Tach's walking away from eachother

[Mike Dunlop]

Hello All,
First I want to introduce myself. My name is Mike and my family is located in Wisconsin. I'm new to ownership as of two weeks ago. I bough a PA-30 and have already put 10 hours on her. I've battled with the concept of ownership vs. rental for a long time. For many reasons I took the leap.

I have a question that I'm looking for ideas or advice. I have two tach's that are walking away from each other. They were even at the time of overhaul about 400 hours ago but the RH tach now reads 190 hours more than the other. I'm considering installing a Hobbs meter and working off that for times going forward instead of the tach's. As time goes by the tach's will diverge much further obviously. Will this affect my residual value if I take this route or am I better off replacing the tach's and zeroing them out. I suspect these use a magnetic pick up's and I might run into the same issue. Is there a tach out there that has a digital hour meter built in.

I'm looking for the most cost effective solution while retaining value.

The corporate aircraft that I manage don't have hobbs meter or a tach. Our times and cycles are generated strictly for a flight log that our pilots record off and on times. If I create a flight log and record out/off/on/in times and made them apart of the permanent records would that be seen as a negative for resale. This could be a simple and zero cost solution.

Thoughts?

[Kristin Winter]

Welcome! I am a displaced Twin Citian enjoying better weather in NorCal and surviving the goofier politics.

I have a 1969 PA-30 with a hobbs mounted in the hatch on the floor up by the nose wheel well and a dual tach. I like the arrangement.

[JIMICS2452]

I am with Kristin. I have a non-recording dual tach and a Hobbs meter that is turned on by an airspeed sensitive switch installed in the pitot line. It turns on at around 50 KT IAS, so it is a pretty accurate recording of flight time.

[Zach Grant L1011jock]

There are many methods to record time. There is no requirement for any one method to be used, other than there must be an accurate recording of flight time as specified in the FARs. Manual log entry is acceptable, as is a recording tach, as is a Hobbs, as is some other timer as installed. Flight time is what must be recorded and all maintenance is predicated on flight time. Installing a Hobbs that runs on the master or an oil pressure switch is common for FBOs trying to charge you for every minute you are in the seat, but I bet they all do their maint. off of the recording tach as they would be cutting their 100 hrs short by counting all the taxi time. BTW, tachs have specific revs that correspond to specific hrs. Some count accurately an hr at 2200 rpm, others at 2400 rpm etc. if you have one that registers an hr differently from the other, you most probably have two different model tacos, and replacing one or just using the lower counting tach as the "true" number for flight hrs would be acceptable, unless you decided to fly around with that engine feathered for extended periods, then it wouldn't be a very accurate recording of flight time...

Zach

[JIMICS2452]

When I bought my Aztec from a Part 135 operator there were 2 Hobbs meters installed. One was in front of the right front seat and was labeled in big letters "FLIGHT TIME". It was activated by an oil pressure switch on the right engine gauge. The second was installed low on the pilot's side and labeled in small letters "maint." It was activated by and airspeed switch. Guess which one I removed and which one I kept.