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Pitot heat check?

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Pitot heat check?

Old 8th Jan 2010, 06:08
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Pitot heat check?

I was flying in a C172 and saw that the pilot was doing this pitot heat check thing.

You needed to after startup put the pitot heat on and then check the amp meter and then turn it off again. You could see a little increase in amp usage when turning the pitot heat on.

Why on earth do you do this check?
And why using the pitot heat for this check?
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Old 8th Jan 2010, 07:26
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A wild guess: to see if the pitot heat works? Think icing and no working pitot heat.

-- Badente
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Old 8th Jan 2010, 07:27
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Well you check it to make sure it works. I check it by feeling whether it gets hot or not.

You can use the pitot heat to put a load on the alternator as it is a relatively high current device, and thus checking the alternator is working ok....
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Old 8th Jan 2010, 08:50
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Yes, but he told you can use landing light to check with as well if you don't see any indication on the amp meter.

And the alternator was not on, it was just battery on and startup and then checking the pitot heat with the amp meter.

You guys don't do this?
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Old 8th Jan 2010, 09:14
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If the aircraft I'm flying has a reliable amp meter I use this to check that my pitot heat is working, if not I check if its warm.

The aircraft I fly at the moment has an amp meter that indicates all over the place, so I have to turn everything on to see any difference (still indicating all over the place but in a different pattern )

Checking landing light and pitot heat with amp meter saves a bit of battery during your walk around (good at this time of the year).
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Old 8th Jan 2010, 10:56
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To be perfectly frank and honest not all pilots always bother to check that the pitot heat is working when intending visual flight - after all, if the pitot does ice up you can fly perfectly happily without the instruments, can't you, we've all practiced circuit and landing with the ASI covered up, haven't we.

To take off intending flight in cloud having not checked that the pitot heater is working would be another matter entirely.
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Old 8th Jan 2010, 11:22
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I check it by feeling whether it gets hot or not
Well... with great caution! if it is working, it will get hot enough to burn you. I suppose that pitot heat for a VFR only aircraft has save a few lives over the years, probably those who have foolishly entered meteorlogical conditions they should have avoided. in more than 30 years of flying I have never chosen to use pitot heat in VFR flight unless it was a checklist item. I certainly have used it many times during flight in icing conditions.

I hold the opinion that it is installed on many light aircraft for two simple reasons: Marketing - it makes the pilot think he's flying a big plane, but more likely (in the case of Cessna) because it won't bend, and the maintainer does not have to keep aligning it with the airflow, as we had to do with the early ones, when people bent them!

As for checking the ammeter/electrical system, operating the landing light or flaps would be a better choice than the pitot heat, as each of those draw twice the current (amps) of the pitot heat. Even the flashing beakon draws more, and you can sometimes see its pulse on the ammeter.

Generally, aircraft electrical systems have a means to indicate the failure of the ammeter anyway, though there is one alternator circuit failure mode which will not trigger this indication in some C 150's, but not other Cessnas.
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Old 8th Jan 2010, 11:23
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Pitot heat check?

we've all practiced circuit and landing with the ASI covered up, haven't we.
Actually no I never have and I wouldnt have thought this would be common practice on safety grounds. In my humble opinion, airspeed is critical when in landing configuration on approach for obvious reasons. I once had a vacuum failure on an approach and was fortunate enough to have a G430 which displayed groundspeed so I made a faster than normal approach to give myself a greater margin for error but it wasnt something I enjoyed.
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Old 8th Jan 2010, 11:36
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I used to teach it as well to the students.

Along with no altimeter circuits as well.

If they wern't fixated on instruments I might not have bothered but almost all of the FS 1000hour pilots got those lessons. And nearly all of them were shocked to find they were more accurate on everything with no instruments than they were with them available.

How do you think instructors fly an approach?

I certainly don't sit there looking across at the parallax error. Set the machine up by ear and look out the window. And when the student is to fast or slow you tell them not by looking at the ASI but looking out the window. It annoys the hell out of them when your looking at the wing tip and saying airspeed low/high. Does the picture look right.
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Old 8th Jan 2010, 11:46
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Well... with great caution! if it is working, it will get hot enough to burn you.
I made this mistake on an SR22. The PA28 I normally fly gets warmish, but the Cirrus had some markings from burnt on rubber on the pitot. I should have known better really!
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Old 8th Jan 2010, 11:49
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Pitot heat check?

And nearly all of them were shocked to find they were more accurate on everything with no instruments than they were with them available.
Im not going to argue with an ex instructor but I dont fully understand how a pilot could say hold 1000ft in the circuit more accurately without an altimeter than with one and the same applies to say holding 70kts as an example over the threshold. I know there are a lot of old school pilots who subscribe to seat of the pants flying but I personally dont see how it could be more accurate then when flying on instruments, in fact again in my humble opinion I would say its simply not possible.
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Old 8th Jan 2010, 12:02
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Actually no I never have and I wouldnt have thought this would be common practice on safety grounds.
Sigh. Apologies for leaving out the obvious:

"Don't try this at home on your own, children, take a grown-up with you in the right hand seat."
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Old 8th Jan 2010, 12:09
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A2B, holding perfect altitude in the circuit is only needed when other traffic is around, and holding the perfect approach speed is only needed when flying into seriously short strips.

All other occasions, it's very well possible to fly a full circuit with zero instruments. Yes, you will not fly at the perfect 1000 feet and will not have the shortest landing roll possible, but you will have gained valuable experience in controlling the aircraft when things go pear-shaped. That's what's learning to fly is about, for a significant part.

Of course if you have a for-real pitot/static failure you're not going to fly into a situation where altitude holding is critical, or into a seriously short strip anyway.
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Old 8th Jan 2010, 12:12
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Pitot heat check?

Im not making a point about whether a safety pilot or indeed an instructor is present. The point I am making is that airspeed is critical when on approach and in landing configuration. I am questioning the wisdom of intentionally covering up the airspeed indicator in this critical phase of flight and indeed making a landing with it covered up. Now any training I have ever done always saw whatever was covered up, removed before making the final approach and I can see the good reason in that. If there are other schools of thought, then I personally havent come across them. I dont see the logic in it but thats just my opinion. I know in the UK we are health and safety barmy but I would actually think this wasnt conducive to safe practice.
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Old 8th Jan 2010, 12:15
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Pitot heat check?

Backpacker I suggest you read the previous posts to which I was referring. Of course its safe to fly a circuit on visual judgement. No one is disputing that. What I questioned was mad jocks comment stating he witnessed a majority of pilots flying more accurately to specific parameters by the seat of the pants judgement as opposed to when using instruments and that is what I disputed. Maybe you was a little quick to get your response in?
Now flying a fast approach with loads of runway is fine but your maybe not taking into account the perils of flying too slow and approach which is certainly more likely when going into a shorter strip.
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Old 8th Jan 2010, 12:27
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Current instructor but unfortunately somewhere that you can't fly GA.

Its all to do how you were taught the first exercises. Personally I am anal retentive about attitute flying and trimming. You are not flying by the seat of your pants when you are doing this by looking out the window.

In the circuit you get the student to stick a bit of the plane on the runway on the down wind and look at the picture. On the PA38 and that sort of type its the wing tip and on a C172 its the tie down bolt on the wing strut.

Then to get the circuit height you just get the picture to match what you want it to be. Power you set by ear then adjust and thats it.

Same on approach get the picture right and configuration right and everything works.

Its pefectly normal for a student who was chasing needles with +- 5 knots and +-100ft in the circuit to get within +- 2 knots and 20ft all in a couple of circuits with no instruments. After that if you are horrible you can throw a bad wx circuit at them at 600ft and 9 times out of 10 they will be bang on 600ft without even showing them the new picture. PFLs again it comes into its own being able to judge your height and speed off attitude and is further refined in that exercise to the point that when you start doing land aways the student can do it with an unfamilar field and still get it pretty much spot on with one quick glance at the alt to confirm that its right.

After they can do this the amount of released capacity is huge. No more panic on the downwind, base etc and all you have to do is get the flare sorted and you throw them off solo.

Day VFR in a fixed prop aircraft in class G it really won't bother me two hoots if all the instruments packed. And for my ex students I don't think it would bother them to much either.

If you can go and do a CRI course at ontrack and it will become very obvious what I am on about after a couple of hours in the RHS.
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Old 8th Jan 2010, 12:38
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O and to answer the orginal post. There is a theory out there that if you test the heating without air going over the tube you reduce the life of the tube.

Also its meant to check that your alternator circuits are regulating the voltage properly. So if you switch it on and see a increase in output and no low voltage light come on your hunky dorry to go.

Persoanlly I didn't used to bother checking it unless I was doing night ratings.
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Old 8th Jan 2010, 13:18
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OK, As a GA pilot and airline Safety Manager, Quite simply, what does the manual/sop/checklist tell you to do? then do it! simple. It doesn't matter what you think you know, these publications are provided for a reason. If you disagree with the publication then challenge it correctly, it may save someone else. Sadly, all to often people ignore them then I end up getting statements like 'with hindsight........'
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Old 8th Jan 2010, 13:29
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Thread drift I know, but;

Learning to "feel" the aircraft as you fly (an approach and landing in particular) is vital. Dependance on an airspeed indicating system in anything other than a very high performance aircraft is to me foolish.

During the early phases of my night training (1970's) more than half the circuits flown were with absolutely no instrument lights at all - thus no instrument information available (yes, I had a flashlight, but it's use was not permitted for training). The object was to learn to feel the plane in it's approach configuration. This has eased my remaining flight many times over that years, as bugs in the pitot tube will cause odd errors in indications (ever seen an ASI read negative once airbornre?) and numerous cockpit lighting failures over the years have meant that you're feeling your way down, not reading instruments to do it, and at night, with fewer visual cues.

I once flew an instructor home after his delivering an aircraft. I purposely flew an extra slow curved approach, while watching and waiting for traffic to clear. Peeping stall warning, 'cause that's what it's there for. Once on the ground, the instructor reported to anyone who listened that I was an "idoit" for "flying around below stall speed". His boss correctly asked him if I was below stall speed, why did I not stall? (He had no answer for that). The truth is, I was looking out the window, and had no idea what speed I was flying, and as long as the approach felt safe and with an adequate margin for safety for the conditions, I really don't care what the airspeed was in numbers - it's AoA and G that matters really.

Several times I have had to "help" with an approcah in its latter stages from right seat. most GA aircraft do not have two ASI's, so I'm not looking at one in front of me. When we're slipping over trees into a small sheltered bay in a lake, I'm not looking over to the left panel in any case! I'm just going to feel my way to the appropriate approach attitude.

Those pilots who depend on indicated numeric information to the exclusion or obliviousness (if that's a word) of flying their aircraft with respect to "feel", in visual conditions, are overlooking their resonsibility to fly as safely as possible, and should refresh themselves with some very basis skills. Those skills are equally valuable for most any aircraft they would fly.

It is certainly possible for the characteristics of an aircraft to change in flight (airframe ice) such that flying an approach by adhering to flight manual speeds would be very dangerous. The pilot must "feel" that the aircraft must be flown faster to be flown safely in that condition. I hold the personal opinion that a Dash 8 400 would not have crashed in New York State last year if the pilots were simply "feeling" the plane.

I know that the flight training community puts a lot of thought into what are appropriate things to train new pilots, but the thought that elementry flight training does not leave a pilot able to confidently land without referring to indicated airspeed alarms me.
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Old 8th Jan 2010, 14:31
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Continuing the thread drift, when I learned in gliders, a circuit without instruments was mandatory before solo. Everyone, bar none, performed better.

Yes, I have taken off in an aeroplane with the pitot cover on and it's no big deal. Circuit, land, remove cover, hope no one noticed that one inevitable result of an interrupted pre-flight...

Similarly, once when the little flappy pitot cover on the Champ didn't flap enough when airborne, it didn't really occur to me that I shouldn't carry on to France as planned. We found another cause to land en route, though, so I did sort it out before carry on.
I might have thought differently without any of my very basic instruments, but the fact is the aeroplane doesn't know what it has inside and will fly nicely if allowed to do so by the klutz inside.

I'm surprised if students aren't given that training anymore.
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