Accurate Timepiece

[Spiral_Diver]

Given the ability of getting the time from a GPS device does this meet the requirements for CAO 20.18?
Cheers,
SD

[dogcharlietree]

There was a time many, many, years ago when a DIGITAL watch did not cover the CAO requirement. :ugh:

[VH-XXX]

As long as the GPS device displays the time in seconds, then it would comply. In theory it will be more accurate than a digital watch as it's running directly off GMT and updated frequently via the satellites.

[tmpffisch]

And I imagine as long as the clock continues to work if you lose GPS signal.

[VH-XXX]

The clock will continue, yes.

There you have it, you now don't need to wear a watch when you fly. That will save you $5.

[43Inches]

The GPS clock does operate but if the signal loss is at power up it may just indicate the last shut down time, that is it needs the satellite to update the clock as well. I have noticed this on some GPS units, they will start counting from the previous shut down time until satellites aquired.

The watch issue will depend on the category of operation. If its a charter or RPT than a clock fitted to the aircraft is required, whether the pilot caries one does not matter. However if the clock in the aircraft does fail then it would be up to the MEL whether or not you could use the GPS clock etc...

[compressor stall]

In theory it will be more accurate than a digital watch as it's running directly off GMT and updated frequently via the satellites.

My understanding is that they run off Atomic clocks. Additionally, every few years as the earth slows in its rotation, there is a leap second inserted at year's end. The GPS clocks do NOT account for this, and consequently the GPS time is now ahead of GMT by a few seconds (I have lost track of exactly how many).

[Capt Fathom]

This was a popular choice in the past!

http://www.mouse-watches.com/images/mickey-mouse-watch-featured.jpg

[Spiral_Diver]

Thanks guys,

Was just curious as it was indicated to me that it was sufficient.

Although not very useful for RNAV holding pattern timing :D (depending on the actual unit)

Cheers

[VH-XXX]

Does a $4.95 Kmart clock run off GMT then?

For 99% of pilots who don't call the Telstra time every day to synchronise their watches, I think the GPS would be fine :)

[ZEEBEE]

My understanding is that they run off Atomic clocks. Additionally, every few years as the earth slows in its rotation, there is a leap second inserted at year's end. The GPS clocks do NOT account for this, and consequently the GPS time is now ahead of GMT by a few seconds (I have lost track of exactly how many).

Sort of true, but not relevant to consumer GPS Receivers.

The GPS Time is corrected back to UTC so you don't have to worry about the correction factor unless you download the raw GPS data.
In which case you'll first have to do some math because it's reported in seconds elapsed after midnight 5th jan 1980 plus the accumulated leap seconds.

[Kelly Slater]

The requirement was for an accurate timepiece with a sweep second hand, making digital clocks unacceptable. The requirement may have changed but I'm not interested enough to look right now.

[Jazzy78910]

Checking CASA, it states "an accurate timepiece indicating hours, minutes and seconds" It no longer indicates analogue or digital.

With regards to synchronizing watches regularly:
If you own a PC with either Win-XP or Vista and are also on the internet, you can double-click the time in the bottom right of the screen, then click on "Internet Time". This will display the options for synchronizing your PC with an insanely accurate Time Keeping Server online. Once you've synced your PC, you can sync your watch with it to the second! No more calls to telstra!

[Darkrampage]

Does this apply to digital watches with the seconds displayed?

Ie. it has to be a physical sweep second hand?

[VH-XXX]

Jazzy has got it in one. Digital is acceptable these days!

[the wizard of auz]

Hell, if my $3 sevo watch is in the same hour, I'm happy. I can't count anyway, so I guess at ETA, circuit at time. :E

[Peter Fanelli]

Geeeeez what is it with you technology freaks.
I've had my old watch for years and it was just fine for use when I was flying.
Bloody young whippersnappers!

Here's mine.
http://i155.photobucket.com/albums/s295/bigt57/sundial.jpg

[FourBalls]

Crikey Pete! Does it work at any time other than midday when the sun is high enough to shine through the arm hair? :ouch:

[ForkTailedDrKiller]

I haven't worn a watch for years. A mobile phone is the pocket watch of the noughties!

Dr :8

[apache]

Pete... does that thing work when in IMC? or at night?

My understanding is that GPS, for every second of error from the satellites equates to about 200nm error on the ground/in the air.

11% .... where are you????????????

besides..... "accurate timepiece displaying hours,minutes AND seconds is a tax deduction EVERY YEAR!!!! just call it a"NDB timer", not a watch, and there are no problems!.... besides... you ONLY need a receipt IF you get audited, or it costs more than xxx dollars!

[freshy1234]

Sort of true, but not relevant to consumer GPS Receivers.
I thought that it was the receiver that calculated position.
Making accurate time very important to the device...

[ZEEBEE]

I thought that it was the receiver that calculated position.
Making accurate time very important to the device...

True, the receiver does calculate the position, but the timing necessary for that is embedded in the PSN code that is part of the signal stream.
That comes from the individual satellite rubidium clock that is uddated periodically by the Ground stations that are locked to a Hydrogen maser standard at Goddard or somewhere like that.

[BPH63]

i went and bought my first watch in 20 years - from Kmart -$19.95 (couldn't find any of those $5 ones - do they exist?) after being told by instructor mobile phone not good enough. Bloody aviation costs! :mad:

[Towering Q]

This guy has the right idea.:cool:


http://i88.photobucket.com/albums/k176/towering_q/flavor-flav-red-carpet.jpg

[apache]

Actually, that guy has NO IDEA!