In regards to operating your own a/c, is it correct in my understanding that it is ok to enter HOBBS or actual time in your personal log book but use TACH time for the maintenance log entries? This would mean you log the maximum amount of time in your personal log and minimum in the mtce log and jounrney log thus maximising the time between 100 hour inspections.
I just need this clarified.
Thanks.
tach vs. hobbs
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Brit_Guy_Ontario
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That's what everybody does. I'm not sure how much sense it makes, but it's quite acceptable to use tach time for maintenance purposes (ie air time).
Many aircraft don't have Hobbs meters. Some are connected to the oil pressure while others are wired to the master switch.
What I do is add 0.2 to the tach time for flight time, which is 6 minutes out and 6 minutes in. I figure it averages out over time, and in the long run, does it really matter if you log 34,000 or 35,000 hours in your lifetime? I mean, who really cares?
Many aircraft don't have Hobbs meters. Some are connected to the oil pressure while others are wired to the master switch.
What I do is add 0.2 to the tach time for flight time, which is 6 minutes out and 6 minutes in. I figure it averages out over time, and in the long run, does it really matter if you log 34,000 or 35,000 hours in your lifetime? I mean, who really cares?
Be careful on this one. Just because "everybody" does that doesn't mean its right.
Check the definition of air time and flight time in your AIP. Air time is clearly "time up to time down". How many tachs measure this??? A tach hour is based on a constant cruise rpm, therefore is not accurate when measuring the time an aircraft spends in the air.
A hobbs meter measures the time there is oil pressure (presumably the time the engine is running). There are very few factory installations that work solely off the master switch.
It sounds like we are looking for a way to cheat the system with inspection times. There is good reason why inspections are 100 hours, not 103 or 112 or otherwise. I have seen a difference of as much as .5 on a 1 hour flight between air time and tach time.
If you want to be most accurate and by the book, use your watch to record start up, time up, time down, and shutdown. Most Journey logs support this format.
Check the definition of air time and flight time in your AIP. Air time is clearly "time up to time down". How many tachs measure this??? A tach hour is based on a constant cruise rpm, therefore is not accurate when measuring the time an aircraft spends in the air.
A hobbs meter measures the time there is oil pressure (presumably the time the engine is running). There are very few factory installations that work solely off the master switch.
It sounds like we are looking for a way to cheat the system with inspection times. There is good reason why inspections are 100 hours, not 103 or 112 or otherwise. I have seen a difference of as much as .5 on a 1 hour flight between air time and tach time.
If you want to be most accurate and by the book, use your watch to record start up, time up, time down, and shutdown. Most Journey logs support this format.
britguy: You should always have your takeoff time recorded anyway, so it is very easy to check the time when you land and record air time. I would use air time rather than tach time, it makes more sense and is what the manufacturer intented. But in another post you stated your aircraft is privately registered, which means that you only have to do an annual anyway, so why are you worried about 100 hour checks?
172driver: If you actually want to be by the book rather than do what "everybody" does, start up and shutdown times mean nothing. Flight time is from first taxi to last stop.
172driver: If you actually want to be by the book rather than do what "everybody" does, start up and shutdown times mean nothing. Flight time is from first taxi to last stop.
While I use a watch, I think someone could also use somes GPSes to get air time, some units like the KLN35A count time as soon as the airplane moves faster than 40 knots (not sure about the exact speed).
While this capability is probably not working the same way on different models, it makes a nice backup should you miss writing down one of your times.
Louis
While this capability is probably not working the same way on different models, it makes a nice backup should you miss writing down one of your times.
Louis
It all depends on what you are attempting to do. Most tachs register at cruise RPM so can be quite inaccurated. Hobbs is better but if I am paying, (not likely) time is from when point of departure disappears over the horizon till the first glimpses of destination. If I am being paid, then time is from when I first think about flying till it is a distant memory. In actuality, flight time is from when the airplane first moves under it own power till it ceases moving after a flight. Air time is from when the airplane first moves under power for take-off till it slows to taxi speed on landing. Fly a trip or two keeping an accurate log and see which is most accurate. Air time to airplane journey log, flight time to pilots log and hours experience. For Commercial pilots, it's air time in the airplane log book and flight time on the pay stub.
The average pilot, despite the somewhat swaggering exterior, is very much capable of such feelings as love, affection, intimacy and caring.
These feelings just don't involve anyone else.
These feelings just don't involve anyone else.
I will admit that I don't know if the same holds for Aircraft Tachs as for the numerous diesel Industrial engines I have known, but in my experience "tach" time is based on a certain continuous RPM of the engine and would be completely inaccurate at idle, or at higher than the rated RPM.
My understanding is that Airframe Time is Wheels off to Wheels On.
Flight time is that, plus time spent taxiing for the purpose of take-off and includes the taxi after landing (engine start, to engine shut down).
There is no Flight time if the aircraft does not take-off, and there is obviously no Air Time either.
My understanding is that Airframe Time is Wheels off to Wheels On.
Flight time is that, plus time spent taxiing for the purpose of take-off and includes the taxi after landing (engine start, to engine shut down).
There is no Flight time if the aircraft does not take-off, and there is obviously no Air Time either.
Pilots get higher, SCUBA Divers do it deeper!
If you were to crawl under the panel, you may see a sticker on the tach that gives the RPM that the hourmeter in calibrated for. Higher RPM will shortchange you, lower RPM will benefit. It just basically counts revolutions. An hourmeter is a clock that starts and stops with some sort of indicator. Twin Cessna's use a vane under the wing that senses airspeed. Some hook the meter up to oil pressure, some to a squat switch and I am sure someone has had one hooked to some poor pilots ass, somehow. A Davtron clock has a timer that is hooked to the squat switch which senses when the airplane is airborne. That is the one that you have to reset when the power is off.
The average pilot, despite the somewhat swaggering exterior, is very much capable of such feelings as love, affection, intimacy and caring.
These feelings just don't involve anyone else.
These feelings just don't involve anyone else.
