Hobbs issue

H. Paul Shuch is a Light Sport Repairman with Maintenance ratings for airplanes, gliders, weight shift control, and powered parachutes, as well as an independent Rotax Maintenance Technician at the Heavy Maintenance level. He holds a PhD in Air Transportation Engineering from the University of California, and serves as Director of Maintenance for AvSport of Lock Haven.

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3Dreaming
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Re: Hobbs issue

Postby 3Dreaming » Sun Jun 05, 2016 1:06 pm

rcpilot wrote:
roger lee wrote:Are you reading Hobbs time or Tach time. You're better off with Hobbs. Tach time can vary from 15%-18% depending on engine rpm and some older style tachs registered time with just the electrical on. Al Hobbs and Tachs should have an oil pressure switch installed. You usually can reset the proper time on either if needed.

My plane only has a hobbs. Next time my mechanic woeks on it I'm going to see if we can verify how it's actually connected. Flew yesterday and it seems to be working OK. I'll keep an eye on it.


You do know since your airplane is experimental you could check to see how it is wired. If it was a SLSA after you get your sport pilot certificate you could still trace the wire circuit.

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FastEddieB
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Re: Hobbs issue

Postby FastEddieB » Sun Jun 05, 2016 1:12 pm

Don't all POH's have at least a simplified wiring diagram?
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Sky Arrow 600 E-LSA • N467SA
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drseti
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Re: Hobbs issue

Postby drseti » Sun Jun 05, 2016 1:59 pm

It's usually in the maintenance manual, Eddie.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof. H. Paul Shuch, Ph.D., CFII, LSRM-A/GL/WS/PPC, iRMT
AvSport of Lock Haven
fly@AvSport.org
http://AvSport.org
http://facebook.com/SportFlying

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FastEddieB
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Re: Hobbs issue

Postby FastEddieB » Sun Jun 05, 2016 2:24 pm

I think I nearly always find them in POH's. I thought that was SOP.

From my POH:

Image

The next page has the legend. The Hobbs is 22, activated indirectly via an oil pressure switch.

Kinda thing I think an owner should have access to, without needing an AMM.

edited to add: the CT CTLS POH has a similar diagram. Are there any that don't?
Fast Eddie B.

Sky Arrow 600 E-LSA • N467SA

FastEddieB@mac.com

3Dreaming
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Re: Hobbs issue

Postby 3Dreaming » Sun Jun 05, 2016 7:03 pm

His airplane is experimental, so who knows haw it was wired, and if there is a diagram

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FastEddieB
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Re: Hobbs issue

Postby FastEddieB » Sun Jun 05, 2016 7:06 pm

3Dreaming wrote:His airplane is experimental, so who knows haw it was wired, and if there is a diagram


I did not see that in his original post nor in his profile.

What kind of plane are we discussing?
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Sky Arrow 600 E-LSA • N467SA

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drseti
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Re: Hobbs issue

Postby drseti » Sun Jun 05, 2016 7:33 pm

FastEddieB wrote: the CT CTLS POH has a similar diagram. Are there any that don't?


Believe it or not, the Evektor SportStar Max AOI doesn't have one. Instead, it says this:

7.13.2 Electrical system scheme
See Aircraft Maintenance and Inspection Procedures - Supplements.


Then later, in Section 8.1, it says:

The manufacturer delivers along with aircraft SportStar MAX the
“Aircraft Operating Instructions (AOI)“ and the “Aircraft Maintenance and Inspection Procedures (AMIP)”.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof. H. Paul Shuch, Ph.D., CFII, LSRM-A/GL/WS/PPC, iRMT
AvSport of Lock Haven
fly@AvSport.org
http://AvSport.org
http://facebook.com/SportFlying

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FastEddieB
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Re: Hobbs issue

Postby FastEddieB » Sun Jun 05, 2016 8:36 pm

drseti wrote:Believe it or not, the Evektor SportStar Max AOI doesn't have one.


Interesting.

Hasty assumption on my part!
Fast Eddie B.

Sky Arrow 600 E-LSA • N467SA

FastEddieB@mac.com

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drseti
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Re: Hobbs issue

Postby drseti » Sun Jun 05, 2016 8:40 pm

FastEddieB wrote:Hasty assumption on my part!


No, logical assumption on your part. Grievous omission on the manufacturer's part.
The opinions posted are those of one CFI, and do not necessarily represent the FAA or its lawyers.
Prof. H. Paul Shuch, Ph.D., CFII, LSRM-A/GL/WS/PPC, iRMT
AvSport of Lock Haven
fly@AvSport.org
http://AvSport.org
http://facebook.com/SportFlying

3Dreaming
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Re: Hobbs issue

Postby 3Dreaming » Sun Jun 05, 2016 8:57 pm

FastEddieB wrote:
3Dreaming wrote:His airplane is experimental, so who knows haw it was wired, and if there is a diagram


I did not see that in his original post nor in his profile.

What kind of plane are we discussing?


It is in his first post in the "Buying Your Own Airplane for Flight Training " thread.

I read almost every post in every thread, and I have a good memory.

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FastEddieB
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Re: Hobbs issue

Postby FastEddieB » Sun Jun 05, 2016 9:11 pm

3Dreaming wrote:
It is in his first post in the "Buying Your Own Airplane for Flight Training " thread.


Found it - Zenith CH601.

Question: Did the builder provide a schematic?
Fast Eddie B.

Sky Arrow 600 E-LSA • N467SA

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rcpilot
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Re: Hobbs issue

Postby rcpilot » Tue Jun 07, 2016 1:49 pm

FastEddieB wrote:
3Dreaming wrote:
It is in his first post in the "Buying Your Own Airplane for Flight Training " thread.


Found it - Zenith CH601.

Question: Did the builder provide a schematic?

I'll have to check the documentation that I have. I'm also going to have the mechanic have a look when I get my next oil change. On the last 2 flights looks like the hobbs is working so it's still a mystery as to what the avionics guys did to make it run ahead.

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azsportpilot
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Re: Hobbs issue

Postby azsportpilot » Fri Jun 10, 2016 12:18 pm

back in my ultralight days we had a club member with a Buccaneer 2 w/ 582

he would routinely forget to turn off his master switch and the Hobbs would continue to run, adding 8-10 hours before the battery completely died........... must have been wired up improperly

he reached TBO in just one summer, LOL
John Sarra CFI-S
1946 Aeronca Chief

-Mankind has a perfect record in aviation; we never left one up there!


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