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On the 737NG 3 pitot tubes are pilot, co-pilot and the elevator control feel input. They aren't averaged, voted upon or compared in any way. I don't know much

On the 737NG 3 pitot tubes are pilot, co-pilot and the elevator control feel input. They aren't averaged, voted upon or compared in any way. I don't know much about the Airbus pitot system, except one ended up at the bottom of the Atlantic due, in part, to a frozen pitot tube.

Someone1234 8y ago
> On the 737NG 3 pitot tubes are pilot, co-pilot and the elevator control feel input. They aren't averaged, voted upon or compared in any way. You're mistaken. To quote Boeing themselves: > The most modern systems today use an air data inertial reference unit (ADIRU), which incorporates the best information from three pitot and static sources and provides a single set of data to both pilots. An ADIRU receives information from air data modules, which are located close to the pressure sources. This is used on, at least the Boeing 757, 737 and Airbus A319, A320, A321, A330, & A340.
- VBprogrammer 8y ago
  I believe your source is unreliable. For example read this report: https://assets.publishing.service.gov.uk/media/578df0f5e5274a0da3000176/Boeing_737-86N_EI-FHG_08-16.pdf https://assets.publishing.service.gov.uk/media/578df0f5e5274...
  - Someone1234 8y ago
    This is the second time you've linked to something without having read it (or understood it) first. And your own link disputes your point: > The Boeing 737 NG series are fitted with pitot probes mounted on the left and right of the fuselage just aft of the radome. The aircraft are also fitted with an auxiliary probe on the right side of the forward fuselage and two ‘elevator pitot probes’ on the fin. The triple redundant system initiated a "IAS and ALT disagree master caution." Which is exactly what a safety critical sensor is meant to do. As an aside I'm done conversing with you on this topic. You keep on saying incorrect things, link to bad citations that don't support your previous statements, and when that fails moving the goalposts to something else entirely. It isn't a good faith way to have a discussion. Keep in mind half a dozen posts ago you claimed no aircraft used triple redundancy or voting logic (which the 737 does, as I've shown and your own citation shows). Now your argument has shifted to some kind of pedantic one about which exact systems consume what data or similar.
    - VBprogrammer 8y ago
      I think you've missed my point altogether. I said that limiting the authority of MCAS was going to be the real fix. You contested that they are going to read from both sensors and possibly add a third. I pointed out that it would be highly unusual for them to cross connect the inputs as that's not normally the design of aviation systems. You said: > The most modern systems today use an air data inertial reference unit (ADIRU), which incorporates the best information from three pitot and static sources and provides a single set of data to both pilots. The report said: > The aircraft was on approach to London Gatwick when the crew was presented with erroneous airspeed and altitude information on one of the two cockpit display systems. These statements are clearly at odds with one another. That isn't a pedantic argument. The systems have a clear A and B system and cross connects between them are minimised. > Keep in mind half a dozen posts ago you claimed no aircraft used triple redundancy or voting logic I didn't claim that. I said on the 737NG the 3 inputs (actually there are 4, the additional one drives an auxiliary set of flight instruments) aren't averaged voted upon or compared. The 3 instruments simply display data taken their inputs, even when they are potentially wrong. Technically the pilot and co-pilot IAS is compared in that it can sound a master caution if they disagree. This is a long way from automatically choosing the best air data. Additionally, the A330 which you introduced to the conversation, has 3 independent systems. However, they however functionally they don't drive the autopilot or the pilots display based on the 'best' data. They simply display their output, unless the input source is manually changed to the hot standby.
- VBprogrammer 8y ago
  > There are therefore three speed information elaboration systems that function independently of each other. The probes known as “Captain” supply ADR 1, the “First Officer” probes supply ADR 2 and the “Standby” probes supply ADR 3. The standby instruments elaborate their speed and altitude information directly from the pneumatic inputs (“standby” probes), without this being processed by an ADM or ADR. The ISIS is a unique standby instrument integrating speed, altitude and attitude information. It uses the same static and total pressure sensors as ADR3. From the report on AF447 an Airbus A330. Again, much as I described.

Someone1234 8y ago

> On the 737NG 3 pitot tubes are pilot, co-pilot and the elevator control feel input. They aren't averaged, voted upon or compared in any way. You're mistaken. To quote Boeing themselves: > The most modern systems today use an air data inertial reference unit (ADIRU), which incorporates the best information from three pitot and static sources and provides a single set of data to both pilots. An ADIRU receives information from air data modules, which are located close to the pressure sources. This is used on, at least the Boeing 757, 737 and Airbus A319, A320, A321, A330, & A340.

VBprogrammer 8y ago
I believe your source is unreliable. For example read this report: https://assets.publishing.service.gov.uk/media/578df0f5e5274a0da3000176/Boeing_737-86N_EI-FHG_08-16.pdf https://assets.publishing.service.gov.uk/media/578df0f5e5274...
- Someone1234 8y ago
  This is the second time you've linked to something without having read it (or understood it) first. And your own link disputes your point: > The Boeing 737 NG series are fitted with pitot probes mounted on the left and right of the fuselage just aft of the radome. The aircraft are also fitted with an auxiliary probe on the right side of the forward fuselage and two ‘elevator pitot probes’ on the fin. The triple redundant system initiated a "IAS and ALT disagree master caution." Which is exactly what a safety critical sensor is meant to do. As an aside I'm done conversing with you on this topic. You keep on saying incorrect things, link to bad citations that don't support your previous statements, and when that fails moving the goalposts to something else entirely. It isn't a good faith way to have a discussion. Keep in mind half a dozen posts ago you claimed no aircraft used triple redundancy or voting logic (which the 737 does, as I've shown and your own citation shows). Now your argument has shifted to some kind of pedantic one about which exact systems consume what data or similar.
  - VBprogrammer 8y ago
    I think you've missed my point altogether. I said that limiting the authority of MCAS was going to be the real fix. You contested that they are going to read from both sensors and possibly add a third. I pointed out that it would be highly unusual for them to cross connect the inputs as that's not normally the design of aviation systems. You said: > The most modern systems today use an air data inertial reference unit (ADIRU), which incorporates the best information from three pitot and static sources and provides a single set of data to both pilots. The report said: > The aircraft was on approach to London Gatwick when the crew was presented with erroneous airspeed and altitude information on one of the two cockpit display systems. These statements are clearly at odds with one another. That isn't a pedantic argument. The systems have a clear A and B system and cross connects between them are minimised. > Keep in mind half a dozen posts ago you claimed no aircraft used triple redundancy or voting logic I didn't claim that. I said on the 737NG the 3 inputs (actually there are 4, the additional one drives an auxiliary set of flight instruments) aren't averaged voted upon or compared. The 3 instruments simply display data taken their inputs, even when they are potentially wrong. Technically the pilot and co-pilot IAS is compared in that it can sound a master caution if they disagree. This is a long way from automatically choosing the best air data. Additionally, the A330 which you introduced to the conversation, has 3 independent systems. However, they however functionally they don't drive the autopilot or the pilots display based on the 'best' data. They simply display their output, unless the input source is manually changed to the hot standby.
VBprogrammer 8y ago
> There are therefore three speed information elaboration systems that function independently of each other. The probes known as “Captain” supply ADR 1, the “First Officer” probes supply ADR 2 and the “Standby” probes supply ADR 3. The standby instruments elaborate their speed and altitude information directly from the pneumatic inputs (“standby” probes), without this being processed by an ADM or ADR. The ISIS is a unique standby instrument integrating speed, altitude and attitude information. It uses the same static and total pressure sensors as ADR3. From the report on AF447 an Airbus A330. Again, much as I described.