Tach to Hobbs conversion for logging

NJP_MAN said:
Regardless of you being wrong, you still don't log flight time until the aircraft moves under its own power for the purpose of flight. That's the FAAs definition not mine.
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I never said otherwise.
But your statement that I should start logging before I get in the airplane is wrong, too.
 
MauleSkinner said:
So your statement that I should start logging before I get in the airplane is wrong, too.
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It was said in jest. If were going to make up our own definitions of what's flight time. I'm going to start logging when I pour my first cup in the morning. Because I need a cup of coffee to fly it's technically preparing for flight.
 
NJP_MAN said:
It was said in jest. If were going to make up our own definitions of what's flight time. I'm going to start logging when I pour my first cup in the morning. Because I need a cup of coffee to fly it's technically preparing for flight.
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You said
NJP_MAN said:
Out and in refers to the out of the chocks to in to the chocks.
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i pull the chocks before I get in the airplane.
 
MauleSkinner said:
You said

i pull the chocks before I get in the airplane.
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Then you might as well log it then. I just set the brake and never stop logging time. Out, Off, On, In is a method that professionals typically use. Not the random piston single fella that flings the chocks across the ramp when there isn't a line guy to help out.
 
NJP_MAN said:
Then you might as well log it then. I just set the brake and never stop logging time. Out, Off, On, In is a method that professionals typically use. Not the random piston single fella that flings the chocks across the ramp when there isn't a line guy to help out.
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you assume facts not in evidence.
 
NJP_MAN said:
Your Out and In are the goofiest thing I've ever read. You log time when you're buckling your belt and stuff? Nothing in the regulations says that logable time. Out and in refers to the out of the chocks to in to the chocks.
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Yea, we pulled our own chocks, briefed the pax, buckled up, took a selfie, drank some coffee, high fifed each other, then right before starting the first engine wrote down the Out time…goofy enough for you??
 
texasclouds said:
Yea, we pulled our own chocks, briefed the pax, buckled up, took a selfie, drank some coffee, high fifed each other, then right before starting the first engine wrote down the Out time…goofy enough for you??
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Very goofy
 
TCABM said:
IIRC, .mil guys use 1.3 for conversion because how we count time is different than how the FAA does.
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That is what I was told when I left the Air Force. We logged flight time from takeoff to landing, not movement with intention of flight to stopping after flight. It would have added about 440 hours to my total time, but I didn't bother.

I didn't keep a personal logbook while in the military. They just gave me a computer printout when I got out.
 
TCABM said:
IIRC, .mil guys use 1.3 for conversion because how we count time is different than how the FAA does.
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Shouldn't be 1.3 times, but add 0.3 to mil time PER flight. Mil (USAF) is take off to touchdown and does not count taxi time.

Otherwise heavies would be making all sorts of time. A 10 hour flight would be 13 hours logged instead of 10.3 or so.
 
The problem is, there is no conversion. If you are doing pattern work, with a lot of low power time, it may be 1.2x. But a cross country at 75% power would be close to 1 to 1.

My Mooney came with tach time only. At 2500 RPM, the tach = actual time. So take off and climb, tach was greater than actual. At cruise at 2400, tach would be slightly less. Taxi time would be tach less than actual.

If you only have a few flights, I would ignore the difference for the time already logged, and note engine start and shutdown for future flights.
 
Pinecone said:
Shouldn't be 1.3 times, but add 0.3 to mil time PER flight. Mil (USAF) is take off to touchdown and does not count taxi time.

Otherwise heavies would be making all sorts of time. A 10 hour flight would be 13 hours logged instead of 10.3 or so.
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My .mil time isn’t convertible so I’ve never paid much attention to the formula.
 
NJP_MAN said:
Regardless of you being wrong, you still don't log flight time until the aircraft moves under its own power for the purpose of flight. That's the FAAs definition not mine.
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Yep, AKA "block time." As a practical matter, engine time (or hobbs time) are generally a close approximation, but technically not what you should log. Some people let off the brakes right after starting the engine for a moment so that they move under their own power. But most of the time, block time and engine/hobbs time are within a minute or two of each other; especially if you only measure in tenths of an hour, block (technically correct) and hobbs/engine (technically incorrect) are basically equal.

MyFlightbook will measure any of these (or flight time - for non-FAA logging rules) and feed them (per your preference) to total time.
 
Pilot-To-Be said:
Hi,

I fly an airplane that doesn’t have a Hobbs meter. I’ve always used the 1 tach hour equals 1.2 hours of logging time method.

For example, I flew a XC yesterday that was 4.4 tach hours, so I multiplied by 1.2 and I logged 5.3. It more or less matched the approx clock time, so I think it’s a good measure, but I was curious of any thoughts. I am not wanting to misrepresent in anyway, but this seems to be an acceptable method. Thoughts?
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The FAA is pretty understanding of a lot of methods, provided that you are consistent in which method you use. However, I would pay attention to actual clock time from start to shutdown as 1.2 is probably shortchanging you a little.

When I joined a club that charged by tach instead of hobbs, I kept track of the difference for a while because I was interested in how I was breaking even vs renting. I found that the actual ratio varied between 1.08 and 1.4 depending on taxi time, power setting, and distance flown. A flight with lots of pattern work or maneuvering would be at the high end, while a long cross country with little taxi time would be on the low end, especially if flown at a higher RPM.
NJP_MAN said:
Out is out of the blocks. That's it. It's not starting engines. It's not combing your mustache. It's pretty clear.
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Show me where in the FARs the definition of Out is.
NJP_MAN said:
I just decided to start logging when I close the door on my house. I'm headed to the airport to fly so it all counts on according to the logic.
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Nope. It counts when the aircraft moves under its own power for the purpose of flight. It has nothing to do with chocks.
EricBe said:
Yep, AKA "block time." As a practical matter, engine time (or hobbs time) are generally a close approximation, but technically not what you should log.
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The prop is part of the aircraft, right? And it is moving, under its own power?

Regardless, the FAA has long accepted Hobbs time as one of the acceptable ways to log flight time.
 
flyingcheesehead said:
The FAA is pretty understanding of a lot of methods, provided that you are consistent in which method you use. However, I would pay attention to actual clock time from start to shutdown as 1.2 is probably shortchanging you a little.

When I joined a club that charged by tach instead of hobbs, I kept track of the difference for a while because I was interested in how I was breaking even vs renting. I found that the actual ratio varied between 1.08 and 1.4 depending on taxi time, power setting, and distance flown. A flight with lots of pattern work or maneuvering would be at the high end, while a long cross country with little taxi time would be on the low end, especially if flown at a higher RPM.

Show me where in the FARs the definition of Out is.

Nope. It counts when the aircraft moves under its own power for the purpose of flight. It has nothing to do with chocks.

The prop is part of the aircraft, right? And it is moving, under its own power?

Regardless, the FAA has long accepted Hobbs time as one of the acceptable ways to log flight time.
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The door is part of the airplane and when I unlock and open that handle, it starts moving. Then just for good measure I run the door up again with the electric motor so it's moving under it's own power. Then I close the door up and head in to the FBO for 2 hours. I'm logging from when that door moved until when I get to the hotel room.
 
NJP_MAN said:
The door is part of the airplane and when I unlock and open that handle, it starts moving. Then just for good measure I run the door up again with the electric motor so it's moving under it's own power. Then I close the door up and head in to the FBO for 2 hours. I'm logging from when that door moved until when I get to the hotel room.
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:rolleyes:

If you didn't fly, it was not "for purposes of flight" and still doesn't count. Nice try though. And the FAA has accepted Hobbs time as valid for logbooks since about the Wright brothers. :dunno:
 
Look at watch. Write down time. Taxi. After landing, stop completely at some point. Write down time. Do the math for how much time passed. Log it.
 
flyingcheesehead said:
The FAA is pretty understanding of a lot of methods, provided that you are consistent in which method you use. However, I would pay attention to actual clock time from start to shutdown as 1.2 is probably shortchanging you a little.

When I joined a club that charged by tach instead of hobbs, I kept track of the difference for a while because I was interested in how I was breaking even vs renting. I found that the actual ratio varied between 1.08 and 1.4 depending on taxi time, power setting, and distance flown. A flight with lots of pattern work or maneuvering would be at the high end, while a long cross country with little taxi time would be on the low end, especially if flown at a higher RPM.
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It depends a lot on the type of flight. I just did a 7.0 XC flight, non-stop. If I had cruised at 2500 RPM, the tach and Hobbes would have been the same for takeoff until entering the pattern. So 1.2x tach would have been a good bit more (8.4 logged). But a flight all in the pattern, might be 1.5 - 2 x the tach.
 
flyingcheesehead said:
Regardless, the FAA has long accepted Hobbs time as one of the acceptable ways to log flight time.
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I'd say not exactly "Hobbs", necessarily. When I owned my plane, the Hobbs was connected to the master switch. This is not common, but certainly isn't rare. One time it accumulated several hours while in maintenance. So while on a normal flight there wouldn't be much time between master on and engine start, on any kind of flight where you're testing something before you go, or maybe demonstrating a preflight, or whatever might cause the master to be on for a while before engine start, "Hobbs" time itself wouldn't be legit. But "Hobbs connected to an oil pressure switch", yes that's long been accepted.

ateamer said:
Look at watch. Write down time. Taxi. After landing, stop completely at some point. Write down time. Do the math for how much time passed. Log it.
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Yes. It's not hard. This is exactly what we do at work. When we start moving out of the parking spot, we write down the Zulu time. When we're back in it, we write down the Zulu time. And do the math. Typically, we round these times to the nearest 6 minutes to make the math easier, but that's just a technique.

Our Hobbs, like most multiengine aircraft, is attached to the weight-on-wheels switch so only starts recording when airborne. And we do sit in the parking spot for a while after startup (6-10 minutes is typical) to bring all of our equipment up (the IRU especially, which if you even move a few inches will require a realignment). So the logged flight time is not equal to either the Hobbs or the engine start/stop times.
 
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Pinecone said:
Hmm, so what about a glider???? :D
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The FAA doesn't care enough to write them regulations for logging it. ;p

I mean, they had the whole section on "wench launching" in the Glider Flying Handbook for years! :rofl:
RussR said:
I'd say not exactly "Hobbs", necessarily. When I owned my plane, the Hobbs was connected to the master switch. This is not common, but certainly isn't rare. One time it accumulated several hours while in maintenance. So while on a normal flight there wouldn't be much time between master on and engine start, on any kind of flight where you're testing something before you go, or maybe demonstrating a preflight, or whatever might cause the master to be on for a while before engine start, "Hobbs" time itself wouldn't be legit. But "Hobbs connected to an oil pressure switch", yes that's long been accepted.
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Yeah, that's what I was referring to. Good old oil-pressure-switch "Rental Hobbs".

I have a Hobbs in my plane but it's for maintenance. It's on an airspeed switch I think.

I have seen a plane with four Hobbs meters: Airspeed, Master, and oil pressure on each of its two engines. Probably owned by the Hobbs corporation or a "Hobbs enthusiast" or something at some point. :rofl:
 
flyingcheesehead said:
:rolleyes:

If you didn't fly, it was not "for purposes of flight" and still doesn't count. Nice try though. And the FAA has accepted Hobbs time as valid for logbooks since about the Wright brothers. :dunno:
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I'm all for logging Hobbs. OP said they start logging when they close the door. Those are not the same in my opinion.
 
I really don’t get why some are so adamant and triggered over how someone else logs time. Is a iation safety harmed if a pilot logs .1 between when the door closes and they start to taxi?
 
MauleSkinner said:
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.
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I know, was trying to be funny. :D
 
flyingcheesehead said:
Nope. It counts when the aircraft moves under its own power for the purpose of flight. It has nothing to do with chocks.
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Airlines and military start with the chocks in place. Ground crew pulls the chocks just before start of taxi or pushback. So chock to chock IS proper for them.

I guess if you wanted to be technical, airline pilots should not be logging push back unless they power back. :D
 
Pinecone said:
Meaning?

You were not a pilot?
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I was one of the first 13Bs when the career field was resurrected as a Rated Aviator career field. I later became a full time ALO/JTAC.

Ironically, I won’t be surprised to see the 13Bs go the way of dinosaurs again and the ALOs and STOs merge into one career field.
 
Pinecone said:
I guess if you wanted to be technical, airline pilots should not be logging push back unless they power back. :D
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I wouldn't be surprised if, since they used to power back, the union fought against tugs for that reason until the FAA agreed to look the other way, and it's all been lost to history since...
 
TCABM said:
I was one of the first 13Bs when the career field was resurrected as a Rated Aviator career field. I later became a full time ALO/JTAC.

Ironically, I won’t be surprised to see the 13Bs go the way of dinosaurs again and the ALOs and STOs merge into one career field.
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Interesting.
 
OK, was logging my flying over the weekend.

I started with a 6.9 hour XC (Hobbs) that was 6.8 hours tach. Next was a Fight Review flight of 1.8 Hobbes, that was 1.8 tach. Then an IPC at 2.2 Hobbes, and 2.0 tach. Then 7.0 Hobbs back home for 6.9 tach.

Total for the trip was 17.9 Hobbs and 17.5 tach.

So no set ratio/formula to convert. But on it shows that on a long XC, tach and Hobbs are almost the same..

Before this trip was a short triangle that was 0.5, 0.5 and 0.6 Hobbs, but 0.3, 0.5, and 0.4 tach. So short flights have a greater % difference, even though the actual time difference is about the same.

So, IMO, adding 0.1 or 0.2 per flight to the tach time is close to being the actual Hobbs time.
 
Pinecone said:
Airlines and military start with the chocks in place. Ground crew pulls the chocks just before start of taxi or pushback. So chock to chock IS proper for them.
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Maybe when you were flying A-10s, but in the C-130 the flight engineer wrote down the time the wheels left the ground and again when we touched down. And that is what was logged. I didn't keep a personal logbook then, but when I left the Air Force, they handed me a computer printout which I consider my first logbook. When I look at it, there is a circle around the total combat hours: 303.6. I transferred that to my first civilian logbook and then realized there would never be a reason to carry that forward.
 
Pinecone said:
Interesting.
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The crux is airborne platforms will retire out before big blue figures out what to do with the 13Bs. Since rated billets are tied to airframe inventory, one if the ways forward is to consolidate the Navs and ABMs a la NFO, but that doesn’t change the fact there’s more ground-based command and control needs than airborne.

www.airandspaceforces.com

What Does the Future Look Like for Battle Managers?

The Air Force is starting to modernize its command and control enterprise, but the future for battle managers in the short term is unclear.
www.airandspaceforces.com www.airandspaceforces.com

The existential question is whether big blue wants to justify a Rated Aviator career field that spends the majority of their career in a ground AOC-type role.
 
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