RAT and Pitots

[Mike-Bracknell]

Just a quick, naive SLF question related to the Aeroperu and AF447 incidents.

If the pitots are covered prior to washing, or are vulnerable to icing etc, would it not make sense from an aircraft design perspective to have a backup pitot set in the RAT housing?

That way it wouldn't be vulnerable from being taped over a la 757, and could give another set of figures a la AF447 purely from RAT deployment?

Just thinking idly, but wouldn't that solve a few issues?

[grounded27]

Pitot tubes are covered to prevent debris from entering them, poor design if a pitot tube heating element results in icing. There are lots of solutions to historic problems with them. I do not think a pitot tube on a RAT would be easy to accomplish, the pitot tube needs a clean ture source if air to do it's job, the rat is a big propeller that disturbs air.

[Mike-Bracknell]

I was thinking more of a covered pitot that's deployable at a later date, thus avoiding being taped over by mechanics or potentially susceptible to icing conditions. Hence the suggestion of the RAT (where it could be droppable into the airstream ahead of the propeller) but generally it could be under any specific flap that could be deployable from the cockpit in times of monitoring disagrees etc.

[Capot]

He's got something. hasn't he? Why isn't there a SBY pitot, warmed and ready to deploy from behind a panel? The act of selecting it could make all the changes needed in the configuration of the system.

It seems so obvious that there's probably a good reason, but I can't think of it.

Or perhaps there is a standby? I've never seen one, but then I've never really looked for one.

[grounded27]

Standby instrumentation has operated off a stby pitot and static port for decades, problem is that they are generally the same as the others, just an additional system that is stand alone and pneumatic/mechanical, old ones not requiring any electricty to operate.

I feel the cost of an aditional system would outweigh the benefit. Feel confident that mfgs's, aviation authorities and airlines feel the same.

Another problem is, if you have a pitot probe that pops out in clean air in an emergency you also need a static port and alot of effort goes into making sure the static source is clean (mostly flush skin within proximity to the port).$$$$$$$$$$$

[Beeline]

I think the auxiliary pitot/static is enough. The belt and braces is employed in this system. It has failed yes, but where do you stop mounting probes.

If we are going down this road they might aswel add another engine somewhere in case the primary fails.

If not, bit of light hearted food for thought. How to spoof the signal from another source using another system.

Pack ram air inlet sensor for pitot and..... Cabin air controller for static

I will have think and look forward to ppls suggestions