We used to practice at Scramento and
>> never felt comfortable making the ILS approach there due to erratic
>> needle movements on final.
>
>I've never experienced anything like this. Is this a Cat II or III
>ILS?
Don't know. It was the initial type that was used for years. Each one
had different beams causing different display in cockpit from the
installation at each field. Some fields were so bad that they could
not install an ILS and meet FAA standards. That was one of the reasons
(to learn the ILS quirks) an Airline Pilot had to make several flights
into an airport before he was checked out to fly as captain to that
field.

>> Does that explain my feelings enough?
>
>Not really I'm afraid. I must say the view that partial panel
>NDB approachs are the most difficult seems to be held by many
>of the local DEs, who will require a partial-panel NDB if there
>is an ADF installed in the plane.

Don't know where you are reading this in my posts. A PP ADF is the
easiest PP approach to fly IFR. Still not easy, but the easiest.

>> It's been so many years since I made a real partial panel approach.
>> It was a Radio Range (A/N) approach as I recall. Hit cone of silence,
>> turned to heading to field, let down to minimum altitude and flew the
>> time (minutes and seconds) to field. All the pilots wore those fancy
>> chronometers to time from cone of silence to field for instrument
>> approaches in those days :o)
>
>Whew...is this the sort of approach being described in "Fate is
>the Hunter"? How would you handle adjusting groundspeed vs. time?
>Would you guesstimate your groundspeed from time between waypoints
>before initiating descent, would someone on the ground give you
>winds from which you'd calculate groundspeed? Would you adjust
>power to always fly the same groundspeed, or adjust time? Sorry
>for all the naive questions, but pilots who actually flew radio
>range approaches are few and far between.
>
Sidney. All of the above <G> The approach plate gave the time to field
in minutes and seconds listing several speeds to accommodate all the
aircraft in inventory. Normally max time would only be 3-4 minutes and
normally just 1-2 minutes after crossing cone of silence. You rarely
landed straight in and many of the headings to field were not lined up
with a runway. After sighting the field you would circle and land on
the active runway. If you were in radio contact with the field/tower
you could get surface wind and compute a ground speed from cone of
silence to field, other wise you made a WAG from forecast and what you
encountered en route. As you only were flying a couple of minutes and
the wind would only make the difference of a few seconds to field it
was not a super big problem in most cases.. Remember a ceiling of
6-800 feet (above obstructions) was the norm in those days. None of
the 200 & 1 (or less) like today.. Hope this gives you a feel for how
crude things were in those days. Norm was when WX was bad we sat until
it improved and then continued cross country. As an aside, in all my
years of flying, I only made one zero zero landing.

>These days, if I time an approach where I could use DME to define
>the MAP my instructor beats me with a board "timing is the least
>accurate way to determine the MAP! Never depend upon time if
>there's another way!" And he's not a young whippersnapper
>either.

If all the instruments and nav aids are working then he is correct but
when the bottom falls out then timing is a very good fall back. Tape
the DME for him and fly time and then uncover the DME and see how far
you are off. If done properly is pretty accurate for short distances.
Doing on occasion gives you confidence in timing, if required.

>Appreciate your comment re practice instrument approaches.

I instructed for so many years in heavy iron I tend to push the
routines I developed to give maximum safety and yet perform the
mission. As I've said, there may be other ways to fly but what I push
has stood the test of time and is a good place to start until one gets
lots of experience.

As I have also said prior, these postings have taken the place of what
we called hanger flying in the old days where lots of tips and tricks
were passed on to the younger pilots by the old gray beards.

For example, I can loop a T-6 starting at zero indicated airspeed. Two
people and normal load of fuel. No tricks, just super technique.

Can also do a double immelman (sp) in a T-33. Only a couple of us I
know who did that. Max use of energy. One good friend of mine who did,
died a few years ago (probably drank himself to death). At reunion in
San Antonio we stayed in the hotel room and knocked off a couple of
quarts of vodka to get ready for evenings activities while the gals
went 'out' to do what women do <G>. He was the one that was shot down
in Europe and stole a FW-190 and flew it back to England. Got gear up
but didn't know how to unlock and get the gear down so had to belly in
<G> His exploit has been published a few times in the War Stories
magazines.

Enough rambling.

I'm going to back out of most of these threads and let yu'all have at
it. I'll just read and enjoy. Might even look at a sport bird since I
can't get a third class anymore. At least with out several years and a
lot of time and money to fight the system. Have you heard of any one
getting by OK City with a pacemaker? I pass a monthly check ok.

Have enjoyed many of your posts. Keep it up. You are not afraid to ask
questions which is good.

Erin go bragh

Big John

Best instruments you can buy and also radio's. Practice instruments
and fly at least 10 hours a month (100 hours a year minimum).

Air Force ran an expensive study that showed 17 hours a month gave
minimum accident rate in heavy iron. Less than 17 hours, proficiency
suffered. More than 17 hours you were exposed to flying hazards more
and more accidents. The 17 hours a month is close to 200 hours a year
which is a very good figure if you have the money and time to fly that
much.

[David Megginson]

Big John > writes:

> Sidney. All of the above <G> The approach plate gave the time to
> field in minutes and seconds listing several speeds to accommodate
> all the aircraft in inventory. Normally max time would only be 3-4
> minutes and normally just 1-2 minutes after crossing cone of
> silence. You rarely landed straight in and many of the headings to
> field were not lined up with a runway. After sighting the field you
> would circle and land on the active runway. If you were in radio
> contact with the field/tower you could get surface wind and compute
> a ground speed from cone of silence to field, other wise you made a
> WAG from forecast and what you encountered en route.

This does not sound a lot different from a typical NDB approach today,
when the NDB is off the field.


All the best,


David

--
David Megginson, , http://www.megginson.com/

[Big John]

David

Wasn't, except you normally didn't have the option of tracking
outbound (on beam) from cone of silence like you can with ADF on a NDB
after station passage. You flew a heading and time for distance. Think
back on those days and shudder <G>

Big John

On Mon, 14 Jul 2003 12:14:01 GMT, David Megginson
> wrote:

>Big John > writes:
>
>> Sidney. All of the above <G> The approach plate gave the time to
>> field in minutes and seconds listing several speeds to accommodate
>> all the aircraft in inventory. Normally max time would only be 3-4
>> minutes and normally just 1-2 minutes after crossing cone of
>> silence. You rarely landed straight in and many of the headings to
>> field were not lined up with a runway. After sighting the field you
>> would circle and land on the active runway. If you were in radio
>> contact with the field/tower you could get surface wind and compute
>> a ground speed from cone of silence to field, other wise you made a
>> WAG from forecast and what you encountered en route.
>
>This does not sound a lot different from a typical NDB approach today,
>when the NDB is off the field.
>
>
>All the best,
>
>
>David

[Michael]

Sydney Hoeltzli > wrote
> What do you think of the conclusions? They seem to be:
> 1) prevent AIs from failing

Well, there's a lot to be said for that. For one thing, it's far from
unlikely that BOTH of the AI's failed, not just one.

Did you miss this: (All quotes from the referenced report)

"These 21 artificial horizons had an MTBUR of 257 hours." That's mean
time before unscheduled replacement, but... "The artificial horizon
fitted to the EMB-110had no specified overhaul life and was treated as
an 'on condition'item" and thus all replacements were unscheduled.

Why was such a shockingly high failure rate tolerated? Well, "The
BCAR Section under which the aircraftwas certificated did not
stipulate the reliability requirementsthat the artificial horizon
should meet in order to ensure thatthe occurrence of a double failure
was a statistically remoteevent." Gotta love the way those regs
protect us...

And sure enough it was not statistically remote - it had happened
before! "An EMB-110 operated by another UK company suffered two
double artificial horizon failures in 1995. The first,on 4 June 1995,
involved a double instrument failure" There were only a handful of
EMB-110's in the UK...

> 2) since 2 AIs weren't enough to keep the plane upright (combined
> with 2 turn and banks, 2 of every other instrument), require
> passenger planes to have 3

Yes, that's the recommendation. IMO it's unmitigated crap. First
off, AI's should not be failing at an average of less than 300 hours.
Second, there were still two good PNI's (basically HSI's) and
turn&slip indicators. But could the pilots use them? Probably not
because "This technique, commonly referred to as 'limited panel' (see
paragraph 1.5.3.2) does not form part of a professional pilot's
recurrency training and testing."

So the most likely causes of the crash are AI failure (quite possibly
double AI failure), and the inability of the flight crew to fly
partial panel because SURPRISE they get no recurrent training in
partial panel flying. Exactly what kind of outcome could one expect
when you fit proven failure-prone AI's to an airplane and don't give
the flight crew any recurrent partial panel training?

> (agree, chilling)

There are plenty of chilling accidents out there. This isn't one of
them. This was inevitable.

Michael

[Michael]

Big John > wrote
> Are you trying to tell me it's not easier to fly a PP NDB approach
> than a PP ILS?

If she won't I will - and I've done both, for real, on the same night.
Flying the ILS was much easier.

> I'd like to see you PP trying to use GPS to make an approach. It's
> hard enough to keep the airplane flying PP without using the benefits
> of GPS.

The last instrument student I taught could consistently fly a partial
panel GPS approach (with moving map) with the needle never leaving the
donut and with altitude control to +50/-0 ft without breaking a sweat.

> I instructed for so many years in heavy iron I tend to push the
> routines I developed to give maximum safety and yet perform the
> mission.

Are you sure they're applicable outside heavy iron? I've never flown
any - all my flying and instructing has been singles and light twins
(with gliders thrown in for flavor) and I just can't see that a
partial panel GPS or ILS would be harder to fly than a partial panel
NDB. In fact, my proficiency approach for hoodwork is the night
partial-panel single-engine circling NDB, simply because that's the
most difficult. A single engine partial panel ILS to Cat II is cake
by comparison. Maybe ILS installations have improved...

Michael

[G.R. Patterson III]

Big John wrote:
>
> The soft
> (silk) white scarf made it easier to keep your head on a swivel like
> they told you.

The British commanders would tell their newbies "It takes three seconds to
shoot down another aircraft. So look around every three seconds."

George Patterson
The optimist feels that we live in the best of all possible worlds. The
pessimist is afraid that he's correct.
James Branch Cavel

[Big John]

Michael

I was talking about basic PP; needle, ball and airspeed (normally
another word is used here <G>). If you only fault the AI then system
is easier to fly and we are closer together.

I also was throwing in the head movements to look at GPS (where ever
it is mounted) and then instruments on panel with the high probability
of vertigo. Also the communications required on a IFR instrument
approach divides your thought process and raises the difficulty. Many
people cannot do two things at the same time (fly and communicate
under pressure) and excel at both.

The basic key to safe IFR flight is good equipment and practice. The
more the better.

Also, some people take to IFR like a duck to water. Others struggle
and never become what I would describe as 'safe' even in benign Wx.

I have thousands of hours instructing in the Air Force plus
instructing GA pilots both SME on instruments so feel I have been
exposed to the best of both worlds. Techniques are not too different.

Fly safe

Big John


On 14 Jul 2003 14:57:48 -0700, (Michael) wrote:

>Big John > wrote
>> Are you trying to tell me it's not easier to fly a PP NDB approach
>> than a PP ILS?
>
>If she won't I will - and I've done both, for real, on the same night.
> Flying the ILS was much easier.
>
>> I'd like to see you PP trying to use GPS to make an approach. It's
>> hard enough to keep the airplane flying PP without using the benefits
>> of GPS.
>
>The last instrument student I taught could consistently fly a partial
>panel GPS approach (with moving map) with the needle never leaving the
>donut and with altitude control to +50/-0 ft without breaking a sweat.
>
>> I instructed for so many years in heavy iron I tend to push the
>> routines I developed to give maximum safety and yet perform the
>> mission.
>
>Are you sure they're applicable outside heavy iron? I've never flown
>any - all my flying and instructing has been singles and light twins
>(with gliders thrown in for flavor) and I just can't see that a
>partial panel GPS or ILS would be harder to fly than a partial panel
>NDB. In fact, my proficiency approach for hoodwork is the night
>partial-panel single-engine circling NDB, simply because that's the
>most difficult. A single engine partial panel ILS to Cat II is cake
>by comparison. Maybe ILS installations have improved...
>
>Michael

[Big John]

G.R.

The brit pretty well said it. Close to what I put up with as a newbe.

The old timers in my outfit however wanted you to keep your head
moving all the time (and got give a 3 second opening).

In the "finger four" we flew in, you didn't clear your own tail. One
of the other pilots in flight cleared your tail and you cleared his in
combat (loose) formation.

And the best.

Big John



On Mon, 14 Jul 2003 22:03:45 -0400, "G.R. Patterson III"
> wrote:

>
>
>Big John wrote:
>>
>> The soft
>> (silk) white scarf made it easier to keep your head on a swivel like
>> they told you.
>
>The British commanders would tell their newbies "It takes three seconds to
>shoot down another aircraft. So look around every three seconds."
>
>George Patterson
> The optimist feels that we live in the best of all possible worlds. The
> pessimist is afraid that he's correct.
> James Branch Cavel

[Dennis O'Connor]

My big, ugly, AN horizon has been working reliably for decades... Makes you
kinda wonder...

Denny

"Michael" > wrote in message
om...
> Sydney Hoeltzli > wrote
> > What do you think of the conclusions?

[Sydney Hoeltzli]

Big John wrote:

> I also was throwing in the head movements to look at GPS (where ever
> it is mounted) and then instruments on panel with the high probability
> of vertigo.

If an IFR approach certified GPS requires extensive head movements
to follow the CDI, something went badly wrong in the install. The
CDI for an approach GPS should not require more head movements
than looking at any other CDI. In many installs, it *is* the same
CDI as nav radio.

> Also the communications required on a IFR instrument
> approach divides your thought process and raises the difficulty.

Very true, but wouldn't this apply no matter what approach is
being flown?

Cheers,
Sydney

[Julian Scarfe]

"Sydney Hoeltzli" > wrote in message
...
> Michael wrote:
>
> >>2) since 2 AIs weren't enough to keep the plane upright (combined
> >> with 2 turn and banks, 2 of every other instrument), require
> >> passenger planes to have 3
>
> > Yes, that's the recommendation. IMO it's unmitigated crap. First
> > off, AI's should not be failing at an average of less than 300 hours.
> > Second, there were still two good PNI's (basically HSI's) and
> > turn&slip indicators. But could the pilots use them? Probably not
> > because "This technique, commonly referred to as 'limited panel' (see
> > paragraph 1.5.3.2) does not form part of a professional pilot's
> > recurrency training and testing."
>
> You Have Got To Be Kidding.
>
> Are you serious? Yes, I missed that. Are they asserting this
> shocking hole in proficiency training is widespread?

I think you're barking up the wrong tree here. Classic teaching of
partial/limited panel involves covering an instrument and then continuing to
fly without it. In the case of the Bandeirante accident, that wasn't the
issue. There was still a perfectly serviceable AI in the panel, and a pilot
sitting in front of it. The issue was identifying the failed instrument in a
complex cockpit environment.

The chances of being left with no working AI in the panel of a transport
aircraft (which starts with 3 AIs) but still having the instrumentation to
fly partial panel are so remote that it's not worth the time to train on it.
That time is better spent on other exercises, one of them *recognition* of
instrument failure.

For GA aircraft the situation is different. The probability of ending up
with a TC but no AI is much higher, and controlling the aircraft
successfully without it is easier. That makes it well worth the practice.

Julian Scarfe

[Sydney Hoeltzli]

Julian Scarfe wrote:

> I think you're barking up the wrong tree here. Classic teaching of
> partial/limited panel involves covering an instrument and then continuing to
> fly without it. In the case of the Bandeirante accident, that wasn't the
> issue. There was still a perfectly serviceable AI in the panel, and a pilot
> sitting in front of it. The issue was identifying the failed instrument in a
> complex cockpit environment.

I'm not sure I'm barking up the wrong tree.

Possibly practicing flying partial panel makes little sense. OTOH,
practicing partial panel *does* teach which combinations of instruments
can be used to provide the same information as the missing AI.

Surely this is relevant to obtaining and maintaining a good
crosscheck -- and wouldn't good crosscheck be the key to identifying
the failed instrument in a "complex cockpit environment"?

BTW, my reading of the accident report is that they weren't
certain but what both AIs had failed -- something that was certainly
within statistical likelihood given the low MTBUR

Cheers,
Sydney

[Sydney D Hoeltzli]

Big John wrote:

>>>NDB approach is a non precision approach. Takes less Partial Panel
>>>proficiency.

>>I'm quite aware of what is and isn't a precision approach.

> You ask and I gave a straight forward answer. Why did you parse my
> answer and get snippy???? If you didn't want to know, why ask?

I edit what I see as extra text routinely. I'm sorry you see
my response as "snippy". To me, defining precision approaches
didn't explain why you feel an NDB approach in particular is
easiest to fly partial panel. That's what I wanted to know.

Perhaps I should clarify that I was assuming comparing "apples
to apples", ie an ILS vs a GPS vs an NDB approach flown down
to about the same height AGL, maybe 700-800 ft ceiling.

If we're talking 200 ft ceiling then I assume we agree it's
a moot point, the ILS or maybe an ASR or a PAR is the only
thing which will get you in.

> Are you trying to tell me it's not easier to fly a PP NDB approach
> than a PP ILS?

Well, that seems to be the general opinion of more experienced
pilots around here, including some folks I generally think pretty
highly of.

It's certainly my opinion from flying both partial panel in
simulated IMC at night.

We've been lucky enough that so far all our failures have occured
day VFR, so I can't speak from experience. And I won't in our
plane, because when we bought it, the ADF came in a cardboard
box having been pulled to install an ifr-certifiable GPS. So
it made the most sense to sell it and use the money to certify
the GPS, and that's what we did.

> If you don't want to take advice from someone who has been
> there and done that then use your own procedure.

Well, when one person who has "been there and done that"
offers advice which runs counter to that of a number of others
who have "been there and done that", I'd like to know the
reason for the discrepency.

It *is* a moot point to us, as explained above. Though I did
have a CFI who insisted I learn to fake NDB approaches on a
handheld GPS as an emergency procedure. Which sort of put me
in mind of modifying an auto to make it into a good horse-drawn
buggy.

> I'd like to see you PP trying to use GPS to make an approach. It's
> hard enough to keep the airplane flying PP without using the benefits
> of GPS.

I don't follow this at all. There have been several articles
commenting on the heading assistance provided by some modes of
common handheld GPS. Unless you are thinking that the GPS is
tucked off to the side and must be scanned by turning one's
head constantly, instead of being readily in view?

In an IFR install, there ought to be a CDI for the thing, right
in one's primary scan and it shouldn't be necessary to turn one's
head much to fly it.

We have a moving map coupled to our GPS in the primary scan
area, between the AI and the CDIs. I find it so useful partial-
panel that our CFI fails it.

Where are you located?

> Another post pointed out an individual practicing using his back up AI
> across the panel and got vertigo. He probably was moving his head back
> and forth which gives you vertigo when on instruments, Your scan is
> only with your eye balls or you will probably get vertigo.

Yeah, that's probably part of the issue. Where my compass is located,
I can't read it accurately eyeballs only. I have to move my head.

So flying an approach like an NDB where I have to constantly scan
the compass is he**. It's much simpler to fly an approach where
I can pretty much drop the compass out of the scan and just center
the needle.

> I'm going to back out of most of these threads and let yu'all have at
> it. I'll just read and enjoy. Might even look at a sport bird since I
> can't get a third class anymore. At least with out several years and a
> lot of time and money to fight the system. Have you heard of any one
> getting by OK City with a pacemaker? I pass a monthly check ok.
>
> Have enjoyed many of your posts. Keep it up. You are not afraid to ask
> questions which is good.

Thanks. Appreciate your info about the 17 hrs a month, too. Afraid
I can't quite pull that right now. A young child has a sad effect upon
free time :) 'fraid I don't have good news about a pacemaker. I know
someone who was a glider CFI/DE, and works for the local FSDO, and he
didn't even fight it. Of course, he's still flying the gliders and
enjoying every minute I assume.

Cheers,
Sydney

[Roger Tracy]

I have a Garmin 196. It has a simulated instrument
panel page on it that is pretty accurate. It would be
the tie breaker in the event of confusion over what
the gyro instruments were saying.


"Sydney Hoeltzli" > wrote in message
...
> Julian Scarfe wrote:
>
> > I think you're barking up the wrong tree here. Classic teaching of
> > partial/limited panel involves covering an instrument and then
continuing to
> > fly without it. In the case of the Bandeirante accident, that wasn't
the
> > issue. There was still a perfectly serviceable AI in the panel, and a
pilot
> > sitting in front of it. The issue was identifying the failed instrument
in a
> > complex cockpit environment.
>
> I'm not sure I'm barking up the wrong tree.
>
> Possibly practicing flying partial panel makes little sense. OTOH,
> practicing partial panel *does* teach which combinations of instruments
> can be used to provide the same information as the missing AI.
>
> Surely this is relevant to obtaining and maintaining a good
> crosscheck -- and wouldn't good crosscheck be the key to identifying
> the failed instrument in a "complex cockpit environment"?
>
> BTW, my reading of the accident report is that they weren't
> certain but what both AIs had failed -- something that was certainly
> within statistical likelihood given the low MTBUR
>
> Cheers,
> Sydney
>

[Dennis O'Connor]

I played with that page on the 196 yesterday in moderately gusty
conditions... You have to be smooth on the controls, make your correction
and then wait for the unit to update... Flown that way it is useable and I
suspect that I could fly an approach with it in real conditions (an ILS to
minimums would be hairy).. The work load is significantly higher than with
the gyros..

But, if you do not wait for the screen to update you get into a world of
hurt... Since it was nice and bumpy I put the hood on and then flew it like
I was panicky - rapid, big,. inputs - It only took about 30 seconds to get
out of sync, with the ship laid over on it's side, whereupon I had the fun
of recovering from an unusual attitude... Other than the speed having
gotten further into the yellow arc than I like it was good exercise... About
this time the controller came on and asked me to say intentions - uh, oh,
busted!

Denny

"Roger Tracy" > wrote in message
...
> I have a Garmin 196. It has a simulated instrument
> panel page on it that is pretty accurate. It would be
> the tie breaker in the event of confusion over what
> the gyro instruments were saying.