Being an Instrument rated pilot and having flown both 'round
dials' or 'Steam gauges'(C172) and glass cockpit(DA42) aircrafts, I was
analysing what are the differences between the two/which is better. But sitting
idle at home whilst preparing for job interviews, I decided to take this
seriously to help me, keep in touch with the subject. Going by my background of
being a software developer in my recent past, I would have a leaning towards
glass cockpit.
To be honest, I was not very accurate with my ILS flying on
glass cockpits as I was with steam gauges. I decided to dig deep, to understand
my fallacy and concluded that ILS representation of glass cockpits, DO NOT enhance the Pilots experience of
flying vis-a-vis Steam Gauges. It’s a very strong conclusion to make
considering my software background and only over 50 hours of instrument flying (Actual
aircraft and simulators) up my sleeve. Let me elaborate my view and would be
happy to be proved right or otherwise. I could also be blamed as ‘making an excuse’
for being a lousy pilot 😆.
First let me explain ILS for all: ILS or Instrument Landing
System is ground based instrument aimed at facilitating an aircraft to
precisely be guided to the runway, specifying the direction and height to be
followed. Aircrafts have instruments to read the data offered by the ground
based equipment and these instruments guide pilot to fly left/right (Localiser
Indicator) and Up/Down (GlideSlope Indicator). The aircraft equipment in older
aircrafts was by a single instrument (round dial - ILS) and in newer aircrafts
by modern software User Interface (UI) representation.
First the software approach: During my software development
days, I was not well versed with UI front end development - however, here I am
commenting on experts UI! From a software development perspective, the current
representation of having a localiser needle associated with direction indicator
and GlideSlope indication associated with the altimeter tape makes great sense.
Wow! It meets the functional requirements - Yay! Let’s Implement! - Really?
Though it makes great sense and looks perfect on FRD
documents, I don’t think it does meet the end user - Pilot's requirement - in
terms of change or added complexity to the pilot’s actions.
Now Pilots perspective: During final approach, 1st task
would be aligning directionally as directed by localiser then latching onto
glideslope and descending as per profile. While descending, the actions of
pilot, which differ with respect to both steam gauges and glass cockpits, that
I am unhappy about and hence this rant.
During the final stages of descent, the pilot must scan the
crucial instruments of Localiser, glideslope, altimeter and ASI besides a
lookout for horizon/runway, approaching the decision altitude. The
workload on Pilot is immense at this stage - his bodily organs/parts like eyes, ears, hands, feet, nervous system and brain have to process and act with utmost
precision.
In glass cockpits, the scan of instruments, as shown in the
picture below of Garmin G1000 cockpit display, follows the pattern of
GlideSlope(scan gathers more information like height and ROD too – In Image
below represented as 1) then localiser (scan gathers more information of
direction – In Image below represented as 2) then Speedtape(In Image below represented
as 3) and finally the horizon looking out for Runway(In Image below represented
as 4 but is actually beyond the image). The eyes follow a quadrilateral scan pattern
(In Image below – 1to2to3to4and1). Even a minimalistic scan would need a scan
of GlideSlope then Localiser and the horizon - here the eyes follow a triangular
scan pattern (In Image below – 1to2to4and1).
In Steam Gauges, The scan of instruments in C172 traditional
cockpit, The glideslope and localizer(In Image below represented as 1) are
covered in single instrument scan, then a straight line scan to left towards
altimeter(In Image below represented as 2) and ASI(speedometer, In Image below
represented as 3) followed by horizon scan(In Image below represented as 4).
The eyes follow a triangular scan pattern (1to2to3to4and1) instead of a quadrilateral
scan pattern, because the need to scan DGI, is avoided with localiser needle
incorporated in the ILS instrument along with GlideSlope needle.
Even if theoretical experts argue that I may be following a
wrong scan pattern, practising pilots on steam gauges even just follow a
straight line scan (In Image above 1to4and1) of ILS instrument and the horizon
which is bare minimum scan. More tolerance towards varying behaviors should be
considered while designing any product. In reality though the pilot flying
would be following the straight line pattern, the Pilot monitoring does scan
all the other instruments and calls out the necessary information.
The scan pattern differences, in my opinion, add to the
complexity of brain processing as well as a few extra micro seconds of time
required to perform the actions on glass cockpits. Careful experts of Human
factors Ergonomics practitioners might see the merit in my argument and request
them to conduct studies around the same and publish data along with findings.
Feel free to comment.
Notes:
1. The scan of all important AI, is not mentioned as the
attitude for descent is finalized when established on glideslope and aircraft
is trimmed in that position.
2. G1000 Image obtained online from the link:
http://krepelka.com/fsweb/learningcenter/navigation/usingtheg1000.htm - a good
learning source. Unfortunately could not find - ‘contact me’ address on the
page.
3. C172 Image obtained online from the link:
https://flyawaysimulation.com/media/images6/images/Panel-And-FDE-For-Default-Cessna-172SP-fsx2.jpg
. Flyawaysimulation is a great place for simulator software downloads.
4. Please excuse my poor Paint skills😞.
Disclaimer:
As it’s a personal opinion of interest to pilots interaction
with systems and scope of learning involved, It should not be viewed in legal
or commercial angles.
