Hobbs

Gig 601XL Builder wrote:

Which brings up a very interesting question. I'm building a plane that will
be licensed as an Experimental. Once inspected I'll have to test fly for 40
hours for phase one. If I use a Hobbs as the official time and hook it to
the MS I would probably end up reducing the phase one time considerably.


That is interesting. Does the FAA specify tach vs. oil pressure Hobbs,
vs. electric Hobbs?

Think of how many pilot logbooks are based on electric Hobbs time.

B A R R Y wrote:
Gig 601XL Builder wrote:

Which brings up a very interesting question. I'm building a plane
that will be licensed as an Experimental. Once inspected I'll have
to test fly for 40 hours for phase one. If I use a Hobbs as the
official time and hook it to the MS I would probably end up reducing
the phase one time considerably.

That is interesting. Does the FAA specify tach vs. oil pressure
Hobbs, vs. electric Hobbs?

Think of how many pilot logbooks are based on electric Hobbs time.

I can't think of a single second in my log book that isn't based on Hobbs
time. Some were oil pressure activated but the vast majority were MS
activated.

Gig 601XL Builder wrote:

I can't think of a single second in my log book that isn't based on Hobbs
time. Some were oil pressure activated but the vast majority were MS
activated.

Me too.

B A R R Y wrote:
Gig 601XL Builder wrote:


Which brings up a very interesting question. I'm building a plane that
will be licensed as an Experimental. Once inspected I'll have to test
fly for 40 hours for phase one. If I use a Hobbs as the official time
and hook it to the MS I would probably end up reducing the phase one
time considerably.


That is interesting. Does the FAA specify tach vs. oil pressure Hobbs,
vs. electric Hobbs?

Think of how many pilot logbooks are based on electric Hobbs time.


If I understand, the stipulated value is "flight time". Not ground time.
Not hobbs time, not engine time.. nor master switch time.

But the feds are also taking it on the honor system that you will not
tie it down and let it run up 40 (or 25) hours on the ground, then sign
off phase 1.

My particular install has an engine monitor that records hobbs time,
when the engine is operating, and flight time, when the ASI is above 30 mph.

Dave

"Dave S" wrote in message
nk.net...
B A R R Y wrote:
Gig 601XL Builder wrote:


Which brings up a very interesting question. I'm building a plane that
will be licensed as an Experimental. Once inspected I'll have to test
fly for 40 hours for phase one. If I use a Hobbs as the official time
and hook it to the MS I would probably end up reducing the phase one
time considerably.


That is interesting. Does the FAA specify tach vs. oil pressure Hobbs,
vs. electric Hobbs?

Think of how many pilot logbooks are based on electric Hobbs time.


If I understand, the stipulated value is "flight time". Not ground time.
Not hobbs time, not engine time.. nor master switch time.

But the feds are also taking it on the honor system that you will not tie
it down and let it run up 40 (or 25) hours on the ground, then sign off
phase 1.

My particular install has an engine monitor that records hobbs time, when
the engine is operating, and flight time, when the ASI is above 30 mph.

Dave

There's flight time and then there's PIC time. I log PIC time from engine
start to engine shutdown. I know some that log PIC time only when they're
moving. I know a guy who logs PIC time from ropes off to ropes on.

I log flight time from wheels off to wheels on (or the amphib equivilant).
None of that is based on tach time. I have no use for Hobbs time.

My personal checklist has Tach at S/U, Start time, T/O time, T/D time,
Shutdown time, Tach at S/D.

--
-------------------------------
Travis
Lake N3094P
PWK

Travis Marlatte wrote:

There's flight time and then there's PIC time.

My answer is regarding a very specific question. The question pertains
to experimental aicraft undergoing phase 1 flight test. The FAA dictates
a minimum of 40 hours flight time prior to removal of phase 1
limitations, or in the case of an engine/prop combination that is
already certified for use in a "certified"/non experimental aircraft, 25
hours.

The airplane is not capable of logging PIC time. The pilot may be. But
I've yet to see a plane log it.

Running the engine on the ground for 40 hours may give you 40 hrs hobbs
time but 0 hours flight time. Having the hobbs wired to the master could
also pad the time significantly, without the engine even running.

Someone could sign off the books and nobody would be the wiser.. but
you'd only be cheating yourself, if you took your family/friends up in a
plane that wasn't shaken down properly.

"Dave S" wrote

Running the engine on the ground for 40 hours may give you 40 hrs hobbs
time but 0 hours flight time. Having the hobbs wired to the master could
also pad the time significantly, without the engine even running.

Someone could sign off the books and nobody would be the wiser.. but you'd
only be cheating yourself, if you took your family/friends up in a plane
that wasn't shaken down properly.

Also add that in those 40 hours all systems are to be checked in all
possible circumstances and all different parts of the flight envelope. The
plane is supposed to be evaluated to see what the limits of the flight
envelope are, and an operation manual written, with all of the applicable V
speeds logged in said manual, and emergency procedures written.

For planes like the RV that have thousands of copies flying, that might not
be too hard to do, but for a plane that is a one-off, or only has a few
copies flying, and likely with different engine and prop combinations, and
with who knows how many slight variations, I would think nailing down one of
these rare airplanes would need all of the 40 hours, to do the job well.
--
Jim in NC

Morgans wrote:
I would think nailing down one of
these rare airplanes would need all of the 40 hours, to do the job well.

Maybe even longer.

One of the first turbo rotary powered cozy's was in phase 1 for well
over a year with teething problems. Primarily related to problems from
attempting to use stock turbo's and clipped versions of the stock turbos.

Morgans wrote:
"Dave S" wrote

Running the engine on the ground for 40 hours may give you 40 hrs
hobbs time but 0 hours flight time. Having the hobbs wired to the
master could also pad the time significantly, without the engine
even running. Someone could sign off the books and nobody would be the
wiser.. but
you'd only be cheating yourself, if you took your family/friends up
in a plane that wasn't shaken down properly.

Also add that in those 40 hours all systems are to be checked in all
possible circumstances and all different parts of the flight
envelope. The plane is supposed to be evaluated to see what the
limits of the flight envelope are, and an operation manual written,
with all of the applicable V speeds logged in said manual, and
emergency procedures written.
For planes like the RV that have thousands of copies flying, that
might not be too hard to do, but for a plane that is a one-off, or
only has a few copies flying, and likely with different engine and
prop combinations, and with who knows how many slight variations, I
would think nailing down one of these rare airplanes would need all
of the 40 hours, to do the job well.

The FAA has a really good guide for phase one testing. But, so many of the
systems to be checked when following that guide don't exsist on the plane
I'm building that I will be flying a bunch hours inside that 25nm circle
after everything has been tested. Not that I have a problem with that but my
particular 25 nm circle is a little boring. I really kind of wish there was
a 3 phase program. Phase 1 as is, Phase 2 larger or unlimited area without
passengers, and then Phase 3 which would be like the current Phase 2.

That is interesting. Does the FAA specify tach vs. oil pressure Hobbs,
vs. electric Hobbs?

Think of how many pilot logbooks are based on electric Hobbs time.


Neither is correct to the letter of the regulation, both are acceptable
to the FAA.

Pilot time is the real time from the time that the aircraft first moves
under its own power for the purpose of flight until it comes to rest at
the destination. The oil pressure time is pretty darned close (I
assert the aircraft moves forward a tiny bit as soon as the engine
starts and isn't really at "rest" until it stops). Unless you leave
the master on for a long time in a prolonged preflight, the difference
is probably within the tenth of an our accuracy of the unit.

For maintenance, it's time in service. Frankly, even putting the hobbs
on a gear switch is acceptable to the FAA (saves you some time if you
operate out of places like Dulles where you can wait / taxi for a long
time before taking off).