Interesting consequence of improperly programming GPS route

[Icebound]

This is from 2003 so it may be old for some of you....

When ferrying from the West Coast to New Zealand, what happens when you
program some key waypoints as Longitude WEST, instead of Longitude EAST in
the vicinity of the dateline.

http://www.tsb.gc.ca/en/publications/reflexions/air/2005/issue_28/air_issue28_sec2.asp#over

[tony roberts]

Kelowna Flightcraft is based on my home field - CYLW - Kelowna BC

Tony
C-GICE

In article >,
"Icebound" > wrote:

> This is from 2003 so it may be old for some of you....
>
> When ferrying from the West Coast to New Zealand, what happens when you
> program some key waypoints as Longitude WEST, instead of Longitude EAST in
> the vicinity of the dateline.
>
> http://www.tsb.gc.ca/en/publications/reflexions/air/2005/issue_28/air_issue28_
> sec2.asp#over




--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE

[Dave S]

So much for requiring crews to know their equipment - if they had not
placed a certain data card in, they would not have had to manually enter
way points... which was one of the first links in the error chain..

Dave

Icebound wrote:
> This is from 2003 so it may be old for some of you....
>
> When ferrying from the West Coast to New Zealand, what happens when you
> program some key waypoints as Longitude WEST, instead of Longitude EAST in
> the vicinity of the dateline.
>
> http://www.tsb.gc.ca/en/publications/reflexions/air/2005/issue_28/air_issue28_sec2.asp#over
>
>
>

[Doug]

You HAVE to have a backup to GPS and USE it. Some sort of non-GPS
system.

[Bob Moore]

"Doug" wrote

> You HAVE to have a backup to GPS and USE it. Some sort of non-GPS
> system.

Doug...recently you are posting a lot about things that you
have no knowledge of.
In this case, you obviously have no knowledge of long-range
oceanic flying.
What would you suggest as a backup in the middle of the
Pacific Ocean?
It was not a GPS problem, it was a programing error that the
pilot did not detect.

Bob Moore
ATP CFI
PanAm (retired)

[Jose]

> What would you suggest as a backup in the middle of the
> Pacific Ocean?

Paper charts, a compass, and dead reckoning.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain."
(chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

[Montblack]

("Doug" wrote)
> You HAVE to have a backup to GPS and USE it. Some sort of non-GPS
> system.


Like the signal from an AM radio station?

One of the more interesting links/stories posted in a while.
<http://www.tsb.gc.ca/en/publications/reflexions/air/2005/issue_28/air_issue28_sec2.asp#over>

(From the report)
The controller was unable to see or identify the aircraft on radar, and
requested that C-GKFJ tune in the low-frequency radio broadcast station 2YA,
frequency 567 kHz, and report the bearing. The crew reported that automatic
direction finding homing was very poor because of thunderstorm activity, but
the most reliable bearing appeared to be astern.


Pilot: We're 80 miles out.
Control: Um, we don't see you on our radar.
Pilot: Yup, we're right here.
Control: No you're not. Tune in to our local Top 40 radio station for a
fix.
Pilot: Hmm. Must be having radio problems, can't seem to pick it up.

Me: That's because you're flying off course to friggn' Antarctica and
don't know it!!!

Glad it all worked out. Whew.


Montblack

[John Gaquin]

"Jose" > wrote in message news:0eCse.1053

>> What would you suggest as a backup in the middle of the
>> Pacific Ocean?
>
> Paper charts, a compass, and dead reckoning.

In a manner of speaking, you're sort of right. I've never flew oceanic with
GPS, only inertial, and we always had to maintain a plot. The best backup
is a disciplined procedure, common sense, a plotting chart, and paying
attention.

Bob probably used similar procedures. During pre-flight setup the PNF (I
think) would read the waypoints from the flight plan, and the PF would enter
them in the keypad. For crosscheck, the PNF would read the waypoints from
the display, with the FE monitoring, and the PF would verify back to the
same printed flightplan.

The inflight loading of downline waypoints was a weaker link, but similar
crosscheck procedures applied.

We would have to verify each waypoint passage, plus do a position check 10
minutes past each waypoint, crosschecking each of the three inertial units.
The weak link with inertials, of course, is that the one driving the
airplane will *always* tell you its right on the money.

The leg that crossed the equator or the 180 meridian was always one of the
downline points, loaded enroute, and a wrong entry would result in a wrong
way turn. The guys in this incident were unfortunate in that their route of
flight was close enough to true south that a reversal error did not result
in too outrageous a turn. When I was flying the So Pacific, it was usually
from Pago or Nadi southwestward toward Sydney or Melbourne, so a missed
longitude entry at the 180 would result in such an obvious wrong turn it
would be immediately noticable.

[Jose]

> The leg that crossed the equator or the 180 meridian was always one of the
> downline points, loaded enroute, and a wrong entry would result in a wrong
> way turn.

By using paper charts, a compass, and dead reckoning as backup, I mean
to actually use a plotter, draw a line on the chart, and measure the
course line. Your paper chart indicates (for example) a desired course
of 170, and your GPS says 190. Something's wrong.

It's like working a calculator without doing a rough calculation in your
head at the same time. Press one wrong button and the calculator will
tell you that you have 143,226.21079 gallons left in your 152. I'm
amazed at how many people would just put that down as the answer these
days, because the calculator said so.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain."
(chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

[John Gaquin]

"Jose" > wrote in message news:IeDse.6352
>
> By using paper charts, a compass, and dead reckoning as backup, I mean to
> actually use a plotter, draw a line on the chart, and measure the course
> line. Your paper chart indicates (for example) a desired course of 170,
> and your GPS says 190. Something's wrong.

Well, I guess I didn't clarify. Oceanic, that's what you do with a plotting
chart. Its a line on paper, but its just a small scale chart so when you
line in the trip pre-flight, you can get the entire trip on one sheet
smaller than an enroute chart. All the DR data that might be needed for
reference...time, distance, course for each leg... is contained on the
computer generated flight plan -- its part of the cross check.
For a local or regional GA flight, your absolutely right -- the GPS data
ought to be periodically back-checked against a chart.

[Nathan Young]

On Thu, 16 Jun 2005 18:33:19 -0400, "Icebound"
> wrote:

>This is from 2003 so it may be old for some of you....
>
>When ferrying from the West Coast to New Zealand, what happens when you
>program some key waypoints as Longitude WEST, instead of Longitude EAST in
>the vicinity of the dateline.
>
>http://www.tsb.gc.ca/en/publications/reflexions/air/2005/issue_28/air_issue28_sec2.asp#over

An interesting read that show the value of MOVING map GPS vs. a
lat/long display and CDI course display.

-Nathan

[Andrew Gideon]

Jose wrote:

> PressÂ*oneÂ*wrongÂ*buttonÂ*andÂ*theÂ*calculatorÂ*w ill
> tell you that you have 143,226.21079 gallons left in your 152.Â*Â*I'm
> amazed at how many people would just put that down as the answer these
> days, because the calculator said so.

Nice long-range tanks you've there.

- Andrew

[Jose]

> All the DR data that might be needed for
> reference...time, distance, course for each leg... is contained on the
> computer generated flight plan

.... and if the computer's wrong, do you draw the wrong line on the
chart? We might be saying the same thing here, but I am advocating
drawing the line with =no= computer help whatsoever, and using a plastic
plotter to figure the course lines. This would be totally independent
of the computer, and then when the computer does its thing, you have a
reality check.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain."
(chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

[Jose]

> he instructor however had supposedly bugged the calculators so that on
> certain problems they gave impossible answers, off by orders of
> magnitude; and in the grading gave lots of bonus points to those
> students who noticed and said something about it.
>
> Probably an urban legend

I hope not!

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain."
(chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

[Montblack]

("Andrew Gideon" wrote)
>> Press one wrong button and the calculator will
>> tell you that you have 143,226.21079 gallons left in your 152. I'm
>> amazed at how many people would just put that down as the answer these
>> days, because the calculator said so.

> Nice long-range tanks you've there.


I hope the calculator person noticed that big number and figured "something"
wasn't right.

143,226.21079 is probably pounds, not gallons. Divide by 6 for gallons
(23,871) ...which is almost 1 gallon per mile at the equator :-)

Next: Weight & balance.


Montblack

[Jack Davis]

On Fri, 17 Jun 2005 22:42:36 GMT, Jose >
wrote:

>... and if the computer's wrong, do you draw the wrong line on the
>chart? We might be saying the same thing here, but I am advocating
>drawing the line with =no= computer help whatsoever, and using a plastic
>plotter to figure the course lines. This would be totally independent
>of the computer, and then when the computer does its thing, you have a
>reality check.

Drawing the line on a plotting chart is done with =no= computer help,
which is precisely why the chart is a valid cross check, along with
the "raw data" contained within the Flight Plan.

>Jose

-Jack Davis
B737

-J. David
B737

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[John Gaquin]

"Jose" > wrote in message news:wlIse.2580
>
> ... and if the computer's wrong, do you draw the wrong line on the chart?
> We might be saying the same thing here, but I am advocating drawing the
> line with =no= computer help whatsoever,

That's actually a little impractical where oceanic crossings are concerned.
Routes are assigned based on several factors, and you only get the
information when the flight plan is generated. The waypoints are merely
Lat/Long points. You could draw the whole thing by hand, but you'd be
starting with computer generated data, anyway.

What you're suggesting is actually covered by quickly pencilling the
assigned route onto the plotting chart, and applying the smell test.

[Rich Lemert]

AES wrote:
> In article >,
> Jose > wrote:
>
>
>>It's like working a calculator without doing a rough calculation in your
>>head at the same time. Press one wrong button and the calculator will
>>tell you that you have 143,226.21079 gallons left in your 152. I'm
>>amazed at how many people would just put that down as the answer these
>>days, because the calculator said so.
>>
>
>
> Heard a tale once of a physics prof who allowed use of programmable
> calculators during the final exam, but only ones supplied by him, "so
> that no one could program in any unauthorized stuff in advance".
>
> The instructor however had supposedly bugged the calculators so that on
> certain problems they gave impossible answers, off by orders of
> magnitude; and in the grading gave lots of bonus points to those
> students who noticed and said something about it.
>
> Probably an urban legend -- but an instructive idea nonetheless.

The college I went to (Colorado School of Mines) has a top-rate
geophysics program. One of the lab courses in the program supposedly
(I wasn't in the program) starts out by having you use sound
transducers and an oscilliscope to determine the length of a steel
bar. If you don't get the right answer, you have to redo the experiment.

The thing students aren't told is that the oscilliscope has had a 2-3%
error built into it. The purpose of the lab is not to learn any
geophysical facts, but to learn that you always need to calibrate
your instruments.