Hobbs Meter

[MLerro1986]

I recently purchased a 2006 Mooney Ovation 2.  Upon inspection, everything seemed to be working properly.  As a former student used to keeping log time by the Hobbs, I frequently open the baggage door and record the hours.  A little while ago, however, I noticed that the Hobbs wasn't moving.  I took the plane to my local mechanic who told me that the Hobbs meters typically go bad and that they are easy to fix.  After a short inspection, however, he told me that the meter itself was functioning properly and that the issue had to be something else.  Doing some research through the threads, it appears (although I am not certain) that the air safety switch controls the Hobbs on the Ovations.  Not knowing enough about the topic, I elected not to have the mechanics dive into the problem at the time.

Speaking with several other pilots, there is a little bit of a discrepancy as to whether or not to even bother to fix the problem as the G1000 still calculates tac time on the panel.  So here's where the question to my fellow Mooney pilots comes into play.  How important is the Hobbs meter to you and would it be worth sending the plane in for maintenance?

[Raptor05121]

Hobbs is useful for renters. As an owner, all of your maintenance is done via tach time. If its not working, I'd leave it unless you are OCD. If you still wish to rent it out, multiply tach by 1.2hrs and it should balance out (depending on how they fly).

[CaptainAB]

You should log Hobbs time though. The multiplier works fine for that.

[jonhop]

2 hours ago, Raptor05121 said:

Hobbs is useful for renters. As an owner, all of your maintenance is done via tach time. If its not working, I'd leave it unless you are OCD. If you still wish to rent it out, multiply tach by 1.2hrs and it should balance out (depending on how they fly).

So by that logic, if all I have is a Hobbs meter, I should divide by 1.2 hours to get the tach time?

[Zwaustin]

Mine wasn't working either on my K when I bought it. Took me a flight or two to notice but all it was a loose ground and I was back in business. I like everything working on my plane so I wasn't going to leave it INOP. Like many, i use hobbs for flight hours but tach for all maintenance. 

[jetdriven]

8 minutes ago, jonhop said:

So by that logic, if all I have is a Hobbs meter, I should divide by 1.2 hours to get the tach time?

Multiply hobbs time by .8 to get tach time, roughly.

 

[1524J]

Or.....you can replace it with a Horizon tach and have a really nice hobbs meter.....

Just venting frustration that Horizon tachs start recording rpm's at 800 vs other electronic tachs that begin around 1100.... or so I've heard. Other than that, I like the tach. 

My understanding is Hobbs time is tied to oil pressure and the tach is an average of rpm's.

[Zwaustin]

My EI Tach turns time when above 1300 RPM. My Hobbs meter is based on the master switch being in the on position.

[jetdriven]

8 hours ago, 1524J said:

Or.....you can replace it with a Horizon tach and have a really nice hobbs meter.....

Just venting frustration that Horizon tachs start recording rpm's at 800 vs other electronic tachs that begin around 1100.... or so I've heard. Other than that, I like the tach. 

My understanding is Hobbs time is tied to oil pressure and the tach is an average of rpm's.

The Horizon tach adds up airframe time at a higher rate than actual, its costing you money in prematurely devalued airplane and engine time.

Theres some paper the FAA put out years ago that said time in service was when the airplane was aloft, IE, a squat switch on a hobbs meter would do it.  Tach time was a good approximation.

[1524J]

3 hours ago, jetdriven said:

The Horizon tach adds up airframe time at a higher rate than actual, its costing you money in prematurely devalued airplane and engine time.

Theres some paper the FAA put out years ago that said time in service was when the airplane was aloft, IE, a squat switch on a hobbs meter would do it.  Tach time was a good approximation.

I agree, it's the only thing about the tach I don't like. Having an indicator that you've lost a mag is a really nice benefit though.

[carusoam]

The O's POH will tell the details of what operates the Hobb's meter on the back wall of the luggage area.

The O1 uses an oil pressure switch to turn on the mechanical clock. I can't tell the hour meter is working from where I usually sit.  But the hours do go up over time.

whoever put the clock back there didn't want me to watch it while flying... 

Best regards,

-a-

[201er]

You can log in motion time on your ipad efb of choice. The hobb's meter is only good for if you need to know how long others have been flying it. Not worth spending a dime on if it's only for yourself.

[Awful_Charlie]

What does your PoH or MM for your s/n say? On my Bravo the Hobbs is triggered by the RPM indicator

[jetdriven]

6 hours ago, 201er said:

You can log in motion time on your ipad efb of choice. The hobb's meter is only good for if you need to know how long others have been flying it. Not worth spending a dime on if it's only for yourself.

It logs hours faster than tach time and its verifiable throught he journey log. It adds up hours faster i your log book which could be valuable for future employment or insurance rates.

[201er]

45 minutes ago, jetdriven said:

It logs hours faster than tach time and its verifiable throught he journey log. It adds up hours faster i your log book which could be valuable for future employment or insurance rates.

What I said that virtual hobbs like using a timer, ipad logger, etc all fills the same role as hobbs. Hobbs vs clock have no practical difference except when you're trying to clock how much someone else flew your bird.

Instructors and flight schools like hobbs time cause they get to charge you for that amount of time. However, technically speaking this isn't all logable time! If you fire up the plane and spend half an hour warming up or the instructor yaking, this isn't logable time. Same thing if it happens back at the tie down after the flight. This gets weighed full price by hobbs time. Tach time on the other hand will be a good deal lower cause the RPMs are low. But in either case, this time isn't supposed to be logged.

The most accurate timer for the purpose of filling a logbook accurately would be a GPS triggered ipad/panel timer that starts when motion begins and stops when motion ends.

 

Far Part 1.1

Flight time means:
(1) 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;

Edited April 6, 2016 by 201er

[Hank]

I fill out my logbook by my watch. Actually, I use the yoke clock, which I wind and set by my watch. The red hands mean I don't need to remember start time, just look at it when I park and record the difference.

Maintenance is done either by the tach time or by the calendar. There's no Hobbs in my plane.

[jetdriven]

Just make sure it moves one inch right after you start it, then set he brake and let the instructor talk.  At the airline we log all of it, including the two hour sit waiting for the weather to pass.