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bakerocb
Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA
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 Posted: Tue Dec 08, 2009 5:10 am Post subject: Who Has Got The Time? |
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12/6/2009 (and again on 11/8/2009)
Hello Fellow Pilots and Builders, The aeroelectric list has been filled
lately with discussions of hardware (meters) that keep track of time. Just
exactly what time is being kept, and for what purpose, is unclear. To shed
some light on the subject let's start by taking a look at what 14 CFR
(FAR's) say about time.
We'll take flight time first, then TIS (Time In Service):
1) Here is how pilot flight time is defined in section 1.1 of the FAR's :
"Flight time means: Pilot time that commences when an aircraft moves under
its own power for the purpose of flight and ends when the aircraft comes to
rest after landing;"
I am not aware of any meter that could keep accurate track of such time.
You'll find many pilots, and airlines, that do not keep track of flight /
pilot time in conformance with this definition. Standard compliance by all
pilots with this definition is unlikely because there is room for
interpretation.
Does "moves under its own power for the purpose of flight" mean the instant
the wheels start to roll as you leave the parking space in order to go
flying? Then that XXX minutes plus that you spend taxiing, doing engine run
up, and waiting for takeoff clearance at the end of the runway, would all be
flight time. Considering the delays involved in operating at some airports
one could become a multi thousand hour flight time pilot very quickly using
that interpretation.
On the other hand one is certainly exercising some very important PIC duties
from the time he leaves the parking space until starting takeoff roll.
Should all of that time be ignored and not recognized in some fashion?
2) Here is how section 1.1 of FAR's defines TIS (Time In Service):
"Time in service, with respect to maintenance time records, means the time
from the moment an aircraft leaves the surface of the earth until it touches
it at the next point of landing."
I suppose that there is hardware that could record this exact time, but it
certainly is not in common use in our category of airplanes.
So let's take a look at three common timing devices: the Hobbs meter, the
mechanical engine RPM based tachometer, and the software associated with
electronic flight instrumentation or engine instrumentation:
A) The Hobbs meter (you can look here for a quick review):
http://en.wikipedia.org/wiki/Hobbs_meter
It doesn't take very long to conclude that "Hobbs meter" has become a very
generic term (like Kleenex or Scotch tape) and that Hobbs meters come in
wide varieties and can be connected to record a wide variety of time. I
guess it is possible for a Hobbs meter to be connected up so that it records
one of the time definitions in the FAR's, but it doesn't seem easy.
B) FAR 91.205 (a) and (b) require an engine tachometer to be installed in
any powered standard category civil aircraft even for day VFR operations. By
far the most common type of tachometer found is the mechanical RPM based
tachometer. Presumably the purpose of the required tachometer is to inform
the pilot of his engine's RPM at any given instant, but somewhere along the
line these tachometers began including the total time of engine operation.
This required someone to decide how to convert instantaneous RPM into total
elapsed time of engine operation.
If, say 2,000 RPM were chosen as the standard mechanical ratio to convert
one minute at this RPM into one minute of elapsed engine operating time then
any engine operation at less than 2,000 RPM generates less than one minute
of elapsed engine operating time and any RPM greater than 2,000 generates
more than one minute of elapsed engine operating time. See some of the
tachometer conversion ratios between RPM and time available here:
http://tghaviation.rtrk.com/?scid=387399&kw=3649251
In any case it does not appear that any mechanical engine tachometer can
generate either of the elapsed times defined by the FAR's.
C) There is such a huge variety of electronic flight and engine
instrumentation systems and their associated software (and the ability of
the operator to modify the software in some cases) that any accurate
comparison of one airplane's / engine's / pilot's time to another airplane's
/ engine's / pilot's time would require some detailed examination of the
processes used to generate that time.
Again the probability that an electronic system would automatically generate
elapsed time in exact compliance with either of the FAR time definitions is
not likely.
So what is the builder / pilot to do? My suggestions:
a) Don't get all wrapped around the axle about generating time. Many people
are not recording flight time or time in service the same way that you are.
b) Pick some hardware and a system of documentation that seems to fit your
needs and go with it.
c) Be consistent in how you do things so that you can view and show the
results with some confidence.
d) Be wary of someone else's time claims, but don't make a big deal of time
unless you are billing by the hour.
'OC' Says: "The best investment we can make is the effort to gather and
understand knowledge."
PS: My choice for my airplane was just to record "Tach time" from my engine
electronic data system for both flight time and TIS. My engine data system
generates zero
tach time anytime the engine RPM is less than 1,500 RPM and constant equal
running time in hours and tenths any time the engine RPM is above 1,500 RPM.
Recording this time for both flight time and TIS short changes me on pilot
flight time since a fair amount of time while practicing landings in the
landing pattern the engine is below 1,500 RPM. On
the other hand it will take much longer elapsed time for my engine to reach
its 2,000 hour TIS to be due for overhaul. This approach greatly simplifies
my bookkeeping.
Back when I was flying rental aircraft I just went with the flow and used
the FBO's Hobbs meter time for flight time -- I paid for it, I should be
able to log it.
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longg(at)pjm.com
Guest
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| Posted: Tue Dec 08, 2009 7:14 am Post subject: Who Has Got The Time? |
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Couple of observations.
1. Regardless of all the wiz bang stuff out there, piloting is still
very much a human engineered activity. The rolling time is what the
pilot enters in his/her logbook and swears to it based on their
signature. If the FAA had the resources (and they don't) they could
easily match Hobbs with book entries to see how much you're cheating.
Until they begin using biometrics which are fed wirelessly to the FBI
database to log activity around and in aircraft, your word is good. I
hope I don't give anyone at the FAA any ideas?
2. Have you ever seen or flown antique aircraft? They don't have spit
for gauges. Ok, one airspeed dial and oil pressure. Again, pilot rules
the books and the sky.
3. Hobbs are useful in rental aircraft for obvious reasons and yes, it's
natural to log from them if you subtract the time the plane wasn't
actually moving under its own power, but idling there trying to warm up,
waiting for you etc. Someday we'll all have remote starters with
automatic shutdown if there is a problem so we can spend more time
drinking coffee by the window and BS'n in the pilot lounge while our
climate controlled cabins warm up.
4. Like many I am more interested in how long to my next service
interval than I am struggling to amass 10,000 hours in my log book.
Accuracy is good at all plateaus. I have two Dynons of which each has
more clocks and time settings than a Swiss train station.
Glenn E. Long
--
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BobsV35B(at)aol.com
Guest
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| Posted: Tue Dec 08, 2009 1:34 pm Post subject: Who Has Got The Time? |
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Good Afternoon OC,
I tried to make the same point when this message first surfaced, but no one seems to care! <G>
Such is life.
Happy Skies,
Old Bob
In a message dated 12/8/2009 7:11:53 A.M. Central Standard Time, bakerocb(at)cox.net writes:
| Quote: | --> AeroElectric-List message posted by: <bakerocb(at)cox.net>
12/6/2009 (and again on 11/8/2009)
Hello Fellow Pilots and Builders, The aeroelectric list has been filled
lately with discussions of hardware (meters) that keep track of time. Just
exactly what time is being kept, and for what purpose, is unclear. To shed
some light on the subject let's start by taking a look at what 14 CFR
(FAR's) say about time.
We'll take flight time first, then TIS (Time In Service):
1) Here is how pilot flight time is defined in section 1.1 of the FAR's :
"Flight time means: Pilot time that commences when an aircraft moves under
its own power for the purpose of flight and ends when the aircraft comes to
rest after landing;"
I am not aware of any meter that could keep accurate track of such time.
You'll find many pilots, and airlines, that do not keep track of flight /
pilot time in conformance with this definition. Standard compliance by all
pilots with this definition is unlikely because there is room for
interpretation.
Does "moves under its own power for the purpose of flight" mean the instant
the wheels start to roll as you leave the parking space in order to go
flying? Then that XXX minutes plus that you spend taxiing, doing engine run
up, and waiting for takeoff clearance at the end of the runway, would all be
flight time. Considering the delays involved in operating at some airports
one could become a multi thousand hour flight time pilot very quickly using
that interpretation.
On the other hand one is certainly exercising some very important PIC duties
from the time he leaves the parking space until starting takeoff roll.
Should all of that time be ignored and not recognized in some fashion?
2) Here is how section 1.1 of FAR's defines TIS (Time In Service):
"Time in service, with respect to maintenance time records, means the time
from the moment an aircraft leaves the surface of the earth until it touches
it at the next point of landing."
I suppose that there is hardware that could record this exact time, but it
certainly is not in common use in our category of airplanes.
So let's take a look at three common timing devices: the Hobbs meter, the
mechanical engine RPM based tachometer, and the software associated with
electronic flight instrumentation or engine instrumentation:
A) The Hobbs meter (you can look here for a quick review):
http://en.wikipedia.org/wiki/Hobbs_meter
It doesn't take very long to conclude that "Hobbs meter" has become a very
generic term (like Kleenex or Scotch tape) and that Hobbs meters come in
wide varieties and can be connected to record a wide variety of time. I
guess it is possible for a Hobbs meter to be connected up so that it records
one of the time definitions in the FAR's, but it doesn't seem easy.
B) FAR 91.205 (a) and (b) require an engine tachometer to be installed in
any powered standard category civil aircraft even for day VFR operations. By
far the most common type of tachometer found is the mechanical RPM based
tachometer. Presumably the purpose of the required tachometer is to inform
the pilot of his engine's RPM at any given instant, but somewhere along the
line these tachometers began including the total time of engine operation.
This required someone to decide how to convert instantaneous RPM into total
elapsed time of engine operation.
If, say 2,000 RPM were chosen as the standard mechanical ratio to convert
one minute at this RPM into one minute of elapsed engine operating time then
any engine operation at less than 2,000 RPM generates less than one minute
of elapsed engine operating time and any RPM greater than 2,000 generates
more than one minute of elapsed engine operating time. See some of the
tachometer conversion ratios between RPM and time available here:
http://tghaviation.rtrk.com/?scid=387399&kw=3649251
In any case it does not appear that any mechanical engine tachometer can
generate either of the elapsed times defined by the FAR's.
C) There is such a huge variety of electronic flight and engine
instrumentation systems and their associated software (and the ability of
the operator to modify the software in some cases) that any accurate
comparison of one airplane's / engine's / pilot's time to another airplane's
/ engine's / pilot's time would require some detailed examination of the
processes used to generate that time.
Again the probability that an electronic system would automatically generate
elapsed time in exact compliance with either of the FAR time definitions is
not likely.
So what is the builder / pilot to do? My suggestions:
a) Don't get all wrapped around the axle about generating time. Many people
are not recording flight time or time in service the same way that you are.
b) Pick some hardware and a system of documentation that seems to fit your
needs and go with it.
c) Be consistent in how you do things so that you can view and show the
results with some confidence.
d) Be wary of someone else's time claims, but don't make a big deal of time
unless you are billing by the hour.
'OC' Says: "The best investment we can make is the effort to gather and
understand knowledge."
PS: My choice for my airplane was just to record "Tach time" from my engine
electronic data system for both flight time and TIS. My engine data system
generates zero
tach time anytime the engine RPM is less than 1,500 RPM and constant equal
running time in hours and tenths any time the engine RPM is above 1,500 RPM.
Recording this time for both flight time and TIS short changes me on pilot
flight time since a fair amount of time while practicing landings in the
landing pattern the engine is below 1,500 RPM. On
the other hand it will take much longer elapsed time for my engine to reach
its 2,000 hour TIS to be due for overhaul. This approach greatly simplifies
my bookkeeping.
Back when I was flying rental aircraft I just went with the flow and used
the FBO's Hobbs meter time for flight time -- I paid for it, I should be
able to log ========================= nbsp; (And Get Some AWESOME FREE to find Gifts tric re b k you for p; -Matt Dralle, List ======================== = Use utilities Day ================================================ - MATRONICS WEB FORUMS ==================================================
|
[quote][b]
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raymondj(at)frontiernet.n
Guest
|
| Posted: Tue Dec 08, 2009 2:35 pm Post subject: Who Has Got The Time? |
|
|
Old Bob and OC,
I read both your posts and appreciate the time spent to write them.
Guess I should have said something. Problem is, then I'd have to write
every day! This list is a great resource and I for one appreciate being
able to lurk while others solve problems and present a variety of
opinions and solutions. I'm sure I'm not the only one. Both of you and
everyone else, PLEASE continue posting, there's a lot of us out here
reading them.
Raymond Julian
Kettle River, MN.
do not archive
BobsV35B(at)aol.com wrote:
| Quote: | Good Afternoon OC,
I tried to make the same point when this message first surfaced, but no
one seems to care! <G>
Such is life.
Happy Skies,
Old Bob
In a message dated 12/8/2009 7:11:53 A.M. Central Standard Time,
bakerocb(at)cox.net writes:
12/6/2009 (and again on 11/8/2009)
Hello Fellow Pilots and Builders, The aeroelectric list has been filled
lately with discussions of hardware (meters) that keep track of
time. Just
exactly what time is being kept, and for what purpose, is unclear.
To shed
some light on the subject let's start by taking a look at what 14 CFR
(FAR's) say about time.
We'll take flight time first, then TIS (Time In Service):
1) Here is how pilot flight time is defined in section 1.1 of the
FAR's :
"Flight time means: Pilot time that commences when an aircraft moves
under
its own power for the purpose of flight and ends when the aircraft
comes to
rest after landing;"
I am not aware of any meter that could keep accurate track of such time.
You'll find many pilots, and airlines, that do not keep track of
flight /
pilot time in conformance with this definition. Standard compliance
by all
pilots with this definition is unlikely because there is room for
interpretation.
Does "moves under its own power for the purpose of flight" mean the
instant
the wheels start to roll as you leave the parking space in order to go
flying? Then that XXX minutes plus that you spend taxiing, doing
engine run
up, and waiting for takeoff clearance at the end of the runway,
would all be
flight time. Considering the delays involved in operating at some
airports
one could become a multi thousand hour flight time pilot very
quickly using
that interpretation.
On the other hand one is certainly exercising some very important
PIC duties
from the time he leaves the parking space until starting takeoff roll.
Should all of that time be ignored and not recognized in some fashion?
2) Here is how section 1.1 of FAR's defines TIS (Time In Service):
"Time in service, with respect to maintenance time records, means
the time
from the moment an aircraft leaves the surface of the earth until it
touches
it at the next point of landing."
I suppose that there is hardware that could record this exact time,
but it
certainly is not in common use in our category of airplanes.
So let's take a look at three common timing devices: the Hobbs
meter, the
mechanical engine RPM based tachometer, and the software associated with
electronic flight instrumentation or engine instrumentation:
A) The Hobbs meter (you can look here for a quick review):
http://en.wikipedia.org/wiki/Hobbs_meter
It doesn't take very long to conclude that "Hobbs meter" has become
a very
generic term (like Kleenex or Scotch tape) and that Hobbs meters come in
wide varieties and can be connected to record a wide variety of time. I
guess it is possible for a Hobbs meter to be connected up so that it
records
one of the time definitions in the FAR's, but it doesn't seem easy.
B) FAR 91.205 (a) and (b) require an engine tachometer to be
installed in
any powered standard category civil aircraft even for day VFR
operations. By
far the most common type of tachometer found is the mechanical RPM based
tachometer. Presumably the purpose of the required tachometer is to
inform
the pilot of his engine's RPM at any given instant, but somewhere
along the
line these tachometers began including the total time of engine
operation.
This required someone to decide how to convert instantaneous RPM
into total
elapsed time of engine operation.
If, say 2,000 RPM were chosen as the standard mechanical ratio to
convert
one minute at this RPM into one minute of elapsed engine operating
time then
any engine operation at less than 2,000 RPM generates less than one
minute
of elapsed engine operating time and any RPM greater than 2,000
generates
more than one minute of elapsed engine operating time. See some of the
tachometer conversion ratios between RPM and time available here:
http://tghaviation.rtrk.com/?scid=387399&kw=3649251
In any case it does not appear that any mechanical engine tachometer can
generate either of the elapsed times defined by the FAR's.
C) There is such a huge variety of electronic flight and engine
instrumentation systems and their associated software (and the
ability of
the operator to modify the software in some cases) that any accurate
comparison of one airplane's / engine's / pilot's time to another
airplane's
/ engine's / pilot's time would require some detailed examination of the
processes used to generate that time.
Again the probability that an electronic system would automatically
generate
elapsed time in exact compliance with either of the FAR time
definitions is
not likely.
So what is the builder / pilot to do? My suggestions:
a) Don't get all wrapped around the axle about generating time. Many
people
are not recording flight time or time in service the same way that
you are.
b) Pick some hardware and a system of documentation that seems to
fit your
needs and go with it.
c) Be consistent in how you do things so that you can view and show the
results with some confidence.
d) Be wary of someone else's time claims, but don't make a big deal
of time
unless you are billing by the hour.
'OC' Says: "The best investment we can make is the effort to gather and
understand knowledge."
PS: My choice for my airplane was just to record "Tach time" from my
engine
electronic data system for both flight time and TIS. My engine data
system
generates zero
tach time anytime the engine RPM is less than 1,500 RPM and constant
equal
running time in hours and tenths any time the engine RPM is above
1,500 RPM.
Recording this time for both flight time and TIS short changes me on
pilot
flight time since a fair amount of time while practicing landings in the
landing pattern the engine is below 1,500 RPM. On
the other hand it will take much longer elapsed time for my engine
to reach
its 2,000 hour TIS to be due for overhaul. This approach greatly
simplifies
my bookkeeping.
Back when I was flying rental aircraft I just went with the flow and
used
the FBO's Hobbs meter time for flight time -- I paid for it, I should be
able to log ========================= nbsp; (And Get Some
AWESOME FREE to find Gifts tric re b k you for p;
-Matt Dralle, List ======================== = Use utilities Day
================================================ -
MATRONICS WEB FORUMS ==================================================
*
*
|
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Tue Dec 08, 2009 3:25 pm Post subject: Who Has Got The Time? |
|
|
At 04:32 PM 12/8/2009, you wrote:
| Quote: |
Old Bob and OC,
I read both your posts and appreciate the time spent to write them.
Guess I should have said something. Problem is, then I'd have to
write every day! This list is a great resource and I for one
appreciate being able to lurk while others solve problems and
present a variety of opinions and solutions. I'm sure I'm not the
only one. Both of you and everyone else, PLEASE continue posting,
there's a lot of us out here reading them.
|
In our own self-interested way, we're participants and
exploiters of what Thomas Friedman has identified as a
constellation of forces that are "flattening the world". See:
http://future.iftf.org/2006/05/thomas_friedman.html
for a brief peek at his thinking.
When EAA was but a gleam in Father Paul's eye,
what we knew and could learn about this hobby we
cherish came through narrow pipes of communication
with barely enough content and clarity to get a
VW powered Headwind flying.
35 years later we find ourselves members of a
world wide community that successfully builds and flies
aircraft that rival (if not surpasses) the cost-
performance figures for the highly touted
production machines. Mr. Friedman has astutely
identified a combination of milestones in our
planet's culture that made this all possible.
Here on the Matronics lists and elsewhere, folks
have an opportunity to tap the time, talents and
resources of thousands of fellow travelers in the
world of OBAM aviation. It grew up not by any
particular grand plan but spontaneously as the
Ten Great Flattenters evolved.
We live in fascinating times of unprecedented
opportunity. We would do well by ourselves and
our children not to screw it up . . . or let anyone
else screw it up either.
Bob . . .
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