night definition

[air med]

Hello All
Can someone give a answer to what is night, as have been told by CASA there is no definition.

EG Day is from 0001 to 2359.
But what is night.
Have fun

[Andy_RR]

Day, as in Day VFR, is surely between first light and last light (or whatever the flaming terminology is in use in Aus). Night must be the complimentary set of day, surely?

[kiwi chick]

What? ?

:confused:

Has someone stolen the sammies from your picnic basket? :bored:

[Desert Duck]

CASA on the website under info for logbooks (or AIC H10/99, if it is still current)

" 'night flying' - means the flight time which accrues during the period between the end of evening civil twilight and the beginning of morning civil twilight."

I am not sure how particular with a definition of night you wish to be?

[Wanderin_dave]

Well if 0001 to 2359 is day then the remainder of the 24hrs must be night....... so 0000. No wonder i'm tired :ok:

[Atlas Shrugged]

Oh for **** sake! :ugh::ugh:

It's in the AIP!

DAY: That period of time from the beginning of morning civil twilight to the end of evening civil twilight
NIGHT: That period of time between the end of evening civil twilight to the beginning of morning civil twilight

http://www.airservicesaustralia.com/publications/current/aip/gen/2_2_1-22.pdf

Now, pay attention - civil twilight is an astronomical event which begins in the MORNING when the center of the Sun is less than 6 degrees below the horizon (the point of civil dawn), and ends at sunrise. Evening civil twilight begins at sunset and ends when the center of the Sun is more than 6 degrees below the horizon (the point of civil dusk).
Sunrise is the instant in the morning under ideal meteorological conditions, with standard refraction of the sun's rays, when the upper edge of the sun's disk is coincident with an ideal horizon. Sunset is the instant in the evening under ideal meteorological conditions, with standard refraction of the sun's rays, when the upper edge of the sun's disk is coincident with an ideal horizon.

Sunrise and sunset both are completley different times to civil twilight.
There is also nautical twilight and astronomical twilight but they have noting to do with the AUS AIP definition.

Here's what I use at work:

http://www.ga.gov.au/geodesy/astro/sunrise.jsp

And here's a list of definitions:

http://www.ga.gov.au/geodesy/astro/definiti.jsp#SUN

Here it is for today:

SYDNEY (KINGSFORD-SMITH) AIRPORT Lat=-33°56'00" Long=+151°10'00"
TIMES OF CIVIL TWILIGHT
(for ideal horizon & meteorological conditions)
Time zone: +10.00 hours
20/09/2007 Rise 0524 Set 1815

Tomorrow will be different.

[Andy_RR]

Tomorrow will be different.

Yes, tomorrow there will be no dumb questions. We will all be studying our AIP instead of reading PPRuNe... :}

[air med]

CASA cant give a answer of the question, they have an answer for day but not for night, you will go black and blue trying to find anything but not there

[air med]

Atlas.
You are correct in what you state, but if a day is stated to be from 0001 to 2359, then how do you determine night, there is no answer

[The Strez]

Geez air med you were on to this quick!

Guys, what air med is referring to, isnt what goes in the log book.

What he (and a few of us) is trying to find out is with regards to rostering. Certain operators, such as the RFDS, require guys to do shift work, ie day and night. Day shift generally being 0600 - 1800 and night 1800 - 0600.

Under the CAO 48 dispo, required time off between shifts is often referenced to local nights eg:
" In any consecutive 14 nights, a flight crew member shall have either -
a. 2 periods free of all duty, each of which is a minimum of 36 consecutive hours duration and comprising 2 local nights; or
b. 1 period free of all duty, comprising a minimum of 60 consecutive hours and three consecutive nights;"

Most required time off mentions the period 2200 - 0600 but nowhere is this defined as "night", especially "local night".

Now when a "day" is referred to as "the period between local midnight and the subsequent local midnight", then what, as air med meant when he started this topic, is a night?

[Howard Hughes]

Astronomical night occurs when the sun is 18 degrees below the horizon...:8
as have been told by CASA there is no definition.
:ugh:

[air med]

this has got them going

[Atlas Shrugged]

You are correct in what you state, but if a day is stated to be from 0001 to 2359, then how do you determine night, there is no answer

Where is it stated (other than on here) that day is from 0001 to 2359?

Day is that period of time from the beginning of morning civil twilight to the end of evening civil twilight.

Civil twilight begins in the morning at civil dawn and ends at sunrise.

Evening civil twilight begins at sunset and ends at dusk.

That between civil dawn and civil dusk is day. The rest (apart from the twilight) is night.

For our purposes, it is defined in the AIP however that definition is reliant upon another definition - see above

What you are describing (ie: from 0001 to 2359) is merely a measurement of time being a period of 24 hours which corresponds to a rotation of the earth on its axis. That's it, nothing else.

The Oxford Dictionary which is used by the Australian courts offers a definition, amongst others, of "day" as the time between sunrise and sunset,
which in turn is defined as that period between dawn and dusk.

Just land 10 mins before last light and have a beer! ;)

[Atlas Shrugged]

HH,

Not quite. Astronomical twilight is the time when the center of the sun is more than 12 degrees below the ideal horizon but not more than 18 degrees - for the measurement an "ideal horizon" 90 degrees from the zenith is used.

The time it takes the sun to travel that 6 degrees is astronomical twilight.

The levels (or altitudes, if you like) of the sun below the horizon are "true geometric" altitudes which means we ignore a number of things but mainly refraction by the atmosphere having an effect on the observed position of the sun.

PS: I just re-read you post and realised you said "astronomical night" rather than "astronomical twilight"

"Astronomical night" does not exist. There ain't no such thing

[bushy]

Are CASA making rubbery rules that no-one can understand again????? That they cannot define themselves???
I remember asking a senior CASA bloke to clarify something, and he said "legal opinion is divided about that"
If the rules are not clear and understandable, they are not complying with the directions they recieved from the minister.

[Peter Fanelli]

Where is it stated (other than on here) that day is from 0001 to 2359?


And what are the other two minutes of the 24 hour period called?

:hmm: :ugh:

[Atlas Shrugged]

Bushy,
I don't really think they are. At the end of the day, it will be decided by the courts. CASA only make the rules. If a precedent has already been set then that's it. If no precedent, then the matter under review will set one, which will become the basis of future deliberations. The problem is that after countless centuries of law, there are so many of them and the courts continue inventing (oops, should have said evolving :rolleyes:) new and interesting laws every day - to suit who is anyone's guess ??

[Howard Hughes]

"Astronomical night" does not exist. There ain't no such thing
So what is it when atronomical twilight ends? Day?;)

PS: I can find many references to atronomical night on google, sadly none from a reputable source...:{

[Creampuff]

Oh dear

The education system obviously no longer imparts upon school students, or at least upon some of the denizens of the aviation industry, the difference between:

‘day’ as an environmental phenomenon (e.g. ‘Make sure you only fly when it’s day, Philomena’)

and

‘day’ as a period of time (e.g. ‘Take your medicine at least 3 times a day, Philomena’).

[Capt Wally]

...........remember boys & girls..........there are no dumb questions in aviation !:):)

Capt Wally:)

[AerocatS2A]

Air Med, do you want a definition of "night" or "a night"? They are different. Night is the period of time that is not day, day is defined by other posters above.

"A night" or "a local night", if not defined by CASA, should be defined in your ops manual.

[compressor stall]

Quote:
Where is it stated (other than on here) that day is from 0001 to 2359?
And what are the other two minutes of the 24 hour period called?


Um, I make it only one missing minute there - that of 0000 :}:p

[Capt Claret]

Forgive me Stallie but I do disagree.
2359 to 0000 = 1 minute.
0000 to 0001 = 1 minute
1 minute + 1 minute = 2 minute.


Me thinks the question might be reference night ops? If so, the CAO 48 exemption I work under defines Night Ops as (something like) more than 30 minutes duty between 2200 and 0530.

[AerocatS2A]

In the context of measuring a day from 0001 to 2359, I take it to mean the end of 2359. From the end of 2359 to the start of 0001 is one minute.

[Desert Duck]

Airmed

If your company fatigue management manual or flight and duty exemption does not specify night then it should.

My outfit when talking about nights free of duty specify
'shall start no later than 2200 hours local time and finish not earlier than 0600 hours'

Perhaps you could be a little more specific about what you really want - or is it just an innocent question ?

[Peter Fanelli]

I'm beginning to suspect that air med is nothing but a bloody trouble maker.

Well done. :E

[The Strez]

With respect to the company that both Air Med and I work for, they have approached CASA for a definition of "night" to ammend / clarify the ops manual but none of the FOI's can either come to an agreement or give a reasonable definition of one. And they have approved the exemption to which we operate.

[AerocatS2A]

What's the context?

Our ops manual has a "local night" defined as being from 2200 to 0600 and is generally used for the purpose of defining days off (a day off must encompass two local nights) or for relaxing time free of duty requirements. Time free of duty can be less than 10 hours in particular circumstances including the time free of duty encompassing a local night.

Then we have "late night ops" which are from (I think, going by memory) 0000 to 0500. Flying between those hours restricts the amount of duty you can do and sometimes increases the time free of duty requirements.

I think your company simply has to come up with some numbers that are agreeable to the employees and submit the change to CASA for approval.

[air med]

Guys believe me not trying to stir up crap here.
As the Strez has said, we had a problem with duty calulations, which had to be clarified, so we asked 3 FOI to give us the answer,only to be told, that there is no definition of "Night".
The 2200 to 0600 is a rest period quote but it does not define the Night.
Casa say that a day is from 0001 to 2359, thats it.But if you then ask well when does a night start for Flight and Duty hours, they dont have a answer.
At the moment we are awaiting for Canberra to tell us, but have been waiting for a few months now.
The reason I asked the question is that maybe there is something that the CASA guys are missing.
All of you have the given what I would have thought as the right answers, but this is not what CASA are saying.
Chat with the Perth FOI and they will in form you that it is on going

[air med]

DD.
Just a innocent question.

[Chimbu chuckles]

The reason I asked the question is that maybe there is something that the CASA guys are missing

Yes...there is something they're missing:hmm:

All of you have the given what I would have thought as the right answers, but this is not what CASA are saying.

Easy...YOU tell them what the definition will be in your operation..2200-0600 sounds like a great start.

Sit down and in the glossary of terms/definitions section at the front of your manual write;

"For the purposes of this document, and any other controlled documents that the company will, from time to time, append, issue or make available to staff the term 'night', whether 'local' or otherwise, will be understood to encompass the period of 8 consecutive hours between 2200LT and 0600LT."

I have seen definitions that say 'any 6 consecutive hours between 2200LT and 0600LT within a time zone 2 hours wide'...but that is just taking the piss:ok:

From that (approved) definition all things flow in an easily understood manner...which makes CASA's reluctance even more sickening.

My experience of CASA...consistantly over decades...is that they will avoid, whenever possible (always), giving you a concise answer...they WILL NOT risk being held accountable...but they will approve whatever reasonable concise answers you give them.

Honestly...deliver unto them a fait accompli and then move on with your life.:ok:

[Desert Duck]

Chimbu

I agree

[desert_rat]

The problem occurs when for example you are rostered on for night shift say on call form Wed night 1800 and than get called out at 0100 on Thursday, does the hours become part of the Wed rostered period or Thurs rostered period and depending on the case when you are running out of Duty hours in 14 days time do you recieve those hours back on the Wed or the thurs or do you click the next day to see how many hours you get back after midnight. Things can get worse, are you doing 90 hours of duty in 14 consecutive days or 100 hours, this problem only applies to a small group of people that are affected by a stanby call out rostering system. Perhaps the days and nights need to be replaced by the word rostered shift, ie not person can work more than 90 hours over 10 rostered shifts in a 14 day (0000-2359.9) there only lost 0.1 of a minute or 6secs. Airmed doesn't affect you anyway you are always overnighting in Perth.....:p

[Flight Me]

eh night time is that red tin time eh and the day time me under that ol tree eh. Sometimes me see the stars in the day time, that after me get knocked out eh.

[desert_rat]

Flight Me, yeah dat be da time turn up da musac party time wot no more red cans where dat bottle a Port

[air med]

desert_rat
Only looking your interests, trying to get you home to party.
:)

[desert_rat]

proposes that the loss of 6 secs a day is why we have a leap year every 4 years.

Air med you know I don't Party.......Now where did I put that Red Can

[air med]

Desert_ rat.
yes you dont party, but you can give a bottle of scotch a good nudge.

[Capt Claret]

Desert Rat

Years ago when flying Airmed I created a spreadsheet in Excel for my F&D. I had two lines per day. This way I could show duty starting at whatever time (0100in your example) and finishing at the appropriate time. When on call again, usually from 1800, the next duty would be entered and the appropriate rest period was obvious to see.

Does that sort of thing solve your dilemma? If so, I might have a copy of the spreadsheet still available.

[air med]

I will try and copy the section that casa are having problems with for all to see

[air med]

had a visit from Terry Robinson from CASA, after a number of pilots contacted him regarding DFT8.
While our session was informative, it would appear that a number of members in the local CASA office have a different interpretation of late night operations compared to the industry and how RFDS has been working the exemption since its promulgation.
The example presented to CASA is outline in the table below
Table 1:
Mon Tue Wed Thu Fri Sat Sun
0700-1700 OFF OFF 1800-0600 1800-0400 2000-0200
RFDS/DFT8 calculation: you have completed 3 Late Night Ops, total hours 38 with 2 hrs remaining for Sun.
CASA calculation: you have completed 3 late night ops, total hours 28, 12 remaining for Sun. Monday (0700-1700) was not included in the calculation.
We discussed the date/day change from Sun to Mon at Midnight and the hours calculation it presented, giving back the pilot 10 hrs, so in theory he actually had 12 hrs available from 2200 Sunday, he did agreed it was a legal calculation based on the definition of a day.
I advised Terry that RFDS WO will continue to calculate late night operations as per the example above and the RFDS/DFT8 calculation.
Terry believed the wording of the late night operations may be causing some confusion and said he would seek a definition of what constitutes a night from the CASA legal department.
At that point the meeting terminated.

Version 8.5 has been installed on the server, this will cure a number of problems. I also spoke to the Software programmer regarding entering duty times, he strongly reiterated, that duty times should not be entered up to midnight and then from midnight as per table 2 below.
This method incorrectly calculated an additional late night operation
Table 2:
Thu Fri
1800 2359 0000 0600

Times should be entered as per table 3,
Table 3:
Thu Fri
1800 0600
The program correctly apportions the duty time to each day.

Table 4: If you commenced duty after midnight on Thursdays night shift the following applies;
(1) you enter your hours in Duty time 1 box on Friday
(2) If you get called out for Fridays night shift, you then fill out duty time 2 box

The program correctly calculates duty time and the number of late night operations
Thu Fri
Duty time 1 0010 1000
Duty time 2 2100 0600