Hobbs or Tacho?

[pistongone]

How many of you object to paying on the Hobbs? It makes you rush through checks whilst watching the hobbs spin and even waiting for the pitot to heat up cost you money! I think the farest way is tacho or airborn, what say you Gents?
PS: i was once stuck at Elstree international, when the ground controler(a/g to the CAA) kept me waiting at the hold for 20 MINUTES:ugh: Whilst Mr Montclare came in a twin! The PA 32 costs £3:00/min so i wasnt best pleased. Before you say i was entitled to go on my discretion, i want to go back as a few friends of mine live very close to the airfield and cheesing them off wont look good on my CV, like they wont accept you back in:=
Your thoughts please:confused:

[Dude~]

Hobbs sucks. At one airport I was held for 45 minutes due to commercial traffic. At least I wasn't paying for it though.

In oz I once hired a Duchess and was charged via an airswitch - basically I paid for all time spent about 50 kts! Definitely the best way. 2 nd best it Hobbs.

I don't like places that just rely on the instuctors watch as the tech logs become horribly out of synch with reality.

[Grainger]

LASORS Appendix A to Section A:Flight time (aeroplane): The total time from the moment that an aircraft first moves under its own or external power for the purpose of taking off until the moment it comes to rest at the end of the flight.

Flight time (helicopter): The total time from the moment a helicopter's rotor blades start turning until the moment the helicopter finally comes to rest at the end of the flight and the rotor blades are stopped.That's what you should be logging, and I guess what you should be paying for.

Whatever, never allow anything to make you "rush through your checks". :eek:

[IO540]

There is just one solution to this frequent problem: get yourself a plane.

Then you log total moving time (brakes off to brakes on) in your personal logbook.

You log the airborne time in the aircraft logbook(s). All time-based aircraft maintenance is (or should be) based on airborne time only.

The above is correct for both G-reg and N-reg ops.

Anything else (like taking the reading from some meter in the dash) is mandated by the fact that a lot of people (both students and instructors) cannot be trusted to report the correct times :)

Charging for BO-BO (common in many schools) encourages crazy behaviour on the ground, but the reality is that if they charged for airborne time only, the hourly rate would have to go up to compensate for the reduced income.

[Say again s l o w l y]

Or you charge for airborne + a set amount. We use 10 mins. This is to stop people rushing checks or not letting the engine warm up.

It also has the added benefit of not ripping people off if they get stuck on the ground for an extended period of time.

[IO540]

How do you measure airborne time?

One could take it on trust, with the sanction that EDM700 data can be downloaded ;)

Despite rumours about their existence, I have never actually come across an airspeed (or landing gear) operated timer.

[slim_slag]

There are outfits out there who will charge on the hobbs, unless the tacho is higher, when they will charge on the tacho.

So if you spend most of the time in the pattern or practice area you will pay on the hobbs - even though expensive stuff like engine maintanance is done of the tacho. If you go on a long cross country and operate at high RPM you could find yourself with a higher tacho and pay more than the hours you actually operated the engine.

Just something else to watch out for :)

[Say again s l o w l y]

Airborne time is taken on trust, though we have the records from the tower to go on if someone is doing a local flight.

There some new things on the market that will end any ambiguity, basically a hard drive that records flight time and is then downloaded when you return to base.

Most people are basically honest though, so it's rare you have a problem, though I usually notice any issues from the fuel burn. If it looks significantly out, then I'll have a dig about, otherwise we rely on honesty.

[Mark 1]

The main reason the Hobbs is used by commercial hirers, is that it allows them to advertise a lower "headline" hourly rate.

In my aeroplane, the tacho is about 20% behind the Hobbs; they both started at zero when the aircraft was flown for the first time.
So, to get the same revenue, the hourly rate would be about 20% higher if using tacho. That may amount to the same cost to the user, but it would be commercially less attractive to advertise the higher rate.

Putting an airspeed switch in the Hobbs circuit is relatively cheap and easy, and makes accurate log keeping easier, but unattractive for the same reasons as using the tacho.

I have always used tacho for group owned aircraft, as it's a fairer way of apportioning costs.

[False Capture]

Pistongone,

How many of you object to paying on the Hobbs? It makes you rush through checks whilst watching the hobbs spin and even waiting for the pitot to heat up cost you money!

For economical flying, try this:
MASTER SWITCH ................ OFF

[Darth_Bovine]

I'm pretty sure the Hobbs (certainly in the planes I hire) only turns over when the oil pressure reacehs a certain level. I.e. when the engine is running. At this point you are most certainly in command of the aircraft and hence should log (and pay) as such.

I can't see how you can pay for a lower time than you log. Surely you can't say that taxiing is not logged time? :ugh: Hence you should pay for it as such. If I could get away for only paying for the time above a certain airspeed I'd have a lot more hours in my log book and have saved a fortune! Most of it would have been spent taxiing around the airport though rather than boring holes in the sky.

Cheers,
R.

[slim_slag]

Long time ago managed to run up 0.3 on the hobbs trying to start an engine after a night at sub zero temperatures at 7000ft. Probably did more damage to the engine than many hours at cruise. So there is enough oil pressure in a cold engine just when being turned over by the battery (which held out superbly!) Asked for some additional instruction on starting cold engines after that :)

[waldopepper42]

False Capture,

Yep, that works - bit difficult negotiating controlled airspace though.

Many years ago, my club did use hobbs as the basis of charging of one of our aicraft. The master switch ploy was one reason for reverting to tacho, the other reason was that the more unscrupulous renters were simply flying the whole trip with the throttle against the firewall. Get there faster and, therefore, cheaper(!)

Not their problem if the engine wears out a bit quicker.....

WP42

[S-Works]

I charge take off to landing on the occassions I let others use mine. That way they are relaxed and dont rush into the air, miss checks or abuse my expensive engine.

I know to the litre what the fuel burn is and know if I am being had over. Touch wood so far everyone has responded to the trust appropriatly.

Hobbs and Tacho just encourages abuse.

[Martin @ EGLK]

Personally, I prefer the Tacho solution that our group PA-28 runs on.

If I fly for an hour at 90kn, the tacho shows about 45 mins. If I fly at 110, it shows about 65 mins. So I get more airtime for my money. If I was on hobbs/clock, I'd go everywhere at 110kn. I think of it as my reward for treating the engine with care. :)

The aircraft at a club that I frequent use the airswitch that Dude mentions. It activates at 40kn. I pay for my time >40 +10 mins ground time. The reason they do this is so that we DON'T rush checks & take care when taxying the old girls around a bumpy grass strip.

[BFMD]

The thing that annoys me at my club is their method of recording the times. I recently flew to a small airfield where you literally parked next to the runway. When getting back to the club I was picked up for putting 0.1 as taxying time and was told to change it to 0.2. I argued the point saying that my taxy time was about 30 seconds, but was told that's what club policy is.

I guess this must happen on a daily basis which means the aircraft's airborne times must be well out. By doing this they are reducing the airborne time they log, thus reducing how often they have to service the aircraft, which ultimately reduces their running costs. Thinking about it, is this illegal?

[A and C]

I lease a number of aircraft to a flying club and I charge for take off to landing.

The taxi time is not an issue to me as I lease the aircraft "dry" but the reason that I charge Take off to landing is one of flight safety after all if a pilot is not paying for taxi time there is no reason to rush the checks or take off with a cold engine.

Only time will tell if this is the correct policy but if the engines reach overhaul with the cylinders only being removed once for a look at the top end I will be happy.

I won't use a hobbs or the tacho to record times but if I suspect that a pilot is cooking the books the fuel uplift is sure to catch him out, I have also considered fitting GPS loggers to the aircraft to automate the invoicing but the drive to do this is to cut down on administration costs rather than squeeze the customers for more money.

[OpenCirrus619]

I know of at least 2 clubs who have a Hobbs controlled by a pressure switch connected to the pitot system fitted to their aeroplanes. This arrangement provides an accurate record of flight time.

One of the clubs adds a little (fixed amount) for taxi time.

Either way there is no incentive to rush checks - it costs the same whether you take 5 or 25 minutes between startup and take off.

OC619

[FullyFlapped]

Must admit I'm confused now, as my tacho always seems to tie up with my watch ... or have I just assumed this ?

What exactly does the tacho measure ?

FF :ok:

[IO540]

A "tacho" (the hour counter inside the rev counter instrument) might measure various things.

Some will measure purely engine running time, but they actually count revs so the "time" will be right only at say 2400rpm.

Some will measure engine running time but only if above 1200rpm or so (I have one of those).

Etc.

These threads always run for ever. There is arguably only one equitable way of doing this: charge for airborne time, and charge for fuel separately.

Technologically this is possible but since there is no tamper-proof flowmeter, you have to take it on trust that somebody has not fiddled with it. I have seen both ordinary renters and instructors fiddle with the flowmeter, to reduce the bill.

In practice almost no flying school is going to install a flowmeter; it's about £2000.

And as has been pointed out, charging for airborne time only results in an hourly rate which appears uncompetitive. You can't win.

[slim_slag]

There is arguably only one equitable way of doing this: charge for airborne time, and charge for fuel separately.

Technologically this is possible but since there is no tamper-proof flowmeter...Oh io540, nothing works for you unless it's full of silicon and costs thousands of pounds. One wonders how people got along in the old days.

How about using a marker pen and a stick of wood. After a little bit of work you can even throw the marker pen away. This will allow you to work out how much fuel you start off with and how much fuel you have finish with. Use some mental arithmentic (remember that??) to calculate the difference and bingo, you know how much fuel you used.

I know you will find objections to this simple solution, but they are all easily worked around.

[Hampshire Hog]

My club charges chocks off to chocks on but, if we experience a taxy/take-off delay, we are told to report it to the club and they adjust the time accordingly. I've done it once, after holding for commercial traffic at Bournemouth. That seems like a fair policy, so long as it is not abused.

HH

[B2N2]

Tach time only works for group operated aircraft.
For Commercial operations (pay for hire) hobbs is the way to go.
Hobbs time is equal to clock time while tacho time is not.
Tach time varies with engine load.
You pay for the time you have the aircraft running under it's own power under your control, it's that simple.
You don't complain about being stuck in traffic with a rental car do you?
You bring it back 2 hrs late, you pay for another half day.
That's their rules.
For economical flying, try this:
MASTER SWITCH ................ OFF
Right, no transponder, no radio, no Nav...and a tacho time higher then Hobbs...big FLAG

[Lister Noble]

Too many sources of time can make us uncertain about which is correct.

Years ago when I first started sailing from the UK to Europe I set one clock to GMT,one to "Eurotime" and one to British summer time.
Boy and did I get into a real muddle,all trips after that I set time on main clock to GMT and used that for all navigation,set wrist watch to local time.
Lister:)

[Pilotdom]

At My school we Log the Hobbs time and them -0.2 to allow for taxi and checks etc so

1.2 on the Hobbs gets charged at 1.0 to the student!