Has anyone ever considered using a RAT as an emergency replacement for Pitots?

[Zionstrat2]

I know we're getting better at managing pitot tube blockage, but considering it is a relative common and has led to so many major events, I wonder if anybody is ever considered an emergency option of dropping the rat or a rat like device to supplement pitot data?

I get the added expense and the drag, but it seems like an obvious and immediate data source that works entirely differently than a pitot and would probably be hard to freeze.

I'm guessing this has been considered before, but I haven't been able to locate anything online.

[Gne]

How many aged eyes misread "pitot" as "pilot" and thought the dog and pilot in a cockpit story had been updated?

Gne
Now back to the technical discussion, please.

[Gne]

How many aged eyes misread "pitot" as "pilot" and thought the dog and pilot in a cockpit story had been updated?

Gne
Now back to the technical discussion, please.

[Gne]

How many aged eyes misread "pitot" as "pilot" and thought the dog and pilot in a cockpit story had been updated?

Gne
Now back to the technical discussion, please.

[skkm]

Being a constant speed turbine, I imagine it would be difficult to accurately determine if a given change in blade angle or torque is the result of a change in load (on the B777 this is both a hydraulic pump and a generator) or airspeed if attempting to use the actual RAT and not a dedicated device.

[andmiz]

The OP's intent here might be more of a 'pop-out pitot' solution, that extends similar to the RAT, not the RAT itself? On modern jets like the A350, the solution has practically been solved by utilising multiple sources of static and dynamic pressure from both traditional probes, multi-function probes, engine sensors and GNSS, with automatic switching. If it weren't for cockpit alerts, generally, the loss of these systems would be transparent to the crew.

[Musician]

Pitot heat seems like a more efficient solution to the freezing problem, and easier to test on the ground.

[Someone Somewhere]

Pitot heat has been around for... I don't know, nearly a century? There's still regular issues, and the wasps etc. deciding to build nests in them has been a problem too.

You might get 10-20% accuracy with a RAT.

Ultrasonic sensors (airspeed and AoA) are proposed and we might see them on the next generation of aircraft.

[Musician]

https://www.rikasensor.com/a-what-is...ly-record.html

The maximum wind speed that a measuring device can accurately record varies depending on the type of device and its design. Cup and vane anemometers typically have a maximum wind speed range of around 60-100 miles per hour (mph). However, some high-quality anemometers can record wind speeds of up to 200 mph or more with a high degree of accuracy. Sonic anemometers have a higher maximum wind speed capability, with some models able to record speeds of over 300 mph.

Remote sensing devices such as LIDAR and SODAR have higher maximum wind speed capabilities compared to traditional anemometers. LIDAR systems can accurately measure wind speeds up to 150 mph or more, depending on the model and technology used. SODAR systems can measure wind speeds at higher altitudes with speeds exceeding 200 mph.

.
Still not near cruise speed.

[safetypee]

Recent Airbus work: https://safetyfirst.airbus.com/furth...rol-in-flight/
'Digital backup speed' (fig.8)
Note practical and retrofittable (software and often free of charge).

[Zionstrat2]

Thanks for good info!

And I never intended it, but I love the reading of replacing pilots with rats :-)

[Amadis of Gaul]

Originally Posted by Zionstrat2

I know we're getting better at managing pitot tube blockage, but considering it is a relative common and has led to so many major events.

Define "so many major events."

[Someone Somewhere]

ASN appears to be down, but to copy straight out of Wikipedia:

Examples include Austral Líneas Aéreas Flight 2553, Northwest Airlines Flight 6231, Birgenair Flight 301 and one of the two X-31s.[6] The French air safety authority BEA said that pitot tube icing was a contributing factor in the crash of Air France Flight 447 into the Atlantic Ocean.[7] In 2008 Air Caraïbes reported two incidents of pitot tube icing malfunctions on its A330s.[8]

Birgenair Flight 301 had a fatal pitot tube failure which investigators suspected was due to insects creating a nest inside the pitot tube; the prime suspect is the black and yellow mud dauber wasp.

Aeroperú Flight 603 had a fatal pitot-static system failure due to the cleaning crew leaving the static port blocked with tape.

Pretty sure there's far, far more.

Sensors are inherently both delicate and exposed, and that tends to result in relatively regular failures.

[safetypee]

Most of the pitot icing incidents identified on A330 aircraft and other types involved rare extreme conditions (e.g.ice crystals) at the limits of certification requirements. Icing requirements have been reviewed / changed,

Continued airworthiness reporting had identified several (20+?) events of similar nature to AF447 which required safety action. The A330 pitots were being replaced at the time of the AF447 accident.

The Airbus improvements above consider other issues associated with integrated airdata and automatic monitoring/switching associated with triple systems, i.e. use best 'two out of three' identical systems; vice pilot choice after comparator alerting with dual systems and independent, different third system.

Not just airspeed but 'air data', its computation and use.

Note that Airbus also considers retrofit cost - down time, training, and common type rating.

[Uplinker]

Originally Posted by Musician

Pitot heat seems like a more efficient solution to the freezing problem, and easier to test on the ground.

Except for AF447 et al, as just mentioned.

I must say; now that Pitot and Static pressure are digitised at the pitot-head and passed on electronically, there is no longer a need for air tubes to transfer air pressure to the instruments - except for the emergency standby instruments.

Therefore, why do we need a Pitot tube ? Why not have special engineered flat patches that measure deflection due to the dynamic pressure from the forward flight but are literally a patch on a suitable surface rather than an enclosed tube.

A number of such pressure patches around the nose cone, wing leading edges and tailplane could be combined to provide a "pitot pressure". No small tubes to get blocked with ice, mud or insects. Ice might still be an issue but the wing patches could be heated by the wing anti-ice hot air for example, and a voting system used to ignore a disagreeing patch, like with the ADIRS.