Instrument Scanning Technique
S.B. Chatterjee
their own Instrument scanning technique. Are they any particular
known technique better (or improved) over others ? I heard from
another student that Ralph Butcher's (Flight Training magazine &
skyroamers.com) 4-step scanning is the "best". I presume there must be
several techniques for scanning (& interpreting) instruments.
Any thoughts ?
SBC
LFransson
I have always taught the "hub & spoke" scan to my students, and it's what I
consciously use when I just don't seem to be scanning well at all.
This uses the attitude indicator as the "hub" of the scan, and the other
instruments as the "spokes," moving in a clockwise pattern: attitude,
altitude, attitude, vertical speed, attitude, heading, attitude, turn
cooridnator, attitude, airspeed....
I find that in normal instrument flying these days, I don't consciously or
systematically scan the panel. I get the feeling that I just sort of look at
the panel and take it all in. Sometimes, especially when I haven't been doing
a lot of recent instrument flying, this doesn't work so well, so I revert to
consciously and systematically scanning as described above.
Larry L. Fransson - ATP (CE-500), CFMEII
Macon, Georgia
"Pilots are just plane people with a different air about them."
Roy Smith
> I have always taught the "hub & spoke" scan to my students, and it's what I
> consciously use when I just don't seem to be scanning well at all.
> I find that in normal instrument flying these days, I don't consciously or
> systematically scan the panel. I get the feeling that I just sort of look at
> the panel and take it all in. Sometimes, especially when I haven't been doing
> a lot of recent instrument flying, this doesn't work so well, so I revert to
> consciously and systematically scanning as described above.
I find I do exactly the same thing. Most of the time, I don't really scan
per se, I just sort of absorb what the panel is saying to me. But,
whenever I sense that things are getting out of hand, I revert back to a
very rigid/regimented AI-ASI-AI-Alt-AI-TC-AI-DG scan. It usually takes me
about 2 trips around the panel to get everything back under control and
then I fall back into my usual "gaze/absorb" mode.
--
Roy Smith <r...@popmail.med.nyu.edu>
New York University School of Medicine
Ron Walpole
I assume your flight instruments are positioned in a T layout with the
AI in the middle, Airpseed to the left, Altitude to the right;
Directional Gyro below the AI, and VSI to the right of your DG.
Firstly, you should scan the AI. Within the AI, there is Pitch and AOB
(If you have an attitude indicator, you should use the pointer at the
top or bottom of the indicator for more precise information).
Additionally there is the Balance needle and Rate of Turn.
Now, given Attitude = Power plus Performance, and depending on what
aircraft manoeuvre you are doing, will depend on WHAT to scan MOST
often. The central point of your scan is the AI, spending most time of
your time looking at the AI. Then use a radial scan, like the Hub and
spoke method as detailed in another news item.
>From the AI, scan the performance instruments (Airspeed, Altitude, VSI,
Heading) you expect to move for the manouevre currently conducting.
For S&L, Scan - Attitude, Airpseed, Attitude, Altitude, Attitude,
Heading, Attitude, Power, and scan VSI occasionally.
For entering a descent, you move your scan to the Attitude to set the
pitch, reducing power when you reach the airspeed required. Then
concentrate on the attitude and airpseed initially, moving the power by
feel.
So the scan for descent would be: Attitude - Pitch, Attitude, Airspeed,
Attitude, Power, Attitude, then occasionally Heading, VSI. Increasing
the scan to the Altitude, for the approaching level ,then back to the
Attitude for S&L, power up, Attitude, Airspeed, back into the S&L scan.
Get my drift.
So what would you scan, during entry to a turn, the maintenance of the
turn, and exit from the turn?
Entry: Attitude - roll, set bank, slight back pressure for pitch, some
power, if required, Aittitude, Power, Attitude, Altitude, Attitude, VSI,
Maintenance: Attitude (bank and pitch), Altitude, Attitude, Airspeed,
(adjust power by feel), Attitude.
Etc.
Entering a descent and a turn, obviously needs more concentration. But
by scanning the correct instruments, reduces workload.
The method of Change, Check, Hold (CCH) and WAIT should also be used to
adjust the errors. For large errors, a more positive action is required.
I try to fly on instruments, by not squeezing the controls. (Eg, for a
control column, you hold the stick as if you are caressing you
girlfriends nipples). So you can feel the out of trim forces, and
therefore TRIM out the forces.
Old saying, TRIM or Die.
cheers
--
Ron Walpole
mailto:rwal...@ozemail.com.au
http://www.ozemail.com.au/~rwalpole
S.B. Chatterjee
up there along with "virginity and orgasm" - who said that there are no
connections between sex and flying ? (also see below).
SBC
Ron Walpole wrote in message <369F42...@ozemail.com.au>...
>control column, you hold the stick as if you are caressing you
>girlfriends nipples).
>cheers
>Ron Walpole
>mailto:rwal...@ozemail.com.au
>
Dave Bethke
>
> I am nearing my ifr checkride. I have not fallen in love with the AI.
Good. The AI is for making changes, such from straight and level to a
climb. Once you're in the climb the DG, altimeter and the VSI will tell
you how you're doing. When its time to level off, look at the AI to push
the nose to level and then use the DG and altimeter. When I did partial
panel in training I never missed not seeing the AI. It was lack of the
DG that gave me fits! :)
--
Dave Bethke - on the fringe of Houston (SGR)
Wcrrun
I am nearing my ifr checkride. I have not fallen in love with the AI. I
find it less precise that the VSI+DG+TC. I fly an Archer, and my partners
[both rated] say the AI is accurate. My instructor has not forced me to use
it, and I think my scan is good.
I think the AI is less precise as to pitch, than the VSI. The lines are
quite thin, and their scale is small, so what does a 10 degree pitch do for my
cruise climb?
The top notch is helpful, but with most of my lessons at night, the white
dot in the notch is still hard to see.
From my readings herein, I see that most of you love the AI, so maybe I
need to revisist its value. I will re-examine this instrument that sits in the
#1 position on the panel.
clayton
wcr...@aol.com
Robert Scott
>I think the AI is less precise as to pitch, than the VSI. The lines are
>quite thin, and their scale is small, so what does a 10 degree pitch do for my
>cruise climb?
While it is true that the VSI is a more sensitive indicator of
pitch than the AI, it has the drawback that it has more lag than
the AI. So if you want immediate feedback (say, while making
a change in pitch), the AI is better information. Long term, you
can use the VSI to trim things out.
Bob Scott
Ann Arbor, Michigan (email: rscott (at) wwnet (dot) net )
(My automatic return address is intentionally invalid.)
Bob
indicator) was covered at all times during the instruction for the entire
instrument instruction. The only time I really saw it uncovered was the one
flight before the checkride. To this day I rarely rely on the use of the AI
for any maneuvers.
The straight and level scan that I used at the time was DG+Alt. The theory
being that if you're in straight and level flight, you're not turning and
not climbing or descending so the compass heading and altitude remains
constant. In turns, the scan shifted to DG+TC+Airspeed Indicator + Alt.
The theory here is that if you're in a coordinated turn, the airspeed and
altitude should remain constant. On the ILS, the scan was basically
DG+Airspeed+Alt + LOC/GS. I would actually mainly just watch the Airspeed,
Alt and LOC/GS with every third pass or so being the DG. I've been flying
IFR using that scan for about the past 16 years and it has served well,
without having to rely on the attitude indicator for any maneuvers. If the
AI did fail, I wouldn't sweat one bit. After you fly IFR long enough, you
basically can just look at the panel and absorb what's going on without
spending so much time concentrating where your eyes happen to be moving.
You just 'do' it.
~ Bob
Wcrrun wrote in message <19990128213116...@ng-fq1.aol.com>...
>Ron,
> I am nearing my ifr checkride. I have not fallen in love with the AI.
I
>find it less precise that the VSI+DG+TC. I fly an Archer, and my partners
>[both rated] say the AI is accurate. My instructor has not forced me to
use
>it, and I think my scan is good.
> I think the AI is less precise as to pitch, than the VSI. The lines are
>quite thin, and their scale is small, so what does a 10 degree pitch do for
my
>cruise climb?
Matthew Whiting
>
> When I did my instrument rating work (circa 1982), the AI (attitude
> indicator) was covered at all times during the instruction for the entire
> instrument instruction. The only time I really saw it uncovered was the one
> flight before the checkride. To this day I rarely rely on the use of the AI
> for any maneuvers.
>
> The straight and level scan that I used at the time was DG+Alt. The theory
> being that if you're in straight and level flight, you're not turning and
> not climbing or descending so the compass heading and altitude remains
> constant. In turns, the scan shifted to DG+TC+Airspeed Indicator + Alt.
> The theory here is that if you're in a coordinated turn, the airspeed and
> altitude should remain constant. On the ILS, the scan was basically
> DG+Airspeed+Alt + LOC/GS. I would actually mainly just watch the Airspeed,
> Alt and LOC/GS with every third pass or so being the DG. I've been flying
> IFR using that scan for about the past 16 years and it has served well,
> without having to rely on the attitude indicator for any maneuvers. If the
> AI did fail, I wouldn't sweat one bit. After you fly IFR long enough, you
> basically can just look at the panel and absorb what's going on without
> spending so much time concentrating where your eyes happen to be moving.
> You just 'do' it.
Sounds like you had my instructor. About half of my training flights
were partial panel - no DG or AI. I'm not sure I understand the logic
of covering only the AI given that in most lightplanes both are vacuum
driven, and the most likely failure mode is loss of vacuum rather than
an actual instrument failure. And in that event you lost both
instruments. I found that by using timed turns and scanning the turn
coordinator fairly often, it is quite easy to fly reasonably precisely
partial panel - unless it is really bumpy. And now with a GPS, it's
almost no challenge at all. :-)
Matt
Bob
I did partial panel on EVERY instrument training flight. Also did partial
in the sim as well. It's true too that in when you're in turbulence, the DG
and the altimeter don't jump like the attitude indicator. But, as I said,
that's why I really never use the AI for anything during IFR flight. I also
got the chance to fly both ASR(no gyro) and PAR approaches during
training... all partial panel. That was the best learning experience.
~ Bob
Matthew Whiting wrote in message <36B25024...@epix.net>...
Matthew Whiting
>
> Matt..
>
> I did partial panel on EVERY instrument training flight. Also did partial
> in the sim as well. It's true too that in when you're in turbulence, the DG
> and the altimeter don't jump like the attitude indicator. But, as I said,
> that's why I really never use the AI for anything during IFR flight. I also
> got the chance to fly both ASR(no gyro) and PAR approaches during
> training... all partial panel. That was the best learning experience.
You may have missed my main point, if you have the DG that isn't really
a very partial, partial panel. The chance of an AI failure is much less
than the chance of a vacuum pump failure. And if you have a vacuum pump
failure you lost the AI AND the DG. So, I really don't consider it a
meaningful (as in simulating a real world failure scenario) exercise
unless you cover both vacuum instruments.
Matt
Bob
Now I see your point (it's been a long week). I agree totally about losing
the vacuum system. Luckily, that hasn't happened to me yet. No pitot heat
has happened.. now that's a scary thing when the airspeed goes to zero and
you're still airborne . But, I think the underlying message we need to send
is that it's absolultly critical to practice those skills.. and not to wait
until an actual occurence to try to remember something you learned 'way back
when'.
Bob
Matthew Whiting wrote in message <36B26B1D...@epix.net>...
Mike Wei
I don't understand the logic of "That AI could fail any time, so let's
fly the old way: needle airspeed and the ball all the time and ignore
that AI crap". Yes, AI could fail, vacuum could fail, that's why we
practice partial panel and keep it sharp, AS A BACKUP METHOD of
instrument flying.
Instrument flying has advanced a lot since the needle+airspeed days.
The development of reliable AI and DG (or even better, HSI) pushes the
advance of basic instrument flying. Attitude flying is based the
concept of control instrument and performance instrument, and the AI is
the most important control instrument.
It's one thing to stress the important of partial panel skill, but it's
totally another thing to ignore the AI and fly a Mooney like a AI'less
taylorcraft.