Lee Marzke on 29 Sep 2009 19:40:58 -0700

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Re: [PLUG] Software for tracking/calculating/presenting time periods (off-topic)

Greg Helledy wrote:
> We have a project which involves studying fatigue in airline pilots. 
> Unfortunately, many pilots are unable to achieve 8-hour sleep periods, 
> napping when and where possible.  As a result, they experience multiple 
> sleep/wake cycles per day...sometimes several.  With an aircraft having 
> two or three flight crew, and looking back 72 hours before an accident, 
> it can become complex to work with, understand and present to others the 
> time periods involved.
> Is there any specialized software for working with time periods?  What 
> would it be called?  If anyone has experience with this, please let me 
> know (off-list is probably best).
> Thanks,
> Greg
The FAA wants instructors to teach that various 'stresses' affect the pilot,
and the 'gap' between the amount of skill required at a certain time
-vs- the amount
of skill available from the pilot due to stress is a critical factor
that changes during the

The amount of skill required required rises slightly on Take-Off,  and
is then usually very low during
flight with an abrupt peak in preparation for landing and flying the
approach.  So the
gap between skills required and available is smallest,  and therefore
the risk greatest at the end
of a several hour long flight from descent though landing.

The Aeronautical Information Manual (AIM) even has a checklist, IMSAFE,
( Illness, Medication, Stress, Alcohol, Fatigue, Emotion ) for pilots to
themselves for stress prior to flight.

The 'stress' is composed of both long-term and short term.  So things like a
divorce or loss of a job or parent or something would have long term
effects,  while
day to day events and lack of sleep are usually short term stress.

So, since the FAA recognizes all these factors including sleep as
contributing to the
total stress on the pilot,  you may need to evaluate these factors as well.

An especially stressful prior flight with complications due to icing or
equipment failures
with only 8 hours of rest may be legal but leave the pilot with residual
stress for the next flight.

There are of course complex rules on maximum flight time , and pilots
flying 'for hire'
under 14 CFR Part 135.261 generally can only be scheduled for 8 hours of
time with a
mandatory 8 to 10 hour rest.    But the 'rest'  defined here is only
lack of duties with
the operator,  it does not imply or require any 'sleep'.

Due to the Feb 13, 2008 incident of 2 pilots falling asleep on a Go!
airlines flight

see: http://www.ntsb.gov/ntsb/brief.asp?ev_id=20080222X00229&key=1

the FAA is looking into possibly seeking additional medical history or
diagnosis of sleep apnea
in pilots as this condition often leads to problems staying awake during
the day.


Commercial Pilot (CPL)
Flight Instructor (CFI)
Flight Instructor Instrument (CFII)

"Between subtle shading and the absence of light lies the nuance of iqlusion..."  - Kryptos K1

Lee Marzke,  lee@marzke.net   http://marzke.net/lee/
IT Consultant, VMware, VCenter, SAN storage, infrastructure, SW CM
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