Steve Crimm wrote:
>
> Evening All,
>
> I would be interested in hearing how everyone calculates maintenance
> time? In my previous life flying helicopters we had two Hobbs
meters.
> One for maintenance based on actual flight time. The other was for
total
> running time that we used for customer billing purposes.
>
> With my Grand Rapids EIS is appears to gather time based on oil
> pressure, so how does everyone else do it?
>
I have a Taskem digital tach, which records time if the prop if
spinning. U.S. rules for amateur-built A/C are fuzzy (an endless
logical loop) as to whether "time in service" needs to be recorded in
maintenance logs at all, but if it is, the rules do say that time in
service begins when the wheels leave the runway and ends when they
touch down, an example of FAA not enforcing every last rule.
Practically, Hobbs time -- engine running -- is useful for logging
flight time, as it more closely reflects how that time is clocked.
And for maintenance of production aircraft, it's cheaper in ownership
costs and thus common to use tach time, as it's proportional to RPM.
So...anything from Post-It notes on the fridge to a strain-gauge
switch on the gear! Simplest is clocking when master switch is on,
but one should have an alarm circuit in case the master were to be
left on. A handy item anyway, but requiring some circuit design.
Hmm...wonder if one could kludge that around a 10-cent, CMOS quad NAND
gate chip, including a time delay before alarm goes off? Might even
have two gates left over to make it flash or a pulsing chime like in
our cars....
Reg,
Fred F.
|