Australian wasps threaten another passenger plane, with help from COVID-19 Australian wasps have once again brought a passenger aircraft to the brink of peril. As The Register reported in 2016, the city of Brisbane's airport is adjacent to some mangrove swamps that are a favorite home of Sceliphron laetum – aka the "mud dauber wasp", so named for its penchant for building nests of mud. In 2013, some …
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))
There was a hang-glider that took off from Byron Bay, from the dunes over the ocean, with tourist strapped in as dual, and the pilot fell out into the ocean. Had missed that 'strap in' item because he was interrupted in the pre-flight checklist. Passenger continued and landed in the sea. No injury to passenger and only a broken arm for pilot.
A known problem with medical and aviation checklists. A checklist becomes learned like a song, with each item following the previous item, but you can still keep in beat.while silently skipping some notes.
Yes. You are taught that if the checklist is interrupted the you start again at the beginning.
In the UK we are taught a mnemonic which - rather ironically - I can never remember, even after flying nearly twenty years... but I make sure I do the same things in the same order every time before I fly.
The pilot and passenger in the case you mention were both very lucky.
Black brown red orange yellow green blue violet grey white? The problem I've always found is that the mnemonic is no easier to remember than the represented values... with the possible exception of Richard of York gave battle in vain, which was drummed into me at a very early age.
To be fair colour coding has kinda dropped out of use with SM components.
I had an IT job in which we had printed checklists of things to be done to each workstation we installed. I quickly learned the value of these when I became so familiar with them that I started doing them "in my head" ... and began occasionally missing steps. When I saw I'd been screwing up, I went straight back to using the paper checklists.
During college, I worked for a music store doing the grunt work of loading, transporting, and unloading pianos and organs. My work partner and I quickly developed a routine. On one job, we had delivered a new piano, and had loaded up the customer's older piano, which was taken as a trade in. The customer's young son helpfully carried the old piano bench outside and up the ramp into our truck. This interrupted our standard procedure, but we dealt with it. Afterward, we climbed out of the delivery truck, stowed the ramp, closed and locked the rear doors, climbed into the cab, and drove away. Our route took us off a level road and onto a steep downhill road. As we turned onto the downhill road, there was a horrible crashing sound from the back of the back of the truck.
We looked at each other and simultaneously yelled, "I thought YOU tied the piano in!"
As it’s a safety critical thing it should be counted in and out, flashing lights and beacons are the warning that it’s still attached and not in its box.
If people rely on it flashing to know to remove it the. They’ve not done their job properly.
Procedure for pushing an aircraft back from gates or even clearance to take off should be that the pito caps should be accounted for, even an rfid tag or qrcode recording that the caps are in storage would do.
No records of the allocated caps in storage then no take off clearance.
Doesn’t stop the plane taking off but a flashing something and radio beacon that sounds a cockpit alert would be a useful fail safe that the aircraft has caps on its pito tubes, but ok don’t bother trying to make it fail proof and live with the likelihood that aircraft will take off with pito caps in place.
https://www.flightglobal.com/safety/communications-coordination-lapses-saw-a330-take-off-with-pitot-tubes-covered/147933.article
When the crew selects all ADRs OFF, then: • The Back-Up Speed Scale replaces the PFD speed scale on both PFDs, • GPS Altitude replaces the Altitude Scale on both PFDs. The Back-Up Speed Scale then enables to fly at a safe speed, i.e. above stall speed and below maximum structural speeds, by adjusting thrust and pitch.
https://safetyfirst.airbus.com/app/themes/mh_newsdesk/documents/archives/unreliable-speed.pdf
Good to know airbus had a pito and gps backup plan. Should be standard.
"As it’s a safety critical thing it should be counted in and out, flashing lights and beacons are the warning that it’s still attached and not in its box."
One of the Brisbane incidents was BECAUSE they're counted in and out
The covers fitted belonged to the airport, not the aircraft, so when the locker count was OK, the aircraft took off with 2 airport-owned pitot socks still attached
I suspect the answer in this particular case is to make the red dangly "remove before flight" things even longer (as in "long enough to reach the ground" or "long enough to clip to the nosegear") , so they're impossible to miss when doing a walkaround or during pushback - even in the dark
"the pito caps should be accounted for..." During college days, I had been working on our family car while shooting the breeze with a friend. When I finished, I put everything away and started the car. A rattling sound came from beneath the bonnet, so I stopped the engine and investigated. I'd left a wrench on a ledge in the engine compartment.
My friend, who was a military helicopter crew chief, looked at me and said, "Always count your tools."
so the pilot can see...
In the aftermath of the Zeebrugge ferry disaster, ferry safety rules require that it is possible to see that bow doors are closed from the bridge. The simplest way being a paddle type indicator board attached to the top of the door that, when door is raised, is visible over the roof of the vehicle deck and is in the line of sight of the bridge.
Absolutely not. There are procedures in place for a pre flight walk around. Anyone who can not follow the standard airline-specific check list and relies on some automatic removal system should be sacked immediately.
There is a lot of unneccessary H & S guff in industry in the UK but this is pretty much the basic type of check that should be done exactly as specified on each and every flight as the consequences can be expensive / deadly.
'old on, where is Paris?
She's there, can't you see the faint outline? -->
She's sick and tired of all the attention she gets and the accompanying photos of the antics she gets up to, that she's taken to drink - drinking invisible portion. So, now she goes along in the buff, without a care in the world.
Traditionally, the Flight Engineer is supposed to walk around the jet prior to take off as part of his acceptance checks for the aircraft and remove all of the plugs and other items tagged "REMOVE BEFORE FLIGHT" in bright orange or red streamers. As many FE positions have been eliminated in commercial aviation it is now the pilot / co-pilot responsibility. The crew starting the aircraft should have seen this before chocks were pulled. The ground staff and wing walkers pushing the aircraft back should also have noted the flags. Not to mention the supervisors for all these people who are supposed to monitor ground operations.
In this case, this was not done correctly and disaster was barely avoided. The number of people who effed up here is staggering. The young man or woman who spotted this should be given a hefty bonus and the others sent on a long ground handling safety refresher course.
"and the others sent on a long ground handling safety refresher course."
Ideally, yes, but as per the article, staffing levels the post-COVID lay-offs and time for proper training. Sounds more like a bit of corner cutting to get back to profitable operations as quickly as possible. I suspect the people on the ground crew were trained, but not as well as they should be. In less critical training situations, I'm sure we've all had the sort of "training" where you get told something once in a course, written, video, whatever, then move onto the next thing, gaining large numbers of "facts" so quickly there's barely time for them to sink in, compared to a properly structured "learning experience" where facts get repeated in different situations and built on and repeated again as the course progresses.
You see what you expect to see. There is a classic video of a man in a gorilla suit walking through people doing various activities. People unaware of the test usually don't see the gorilla because they have been asked to observe something like counting ball throws. However when they are then told about it and re-watch the video - they can't understand how they missed it.
The human brain and vision is hypothesised to work by predicting what will happen next. So what you think you see - is only what your brain thought would happen from previous experiences.
That tag is also a normal, expected part of the "airplane on the ground" environment, so your brain starts to edit it out after a while. This is the same problem that's caused pilots to try to take off with a control lock on even though the lock was obvious and bright red.
Yes but how long from the pilot inspection till completing cockpit checks/paperwork and actually taking off, and is that long enough for a wasp to sneak in. I don't know, but I'd suspect the pilot checks the covers are on during the walkround. Maybe the groundcrew should wave the covers at the pilot before he sets off?
and is that long enough for a wasp to sneak in.
Oh, definitely. But not long enough for one to start building a nest and having the mud harden, which is where the problem lies.
But maybe those pitot intakes should have a mosquito screen fitted permanently.
I've always wondered about the opposite course of action - having some way of blowing the pitot out using pressurised air (after isolating the sensor if they can't handle pressure)
It's one of the ways of cleaning them when they're off the aircraft, so would essntially be a way of automating the procedure
The problem (of course) is that on an aircraft there are many ways these days of measuring speed but what counts for staying aloft is indicated airspeed (IAS) and the pitot is one of the few methods to accurately give this information most other methods give ground speed. (IAS varies not only with wind, but altitude - at 30,000 ft a plane travelling at 700km/h will show a IAS not much above ground level stall - because the lift is quite low at these altitudes)
That's why pitots - despite all their disadvantages - are still used. Nobody's come up with a better instrument. If they do, the world will beat a path to their door
This is one of the big items on a pre-flight check so any airline who almost took off without checking would have been in breach of a pile of in house regulations I suspect.
Also, not sure of how this lot did it but in my experience, these covers would be a lurid colour with a huge banner hanging down stating 'remove before flight'
Wasn't a crew member that spotted it. It was a guy refuelling an aircraft at the next gate, and he notified the ground crew that working the aircraft (and had missed things).
A warning placard was put in the cockpit, but the ground boss removed it assuming that the pitot covers were removed. There's the flaw -- the walk-around wasn't done.
From reading the ATSB report it seems that the ground contractors were new to the job and were dealing with multiple aircraft. So this is a system accident caused by cost-cutting and under-resourcing of a critical function.
The amount of things that must be checked to ensure that any airplane can fly is mind-boggling.
Not that many things, Shirley? The bloke who spins the prop needs to kick the chocks out too I suppose.
Granted, it's been a few years since I last flew. Maybe aeroplanes are a little more complicated now.
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.
...so the pre-flight check item would be "Suck it and see"?
No, it should be an automated test at some point in the start sequence and before start of the take off roll, build up pressure in the tube, if it doesn't succeed, the tube is open. If it does succeed but subsequently drops, the tube was blocked but blown open, notification but no problem. If it does succeed and doesn't drop again, the tube is blocked and an alarm should be raised.
WRONG. Never assume that it's "Okay, now." Upon a "temporary" or "transient" error indication, you should immediately stop and visually check the situation. I learned this from my experience as a cyclist: a temporary "funny noise", which I ignored, was an indicator of a developing mechanical failure, which occurred and led me to a very-painful crash.
Check these things while you're still on the ground, 'cause it's hard-to-impossible to check them when you're airborne.
Since a pitot tube traditionally looks like this on most aircraft I have seen, any crap inside of it, if internally pressurised to blow it out would likely cause a compressed blockage at the tubes entry, much like a three tanker lorries pileup in the Dartford Tunnel.
https://www.tech-faq.com/wp-content/uploads/2011/03/Pitot-Tube.jpeg
* Not actually going, but the quote was too good to pass up.
It's not that simple on an Airbus, remember that they are fly-by-wire. Unlike a Boeing, in which the airspeed sensors will be used to display airspeed or used by the computers when a system demanding such data is activated (read: autopilot), the Airbus computers demand constant airspeed readouts in order to compute every single maneuver operation.
In other words, you can't 'handle' an unreliable airspeed indication on an Airbus well at all, the computers that actually operate the flight surfaces can ignore pilot input if said computers think they know better. And, without airspeed indications, they think that something is happening beyond what the *pilots* know, and act accordingly. And sometimes that's not a good thing.
@snake
Complete and utter garbage
When the aircraft detects inconsistent speed data it dumps the auto pilot and regresses into more manual mode. The computers don’t stop pilots doing stuff in the more manual modes, they do what the pilots instruct them to as the pilots have more data at that point.
I assume your thinking of the Air France tragedy where the tubes froze and ap stopped functioning as it had no reliable speed. In that scenario the Co pilot was pulling hard up on the stick causing a stall while the pilot was trying to get a slight nose down to avert the stall. They didn’t realise until it was too late. The computers allowed the hard up causing the stall, the Co pilot thought it wouldn’t allow it hence held it back as would be the case in normal modes.
When the crew selects all ADRs OFF, then: • The Back-Up Speed Scale replaces the PFD speed scale on both PFDs, • GPS Altitude replaces the Altitude Scale on both PFDs. The Back-Up Speed Scale then enables to fly at a safe speed, i.e. above stall speed and below maximum structural speeds, by adjusting thrust and pitch.
Airbus have a backup speed solution, not as accurate as pito tubes but good enough to get on the ground safely.
On planes these things are installed for safety. In cars they are used to justify obligated visits to a garage to clear the faulty faults before the car will not start and you need a tow, all because there was a micro amount of static that the sensor read as a fault.
Sore, not me - I am happy to pay best part of a grand for a fault that comes and goes.
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.
I had an Australian wasp cause me some grief once in Canberra. My trail bike would start and tick over, but die when the throttle was opened. Much scratching of the head, until I decided to remove the drain screw in the high-level exhaust chamber in case there was a build-up of oil residue, etc. Bike started and revved fairly cleanly, with a jet of blue smoke streaming out of the drain hole.
Hmm, yep, a wasp had built its nest in the baffle, blocking the exhaust. The reason I'd missed it on first cursory glance was that I still hadn't washed the mud off the bike after my last off-road adventure...
Brisbane is a bit special because of the speed the wasps can block things up. At many airports there is a minimum "parking time" before covers are fitted (ranges from 2h to 24h), but for Brisbane it's "always" for most airlines.
There have been a few cases of pitot covers being left on. And if the aircraft does take off then the pitot heaters will be turned on and that melts the covers onto the probes.
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 hope you enjoyed your shot at faux-superiority. OP was clearly asking to learn knowing that it was more than likely a stellar commentary would be happy to leave them (unlike you dear sir, and I know you're a man) knowing more than when they got up this morning.
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.
This post has been deleted by its author
Generally correct, but in the specific case of a pitot tube, the higher reading is almost always the correct one. (Plugged tube, tube not pointing perfectly forward, etc. all result in lower readings.) Especially if the plane is in flight and one of the sensors is reading near-zero.
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?
Not strictly that guy it was 3am when I wrote the post & things were a little ahem hazy.
Debris/Damage is the usual term, though I had seen detection in something & mentioned in a few other fields like food* & my waters (or beer) may have muddied things.
*FOD is a rather vital thing that we had a vendor impliment in the early 000's, when dredged up sand brought into the Kent Pharma I worked at as landfill on a project was found to have a rather large metal FOD in the form of a unexploded WW2 bomb.
This is an excellent and highly instructive video about the problems the wasps cause, how the Brisbane Airport authorities decided to manage those problems, how standard procedures can still be flawed and can cause horrendous subsequent difficulties with aircraft, and how excellently-trained flight crew can save the day (and the lives of the aircraft's passengers and crew).
Get rid of the hole altogether.
Issues ropes with knots tied in them every 14.3 meters.
Pilot simply opens his window, throws out the "log", counts the knots let out for 28 seconds.
Job done.
Admittedly, might need to count very quickly.
What could possible go wrong?
Who needs windows?
https://cdn.airplane-pictures.net/images/uploaded-images/2016/10/18/795406.jpg
there really is nothing better these days ?
Self closing pitot tube ? once on the ground the opening closes itself so nothing can get in, not even dust.
Airpressure opens it. A sensor lets you know the tube did not open. Five fold reduntant sensors so if one malfunctions the flight can proceed. As a plane speeds up on the runway the air pressure opens the entrance. There could be a motorized override to perform selfcheck or open in case of issues. Airpressure and motor should perform an active open function. Motor can not "close" the intake. if the intake does not close after landing : flag maintenance error.
i don't know. just freewheeling here.
It is NOT archaic. It is technology that works and as such needs to be maintained. Your solution is what is causing much of the carnage in software / hardware design.
Find a buggy complex solution to something that does not need to be changed.
Pitot tubes have one role and should be left to do so not fucked about by some microsoftian 'experience' solution which is guaranteed to break at least 90 % of the time.
https://uvamagazine.org/articles/adding_complexity_when_we_should_be_subtracting_it
It's the complexity problem. Aircraft are already so complex that there is a list of faults they are allowed to fly with and faults they are not. So whenever complexity is added there is a slightly greater risk that the aircraft will be flown in a degraded condition.
This case is a nasty one because the caps are only required at Brisbane, not everywhere. It will be interesting to see the final report, but I gain the impression that the licensed Engineer was flitting from aircraft to aircraft and lost concentration.
CASA: Airworthiness Bulletin AWB 02-052 Issue 6 - 14 July 2021: Wasp Nest Infestation - Alert (PDF)
Good reading for background, and pictures.
While the ATSB Report AO-2013-212 in relation to this occurrence indicates that a mud dauber wasp nest can completely block a pitot tube inside two hours, CASA has received anecdotal evidence which indicates that the wasps can begin to build a nest rapidly and within 20 minutes, can significantly block a pitot tube by applying a closing plug of mud. The BAC sponsored study also reiterates that wasp nests do not need to be complete to pose a danger to aircraft. The first addition of mud or introduction of the first prey item can impede air flow enough to cause anomalous airspeed readings.
The pre-flight check can take a while, and administrative procedures on the flight deck can also, so it is entirely possible for the pitot covers to be removed more than 20 minutes before push-back/take-off. If you want to remove the covers 'just' before push-back, then it has to become the formal responsibility of ground-staff, who would then need to demonstrate to the pilot-in-command that the job had been done. Unfortunately, the pitots are not visible from the flight deck, so you can't check yourself. This is an 'alternative procedure', which went wrong in this case.
Link to preliminary report from Australian Transport Safety Bureau (ATSB)
Direct link to full preliminary report from Australian Transport Safety Bureau (ATSB)
Link to PPRuNe thread discussing this incident.
Reading all three linked documents will answer many questions people might have,
NN
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