A320 loss of all pitot vs Mach
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Joined: Apr 2001
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From: various places .....
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 ?
.. I think you'd best produce some authoritative information to support that contention .. perhaps a schematic of such an unusual installation ?
Joined: Jun 2004
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From: Australia
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)
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)
Joined: Dec 2006
Posts: 2,486
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From: The No Transgression Zone
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
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 March 2010 at 05:46.
Joined: Nov 2008
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From: Country Victoria, Australia
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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Aviation Qualifications: ATPL
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From: various places .....
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.
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.
