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A320 loss of all pitot vs Mach

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A320 loss of all pitot vs Mach

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Old 4th Mar 2010, 04:39
  #21 (permalink)  
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Mach only uses the TAT probe, not pitot.

.. I think you'd best produce some authoritative information to support that contention .. perhaps a schematic of such an unusual installation ?
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Old 4th Mar 2010, 15:50
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Mach only uses the TAT probe, not pitot. ...... Say again all after the first word

Ditto to John_Tullamarine's wise words.

Whether it be old 'steam driven' equipment, or modern high fallutin' electronic ADCs, Mach Number is derived by comparing the degree of compression of the Total Pressure on the aircraft against the Static Pressure.

And where does the Total Pressure come from?............The Pitot Tube of Course
And where does the Static Pressure come from?...........The Static Port of course
And where does the TAT probe come into measuring Mach Number?.......It DOESN'T

No Pitot and no Static, no Mach Number

From the 'raw' Total Pressure gauged in the Pitot Tube, we can obtain -

.1. CAS/RAS after removing position error,
.2. EAS after removing compressibility error,
.3. Mach after comparing CAS with Static Pressure.

The only time that TAT/SAT comes into play with the manometry of the aircraft is by comparing to Mach Number to obtain TAS, and as one of several temperature components in correcting Indicated Altitude to TRUE Altitude. Not forgetting that Mach Number (or TAS) and TAT (or RAT) can be used to calculate SAT, but that's not a manometry issue, which is what this thread is all about.

Regards,

Old Smokey (With apologies to J_T for chipping in, I couldn't help myself, as usual)
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Old 5th Mar 2010, 03:18
  #23 (permalink)  
 
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O_S and J_T I'm actually about to design a mach meter with a Temp probe just so that the madness stops

after I finish my two machines;....one of the first kind

and

------ like Bernoulli's dad


....one really good idea of the second kind so that we don't use any more energy to make the world run




Last edited by Pugilistic Animus; 5th Mar 2010 at 05:46.
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Old 5th Mar 2010, 03:33
  #24 (permalink)  
 
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The simulators don't necessarily reproduce exactly what the aircraft will do in all failure situations. Just a few days ago, I attempted to emulate an actual failure sequence experienced in an A380, and whilst the sim apparently allowed the particular failures to be entered, the failures and warnings that followed were totally different to what was experienced in the aircraft.
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Old 5th Mar 2010, 10:38
  #25 (permalink)  
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I'm actually about to design a mach meter with a Temp probe just so that the madness stops

Thank heavens for that - then OS and I can go back to sleep.

The simulators don't necessarily reproduce exactly what the aircraft will do in all failure situations

Absolutely. Sims are fancy PCs at best and hopeless at worst. The further one gets away from the run of the mill stuff (as tweaked by the owner's sim techs) the more fanciful the whole thing gets. I've seen sims do things which are so far removed from reality that one can only shake one's head. Caution is required when being innovative in sim training as it is a short step to negative training.
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