Time Measurement for Inspections

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

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

Absence of evidence is not evidence of absence.

My Twin Comanche does not have a recording tach, because it has a
single instrument (dual needle) for both engines. Hobbs time would
have meant inspections at unnecessarily frequent intervals. My
solution was to interface an hourmeter to the squat switch using an
isolation relay. That gives me the real time in service, defined as:

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."

The truly hilarious part of this - in order to get the installation
approved, I generated so much paperwork that the weight of the paper
exceeded the weight of the installed components.

Michael

Michael wrote:

My Twin Comanche does not have a recording tach, because it has a
single instrument (dual needle) for both engines. Hobbs time would
have meant inspections at unnecessarily frequent intervals. My
solution was to interface an hourmeter to the squat switch using an
isolation relay.

snip

The truly hilarious part of this - in order to get the installation
approved, I generated so much paperwork that the weight of the paper
exceeded the weight of the installed components.

In order to reduce the chance of this happening again, I'd suggest using
lighter paper next time. :-)
http://www.xerox.com/Static_HTML/xsis/lwpaper.htm

Russell Kent

On a related note,
I just got a (new to me) 1962 Cessna 172. Are the fuel burn tables in
tach time or hobbs time (I have both) and have been using tach time as
it gives me a slightly higher fuel burn (but is more conservative).

Or am I way off base...?

Ryan Wubben
Madison, WI

"R. Wubben" wrote in message
om...

On a related note,
I just got a (new to me) 1962 Cessna 172. Are the fuel burn tables in
tach time or hobbs time (I have both) and have been using tach time as
it gives me a slightly higher fuel burn (but is more conservative).

Fuel burn tables are in real (clock) time.

--------------------
Richard Kaplan, CFII

www.flyimc.com