Correct use of pitot heat

[modelman]

Could use some advice on this.
TIA
MM

[tmmorris]

You'll get a lot of different answers...

For me, because the compass is swung with the pitot heat on, it's always on in flight and off on the ground:

1. on as part of a last-gasp check as I line up on the runway: strobes, pitot heat, transponder.

2. off as part of the after-landing checks before I taxy in.

Tim

(edited to add: off on the ground to prevent overheating and burning out, of course)

[IO540]

The first one is interesting and subtle, TM. Otherwise I would have said: anytime below +5C.

The last one would (I hope) be type specific :)

[henry crun]

Always on pre takeoff, and off after landing.

That way if you forget to remove the cover there is a good chance it will burn off before you have to land........................................................ ............................................................ ............................................................ ......so I am told ;)

[scooter boy]

I encountered this earlier this year at FL120 while flying through a non-forecast trough in central France on a trip back from Palma de Mallorca. The tops were well above my service ceiling and the bottoms were down to the ground (according to ATIS/volmet).
Conditions were IMC, very cold and wet with moderate turbulence. I had the airframe deicing on but forgot to put the pitot on. The G1000 suddenly started showing all kinds of incredibly low airspeeds and very high outside windspeeds (trying to make sense of the data it was getting I suppose).
Fortunately I rapidly realised the error of my ways and about 5 seconds after switching it on the airspeed readout returned to normal. Nothing in the pitot drain after shutdown.

In answer to the question I usually leave it off except when I would consider using airframe deicing.

SB

[S-Works]

Clear of cloud and in sight of the surface I leave it off. Airways flying it goes on at the same time as the transponder and off at taxi.

If I encounter cloud at any time it goes on.

[smith]

MOSTA checks every thousand feet.

M= manifold pressure (increase/decrease as alt/FL inc/dec)

O= OAT, when approaching zero pitot heat on

S= suction

T= T's and P's

A= alternator


Run thru these checks climbing and descending

[mad_jock]

Whats the reasoning for not having it on from takeoff to landing?

[RatherBeFlying]

My only pitot problem has been with mud daubber wasps which I discovered a considerable way down a short runway; so lifted off and eventually worked out that the a/s had been converted to an altimeter:confused:

Have flown quite a bit at temps well below freezing without pitot problems. If you need pitot heat in your average light a/c, you likely also have an airframe icing problem:uhoh:

[scooter boy]

Whats the reasoning for not having it on from takeoff to landing?

Not living in subarctic Scotland!

SB ;)

[tmmorris]

Nobody's commented on the compass-swinging issue I raised...

Depends on the aircraft, but in some cases it can have a significant effect, depending on how close the pitot tube is to the compass, of course. Try it next time you are in the aircraft and see. It will be greater on some headings than others - you'll need to be on the ground to see it, of course, as we're only talking about 1 or 2 degrees, but it's careless to let that sort of thing escape you unnecessarily.

The point being that the compass is swung with everything on, i.e. all the radios, &c., so the deviation card is only accurate under those circumstances.

Tim

[jamestkirk]

Henry Crun - You may be joking so forgive me. But, who told you that about the cover. If anyone forgets to remove a pitot cover before flight, needs to go back to student pilot mode and do some re-training. It certainly is one of the strangest things i have evr heard. Please get no more advice from whoever that was.

The person who asked about not having it on b4 t/o and after land. They can get so hot that the elements burn out. Also some pitot heats have a plastic sleeve inside that can melt. We had two C152's do exactl that.

I was taught that whenever you are near/in/around etc. visible moisture in temperatures of +2 degrees or below, you show activate de/anti icing equipment. It's an IR thing so may vary a little from aircraft to aircraft.

[llanfairpg]

So Boys and Girls operate aircraft as the maker intended and you will not go far wrong. Listen to rubbish on forums and----well i will leave that to you!

[bookworm]

So Boys and Girls operate aircraft as the maker intended and you will not go far wrong. Listen to rubbish on forums and----well i will leave that to you!

Sounds prudent, but it's worth reflecting that the maker writes the POH prior to S/N 0001 being delivered, based on practices of the day and a limited amount of test flying.

For my aircraft, those practices derive from 1964, and the pilot community has a few million hours of operational experience since the POH was written. POHs are all very well, but in GA operations they're no substitute for thought and good risk management.

[jamestkirk]

One of our PPL's was berated by an air ground operatoer when he said he was going to use 10 degrees of flap for take off.

He told the PPL that there was no such techniques for the PA28 as it did not state it in the POH.

He obviously did not read the supplement from Piper dated August 1989.

[P.Pilcher]

Just getting airborne in my Twin Otter VMC on a cold frosty morning, 16 pax behind me on a scheduled service to Gatwick. Everything normal, aircraft climbing well, altimeter winding up as expected. Airspeed slowly starts to fall. Funny - engine instruments O.K., altimeter still winding up, attitude as expected in the climb, controls feel totally normal. Airspeed continues to drop. Even more mysterious! Think about it some more, check overhead panel, switch on pitot heat that I must have missed on my pre-takeoffs, ASI reading rapidly returns to normal, flight continues as planned.

P.P.

[bookworm]

These guys (http://aviation-safety.net/database/record.php?id=19741201-1&lang=en) weren't as lucky as you.

[IO540]

I wonder what the psychology involved in that was, bookworm.

Let's face it, if you were flying along, and the engine is doing fine, the fuel flow is fine, you are straight and level (you have at least two AIs), but the ASI is showing you are doing mach 3, what would you suspect, initially?

It's like that bizzare 757 accident off South America which had the static vents taped over, and crashed into the sea.

It's of course easy to pick cheap holes in accidents and one must avoid that, but it seems that the pilots concerned lacked the most basic systems knowledge.

[matelot]

One of our PPL's was berated by an air ground operatoer when he said he was going to use 10 degrees of flap for take off...

What on earth has that got to do with an a/g operator, unless he was genuinely concerned about safety?

[flyboyike]

On our airplane, the probes are heated automatically regardless of switch position whenever the engines are on.

[Kit d'Rection KG]

it seems that the pilots concerned lacked the most basic systems knowledge.

Pitot/static problems are possibly the most unpleasant things to encounter in a large transport aircraft, and are not well trained in many operations. It may be very difficult indeed to comprehend what is going on, and it may be almost impossible to dismiss visual cues which are deeply ingrained as reliable.

That accident had precious little to do with systems knowledge, in my opinion.

On the plus side, I'm sure the bereaved relatives will be most heartened to read your analysis...