112th_Rossi Posted April 16, 2012 Posted April 16, 2012 Hi guys I was flying a mission last night, which involved some high altitude flight. As I was climbing through 10,000ft I forgot to enable my pitot heat switch. As a result, when I was returning to base and reducing speed, my IAS indicator was all over the place causing a speed caution warning. It recovered eventually (I guess as I was at a lower altitude or something). I am right in thinking this is what happens if you neglect the pitot heat arent I? Also, is there a way of switching to an alternate speed indication system if this happens? Thanks.
Eddie Posted April 16, 2012 Posted April 16, 2012 I am right in thinking this is what happens if you neglect the pitot heat arent I? Yes. Also, is there a way of switching to an alternate speed indication system if this happens? No. Just switch on the Pitot Heat and the fault will clear in a minute or so.
badger66 Posted April 17, 2012 Posted April 17, 2012 Dont forget to heat your peter heater ..... it can do funny stuff otherwise .
amalahama Posted April 17, 2012 Posted April 17, 2012 Also, is there a way of switching to an alternate speed indication system if this happens? Thanks. Well, you always can check your TAS in CDU screen Regards!
viethson Posted April 19, 2012 Posted April 19, 2012 Well, you always can check your TAS in CDU screen Regards! And what do you think where this information is taken from? ;-) You could take the groundspeed as this is only calculated by INS and/or GPS
bluepilot76 Posted April 19, 2012 Posted April 19, 2012 If you don't heat it, and fly through moisture below zero, it can freeze over the tube. Then your ASI will will be inaccurate. So turn it on, pretty sure you would do this before takeoff. AF447 started to go wrong when the pitot froze over. Technical Specs: Asus G73JW gaming laptop... i7-740QM 1.73GHz ... GTX460m 1.5GB ... 8GB DDR5 RAM ... Win7 64 ... TIR5 ... Thrustmaster T16000m
bluepilot76 Posted April 19, 2012 Posted April 19, 2012 Ground speed from GPS etc might be slightly useful, but you need to be cautious: if the winds are 100 knots at your altitude (not unusual), this could easily be the difference between stalling or exceeding red line speed. Technical Specs: Asus G73JW gaming laptop... i7-740QM 1.73GHz ... GTX460m 1.5GB ... 8GB DDR5 RAM ... Win7 64 ... TIR5 ... Thrustmaster T16000m
viethson Posted April 21, 2012 Posted April 21, 2012 (edited) In level flight you should have no problem with overspeed even at full throttle, this is not Concorde :-) During approach speed is vital. Here groundspeed can be useful. As there normally should be headwind on final flying your normal app speed as groundspeed is on the safe side. Also use your AOA gauge. You can perfectly fly the aircraft without any speed indication just by looking at this vital instrument. Cheers Edited April 21, 2012 by viethson
112th_Rossi Posted April 21, 2012 Author Posted April 21, 2012 Will an erronous air speed indication affect the TVV?
Tornado_Pilot Posted April 22, 2012 Posted April 22, 2012 Mhh, interesting question ,though I#m not quite sure about this one. Since the TVV is somewhat of an "impact point" calculated with a given time and speed, it could lead to an erroneous TVV calculation.
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