If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
Roger
The pitot heater when bird is flying is cooled by the airflow and doesn't get super hot which could cause a failure in a short period of time. In my thousands of hours I have never experienced a pitot heater failure. Have you BOb? Flying All Weather Interceptors we did check heater on preflight. You can do same in GA if visable moisture is seen or forcast.. I've had insects get in pitot tube and block but that should be caught on pre-flight. If it (heater) were to fail and the pitot tube ice up and become blocked then you can fly partial panel until you can get to an altitude where the ice will melt. In fact you can land partial panel if you have any experience partial panel. The pitot system is a 'closed' system and anything entering the pitot tube will not migrate back to the airspeed indicator. The 'L' shaped pitot tubes have a small calibarated hole as I recall in the bottom just as they bend up and go insuide the wing/fuselage and any water that gets in the front of the tube is drained out by ram air pressure and gravity. May have used some wrong words so anyone current on systems feel free to take me to task. Bottom line is that moisture in pilot tube is not a real big problem in my estimaton, Visable moisture, just turn on the pitot tube and go fly. Big John On Sun, 02 Nov 2003 16:43:54 GMT, "Roger Long" om wrote: Did I miss this in my training? I thought Pitot Heat was only needed in icing conditions. Tom Haines column in this months AOPA mag recommends turning it on in or near moisture at any temperature. Is this a typical recommendation? Is there an effect like a carburetor that could cause ice to from in the pitot at above freezing ambient temperatures? Since the heat is provided by a hot filament, having it on a lot unnecessarily would make me worry about finding that it's not there when you need it. |
#12
|
|||
|
|||
Big John wrote
In my thousands of hours I have never experienced a pitot heater failure. Have you BOb? Not personally, but it was apparently a problem when I first started airline flying (1967). Maintenence was constantly complaining about flightcrews turning it on too soon before takeoff or not turning it off quickly enough after landing. After a couple of airline accidents related to pitot heat, a switch was added to the squat switch to turn the heaters on regardless of the cockpit switch positions. I've had insects get in pitot tube and block but that should be caught on pre-flight. I've had both pitots blocked on a B-720 (Belize Airways, 1978). It was not obvious during preflight due to high location of the pitot tubes and did not manifest itself until about 100kts by which time it was time to fly. Pitch/Power solved the problem easily. If it (heater) were to fail and the pitot tube ice up and become blocked then you can fly partial panel until you can get to an altitude where the ice will melt. In fact you can land partial panel if you have any experience partial panel. May have used some wrong words so anyone current on systems feel free to take me to task. Although technically correct (anything less than full IS partial), "partial panel" in GA usually refers to loss of gyro instruments. Pitch/Power would be a better way to describe flying without the airspeed instrument. Bob Moore |
#13
|
|||
|
|||
Bob
Smart move to tie to "Squat" switch in. I had my RO read the check list to me every flight so never forgot to turn heat on and off. On Tue, 04 Nov 2003 14:03:47 GMT, Robert Moore wrote: Big John wrote In my thousands of hours I have never experienced a pitot heater failure. Have you BOb? Not personally, but it was apparently a problem when I first started airline flying (1967). Maintenence was constantly complaining about flightcrews turning it on too soon before takeoff or not turning it off quickly enough after landing. After a couple of airline accidents related to pitot heat, a switch was added to the squat switch to turn the heaters on regardless of the cockpit switch positions. I've had insects get in pitot tube and block but that should be caught on pre-flight. I've had both pitots blocked on a B-720 (Belize Airways, 1978). It was not obvious during preflight due to high location of the pitot tubes and did not manifest itself until about 100kts by which time it was time to fly. Pitch/Power solved the problem easily. If it (heater) were to fail and the pitot tube ice up and become blocked then you can fly partial panel until you can get to an altitude where the ice will melt. In fact you can land partial panel if you have any experience partial panel. May have used some wrong words so anyone current on systems feel free to take me to task. Although technically correct (anything less than full IS partial), "partial panel" in GA usually refers to loss of gyro instruments. Pitch/Power would be a better way to describe flying without the airspeed instrument. I'll sure accept the terminology Pitch/Power. I just haven't heard it used very much in GA so used the terminology that has been around for years and years. Oh Belize! Terminal used to be a couple of men in white shirts sitting behind a rough hew'n (sp) table in a old palm limb Boheia (sp). Used to fly the B/A-26 in there from Panama to 'show the flag. The only bar in town was run by a German expiate (sp) (probably a Nazi????) We always had to refuel and on every take off I had an engine cut out ( With the R-2800 (with water) cranking out 2500 HP and the 'Lord' mounts cranked all one way and engine lost power (quit), the cowling that set about 5 feet from cockpit, would rotate about two feet with this loss of torque. Engine would then catch and engine torque go up again and cowling would rotate back two feet. One never knew if engine was going to stay on nacelle or come off??? Never found out why and even took a chamois one trip and ran all the fuel through it and still cut out. Was the road into town still built on a dike with dead trees an alligators in the water along side? Big John |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Burning out the pitot heat? | Mitty | Instrument Flight Rules | 3 | December 30th 04 05:04 AM |
Painting and air cooled motor? | CitizenX | Home Built | 5 | June 30th 04 12:47 PM |
28 volt pitot heat | B2431 | Home Built | 15 | April 17th 04 03:25 PM |
pitot heat question | K. Ari Krupnikov | Instrument Flight Rules | 7 | December 11th 03 01:51 AM |
Pitot heat | Paul Mennen | Owning | 10 | November 6th 03 09:54 AM |