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johnm

1500 hour paperweight

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I know its been discussed before ................. but just tapping into the huge think tank:book:

 

For a Rotax 912 is the engine life (or for some 2000 hrs - whichever) is it Tacho time only ? (in other words you can't use air switch time .......... has to be tacho)

 

Is this correct ?

 

thanks

 

 

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It is engine hours not flight time. So either hobbs meter or similar. My Brauniger starts flight time after 26 knots but also monitors the engine as a rule of thumb it seems to take around 6 to 8 mins engine time compared to flight time depending on taxiing time and warm up. The brauniger looks at the rpm for engine so when the engine is running it s the same as a hobbs

 

 

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As far as CASAs and the regs are concerned, time in service, (TTIS) in respect to maintenance is considered time from liftoff to touchdown, not chock to chock time. This would then generally be the time on a hobbs operated by an air switch, not the time on a tach (tach time). As a private operator however performing your own maintenance on your own aircraft, (Level 1 maintenance privilages) you may please yourself which time in service you wish to follow for maintenance, or to simply respect the recommendations of the engine and/or aircraft manufacturer.................................................................Maj...024_cool.gif.7a88a3168ebd868f5549631161e2b369.gif

 

 

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This 'Grey' area between what CASA will accept, and what Rotax states in it's manuals, stems from many, many years ago when aircraft had mechanical cable driven Tacho's with a built in hour meter.

 

These Tacho's were usually just modified and refaced automobile speedometers.

 

This meant that they clocked at various times depending on the RPM the engine was set to.

 

Small gears were used to adjust the cable speed so that when the engine was running at cruise speed, the odeometer, now being used as an hour meter, would tick over one hour every hour.

 

This also meant that a motor running at idle would probably only tick over about 0.6 in an hour, conversely, running an engine at full power will will read an 1.0 in less than an hour.

 

It was accepted that this variable time rate was reflective of an engines actual 'wear' or usage time, so was acceptable.

 

Because of this, when the electronic (Hobbs) hour meters turned up, people started using 'air-switches' to log times.

 

Arthur.

 

 

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You will find that Jabiru specifies from start to shutdown related to engine hours. Engine hours can be as much as 10 to 15% higher that flight hrs.

 

 

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thanks techo's 010_chuffed.gif.c2575b31dcd1e7cce10574d86ccb2d9d.gif

 

from the above .................. looks like the majority say you can log airswitch time - lift off to landing - for Rotax 912

 

that's good news ! - the finance ministries budget sheet looks healthier

 

the difference between tacho and airswitch over 1500 hours would easily amount to ..................... (guessing 150 hours)

 

 

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you can log airswitch time

I'm assuming you mean log engine time against air switch?

 

As stated, this is plausable.

 

If your talking about times for your flying log you can log total time, hobbs, master, whatever, as once you are seated in the aircraft with the engine running, you are in charge of it.

 

Always remember though that your flying log is your record, adding extra time anywhere is only fooling yourself if you are not gaining knowledge and/or ability.

 

Arthur.

 

 

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thanks techo's 010_chuffed.gif.c2575b31dcd1e7cce10574d86ccb2d9d.gif

from the above .................. looks like the majority say you can log airswitch time - lift off to landing - for Rotax 912

 

that's good news ! - the finance ministries budget sheet looks healthier

 

the difference between tacho and airswitch over 1500 hours would easily amount to ..................... (guessing 150 hours)

 

For a rotax oil changes and time before overhaul you have to use tacho time from engine start to engine shut down

 

for airframe maintenance I believe it is lift off to landing

 

 

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I have always logged flying time as from engine start till engine off , for personal logbook. That's the time you are managing the aircraft. Sully on the Hudson river may have used the time to contact but I don't think he was worried about logbook hours at that stage .Nev

 

 

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? .............................. ! = ?

 

 

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He did a bit of unplanned gliding in a heavy. Nev

 

 

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I heard about the unplanned gliding - I was just going strange about the variance in the replies

 

I'm gunna summarize

 

 

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Whhooooooooooooops - summary is

 

- Rotax with 1500 hr (or 2000) life

 

- You can use air switch (take off to landing) to calculate this 1500

 

- for maintenance its engine time - tacho

 

anyone want to argue - come on then ............ lets:bash:

 

john m

 

- jabbies are different (those without Rotax)

 

- don't go cheating your hours in your log book

 

- all that other stuff

 

 

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