Can EFIS / EFMS lead to removing basic safety checks?

Beavis wrote:

In article jchKg.2674$c07.2060@fed1read04,
Sam Spade wrote:


In the modern jets and many GA airplanes too the DG automaticly aligns
the correct magnetic heading. Checking the EFIS heading prior to take
off was not on our companies checklist.


It should not have to be on any company's checklist. Some things are
basic airmanship.


No, they're equipment-specific procedures. Doing a mag check prior to
takeoff is not "basic airmanship" either, nor is realigning the DG every
15 minutes. They're specific procedures required by specific equipment,
and neither is relevant on a modern turbine-powered airplane.

Did you align the IRUs in your 152 before you started moving? Check the
landing gear doors as part of your walk-around? Of course not, because
they're not appropriate procedures for THAT AIRPLANE. See what I'm
getting at?

I think the context of the thread is air carrier equipment. Virtually
all airliners have heading bugs. They all had them at my airline when I
signed on in 1964, and that continued to the 767.

In article ,
Ron Natalie wrote:

Why would the EFIS be any different than an HSI (or as Bob already
posted the 707 RMI). It still has a heading which ought to be
verified with some real reference (Whiskey compass or runway).

It is verified, by two redundant computers that will set a warning flag
if they're off by more than a few degrees. (4 degrees in the plane I
fly.) If either gyro isn't tracking correctly, or isn't agreeing with
the actual magnetic heading (sensed by two independent flux gates), the
warning will trigger the second the airplane makes its first turn on the
ground.

This system provides MORE accuracy and MORE redundancy than correcting a
manual DG to a whiskey compass, and frees the crew to check the myriad
of things that do require human interaction to verify before flight.

Now that I have a slaved HSI, it's almost always right so I could see
forgetting to check it.

These airplanes have more than a slaved HSI. They have two (or more)
separate, independent remote heading gyros, slaved to two (or more)
separate, independent heading sensors (flux gates). If anyone ONE of
those 4+ systems reads differently from the others, a warning will trip.

I think you guys are barking up the wrong tree here. This isn't a case
of losing redundancy, it's the case of an automatic system being able to
do a better job than a human at this particular task. (Do you think an
old-style, manual variable-pitch prop is a better system than a
constant-speed prop, because it keeps the pilot more involved? I sure
don't.)

Placing the runway heading on a steam gauge HSI was considered good form at my company

Why? The runway heading is rarely a factor of ten on the nose, and
having an even heading is only good for an instrument takeoff. So,
you'd be usually setting the DG to an incorrect heading just before takeoff.

Makes no sense to me.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

Jose wrote:
Placing the runway heading on a steam gauge HSI was considered good
form at my company


Why? The runway heading is rarely a factor of ten on the nose, and
having an even heading is only good for an instrument takeoff. So,
you'd be usually setting the DG to an incorrect heading just before
takeoff.

Makes no sense to me.

Jose

I am not speaking of DGs, Jose. This is about an accident involving air
carrier equipment.

We set the exact runway heading. Often, the departure clearance is to
fly runway heading. Even if it is not, runway heading is to be flown to
at least 400 feet.

Our steam gauge autopilots or flight directors all had a heading mode.

The EFIS/FMS birds had a heading mode and a track mode. ATC got unhappy
with folks flying track mode when they were instructed to maintain
runway heading; thus the reason for today's AIM language in that regard.

I cannot image why a professional crew flying today's air carrier
euipment would not set the runway heading. It could have saved a lot of
grief at LEX.

This is about an accident involving air carrier equipment.
Often, the departure clearance is to fly runway heading.

I infer you mean that you set the heading bug on the exact runway
heading, not that you set the DG to the runway numbers (times ten).
That makes more sense.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

-----Original Message-----
From: Michelle P ]
Posted At: Saturday, September 02, 2006 1:17 PM
Posted To: rec.aviation.ifr
Conversation: Can EFIS / EFMS lead to removing basic safety checks?
Subject: Can EFIS / EFMS lead to removing basic safety checks?

....
You would only check the EFIS heading if the Comparator smelled
trouble
and triggered a warning. The computer cross checks the left and right
systems so the pilots do not have to.
Michelle P

I think that is my point; if the computer cross-checks the left and
right systems and not the pilots, then who tells the computer to depart
on runway 26 instead of 22?

It seems to me that when the task (not the responsibility) of checking
the HSI or DG was assumed by the computer, the pilots abdicated the
responsibility of making sure everything balanced: runway heading, HIS
or DG, taxi instructions, and take-off clearance. I think if they had
included a manual check of the headings they might have noticed they
were off by 40 degrees.

I believe it is the pilots' responsibility to observe these things and
not the controllers' responsibility to run traffic signals at the
hold-short line.

Jose wrote:

This is about an accident involving air carrier equipment.
Often, the departure clearance is to fly runway heading.


I infer you mean that you set the heading bug on the exact runway
heading, not that you set the DG to the runway numbers (times ten). That
makes more sense.

Jose
Airliners don't have light aircraft type DGs. It is either an HSI or,
far more likely, a track-up moving map with an appreviated compass rose
at the top. Or, like the G-1000, it could be an electronic HSI.

Jim Carter wrote:



I believe it is the pilots' responsibility to observe these things and
not the controllers' responsibility to run traffic signals at the
hold-short line.


That cuts to the chase.

In article 005b01c6cf0f$0425e810$4001a8c0@omnibook6100,
"Jim Carter" wrote:

The computer cross checks the left and right
systems so the pilots do not have to.

I think that is my point; if the computer cross-checks the left and
right systems and not the pilots, then who tells the computer to depart
on runway 26 instead of 22?

The computer manages the heading information, not the departure path.
The pilot normally sets a heading bug on the runway heading before
takeoff.

Look, these guys *thought* they were on runway 22, obviously. So if
they'd been in a plane with a regular DG, and realigned their DG to a
"runway heading" of 226 degrees while pointing down 26, what's the
difference?


I think if they had
included a manual check of the headings they might have noticed they
were off by 40 degrees.

Put simply, the headings are never wrong; it's a pointless check to
make. How often do you calibrate the speedometer in your car? Exactly.
It's that reliable.

Believe me, these guys have plenty to check before takeoff, including
programming the FMS for the trip, running checklists, calculating power
settings, etc. One of them is to verify there are no caution flags on
the flight displays -- if there aren't, then the heading is fine. In
many modern jets, the magnetic compass is in a delicate retractable
mechanism in the ceiling, and is only pulled down in the event of a
heading gyro problem.

Yes, there should be a check between the heading *BUG* and the runway
heading, and this might have been missed on the fateful takeoff;
hopefully that's one of the things the data recorder stored.


I believe it is the pilots' responsibility to observe these things and
not the controllers' responsibility to run traffic signals at the
hold-short line.

On that, I absolutely agree. While I'm sure the controller feels guilty
here, he shouldn't. ATC's job is to keep the planes from hitting each
other.

-----Original Message-----
From: Beavis ]
Posted At: Sunday, September 03, 2006 12:15 PM
Posted To: rec.aviation.ifr
Conversation: Can EFIS / EFMS lead to removing basic safety checks?
Subject: Can EFIS / EFMS lead to removing basic safety checks?

....
Look, these guys *thought* they were on runway 22, obviously. So if
they'd been in a plane with a regular DG, and realigned their DG to a
"runway heading" of 226 degrees while pointing down 26, what's the
difference?

Don't overlook the part in the process where the pilot is supposed to
compare the COMPASS heading to the RUNWAY heading before setting the
gyro heading. If they'd done that, the accident might have been
prevented. (I say might because we still don't know if everything
mechanical was functioning properly during the accident.)

....

Yes, there should be a check between the heading *BUG* and the runway
heading, and this might have been missed on the fateful takeoff;
hopefully that's one of the things the data recorder stored.


This goes to the root of my question - has the new technology allowed us
to eliminate these types of checks from the checklist? I believe it may
have, so the only point of this thread is to get us all thinking about
how technology also has a tiny "dark-side" component for which we must
be on guard.