Originally published at: https://boingboing.net/2020/11/30/wasps-threaten-airplane-safety.html
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Blocked pitot tubes are one of the reason why Air France 447 went down: https://en.wikipedia.org/wiki/Air_France_Flight_447. In that case it was because they weren’t deiced, but I can see why they want to get rid of the nests to reduce the chance of it happening here.
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It sounds glib, but the easiest answer is to use a pitot cover while the aircraft is parked. While reaching the pitot tube of an airliner is a bit of a climb, the fact that the article mentioned the grass parking area indicates they’re talking about smaller aircraft, more along the lines of your standard Cessna. Wildlife love small planes (we once found a bird’s nest with three eggs under the engine cowl of a 152–a plane that had been parked for about two days).
The only drawback then lies in remembering to take the pitot cover off during preflight, and that should be part of your checklist anyway.
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You seem to have experience, so forgive a dumb question, but why not have a screen over the opening? Adjust the readout to compensate for the reduced airflow, and done. No worries about missing an item on the checklist.
Surely someone has thought of this already, so what am I missing?
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I’d think that any screen would create new concerns, such as, has any portion of the screen somehow broken off or become misshapen (screen material now in the pitot tube; screening ability compromised; compromised pressure reading).
For icy conditions, pitot tubes can be had with heaters. As far as anything else getting in, I wonder if a/c have ways of blowing out any unseen debris; something involving a 3-way solenoid valve on the a/c: one port ‘talks’ to its pressure transducer for normal operation; the other port ‘talks’ to an upstream pressure source that could help force out blockage and (by measuring blockage-induced backpressure) determine that there is blockage. All of that can happen before flight. Obviously that adds other concerns: stuck/leaky solenoid valves! Perhaps a better way along those lines is a simple port tie-in on the a/c accessible for ground crew auxiliary equipment that can handle the above operation before flight. Just talking big a/c here.
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Its interesting that both Boeing 737-Max disasters happened in aircraft roughly the same age (and quite new) which were operated in places where the native insect/animal life is quite different from that in the USA.
The angle of attack sensor is a free swinging vane on the side of the aircraft, not a pitot tube, but its still possible that some organism interfered with it.
I don’t have a direct answer for you, but as it has been mentioned, screens offer their own sets of problems, from broken-off pieces getting stuck inside to the screens blocking airflow and causing inaccurate readings. A similar question was addressed by Mentour Pilot regarding why aircraft designers don’t just put screens over jet engine intakes: https://youtu.be/Wm4Z7dAfrP0
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The pitot tube depends on air being rammed into the opening. If you put anything in front of it, you’ll change the airflow especially if the angle of attach changes. Additionally, a screen could serve as a ‘junk catcher’. If you’re flying in cold weather, it would tend to freeze up before the normal tube (which is often heated) would. The tube is part of the pitot-static system and provides data to the airspeed indicator, vertical speed indicator, and altimeter.
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Something like this?
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Yeah there was at least one incident where a commercial jet took off from Sydney or Brisbane with pitot covers in place. The flight control system freaked out and the crew hand flew the aircraft to a landing.
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If a commercial flight, I am surprised that it wasn’t on the captains checklist, and the tug operator didn’t see the “Remove Before Flight” trailing sock flapping in the breeze.
Troubling, especially on certain (Airbus) aircraft there is a pin, along with its own “Remove Before Flight” trailing sock, on the nose gear that has to be removed to allow it to be steered by the plane, and not the tug. This pin is removed upon disconnecting the tow bar.
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May I mention that my first interpretation of the headline involved White Anglo-Saxon Protestants as air safety threats? Who do air marshals mainly arrest?
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I think it’s safe to assume that WASPs are low on their target list.
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They’ve even got red “Remove before Flight” tags.
I’ve seen plenty of videos of Aussies having to remove mud wasp nests from deep inside cars that were parked for only a few days, so this sounds like just more evidence that all Australian wildlife is homicidal.
It wouldn’t be acceptable for jets, but my old Champ had a wind-driven pitot cover. https://www.aircraftspruce.com/catalog/graphics/1/10-02000a.jpg Bugs in the static port are also a problem, of course.
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I can’t see anyone covering pitot tubes on commercial aircraft. (1) The aircraft are at the gate for a limited time, and it takes about 30 minutes for the heated pitot to cool off enough to put a cover on. (2) the pitot is so high off the ground on large airliners that special equipment (e.g a pole) is needed to reach, increasing the risk of damage (3) every airport would have to be outfitted for the necessary pitot covers for all aircraft that potentially park at the gate.
I was thinking about how one might install pitot covers on an A380. Stumbled across a paper in their safety newsletter.
Https://safetyfirst.airbus.com/app/themes/mh_newsdesk/pdf.php?p=25833
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Wasps nesting in pitot tubes have been the cause of more than one aircrash…
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Why not simply provide more enticing habitats for the wasps nearby?
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