Time Measurement for Inspections

OK, dumb question. For 100-hour inspections (or 50 hours until oil
change), is this measured in Hobbs time or Tach time?

-Sami
N2057M, Piper Turbo Arrow III

The tach is the instrument for measuring engine hours...
denny

"O. Sami Saydjari" wrote in message
...
OK, dumb question. For 100-hour inspections (or 50 hours until oil
change), is this measured in Hobbs time or Tach time?

-Sami
N2057M, Piper Turbo Arrow III

"O. Sami Saydjari" wrote:

OK, dumb question. For 100-hour inspections (or 50 hours until oil
change), is this measured in Hobbs time or Tach time?

Everyone I know uses whichever gives them the longest period between inspections.
This is usually tach time, but I know a few people who have wired a Hobbs to the
squat switch on a retract so that they can schedule maintenance based on time spent
in the air.

Me, I use calendar time, since I never log over 50 hours in a 4 month period and have
annual inspections, rather than 100 hour.

George Patterson
This marriage is off to a shaky start. The groom just asked the band to
play "Your cheatin' heart", and the bride just requested "Don't come home
a'drinkin' with lovin' on your mind".

Not a dumb question at all. You can use a sand hourglass if you want, just so
long as you use the same method all the time. That is, use hobbs OR tach OR
wris****ch, just be consistent.

No, the regs do not REQUIRE you to use the same method every time, but you'll
play hell explaining your method to the FAA if they come a'snoopin'.

Jim


"O. Sami Saydjari"
shared these priceless pearls of wisdom:

-OK, dumb question. For 100-hour inspections (or 50 hours until oil
-change), is this measured in Hobbs time or Tach time?
-
--Sami
-N2057M, Piper Turbo Arrow III


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

Technically, neither...
In Part I, Definitions,
"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."

As a practical matter, for Part 91 operations, I've never heard of
anybody using anything but tach time.

Rich



O. Sami Saydjari wrote:
OK, dumb question. For 100-hour inspections (or 50 hours until oil
change), is this measured in Hobbs time or Tach time?

-Sami
N2057M, Piper Turbo Arrow III

There is no tach on a jet. Lots of part 91 operations.

Karl

"Rich" wrote in message
...
Technically, neither...
In Part I, Definitions,
"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."

As a practical matter, for Part 91 operations, I've never heard of
anybody using anything but tach time.

Rich



O. Sami Saydjari wrote:
OK, dumb question. For 100-hour inspections (or 50 hours until oil
change), is this measured in Hobbs time or Tach time?

-Sami
N2057M, Piper Turbo Arrow III

On 3-Apr-2004, "kage" wrote:

There is no tach on a jet. Lots of part 91 operations.

Karl

"Rich" wrote in message
...
Technically, neither...
In Part I, Definitions,
"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."

As a practical matter, for Part 91 operations, I've never heard of
anybody using anything but tach time.

Rich


I wonder what they use for sailplanes.

-Elliott Drucker

Just did that Saturday. At annual time, I make a single line entry in the
aircraft logs that says "nxyz flew x hours from xx/xx/xx to yy/yy/yy" and
sign my name and date it. After that, the mechanic makes his entries
for the annual.

Some pilots actually log each flight. That is neat because it is interesting
to see what kind of adventures and places the gllider has seen during it's
life.

In article ,
wrote:
On 3-Apr-2004, "kage" wrote:

There is no tach on a jet. Lots of part 91 operations.

Karl

"Rich" wrote in message
...
Technically, neither...
In Part I, Definitions,
"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."

As a practical matter, for Part 91 operations, I've never heard of
anybody using anything but tach time.

Rich


I wonder what they use for sailplanes.

-Elliott Drucker

"Dennis O'Connor" wrote in message ...
The tach is the instrument for measuring engine hours...

Not necessarily. The FAA just wants a consistent reasonably accurate way of
recording time in service. Some aircraft, like late model Bonanza's (and now my
Navion) don't even have a recording tach (no tach time at all). We use the elapsed
time meter (hobbs).

"Ron Natalie" wrote in message
m...
Not necessarily. The FAA just wants a consistent reasonably accurate way
of
recording time in service. Some aircraft, like late model Bonanza's (and
now my
Navion) don't even have a recording tach (no tach time at all). We use
the elapsed
time meter (hobbs).

What do you consider "late model Bonanza"? Every one I've looked at (from
1987 onward until they stopped making them in 1994 has one (at least in the
F33A model).

Guessing that Hobbs time is 25% higher than Tach time, I'd put a recording
tach in if it didn't have one already.