The amount of things that must be checked to ensure that any airplane can fly is mind-boggling.

Kudos to the eagle-eyed crewmember who spotted that tiny detail.

Not quite so eagle eyed as "actually trained at all".

The covers have a big, brightly coloured dangling tag so you can see them from very far away.

Exactly:

big, red, "REMOVE BEFORE FLIGHT". Can be seen from hundreds of metres away, and around a hundred at night - not, that it tends to be significantly dark on the apron anyway. Even if it would have been dark, pre flight check has to be carried out with a flashlight.

One does wonder how the pilot missed the big REMOVE BEFORE FLIGHT tags on his preflight inspection... I don't know how they manage these things, but perhaps there is (or could be) some sort of plugboard into which all the removed tags must be inserted to give a green light when they're all in?

(Curiously, I saw a paraglider harness only yesterday which had a big red strap marked in large letters 'INSERT BEFORE FLIGHT' which struck me as kind of not quite right (not that it shouldn't be inserted, but that the warning was somehow wrong))

The tag should loop to the windscreen wipers so the pilot can see it’s still attached from their seat.

That's why there's a preflight checklist.

This is the pilot's fault. He's supposed to walk around the aircraft and at least do a visual check. He needs a week without pay.

No self-check built into the airspeed sensors? If the Lambda sensor in a car exhaust fails, it usually flags up on the dashboard and car engine goes into limp mode. If an indicator or headlight fails, there a warning. I'd always assumed that aircraft instrumentation had similar self-checks.

If the aircraft is static on the ground, the correct reading will be zero. It's only when you're flying and it's still zero that you know there's a problem. Handling "unreliable airspeed indication" is pilot 101, unfortunately some Air France pilots seem to have missed that module.

How about a pressure check - blow some air into the thing and see if the pressure goes up - should blow the tag off if present, and launch the baby wasp to an early heaven.

And blow any crap further in, while you're at it.

...your correspondent recently flew to Brisbane and back without incident.

Without incident,... that you know of...

At least, it was non-lethal, unless you hit some wasps on your way, that is.

Mud dauber wasps are a well known issue to pilots around the world for building their nests in Pitot tubes. They have been listed as the cause of fatal accidents before.

Back in 1996 Birgenair flight 301's crash in the Dominican Republic was attributed to them blocking one of the Pitot tubes on a 757 and the resulting incorrect data confusing the pilots.

Came here to highlight the same flight.

It's one of the many, many reasons I hate flying. Putting an aircraft with such delicate controls that just so happen to be part of the most important parts of a plane in the hands of humans who you're relying on to not have a bad day when they see your plane.

but surely some sort of mesh (with everything suitably calibrated for any reduction in airflow) could be placed over the inlet ?

It's not dim to ask a question.

You can't put a mesh over a pitot tube. It's a highly polished tube which uses the Bernoulli effect to measure the difference in airflow between between its tip and across it's surface. If you put a mesh in front of it you won't get a laminar air flow which will make it very unreliable. They mount them pointing forward and ahead of anything which will make turbulence over its surface.

Many years ago I had a vacation job polishing hundreds of the damn things (not aircraft grade) to a 'perfect' finish. My supervisor laughed at my initial attempts and showed me the difference between my efforts and a properly finished pitot at high magnification.

I was always under the impression all vital aircraft systems were operated in pairs for resilience in case one failed or malfunctioned and provided erroneous data. I would have thought that such a critical system as this would have two fitted if one were to become inoperable, shirley?

The old problem of redundancy..... Two sensors might be less reliable than one (more parts to go wrong). And if one sensor goes a bit wonky, how do you know which is true?

Pitot tubes and their 'static' partner are a brilliant device for measuring flowrate/speed in clean fluids under certain known parameters. I didn't need to wonder why a colleague couldn't get a sensible answer when trying to measure flows in a sewage pipe using his new instrument.... "But, but, the Salesman said it could....." Little chance of returning the instrument after such exposure.

There are indeed 3 pitots and three Air Data Computers. If one fails, the other two will "vote out" the erroneous data.

The problem in this case is that all three pitots were presumably "protected" with their covers as teh plane departed.

I started my work career on DC3's & other aircraft (Aircraft stores). Over the years moved into electronics & IT.

I'm now in aircraft engine rebuilding facility combining most of my entire work history experience, FOD* is a BIG BIG thing for the smallest of items (Even graphite from a pencil on the shop floor is a NO NO). I've seen the production areas halt looking for a dropped washer, the level of QC is way different from when "Garth" was rebuilding engines in 1979.

That's even before the various robots for blade sorting, engine inspection & engine testing in specialised test cells come into the areas of my responsibilty (Dodgy sensors on the engine or is it the test cell infrastructure).

**Foreign Object Detection.

Sorry to be that guy but I've always heard FOD to be either Foreign Object Debris when talking about the miscellaneous items left lying around or Foreign Object Damage when talking about the damage those items do to the various aircraft systems. This is the first time I've ever heard Foreign Object Detection. Is it an industry specific thing?