Window of Circadian Low

  • Thread starter Thread starter Hans Knudsen
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Hans Knudsen

Hello
The flight department at my place of work has asked me to set up something in Excel to help them manage duty and rest scheduling for
pilots. The rules are (to me) very complex and I need some help just to get started.

Window of Circadian Low (WOCL) means the hours between 0200 and 0600 for an individual's normal day-wake/night-sleep schedule
........

There are different guidelines for rest periods depending on whether operations have been either outside or during the Window of
Circadian Low.

As the very first I hope for some help to determine if some trip has been "in touch with" WOCL that is if some or all of the flight
time has been during WOCL

Example:
Departure: 04-10-04 22:00 (4th October 2004 at 10:00 PM)
Arrival: 05-10-04 07:00 (5th October 2004 at 7:00 AM)

Arrival time will always be either on the same day as the day of departure or the next day.

The formula should just return TRUE or FALSE.

I am not sure Excel is the best tool for this task, but I don't have and I won't get anything better.

Regards
Hans Knudsen
 
Hello Hans,
Please verify:
1. Dep/Arr times always in same time zone
2. If 1 is not true, is Dep or Arr time zone the base
time for WOCL (I would assume Dep time zone)? Also, if
there is a time zone difference, how do you track that?

If 1 is true, the logic is pretty simple. Will follow
your reply with a proposed equation.
-----Original Message-----
Hello
The flight department at my place of work has asked me to
Click to expand...
set up something in Excel to help them manage duty and
rest scheduling for
pilots. The rules are (to me) very complex and I need some help just to get started.

Window of Circadian Low (WOCL) means the hours between
Click to expand...
0200 and 0600 for an individual's normal day-wake/night-
sleep schedule
........

There are different guidelines for rest periods depending
Click to expand...
on whether operations have been either outside or during
the Window of
Circadian Low.

As the very first I hope for some help to determine if
Click to expand...
some trip has been "in touch with" WOCL that is if some or
all of the flight
time has been during WOCL

Example:
Departure: 04-10-04 22:00 (4th October 2004 at 10:00 PM)
Arrival: 05-10-04 07:00 (5th October 2004 at 7:00 AM)

Arrival time will always be either on the same day as the
Click to expand...
day of departure or the next day.
The formula should just return TRUE or FALSE.

I am not sure Excel is the best tool for this task, but I
Click to expand...
don't have and I won't get anything better.
 
Looking ahead to 1 (below) being true, try:

=IF(DAY(D16)=DAY(D17),IF(OR(HOUR(D16)>=6,HOUR(D17)
<2),"no time in WOCL","some time in WOCL"),IF(AND(HOUR(D16)
=6,HOUR(D17)<2),"no time in WOCL","some time in WOCL"))
Click to expand...

where D16 contains date and time of departure, and D17
contains date and time of arrival. I might suggest
modification(s) to test for arrival time being later than
departure time (trap those pesky input errors!) and/or a
calculation of the length of the flight.

If 1 (below) is not true, then the calculation will
have to correct for time zone differences, a LITTLE more
complicated, but can be done.

Hope this helps.
 
Hi again,
I had posted a follow-up solution, but my response no
longer appears in the thread - here's a repeat:
If 1 (below) is true, try:

=IF(D17<D16,"Error - Arr time less than Dep time",IF(DAY
(D16)=DAY(D17),IF(OR(HOUR(D16)>=6,HOUR(D17)<2),"no time in
WOCL","some time in WOCL"),IF(AND(HOUR(D16)>=6,HOUR(D17)
<2),"no time in WOCL","some time in WOCL")))

where D16 contains departure date and time, D17
contains arrival date and time.

The very first part of the IF contains a logic error
trap to catch those instances where arrival time is
inadvertantly input as being earlier than departure time
(date error, clock error, AM/PM error). If there are
time zone issues, then the equation will have to change to
catch those, but it can be done.

Hope this helps.
 
Thank you!
I will take a closer look at your formula. Until further I will only consider case 1 (Dep/Arr times in same time zone). I might like
to come back with further questions later on and hope you will still be there.

Regards
Hans
 
Hans,
You're welcome. I will track this thread for a few days.
If you lose the thread and want to discuss this further,
I'd be interested. Post with subject "HCJ - more WOCL
issues".

I can imagine you'd like to compute how much time was
spent in the WOCL for TRUE cases, among other
possibilities. Thinking ahead, are there rules about how
much total flight time is allowed in a given span? For
example, is it possible for a flight to begin within a
WOCL and end in the next WOCL?

There may be better software for this application, but I'm
not in aviation so am unfamiliar with possibilities.
However, in my opinion, if your operation has strict rules
about flying/rest hours and is subject to penalties if
they are violated, an investment in commercial software
tailored to aviation flight logging might be worth
considering.

Regards, Howard (US Central Time)

-----Original Message-----
Thank you!
I will take a closer look at your formula. Until further
Click to expand...
I will only consider case 1 (Dep/Arr times in same time
zone). I might like
to come back with further questions later on and hope you will still be there.

Regards
Hans

<[email protected]> skrev i en
Click to expand...
meddelelse news:[email protected]...
 
Yor formula works absolutely perfect. Thank you.
As you expressed an interest in discussing this further I will not miss that chance.

First of all - I too am not in aviation, I am in Finance at my place of work and I often try to help colleagues in other departments
with Excel related questions, and that's also what I am trying to do here. So "Window of Circadian Low" and other aviation concepts
are completely new to me.

Yes you are certainly right that there may be better software, but I am not in a position to decide on buying such software.

As far as I have understood it our flight department (3 aircrafts and 7 pilots) has no strict rules about flying/rest hours, but has
voluntarily chosen to adhere to the rules described among other places here:

http://humanfactors.arc.nasa.gov/zteam/PDF_pubs/FSF_corp_dutyrest.pdf

If, after having seen this document, you decide that you are no longer interested, then I will understand :-)

What I have promised our flight department is to see if I can set up something in Excel which can help them manage flying and rest
hours in accordance with the guidelines described in Table 1 and Table 2 (page 5 and 6) of the above document. Table 1 is for
operations outside "Window of Circadian Low" and Table 2 is for operations during the "Window of Circadian Low".

Another link which might be of interest.
http://cf.alpa.org/internet/projects/ftdt/principles/8hrs.html

I would appreciate any help whatsoever.

Regards
Hans
 
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