Logging Tach Time

gomntwins

gomntwins

Well-Known Member
If you don't have a hobbs meter in your aircraft, what's the correct way for logging flight time? Is looking at your watch when you start up and again when you finish the flight exceptable? The reason I ask, I've had people tell me to just multiply the tach time by 1.1, and yet others have told me to only log what's on the tach at the conclusion of the flight so as to not run into any problems if future employers ask you about your logged time.

I apologize ahead of time if this subject has already been covered. I searched, but didn't find any threads that had covered this topic.

Thanks!
 
Log what's on your watch. That's what I've done in the past, and when I took my PP checkride the DE even did that - which ended up being 0.1 over the hobbs time. What was I gonna do, argue with him?

Future employers won't question your time unless you give them a reason to. Why would they dig? Are you hiding anything? I mean there's no way a company would know if your airplanes had hobbs or tachs or grandfather clocks for that matter.

Log it however your want, just be consistant and don't over estimate (or under estimate, you're building hours!). Tach time is normally 80% of hobbs time (so i'd multiply by 1.2 if you're going that route, i'd suggest your watch though).

~wheelsup
 
All "tach time" tells you is how many revolutions the engine has made. The counter will go faster at high RPM settings and slower at lower RPM settings. Just get a timer start it when you start the engine and stop it when you stop the engine. Just remember to do it religiously.
 
When instructing, I just go by the Hobbs time. Since I'm paid by Hobbs hour, this allows me to make sure my paycheck is correct.

When flying the King Air, we record Out/Off/On/In times, so I log Out to On. I also do it this way if in an aircraft with no Hobbs meter. I've also heard multiplying Tach x 1.2 is pretty close too.
 
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I believe you should multiply the tach time by 1.2

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Use a watch. The tach vs. hobbs amount can differ wildly from aircraft to aircraft and depending on the type of flying you are doing. I have flown several aircraft that had no hobbs and the tach amount could be .2 under per hour one flight and .5 under the next. Using a fixed amount of time based on the tach is very inaccurate.
 
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I mean there's no way a company would know if your airplanes had hobbs or tachs or grandfather clocks for that matter.

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LOL
spin2.gif

The weight and balance would be tough with that strapped to the yoke!
 
I fly out of KORL, so the x 1.2 would gip me hard. Taxi forever, do your run-up, then you're number three for take off while the rest of the guys in the air are still doing touch & gos. Took me 20 min to get off the ground one day. If you try to fly around NBAA, forget it! I tried that with my instructor once, and we shut the engine down to save $$$. I guess I REALLY wanted to fly that day. That and we were blocked in by four ATA planes behind us.
 
I just use the elapsed time instead of the tach time. I can't imagine anyone would have a problem with that. After all, before I started paying for the plane based on tach versus Hobbs, the meter was running from the second I turned on the master until I turned it off!
 
From the FAR/AIM, part 1.1, definitions:

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; or
(2) For a glider without self-launch capability, pilot time that commences when the glider is towed for the purpose of flight and ends when the glider comes to rest after landing.

The funny thing is that Hobbs time will actually overstate this time, since it begins counting from engine startup to engine shutdown (if triggered by engine oil pressure) or all the time that the Master switch is on (if triggered by the Master switch). So the time you spend after engine startup getting the weather, completing any checklist items, etc. is counted even though, technically, it shouldn't be. I wouldn't use tach time because it's not consistent with clock time. The Hobbs meter is there so the FBO can charge money for all time the airplane is experiencing wear and tear. It's generally accepted for measuring flight time for logging purposes, too. Watch time is the most accurate.
 
That's fixed gear thinking.

On many retractible gear airplanes, the hobbs start when the weight is off the wheels of the gear is up and locked.
 
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That's fixed gear thinking.

On many retractible gear airplanes, the hobbs start when the weight is off the wheels of the gear is up and locked.

[/ QUOTE ]Unfortunately not in any rental that I've ever been in.
 
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From the FAR/AIM, part 1.1, definitions:

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; or
(2) For a glider without self-launch capability, pilot time that commences when the glider is towed for the purpose of flight and ends when the glider comes to rest after landing.

The funny thing is that Hobbs time will actually overstate this time, since it begins counting from engine startup to engine shutdown (if triggered by engine oil pressure) or all the time that the Master switch is on (if triggered by the Master switch). So the time you spend after engine startup getting the weather, completing any checklist items, etc. is counted even though, technically, it shouldn't be. I wouldn't use tach time because it's not consistent with clock time. The Hobbs meter is there so the FBO can charge money for all time the airplane is experiencing wear and tear. It's generally accepted for measuring flight time for logging purposes, too. Watch time is the most accurate.

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It doesn't really overstate it. You are holding the brakes or the airplane would move. The airplane is capable of moving on its own and you as the pilot are preventing it.
 
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It doesn't really overstate it. You are holding the brakes or the airplane would move. The airplane is capable of moving on its own and you as the pilot are preventing it.


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Exactly. If you're the pilot in an aircraft that is running you are liable for whatever that aircraft does. If I'm liable/responible for the aircraft and any damage it might cause, I log the time. It's that simple.
 
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It doesn't really overstate it. You are holding the brakes or the airplane would move. The airplane is capable of moving on its own and you as the pilot are preventing it.

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Good point, I didn't think of it that way, but it makes good sense.
 
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