Class C - Before or after Engine start for clearance

steviedeviant

steviedeviant

Pre-takeoff checklist
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StevieD
POA,

So a somewhat dumb question. I rent when I fly and I fly out of a class C airport. After I do my preflight, I turn on the master, engine start, radio, etc. and then ask for my clearance. While it is often somewhat quick, is there any reason or do any of you ever get clearance from CD prior to starting the engine? I was thinking this might save a little on HOBBS.

S
 
steviedeviant said:
POA,

So a somewhat dumb question. I rent when I fly and I fly out of a class C airport. After I do my preflight, I turn on the master, engine start, radio, etc. and then ask for my clearance. While it is often somewhat quick, is there any reason or do any of you ever get clearance from CD prior to starting the engine? I was thinking this might save a little on HOBBS.

S
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It saves a few minutes.
 
I was told that the Hobbs meter doesn't start turning until you raise the engine RPM above a certain level, like 1,000 rpm or something. No idea if that's even true. I should probably check, as I have a Hobbs meter in my plane.
 
jordane93 said:
It saves a few dollars.
Click to expand...

FIFY ;)

At a Class C doesn't matter as you'll call for taxi clearance anyway, and if they have any changes or additional info they'll pass them along to you. Could be courteous and tell them you're shutting down for engine start but not necessary.
 
Rykymus said:
I was told that the Hobbs meter doesn't start turning until you raise the engine RPM above a certain level, like 1,000 rpm or something. No idea if that's even true. I should probably check, as I have a Hobbs meter in my plane.
Click to expand...

Most operate by that red rocker (not Sammy) switch over thar.
 
Lots of folks will call before engine start on a handheld for the very reason you mention.
 
Rykymus said:
I was told that the Hobbs meter doesn't start turning until you raise the engine RPM above a certain level, like 1,000 rpm or something. No idea if that's even true. I should probably check, as I have a Hobbs meter in my plane.
Click to expand...

You were probably told wrong. Most HOBBS meters are wired to either the master or an oil pressure switch (oil pressure = HOBBS starts ticking). Some, typically twins, will start when the gear comes up. I've never heard of one tied to a certain RPM (and that's next to impossible unless the HOBBS is displayed as part of a digital engine monitor or EFIS system (G1000, etc.). ).
 
I'm assuming you are talking about a VFR departure. Class C can be very busy or very quiet. But I can't recall any time I have been delayed enough getting Class C departure instructions (VFR, it's not really a "clearance" and that's not just semantics) to make much of a difference. Recall that 0.1 on the Hobbs is about 6 minutes.
 
Even for IFR clearance and departure, I spend MUCH more time checking instruments and running up than I do talking to CD at a Class C. And the taxi is usually much longer, too. It just doesn't take that long.
 
MAKG1 said:
Even for IFR clearance and departure, I spend MUCH more time checking instruments and running up than I do talking to CD at a Class C. And the taxi is usually much longer, too. It just doesn't take that long.
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True but nothing wrong doing it the way the OP wrote either. Just another way to do it. Less distraction taxing also if you already have your "clearance".
 
mscard88 said:
True but nothing wrong doing it the way the OP wrote either. Just another way to do it. Less distraction taxing also if you already have your "clearance".
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If you have to talk to CD for VFR departure, you already have your "clearance" when you first contact Ground. It won't come during taxi like it does at some Class D's.
 
Rykymus said:
I was told that the Hobbs meter doesn't start turning until you raise the engine RPM above a certain level, like 1,000 rpm or something. No idea if that's even true. I should probably check, as I have a Hobbs meter in my plane.
Click to expand...
The Hobbs begins rolling from the time the master is turned on, to the time it's turned off.

As for the OP. Either works, personally I've always had the engine running as I like to limit my electrical use while the engine is off.
 
Interesting, I always thought the hobbs meter was activated by an oil pressure switch on the engine. Maybe different aircraft are wired differently? Seems like someone flying VFR outside of controlled airspace could just flip the master off and get free time if that was the case...
 
MAKG1 said:
If you have to talk to CD for VFR departure, you already have your "clearance" when you first contact Ground. It won't come during taxi like it does at some Class D's.
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Man you'll argue about anything. Are you this rigid in everything? All this thread was about is the way the OP does it. And it's fine OP. :rolleyes:
 
Over 40 years of flying when renting I've run across several different ways of activating the Hobbs. For Cessnas it seemed the most common was wired to the oil pressure switch. My experience with Pipers were that most of them were wired to the Master. I've even seen the Hobbs wired to the RB (Rotating Beacon). One Piper I flew years ago the Hobbs was wired to the Avionics master.
 
mscard88 said:
Man you'll argue about anything. Are you this rigid in everything? All this thread was about is the way the OP does it. And it's fine OP. :rolleyes:
Click to expand...

thanks. At KBHM, I have to call clearance first and tower handles ground. I was curious about how others do it which is what promoted the question. I was taught to call after start-up and really never had much of a problem. But as I develop hours, I like to see how others have done it. Thanks for the feedback.
 
Stevie,

My planes based out of a class C and we are the same way you contact clearance delivery prior to taxi, if you don't ground will tell you to call clearance then call them back (unless we are doing closed traffic then it's just straight to ground)

Anyway to answer your question whether I get it on a hand held or after I start the engine is almost 100% a factor of how hot it is outside. If it's hot, I'll get the clearance on my hand held, that way I'm not sweating in the plane with no airflow! If it's a nice cool day I'll get my clearance in the plane after I start!

Spending many many hours at Class C airports I've seen people do it commonly both ways, i'd say there's no right or wrong way
 
Van's SOP is to trigger the Hobbs with an oil-pressure switch (top of frame, jutting out at an angle). EFIS will tally engine hours too, but I liked the idea of an old-fashioned Honeywell Hobbs meter on the panel.

 
A Hobbs meter is just an elapsed time meter. It counts time when it is powered on. What it's connected to indeed is dependent on the details of the installation. As pointed out they are often connected to an oil pressure switch so they roughly run when the engine is stared but some are just connected to the master. As pointed out, mine is connected to the gear which gives the closest approximation to the FAA "time in service" that maintenance should be based on (though the FAA will take just about anything that's consistent as TIS, usually a recording tach).

There are some electronic recording tachs that don't record time at idle, but that again is atypical. They tend to just count revolutions of the engine divided by some nominal cruise rpm. For example, every 2400 revolutions clicks off a minute on the tach.

As far as maintenance is concerned, time in service is time the airplane spends off the ground.

As far as your pilot flight time is concerned, time is the time the airplane first moves under its own power (so it includes taxi time and arguably other time you spend on the ground with the engine running as the airplane almost certainly moves a bit when you fire it up).

The time to get a taxi clearance at a class C for VFR is rarely much longer than to get one at any class D. You may bet a squawk code in the process, but you're typically not going to spend a long time waiting. Getting an IFR clearance even isn't that bad. In fact, it's better at a Class C or B airport then getting one for a class D or uncontrolled field (the latter I may do before engine start in some circumstances).
 
Rykymus said:
I was told that the Hobbs meter doesn't start turning until you raise the engine RPM above a certain level, like 1,000 rpm or something. No idea if that's even true. I should probably check, as I have a Hobbs meter in my plane.
Click to expand...
You're thinking if the recording tachometer. As others have pointed out, the Hobbs meter will start running depending on how it is rigged (electrical off the master, oil pressure, gear squat switch...etc). RPM won't effect a Hobbs.
 
steviedeviant said:
POA,

So a somewhat dumb question. I rent when I fly and I fly out of a class C airport. After I do my preflight, I turn on the master, engine start, radio, etc. and then ask for my clearance. While it is often somewhat quick, is there any reason or do any of you ever get clearance from CD prior to starting the engine? I was thinking this might save a little on HOBBS.

S
Click to expand...
It really depends on the airport and how busy it is. At most Class C airports, it really doesn't take that much more time. Think about this: 0.1 on the Hobbs is 6 minutes. It doesn't take anywhere near 6 min to get a clearance. Now, if it is a busy airport and you know it may take a while to get out, then it might make a little sense. I usually carry a handheld when I fly, but never really felt the need to use it to pick up my clearance.

Also, this time of year as temps drop, you might as well use that extra run time to warm the engine/oil up.
 
Personally, the only times I have found it advantageous to call for clearance before engine start is in the jet, but in that case we are hooked up to a power cart (not HH radio) and we do it that way to be able to program the flight computer and have it all ready to go when we do start up.

And FWIW, I am based at a Class C.
 
steviedeviant said:
POA,

So a somewhat dumb question. I rent when I fly and I fly out of a class C airport. After I do my preflight, I turn on the master, engine start, radio, etc. and then ask for my clearance. While it is often somewhat quick, is there any reason or do any of you ever get clearance from CD prior to starting the engine? I was thinking this might save a little on HOBBS.

S
Click to expand...


I have been known to use my handheld for this...
 
Just a question about the class C comments and CD. I flew (VFR) out of a class C for many years and not so much now, but the procedures at this class C were to listen and take down ATIS information and then contact CD with that information and tell them where I was going. They would give me my transponder code and some departure instructions (stay at or below) some of the time. There's mention about VFR in this thread and about clearance. Are there some class C that you do not contact CD for VFR and just go to ground, tower and departure? I just assumed that my class C was the same as others (only because I haven't or do not remember ever going into another class C).
 
FlyBoyAndy said:
Just a question about the class C comments and CD. I flew (VFR) out of a class C for many years and not so much now, but the procedures at this class C were to listen and take down ATIS information and then contact CD with that information and tell them where I was going. They would give me my transponder code and some departure instructions (stay at or below) some of the time. There's mention about VFR in this thread and about clearance. Are there some class C that you do not contact CD for VFR and just go to ground, tower and departure? I just assumed that my class C was the same as others (only because I haven't or do not remember ever going into another class C).
Click to expand...

Yes, whether CD is used for VFR at Class C is not standardized, and it varies seemingly randomly. For instance, CD at Oakland is strictly for IFR. If you contact them for a VFR departure, they will hand you off to Ground.
 
I think it was mentioned above, but whether to (or not to) contact CD for VFR departure should be included on the ATIS for the airport, but may not be always. Lacking specific guidance, when in doubt, contact CD. Worst they can do is push you to ground.

Regarding the OP, I've always contacted CD after engine start. The time to obtain and read back clearance is minimal, and allows engine temps to come up and stabilize (which is handy in cooler climates with a short anticipated taxi, IMO). The only exception to this that I have exercised, is when I have to contact Potomac TRACON to obtain a beacon code/departure frequency for DC SFRA ops. This is done via telephone, and I do it prior to engine start because it's too noisy in the airplane to do it after engine start.

So, long story made even longer, it's your choice unless it's spelled out in writing or on the ATIS.
 
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Rykymus said:
I was told that the Hobbs meter doesn't start turning until you raise the engine RPM above a certain level, like 1,000 rpm or something. No idea if that's even true. I should probably check, as I have a Hobbs meter in my plane.
Click to expand...

That sounds like a Tach.
 
cowman said:
Interesting, I always thought the hobbs meter was activated by an oil pressure switch on the engine. Maybe different aircraft are wired differently? Seems like someone flying VFR outside of controlled airspace could just flip the master off and get free time if that was the case...
Click to expand...

Yep and with a handheld radio plus an iPad w/ ForeFlight, you won't lose much in the way of VFR capability. But it would be a criminal act.
 
Thank you everyone for the feedback. I realize the question was somewhat silly, but I was interested in what everyone was doing. I always learn a lot from asking and it usually leads to other comments and questions from others. So thank you again.

I also see that many of you have a handheld, which I do not have. I am sure it would be something worth getting for a backup.

Stephen
 
steviedeviant said:
Thank you everyone for the feedback. I realize the question was somewhat silly, but I was interested in what everyone was doing. I always learn a lot from asking and it usually leads to other comments and questions from others. So thank you again.

I also see that many of you have a handheld, which I do not have. I am sure it would be something worth getting for a backup.

Stephen
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Yup. I picked one up after I lost an alternator at a remote airport, and the battery discharged enough that I couldn't transmit to get takeoff clearance. You find uses for them.
 
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